Engine Masters Full Episodes – Boosted Madness: Turbo vs Supercharger Showdown

Hinzugefügt: 2026-05-11

[00:00:01]You say you've got a mild turbocharged street car and you'd like it to be quiet and you're thinking to yourself, should I put a muffler on it or will I pay the price in power? Well, tell you what, we are going to find out so you don't have to because let me tell you, it's grizzly.

[00:00:32]>> [music] [music] >> Just when you thought you had seen every exhaust test on Engine Masters, I came up with a new one and I'll tell you this, it's going to be the most interesting and critical one ever cuz what we're going to do is run different exhaust systems off the backside of a turbocharger and as a result, it's not just about the exhaust flow, it's about what it does to boost and the turbocharger and the wastegate. This is going to be fascinating. So, here's the scenario. Let's say that you're a guy who's got a typical street strip car and you got a turbocharger on it and you're not going for a thousand horsepower.

[00:01:21]You're not a guy who just wants to take this dump tube and run it straight out the side of your fender, no matter how hip that is these days. You actually want it to be a little bit quiet. So, you're thinking about putting a muffler on it. Well, that's the scenario we're sort of going to test here. What we're going to do is start with this turbocharger with a 4-in open pipe, kind of like you would do if you were just dumping it out the side of the fender.

[00:01:43]Next, we're going to put 3-in exhaust on it and we're going to run it open all the way out to the back bumper your car.

[00:01:50]We're going to try it with a 3-in Flowmaster muffler, a chambered unit.

[00:01:54]We're also going to test it with a turbo muffler. That's what it's for, right? It says turbo right in the name. We're also going to run what I've always said is the best muffler for power, which is as you know, the one that you can see through. And this one is a Flow Monster 3-incher, not a Flowmaster, but a Flow Monster. So, that's what's going to happen with the 3-in exhaust and after we analyze all of that, we're going to go ahead and step it up to a 4-in exhaust just like this, but all the way out to the back bumper and open. And after we run it open, we will try it with another Flowmaster chambered muffler and then with a Flowmaster Pro Series muffler. So, through all of that, you're going to see us analyzing not only the horsepower, but what it does to turbocharger boost. We're also going to be looking at back pressure, which is the pressure in the exhaust system between the port or the exhaust manifold and the turbocharger itself cuz we're going to look at how that interacts with boost and how it all ties in with power.

[00:02:57]This gets really fascinating. So, this is really applicable to a lot of different engines, but let me tell you about the actual one we're using in the test. It's your typical 5.3 L LS engine.

[00:03:07]It's actually an LM7 iron block truck motor. We've upgraded it in past episodes. It's got a stock crank, but Wiseco forged pistons and boost line rods in it. The camshaft is a Brian Tooley Racing Stage 2. The cylinder heads are from TFS and they're a 205 cc CNC ported cylinder head. This time, we've got a carburetor on it, which is a Demon 650 CFM blow-through unit. The timing is being controlled by MSD.

[00:03:35]They've got a special controller for these things and we're running 23° of total ignition advance in every test that you're seeing here. The exhaust manifolds, I think, are pretty cool.

[00:03:45]These are from Hooker Headers and they are a cast iron manifold kit that you can buy specifically for a single turbo application. Now, these are really going to be for what I'm seeing as most applicable for this test, which is a mild street deal, less than 700 horsepower or something like that. The cast iron means that they're going to be quieter, they're not going to crack, you can hang the turbo off of them. It's just a much better deal than having to fabricate something for an engine at this lower level.

[00:04:13]What's counterintuitive to that is the turbocharger that we're running, which honestly is overkill for what we're doing here. In past episodes, I have mistakenly referred to it as a BorgWarner S485. It's actually an S480 with an 80 mm billet wheel on it and an AR ratio of 1.25 to 1. So, that thing is 1200 horsepower capable and we're tuning it down here to about a 600 horsepower level. In order to manage that with a wastegate, we've got a 45 mm wastegate on it, which is just large enough that we shouldn't see any boost creep in what we're doing in this show cuz we're going to be running 10 to 11 psi at max and making just over 600 horsepower. So, that's the combination with the engine.

[00:04:54]Now, I'm going to send you to Steve Brule on the dyno cell, who's going to show you some of the different data that we're going to pick up so that we can look at back pressure and things like that and once he walks you through the tech on the dyno, we'll sit down and have a chat about our favorite new [music] turbo buddy and then we're going to put it on the pump with a 4-in open pipe and show you the biggest power it's going to make throughout the episode before we start killing it off. And at the end of the show, I promise you, we will bring it back [music] to its former glory.

[00:05:24]So, a couple of the sensors that we felt were important to look at since we're testing the exhaust system is this sensor right here measures the back pressure of the exhaust system. We also have boost pressure right here measured at the manifold in psi. And one of the other things that we added in case we wanted to change [music] the boost or needed to change the boost. We're not even sure of that yet, but we just wanted the ability to this is manual boost controller and all it really does is lie to the wastegate. So, we've got a little bit of adjustment.

[00:05:50]>> [music] >> Guys, there's a lot of tests that we've done in the past that I think you and I have re-treaded from old magazine stories that you've seen a dozen times and this is one that not only have we never done before, but I've never actually seen before. I'm sure it's done. I mean, people have tested exhaust on turbos forever, but it's not something that I have consumed. So, this is going to be a 100% learning experience. The thing that takes this out of what you normally see is every time somebody's got a turbo LS, they're trying to throw the world at it and make a thousand and be a superhero and I'm trying to package this towards somebody who actually wants to drive the car around every day. I'm thinking it's more, you know, practical information instead of like, "Yeehaw, hold my beer" kind of information.

[00:06:33]So, I haven't seen what you've done with the baseline on this thing. So, let's fire it up and look at numbers. I can go do that. It's good.

[00:07:02]Here's our baseline power. We made 617.2 horsepower and 575.5 pound feet of torque. And because we're not using electronic boost control, we've got a rising boost curve and therefore a fairly what we would call normal looking curve. In other words, it's not just starting up here and making dead flat power the whole time.

[00:07:23]So, let's have a look at that boost curve. You'll see that it's going to start low and move up high. [music] Looks like it starts at about 5.2 and it's going to end at 10.9.

[00:07:33]Everyone's like, "Well, how much boost does it take to make that 600 horsepower?" It's basically 11 pounds on this thing. Now, how does that boost curve compare to the back pressure curve of pressure inside those manifolds? So, this is going to be that thing that we had Steve show you, the sensor that is in between the exhaust port and the turbo. So, it's back pressure in the exhaust system before it reaches the turbine. Upper scale is the back pressure and from the research I've done, 2:1 ratio is kind of normal. So, that's actually quite a lot of back pressure for what we're doing here and >> Especially at this step.

[00:08:09]>> Exactly. I consider that pretty bad.

[00:08:12]Now, is that because this exhaust manifold is kind of restrictive and the way the crossover is configured?

[00:08:18]>> that great. This is kind of typical with an exhaust manifold. It would certainly be better with a header. And what about the crossover configuration?

[00:08:27]It's the whole design of kind of the way the dumps and cross over in the short manifold and just not being a good exhaust design. I mean, the same thing you run into in an NA engine. It's just not a great manifold. Yeah, especially when you're cramming 600 horsepower through it. Exactly. I guess that is what it is. So, we got to move to our next step of choking this thing with some exhaust. So, my thought is to start with the worst possible configuration and then improve it. In other words, start with 3-in exhaust and go to 4. So, I guess what we'll do right now is put [music] on our 3-in pipe with a Flowmaster muffler. And And then I've also got a after that.

[00:09:06]So, we're going to go Flowmaster, turbo muffler and then Flow Monster and come back here and look at the data.

[00:09:17]Next up, can you hear it? It's the Summit TURBO MUFFLER.

[00:09:23]WHERE DID THE HORSEPOWER GO?

[00:09:25]>> THAT is gruesome. Yeah.

[00:09:29]>> [music] >> Wow, Delsich, way to put in a day's work, bro. And the last of the 3-in mufflers is the straight-through Flow Monster.

[00:09:43]This will be the very last one with the 3-in exhaust and now we've got no muffler on it at all.

[00:09:52]That was horrible. You really know how to hurt a guy. [laughter] Yeah, ruin a motor.

[00:09:57]That was terrible. We've opened up all of the curves for all of the stuff we did with the 3-in exhaust system and it's gruesome. Oh, no. It's really bad.

[00:10:07]I'm going to start with the best and move my way to the worst. So, the best strangely enough was with the Flowmaster Monster, which was that straight through stainless steel little round muffler. It made 579.7 horsepower and 542 pound-feet of torque. Then, we removed that muffler and ran open completely and made 572.6 horsepower and 536.4 pound-feet of torque. Next was the Flowmaster chambered muffler. That made 547.6 horsepower and 519 pound-feet of torque.

[00:10:43]And absolutely ghastly was [laughter] the the turbo muffler from Summit, which made 461.8 horsepower and 449.3 pound-feet of torque. Just look at that.

[00:10:58]This green one is ironically the turbo muffler. It has it right in the name, but clearly don't be shopping for your turbo muffler by buying a turbo muffler.

[00:11:11]The muffler restriction kills the boost.

[00:11:13]>> It does. Yeah. Every time we tested and it got quieter, the boost got worse. And and and you know, the two kind of went together and the power went down. I mean, it was just hideous how how we were just knocking The last change was 150 horsepower.

[00:11:27]>> 150 horsepower down.

[00:11:29]>> That that change in mufflers would never act that way in a And that is the point of the episode actually because the reason we're seeing these power losses is not just on outlet restriction, it's because of what it does to boost. So, let's look at those curves all together.

[00:11:44]Uh-oh.

[00:11:45]Gee, that looks a lot like the horsepower curve.

[00:11:47]>> Lot like the horsepower [laughter] curve.

[00:11:49]>> Yeah. Since the worst down here is with the turbo muffler. And then moving up in blue is the Flowmaster, in red is is an open pipe, and then black is the Flowmaster muffler. I still can't quite put my finger on why that Flowmaster would make more power than an open pipe.

[00:12:05]>> some other things that happen when you get the turbo a little hotter, it will spool differently, it can make a little more boost. You know, it's possible that I drove it a slight bit different and didn't preload it long enough to build the heat to make it have it make a little more boost. There's there's some driving going on there, too. That's why you see guys so adamant about staging the same way, doing that sort of thing at the races.

[00:12:24]>> What is the difference on the green line? Like, what's the peak boost? Mm, 5.8 lb and up there it's 9.3.

[00:12:32]So, that's how much boost was killed just by adding that muffler onto the tail end. Conversely, and we'll I suppose if you want to look at this, but the back pressure went up with every one of these as the boost went down.

[00:12:45]>> next thing I wanted to look at. The change in back pressure isn't as radical as I thought that it would be, but as compared with the resulting boost, the ratio's going to get much more horrible.

[00:12:57]For example, uh what is the back pressure for the uh turbo muffler? 18.8, but the boost from that one was only 5.8. So, 3.24 to 1 and that's what makes that horrible. Is the back pressure ratio's hideous. Okay.

[00:13:16]>> is down, but I mean, with that sort of back pressure, I have to imagine that it's causing other issues like heat and and other problems, you know, potentially. I I have seen too much back pressure cause issues with exhaust valves, like they keep burning exhaust valves and tearing motors up and it causes detonation issue because of combustion chamber temperature. There's a lot of other bad things that go on there with that ratio being or the exhaust pressure side being way too high. This whole segment has been an eye-opener for me. I mean, flat out, don't put an exhaust restriction on your turbo and it'll be a happier day. So, I think this has been crippling. Next up, I want to move to a 4-in exhaust system and see what we can do with a Flowmaster on that.

[00:13:55]>> Okay. Yeah, cuz I'm thinking maybe the larger [music] pipe and everything makes it not as bad a scenario as what we've got going on here. All right, next up, 4-in pipe with a muffler.

[00:14:09]>> [music] >> The 4-in pipe we just added is a longer than the very first one that we ran, so we're going to retest it open before we install a Flowmaster chambered muffler and then a Flowmaster straight through muffler.

[00:14:35]Ran it open. Now, we've got the 4-in Flowmaster chambered muffler on there.

[00:14:45]Look at the paint smoking off the muffler.

[00:14:51]>> [music] >> Yeah.

[00:14:53]And our last muffler, the Flowmaster Pro Series with a cone of silence.

[00:14:59]That's the the twin cones of silence inside.

[00:15:06]Steve just graphed all of the 4-in pipes and [music] finally we're getting somewhere. Check this out. The red line here is the Flowmaster chambered muffler, but the interesting part is that the black line is the longer pipe open and the blue line is the Flowmaster Pro Series, which is that cone of silence type muffler. And it's essentially unchanged. It's not a straight through design. You can see through it, but there is a lot of mesh and things going on. It has a a very deep tone to it and basically didn't hurt power except for a little bit at the bottom and a little bit at the top.

[00:15:41]And that's going to follow the boost curve for whatever reason that's going to change a little bit. Every time we've looked at this when the back pressure goes up, the boost goes down. The higher the back pressure, the lower the boost. I mean, it doesn't matter whether it's 3-in or 4-in or what muffler's on it, those two things are consistent. It's also consistent with the power. I mean, more restriction, the less the power. It lowers the boost and raises the back pressure. Well, I also wrote down the back pressure numbers on all of these. So, what's interesting about it is that the open and also the Flowmaster chambered had 18.6 back pressure. Strangely enough, the Pro Series muffler, 18.4.

[00:16:20]Down just a little bit, testing anomaly, you know.

[00:16:23]>> Yeah, we're talking 2/10 of a PSI. I mean, that's And [clears throat] but also the boost was not affected nearly as much as what we saw with the 3-in. So, with the open 4-in pipe, we had 10.8 PSI of boost.

[00:16:36]With the chambered muffler, 10.1. And with the the Pro Series, 10.6.

[00:16:41]>> Yeah. So, our back pressure ratio, let's see, in the worst-case scenario is probably open. Let's see, 18.6 / 10.8. It's 1.72. Yeah. That's not bad.

[00:16:55]That's Well, relatively speaking with these not bad versus everything else that we've seen in this show and that's why it's making the best power. So, pretty cool. Can we compare the 4-in muffler to what we did earlier today with the much shorter 4-in open pipe cuz I'm curious how that pipe length itself affects what's going on with the turbo?

[00:17:16]Okay, so the black line is open long pipe and blue is open short pipe?

[00:17:23]>> Yes.

[00:17:24]So, it preferred the longer length of pipe actually for power.

[00:17:28]And and again, I mean, we're looking it changes the curve slightly, so we're looking at as close as it can be adjusted without an electronic boost controller.

[00:17:36]With the manual boost controller, I mean, we're still maybe looking at a 10th or so difference here.

[00:17:40]I'm kind of inclined to lean towards it's really not making much difference at all between the pipe length. I mean, that's a massive diameter pipe.

[00:17:49]And so, I don't think we're going to see the effects of that as much as we might on some smaller stuff. Nevertheless, we ended up making our best power overall from this whole day with the longest length of 4-in pipe with no muffler on it and that was 623 horsepower and 579.9 pound-feet of torque. Now, with the Flowmaster chambered muffler, we made 604 horsepower and 563 pound-feet. And with the Pro Series Flowmaster, it was 617.7 horsepower and 580 pound-feet of torque.

[00:18:20]And the boost for all of those ranged from 10.1 for the chambered muffler to a high of 10.8 for the open pipe.

[00:18:28]I really like this thing. The big thing to me really that this test showed was the spread from a really bad 3-in muffler in terms of a turbo setup >> Yeah. to the best was way broader than what we saw with this. With the 4-in pipe isn't forgiving because you're way bigger already. The other thing I think is that when we did that step down off the back of the turbo from 4 to 3, we created a massive back pressure ratio problem and I think the worst the back pressure ratio gets, the more damaging everything else that you do. It's just it starts to fall off the cliff and pick up steam and that's why the mufflers were a much more radical difference. And that taper was a nice taper. It wasn't ugly or anything.

[00:19:14]No, it it doesn't That's what my point is. It doesn't matter. I mean, it wasn't like it was some hack job. I mean, it was a nice cone-shaped taper. So, it's just gets down to be that small and causes a lot of restriction. Yep.

[00:19:26]So, I guess that brings us to the point of being able to make clear conclusions, which we've sort of said it all along, but let's just put a point on it. First of all, I think if I was running a turbo, I would attempt with all of my life to never run a smaller diameter exhaust pipe than the outlet of the turbo itself. And if I have to restrict it, don't do it just boom, right there in the first 6 in after the turbocharger.

[00:19:49]That was a mess. But that just adds up to the bigger conclusion is don't restrict the outlet of your turbo.

[00:19:56]Just don't. I thought that with this only making 600 horsepower, that would be an application where a guy doesn't want to just put a dump out his fender.

[00:20:04]But, in truth, you would be better off if you did. If you're going to run a full exhaust system all the way out to the back of your car to try and quiet it down for the street, don't run a muffler. Just run as big a pipe as you can fit all the way to the back of the car.

[00:20:18]I agree. Back pressure is poison on turbo setup.

[00:20:23]The conclusion for me is this.

[00:20:26]I will confess that I've made some derogatory statements about forced induction and that sort of thing. But, I'm going to take it all back. This thing is just awesome. I mean, the kind of power it makes for this many cubic inches, I'm a believer. I see why so many guys love this technology.

[00:20:42]Um it's just awesome. You and I were looking off camera earlier at idle at 18 in of vacuum. You can have a 2200 RPM converter and your air conditioner on it, goes into gear, smokes the tires for a quarter of a mile and makes 650 horsepower. You know, it's just I see why. And it's we've been running it on Sunoco 116 just because we do because we don't want to leave parts on the floor, but it's a pump gas combo.

[00:21:04]>> I I think it could be at this at this boost level, I think we're right there probably as far as pump gas, but that latent vaporization blowing through the carburetor helps with the intercooler stuff. But, realistically, if you go this far, why not put an intercooler as well? Plumbing nightmare. That's the big thing that keeps me away from a lot of it and it's why I'm glad to know that an exhaust system is kind of bad. It gives me more reason to simplify the exhaust and just dump it out here this side. You know, no intercooler, no mufflers, no real exhaust. I mean, how much simpler does it get? You can bolt one of these things on in about 3 hours. You can. So.

[00:21:35]Yeah. So, I think I just came up with what my final conclusion is of the day.

[00:21:41]Let's hear it, Freiburger. The turbo is the muffler.

[00:21:45]Get over it. End your exhaust system with a turbo and have a nice day.

[00:21:49][laughter] Great.

[00:21:51]And you know what? Probably we need to find out someday whether those cast iron manifolds really are giving a lot of power up versus a header. We've got to do a comparison of manifold versus header. What does that sound like?

[00:22:04]Another episode of Engine Masters.

[00:22:08]Can anyone spark plug make more horsepower than another? YOU GOT TO KNOW AND YOU'LL find out this time on Engine Masters.

[00:22:33]>> [music] >> Spark plug power. It's the episode that applies to everyone. Well, unless you're a diesel guy, in which case I guess you can be forgiven. Or if you're an EV guy, in which case you're not watching the show. But, spark plugs, this is the source of glorious internal combustion.

[00:23:04]Speaking of that, the spark plug goes all the way back to the mid-1850s.

[00:23:08][music] I would say there's probably no automotive part outside the spark plug that has had more different designs all in the hunt of horsepower. And that's what we're going to do here is look for horsepower. Now, for full disclosure, I got to tell you there is a lot about spark plugs we are not going to be able to test. There's some legitimacy to the fact that some plugs are designed for longevity, like they have a harder electrode. We can't test that here. We can't test reliability as far as like maybe opening up the resistor inside and breaking. We can't do that. We can't test like misfire at really lean part throttle cruise. We can't test economy.

[00:23:47]There's a lot of stuff we can't do. So, we will only be looking at power. And I have to be completely honest, I'm guessing that none of these different brands of spark plugs are actually going to make extra horsepower more than any of the other ones. So, we're just going to lay that on the table right now. But, we are going to look at a whole bunch of different types to sort of demonstrate that to you. And we'll have a lot of discussion based on our experience, industry knowledge, and some tips and tricks along the way. Let's look at the spark plugs that we're going to test.

[00:24:17]First up is going to be the very basic Autolite spark plug. These are the ones that we buy all the time at the local corner parts store. There's nothing special about them. They're just a good basic spark plug. Moving on to what's in my hand is the NGK racing plug. This is the only non-resistor spark plug that we'll be testing. You see, a lot of plugs that started coming out in the late '60s had a resistor in them, which helped cut down on electrical noise so you wouldn't hear that buzzing in your radio. Of course, the resistors are used today so you don't have frequencies that are getting in trouble with like your EFI and things like that.

[00:24:55]That NGK racing plug, once again, the only non-resistor, this is our personal favorite spark plug for running in a performance application. Once we get to running these, we'll give you a lot of tech tips about that spark plug. Next up, you're going to have the NGK iridium plugs. There are a ton of brands of spark plugs these days with a center electrode and maybe even a little pad on the ground strap that are made of iridium, platinum, all sorts of different materials. Typically, it's for longevity. We're going to find out if they make a difference on our engine.

[00:25:29]Now, when we get into sort of our unusual plug, we're going to run this Bosch. Atypical of the normal Bosch spark plug and made in Russia [clears throat] of all places, that's the one that we say is like this. It has two ground straps on it. That doesn't mean it has two sparks per sparking event, but a lot of people over the years have put multiple ground straps on plugs and there's a lot of theories about how those can work. We're going to see if that works in our application.

[00:25:57]Now, here's the disappointment. We really wanted to run the E3 spark plug.

[00:26:02]This is probably the most popular specialty plug today, but if you look at it closely, you can see our issue. I bought these spark plugs and we discovered that they are so long that they hit the pistons in our engine. So, unfortunately, we're not going to be testing that one in our engine. However, we're going to run all the rest of these and we're going to get through it pretty quickly. I think the meat of the episode is going to be in a lot of tips and tricks and we did find something that makes power. And it's not new, but it was a shock.

[00:26:34]Yeah, I said that.

[00:26:35]Let me walk into the dyno room and I'm going to tell you all about the big block that we're testing and how we're going to configure the ignition system to give the spark plugs the best chance of making power.

[00:26:49]Here's the engine we're going to use. I wanted something with a little bit of cylinder pressure to give the spark plugs some opportunity to show a difference. So, this thing has 12 and a quarter to one compression. That's not off the plot in any way, but it's the highest compression engine that we had sitting around here. This is a 478 cubic inch big block Chevy and this thing should make 800 horsepower and it should run to 7500 RPM. So, I think it's going to be what we need, but I asked Steve to [music] change the distributor and that's because once again, I wanted to give the spark [music] plugs the best opportunity to make a difference.

[00:27:22]Meaning, I wasn't going to use the MSD Digital 7 Plus that we normally run for ignition because that thing just has like the the spark of death. So, what we're going to install is an MSD HEI, which is an aftermarket clone of the GM distributor that came out in 1974. It has an integral ignition module so it doesn't use an external box. It also has an integral coil in the cap. So, what Steve did is he took the old distributor and lined it up pointing at the number one cylinder, which is how we like to arrange our spark plug wires. Right now, the engine is at 35° before top dead center, but it's not dropping into the oil pump drive. So, he's going to tick it and make it drop all the way in on the helical gear.

[00:28:10]All right, guys. Every time I learn the lesson, I break my own rule. In my stand-up, I actually went on record and said I don't think any of this is going to make a bit of difference.

[00:28:19]>> You made a prediction?

[00:28:20]>> Yeah, I did. Oh, Freiburger.

[00:28:22]Oh, no. I'll be wrong. Here's the thing.

[00:28:24]We want to see some kind of change and so now I guaranteed it so that I can be wrong because that's a trend. I disagree. You're always right.

[00:28:31]>> [laughter] >> No, I'm not. Steve is. You think this is going to make a difference on all the spark plugs? Oh, yeah. I think the big deal here is going to be on you to make sure that our oil temp, water temp, everything is the same on each pull cuz if we see any warbles in there, it could be temperature related.

[00:28:47]>> We're talking onesies, twosies. They add to the dyno. One or two horsepower. And I think it's important to note that onesies or twosies are zeros. Uh-huh. Um you know, engine repeatability, dyno cell repeatability, there's something called cyclical variance. An engine does not do exactly the same thing every time you run it. So, we're going to see onesies and twosies. I expect to see that, but for all intents and purposes, in my mind, that's nothing. Okay. So, a little bit of a self-fulfilling prophecy here. I mean, we've all got a chip on our shoulder about this except for apparently Dulcich who thinks it's going to make a difference. I want to take the contrarian viewpoint. I mean, I don't think it's going to do anything anyway.

[00:29:24]Yeah. So, I'm going to run in the cell and show you what we're going to do for our very first spark plug. What's going to happen is we're going to show you a plug, run the engine, show you a plug, run an engine, and at the end, we'll go back and look at all the results. All right, I'm going to go throw in Autolites. Perfect.

[00:29:44]Our first spark plug is going to be the Autolite 3924. Absolutely nothing special about this. Part store standard.

[00:29:50]I've run them a million times. The gap right out of the box was 45,000 and that's where we left them.

[00:30:00]>> [snorts] >> The next thing we're going to do is take our exact same Autolite 3924 plugs and we're going to start messing around with the gap. These things are 45,000 right now. That is the air space in between the ground strap and the center electrode. The interesting thing about spark plugs is that they're designed with the ground strap sort of to match the gap that they expect you're going to run for the application that the plug is designed for. You can see that the ground strap and the center electrode are pretty much parallel with each other. Now, when we start to change the gap, that's going to change, too. We're going to stretch these out to 65,000 of an inch, which means we're going to bend this up, which means it's not going to be parallel anymore, but that's what you get.

[00:31:10]All right. We'll dyno it and then we'll come back and run them tight.

[00:31:32]What we're in the process of doing right now is removing all the spark plugs.

[00:31:35]We're going to go ahead and change the gap from 65,000 where we had it down to 20,000. MSD actually doesn't recommend going anything less than 20,000 because it can cause some arcing in the caps and some other problems. So, we're going to go ahead and follow their recommendations and take it to the minimum that we can that they recommend.

[00:32:05]Now, we're going to go to the NGK racing plug. This is my personal favorite for any kind of muscle car V8 and performance application. And honestly, why wouldn't you run these on a four-cylinder, six-cylinder, whatever if it's Yeah, they're pretty good on everything.

[00:32:19]>> this plug. Let me talk about why.

[00:32:21]There's a couple of reasons. First of all, you can get them in a bunch of heat ranges and they're very easy to understand. This one here says seven on it. That one says 11. In NGK parlance, the bigger the number, the colder the plug. The cold and hot refers to the temperature of the center electrode. Is it It's the center electrode, isn't it?

[00:32:41]>> It It's actually My take on it is is the length of the porcelain. The porcelain is like a fuse. And the shorter it is, the quicker it gets to the spark plug body and then to the head, which pulls heat away. And you can see exactly that in these two plugs. This one right here has a longer porcelain. That is the hotter plug because the path to the coolant is much longer. You can tell this one is the number 11 plug because it's much colder. See how the porcelain's much closer and attaches kind of at the top. That is the difference.

[00:33:15]The last thing we really love about the NGK racing plug is that see how silver it is and it's got some sort of coating on it. This is the spark plug that I personally can read the timing on the easiest. You'll be able to see after we run the thing, maybe I can show you again, that the coating on that strap will be burned. And if it's closer to that end of the strap, that means that it's too If you move it out towards the threads, that means it's more advanced. And you tend to want it just rolling over the other side of the bend right there.

[00:33:46]>> All right, Steve's putting in the sevens right now.

[00:34:12]First of all, here's the NGK racing plug that we just removed and I wanted to show you that tip that I talked about earlier about how you can look at the burn mark on the ground strap and determine if your ignition timing is right. You can see that it's burned right there. It's just on the upside of the turn on the strap. I would say that means that it wants a degree or even degree and a half or so of more ignition timing advance. We're not going to do that because we're trying to run an AB test here, but I thought I'd show it to you. Here's the next thing that's going to happen. Right there. The NGK iridium, the material that comes from meteors.

[00:34:51]You can see on this that it's got a really, really pointy center electrode.

[00:34:57]Basically, you use these if you want a lot of longevity because the iridium is a really hard, but we're just throwing them in at about a 30,000 gap to see what happens. One more tip, if you're using spark plugs in aluminum head, it's a good idea to put a little anti-seize on them. We're not doing that, but it's a good idea.

[00:35:16]>> [music] >> Out with the NGK iridium, in with the Bosch, the first of our unconventional plugs. This has two ground straps on it.

[00:35:48]I don't know what the theory is here because in our opinion, the laws of physics say that electricity jumps to the path of least resistance. So, you're not getting two sparks here. Our belief is that there's just one. The part number on these things, F L R 8 L D C U plus 7404-9.

[00:36:09]>> [music] >> We had the NGK plugs installed at the factory gap of 30,000. Now, I'm going to open it up to 65,000 and see if that makes any difference.

[00:36:41]>> [music] >> That ended up being a lot more interesting than I thought, but not for the reasons that I thought. Exactly. I agree. I think we should get to that in a minute, but let's call up each spark plug in the order that we tested them and see what's what.

[00:37:20]And the first up, the regular old Autolite, 807.7 horsepower, 609.3 pound feet of torque. When we opened up the gap to 65 thou on the Autolite, 809.7 horsepower, 611.2 torque. Now, we closed up the gap on the Autolite to 20,000, which delivered 807.9 horsepower and 608 pound feet of torque. I think the thing I learned about the Autolite is you can just grab them off the shelf and they run pretty good.

[00:37:46]>> Yes, absolutely. Well, they are my go-to for a cheap inexpensive spark plug that's going to do the job for a regular application. I slam them in everything all the time.

[00:37:56]>> No, I see them in a lot in racing engines as well as the NGKs. There are builders that prefer the Autolite. So.

[00:38:02]Well, this is the standard lowest level Autolite, but that shows you you don't need a super trick plug right out of the box to make power. The next one that we tested was the NGK. The racing plug has a little bit less horsepower than I wanted, 804.4, but the torque's pretty good, 610.1.

[00:38:19]And look at that, the black line dressed that. And you know what? That NGK racing plug, I will continue to use and perform on Plug, I mean, it's silver. Actually, as it's dissipating heat, it's going to discolor the the CAD plating. And so, about three threads down seems to be a proper heat range for most applications that you're attempting. It should be blackened it. Yeah, it's a good guide.

[00:38:42]Now, we've got the super trickadero iridium plugs, the NGK iridium, and it made 802.7 horsepower. The torque, 610.7. Market because they last forever.

[00:38:53]We grew up in an era where you changed spark plugs at 12,000 miles along with your points and cap and whatever after every cruise night because I was huffing raw fuel out the exhaust. Well, and that doesn't happen anymore with air fuel management being what it is. Spark plug a standard spark plug interval is 70,000 miles on a late model vehicle.

[00:39:12]>> Really?

[00:39:12]>> Yeah, and the iridiums last. You pull them out and they look like they're untouched. Well, a lot of that also is by regulation because those [music] engines have to be able to maintain their emissions for X number of miles as an OEM requirement. One other thing that I have heard about the iridium and manufacturer making claim that because it's a smaller diameter wire, it's easier to create a flame kernel under higher pressure applications. So, they sell them for boosted applications typically or they applaud them for that.

[00:39:40]>> When I was at Jacob's Electronics and aftermarket ignition manufacturer, we would tell people that if you choose to have like a weak ignition system, [music] old points, stock coil, or everything, that it's easier for that to jump the gap >> Yeah. because the point [music] is so pointy. Yes. Yeah, that's easier to create a flame kernel. The spark jumps from the center electrode to the ground strap unless you hook up the coil backwards with points, and then it jumps from the ground strap to the center electrode.

[00:40:07]A tip I didn't know. There you go.

[00:40:09]>> Wow.

[00:40:10]All right. Next one. We tested the Bosch.

[00:40:15]Yes.

[00:40:16]>> What happens when you put two ground straps on the same plug? You make 803.1 horsepower and 610.6 pound feet of torque. And the Bosch is now red, and once again, dead overlay, you can't even see that we pulled up another one. I think we all agree that it's not throwing two sparks per cycle.

[00:40:34]>> [music] >> It's the path of least resistance is where the spark is going. I think it might change, alternate, go back and forth, and I think the plug lasts longer because you've got twice as much material to eat.

[00:40:45]>> Yeah, there you go. Yeah, good point.

[00:40:47]Actually, the reason plugs often don't last is because there's actual metal transfer between the center electrode and the ground strap every time the spark throws, and eventually, you've probably pulled plugs out and you can see the buildup on there. Uh so, final conversation about all these plugs that we tested. There's a lot that [music] we didn't run. I mean, obviously, there's ACDelco, there's Champion, there's platinum. You can go on down the list.

[00:41:09]This cross-section tells me that with a great ignition system, with a brand new plug and brand new engine, it [music] just doesn't make a difference. It's it's almost nothing as far as out of the box spark plugs go. On power.

[00:41:23]>> Yeah. But we think there are other reasons to choose some of these plugs, like the platinum and the iridium and things like that.

[00:41:31]>> Longevity, yeah. But then, there's the very last thing, which is what we actually learned. Steve has called up our proof about spark plug gap that we saw with the Autolite plugs. In the black lines here, we've got 45,000 s gap. In the red, 65,000 s. And over and over and over, it repeats, so that we believe the trend is that the bigger gap made a little bit more power, as you can see. Yeah, I was a non-believer initially. I was like, "Oh, that's not going to matter." Well, once it started the flame, it's taken over.

[00:42:01]But it did it again.

[00:42:03]>> Yeah. And we didn't believe it, so we went went back and did it with another set of spark plugs, and did it it did it again. So, watch this with the NGK racing plug. The last thing we tested is opening up the gap to 60,000 s on our NGK racing plug, and that saw 806.9 horsepower and 609.7 pound feet. Black lines here are going to be the NGK plug right out of the box, and then in the red lines, we opened it up to 60,000 s, and you can see it's definitely trending better all the way up to I'm going to call it 5,800 rpm, and then, once again, all the way up at the top, a little peak right there. I I have to admit, I I was a real naysayer.

[00:42:43]This gap thing kind of >> [music] >> doing AB AB, the way we should test things. There's something going on. I'm heading the other direction towards big versus small. It's definitely a a trend you can see. I mean, it's not huge, but it's there. There is something there.

[00:42:57]Well, once again, what we see all the time is that it's just that little stuff that ends up adding up, and next thing you know, you're making 20 more horsepower than the next guy. And more horsepower than the next guy is what we strive for every single time on Engine Masters.

[00:43:15]You know what? Maybe I should go 65.

[00:43:17]>> No?

[00:43:18]I don't know, Stephen.

[00:43:22]I think I am going to go 65. Steve's made the executive decision to go 65,000 s, probably because he bent one too big and didn't want to tap it back. That'd be my guess. Probably. I don't know.

[00:43:33]It's go big or go home.

[00:43:35]Widening out the gap. Yep, but I would have gapped it at the sharp point instead of at the dull point.

[00:43:42]I feel like my entire discussion's the dull point.

[00:44:22]>> [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] [music] >> How much extra power do you get with mandrel bent exhaust versus [music] regular old muffler shop garbage? That answer and a bunch more this time on Engine Masters.

[00:47:29]>> [music] >> The aftermarket will tell you that you've got to have mandrel bent exhaust for improved flow versus the standard muffler shop crunch bending type of stuff. But is it true? [music] That's what we're going to find out in this episode, but there's a whole lot more. We're going to see a comparison of the straight-through muffler versus [music] a Dynamax Super Turbo. And then you're going to see mandrel bent versus crunch bent, and we're going to do that both with the mufflers and also with no muffler at all. First of all, the implement of horsepower that we're going to be using on this episode, this is a Blueprint Engines crate motor. It comes almost exactly as you see it right here.

[00:48:16]It's 7,400 bucks. It has a 30-month, 50,000-mile warranty, which [music] is pretty cool. Here's sort of the specs on this thing.

[00:48:25]Pretty typical. Stock type intake manifold. The throttle body is the one thing that changed. This is a Holly 90 mm, and it's for cable. The engine as it comes straight from Blueprint uses a fly-by-wire, so we changed that up. The cylinder heads on this thing are Blueprint's own 359 cc inlet runner aluminum head, and the compression ratio is 10.7:1.

[00:48:48]The camshaft, the duration at 50 is 225 and 239. It's on 113° lobe separation angle. And the rest of the bottom end is very much like a factory LS3 6.2 L aluminum block, all of that stuff. This thing is advertised to make 530 horsepower and 495 pound feet of torque.

[00:49:10]Now, let's look at these mufflers.

[00:49:12]You've seen this particular test on Engine Masters before, but it's always interesting to see how it changes up.

[00:49:17]This is a knockoff of a Magnaflow type stainless steel straight-through perforated core. The exhaust on this thing comes right through here, makes a little bit of a whoop-de-do, and goes right out there.

[00:49:30]>> [music] >> Then, we're going to test the Dynamax Super Turbo muffler. I remember using these things for years. Here's what happens inside this thing. The exhaust needs to come all the way down over here and it needs to make a U-turn and go down the core over here and another U-turn before it heads out. So, you'd [music] think that would be a bigger restriction.

[00:49:53]Next up, the main meat of the episode, mandrel bent versus crunch bent exhaust.

[00:50:00]Let's talk about what that means. First of all, this is the typical tube that you will get from a local exhaust shop, which is exactly what we did. We had them match our aftermarket mandrel bent system. If you look closely at this thing, you can see that it's got a lot of dents in it and at every curve, it actually reduces the diameter of the outside of the tube. You can see it's got a lot of deformations in it all throughout the thing. Now, if we go over to the mandrel bent unit, this uses a fixture inside the tube that prevents the metal from getting deformed as it's bent. [music] So, you get that nice, pretty, smooth turn right there.

[00:50:44]You got to admit, it looks a whole lot better. But, does it flow better? Does it make more power? Now, the way we're going to do this is roll this in, put it on the dyno, we're going to do initial baseline numbers with open exhaust headers so you can see kind of typically how we would test an engine like this.

[00:51:00]Then, we're going to move on to the crunch bent exhaust, test both mufflers and no muffler, and finally, you'll see what happens with the mandrel bent exhaust.

[00:51:10]>> [music] >> Is it going to make a difference at all?

[00:51:12]You got to wait till the end.

[00:51:17]Okay, back with the dyno bros. Yeah.

[00:51:19]>> [laughter] >> I think this one's probably going to challenge the limits of your comprehension.

[00:51:25]Certainly mine because I know nothing about mufflers.

[00:51:28]>> Well, I don't know where to start other than Our power numbers for our open header baseline are 501.7 lb ft of torque at 5200 rpm and it made 543.8 horsepower up at 6400 rpm, which is really close to what Blueprint advertises this thing at.

[00:51:46]>> What we found over time is that their numbers really are very close to ours on almost everything we've ever seen. Yep.

[00:51:52]So, we're going to jump into the dyno cell and install our crunch bent exhaust with our most restrictive mufflers, which is the Dynamax turbos.

[00:52:06]So, I say this kills 50. How about you guys?

[00:52:09]Oh.

[00:52:10]That is way too pessimistic. Think so?

[00:52:13]Yeah.

[00:52:15]I'm saying 35.

[00:52:38]So, here's why nobody's ever going to call me an exhaust system soothsayer.

[00:52:43]Cuz the power didn't change that much.

[00:52:45]The horsepower 534.1 at 6300 rpm and 491 lb ft of torque at 5300 rpm. And the other thing we should really mention here is that we actually made another pull off camera and what we saw is the exhaust system richened the thing up by one full point. Can we look at the comparison? Okay. So, it did kill the >> where Yeah. It makes it look way worse than it is.

[00:53:12]>> Look at the crossover. Look how it made more torque down here because of the length of the exhaust system.

[00:53:16]>> Yes.

[00:53:17]Look at that. All the way up to 3500 rpm, actually, the exhaust made more torque. Then, after that, it really killed power everywhere. So, >> it was only 10 at peak horsepower, but still. And there was a little chunk of torque there around 4000, 4200. And what's the reason for that? Because this is not as much exhaust flow as it would be up at higher rpm. It's got to be once again the resonance length.

[00:53:44]>> of length thing again, certainly.

[00:53:46]Interesting. I I don't know how it didn't kill power. I thought those mufflers would be junk. They reverse the exhaust flow and look at all the bends in that thing.

[00:53:56]Okay, um let's look at the back pressure on this thing.

[00:54:02]Okay, here's our map of the pressure curve in the exhaust system. At peak, it's 3 psi of back pressure.

[00:54:10]It's actually more than I thought. I mean, 3 psi is quite a bit of restriction, but the fact that only that 3 psi didn't hurt more power than that, I I would have thought it would have done more.

[00:54:20]>> An engine likes back pressure.

[00:54:21]>> [laughter] >> I want to know why it didn't make more power at 3 psi. But, it made more torque, so remember. All right, that could be it. I'm being facetious. That's one of those old muffler shop rumors.

[00:54:30]It's like, "Oh, an engine likes a little bit of back pressure." It'll be interesting to see if we see a pressure change when we do something with a better, less restrictive muffler. Well, define better. That thing's shocking.

[00:54:42]Well, no, it's it's awfully good, but if there's a straight through, if the power comes up and the back pressure goes down, then we have some sort of relationship between the two. Right.

[00:54:51]Okay, let's do that. We're going to run in and install straight-through mufflers that should be less of a restriction.

[00:54:57]We'll see if it makes more power. We'll see if it makes less back pressure.

[00:55:05]>> [music] >> On goes the straight-through mufflers.

[00:55:11]>> [music] >> Magnaflow knockoffs.

[00:55:14]Here we go.

[00:55:31]>> [music] >> Well, this is not going as I planned whatsoever because the straight-through muffler made essentially the same exact power as the turbo muffler. We're now at 490 lb ft of torque at 5300 rpm and we made 535.1 horsepower at 6400 rpm. Can we see anything different in the curve?

[00:55:59]>> [music] >> There's not much difference in the curve. There was, I noticed, about an inch difference in back pressure. You're going to compare it to the Dynamax.

[00:56:08]Dynamax still makes a little bit more power down here.

[00:56:12]But, not as much difference as open header.

[00:56:16]And aside from that, it's the same.

[00:56:19]Yeah, and I'm not really sure what to make of the back pressure versus muffler either.

[00:56:25]Changed about a pound.

[00:56:26]>> Yeah, [music] it doesn't care.

[00:56:28]>> anything. What's the back pressure here say at 3300 rpm where we're seeing a torque difference?

[00:56:35]>> I bet it's nothing.

[00:56:38]So, this is a comparison of black is the straight-through muffler and red is the Dynamax. So, obviously, there's more back pressure with the turbo muffler.

[00:56:47]Down here, like with the Dynamax, I mean, it's less than half a psi. So, that can't be attributed to the torque gain, which just once again says an engine likes a little back pressure, not true.

[00:57:00]>> Not true. This thing made the same power at 3 psi or at two two psi. The little thing that we're neglecting here is the exhaust system sees that straight-through muffler as just a piece of pipe. Right. So, when you change to the Dynamax, which is a reverse flow, the pressure wave tuning point ends right at where the muffler is because it's a huge change in volume.

[00:57:26]The gas hits there and that's like the end of the pipe. Here's a test I did not anticipate and I think we should do it.

[00:57:33]Just take the muffler out entirely because I think it's the exhaust system that's killing the power versus open, not the muffler.

[00:57:41]That might be worth it just to show whether it's the muffler or the pipe that's smaller and, you know, if it makes 534 with no muffler and that diameter and length, then it's not the muffler. Right.

[00:57:53]>> Right.

[00:57:58]>> [music] >> The goal here is to find out if the power reduction of 10 horsepower that we're seeing is a result of the crunch bent exhaust system itself or if the muffler is contributing. [music] And it seems like this mufflers are pretty free-flowing, so maybe this is the difference.

[00:58:34]>> [music] >> Let's have a look at this power curve with the straight-through muffler >> [music] >> just for curiosity.

[00:58:44]And there it is with the with the straight-through muffler on there. I mean, there's a little wiggle here and there as far as power separation, but it's the same. The muffler is not a restriction [music] and the length of the exhaust system that we just shortened up a little bit with no muffler didn't really make a difference.

[00:59:02]Yeah, it's past that point of where length matters and now it's Image-wise, it's not that big of a change when you look at how long the overall system is.

[00:59:09]Okay, so now the big question will be, does the mandrel bent bring back the [music] less than 10 horsepower >> [laughter] >> that we were killing before?

[00:59:19]Yeah, that's the question.

[00:59:21]Okay, so we're going to go kind of out of logical order a little bit. You know, normally I would run the same test regimen we just did with one muffler, then the other, and then no muffler, but I think what we're going to do now is put the mandrel bent on and run it with no mufflers so that we have a distinct AB test of nothing but the exhaust system. Then maybe for fun we'll throw the straight-through mufflers in after that. Yeah.

[00:59:45]Okay. Everyone agree? That sounds like a plan, Freiburger.

[00:59:47]>> Yeah. So, our next test is going to be installing the mandrel bent exhaust with no mufflers.

[01:00:37]I think there's our answer. I'm surprised. Are you really? Yeah. What are you surprised about? I look looking at the back pressure, it dropped.

[01:00:45]>> It did. The power picked up three or four. I'm Here's the data.

[01:00:51]The torque was 493.6. [music] The horsepower 538.3, which is the same RPM peaks before. We picked up 1.7 horsepower.

[01:01:01]>> Oh, I thought it was like four or something at the top. 1.7 is negligible. That's the difference between two dyno runs and 2.8 pound feet of torque. I mean, let's look at the overlay of the two curves to see if I'm wrong, but >> No, I hadn't looked at that yet. I thought I'd see saw a couple numbers higher and Oh, yeah, you're right, Freiburger. It's just a hair.

[01:01:21]>> It's just a hair. As a matter of fact, the the peak numbers that I read off don't really tell the story cuz it's the same up top, but for some reason the mandrel bent picked up a little bit down below 4,000 and a little bit between 4,500 and 5,000, but what's the difference there? Is it two?

[01:01:42]445 to 451.

[01:01:46]So, the biggest difference we saw anywhere in the curve was 6 pound feet.

[01:01:50]So, I guess it does make a little bit of a difference. Yeah. There's a little something there. It's small, but I think we're kind of in that area of where we're looking at two z's, three z's, four z's in anything we do because we only had an initial spread of 10 total.

[01:02:03]Yeah. From open exhaust.

[01:02:04]>> minor. All right, I want to First of all, I want to hear your camshaft theory. Second of all, I've got some more data from past tests that it's a little interesting. And finally, I have some conclusions I want to go through.

[01:02:17]So, Steve Dulcich, camshaft theory.

[01:02:20]Well, I mean, an LS like this, it has a pretty mild cam in it and it's got a wide lobe separation angle, so it doesn't have that much overlap. That engine, I think, is going to be less sensitive to the exhaust than say an engine with similar power but using a big cam to get there. I mean, that's using really good heads and the intake manifold runner length and all that.

[01:02:44]But, what if you had a small block Chevy with a real choppy, raspy idle like your COVID 350? Something with a lot of overlap.

[01:02:51]>> And depending on that overlap scavenging to really get on the torque curve and make power, it may show different result or more sensitivity to back pressure and and all these factors. This is on a wide lobe set, but these LS engines have a huge exhaust spread from intake to exhaust.

[01:03:12]Much more duration than you would typically see on a small block Chevy.

[01:03:15]So, does it really have less overlap? Well, less overlap than your raspy little 350, right?

[01:03:22]>> Which would be a 242 248 on a 110. Yeah, those are bigger lobes on both sides.

[01:03:27]It's got to have more overlap. So, you think overlap is the difference on why this doesn't make that much change?

[01:03:33]>> Well, I've noticed testing headers, if you've got a really mild cammed engine, it's very insensitive even changing from manifolds to shorty headers to long tubes. You'll have a completely different result if you're testing a more cammed out engine. Like Burley was saying to me earlier, if you're changing cam and headers and you want to make the cam look good, put the headers on first and vice versa Yeah, make the cam look good.

[01:03:55]>> work together and they the way they work interrelate with each other. So, that's that's part of it.

[01:04:01]Interesting. I think. You know, a month ago I might have said, "No, it's just all about airflow and power numbers when you come to the muffler." But, after Steve mentioned that earlier, I'm really kind of starting to have to think about that a lot more. And after what we've seen on exhaust system testing as far as the resonant wavelength in the thing also makes a big difference and that's going to affect what the engine's doing on the time of that overlap.

[01:04:24]>> Yeah, and we saw the the curve change dramatically when we had just collector extensions to when we put the full exhaust on and then it stayed the same throughout all those iterations of of the full exhaust system, What's interesting is that when we put the exhaust system on, remember we saw the kick up in the torque curve below 3,500 RPM? I'll bet you what that is is the source of an engine likes back pressure.

[01:04:50]I bet you guys back in the day before there was dynos or anything like or the average guy had dynos, they put exhaust systems on the car and they're like, "Wow, this thing has more low end. It must like back pressure." When it's that resonant wavelength that's really doing it. The length of the I'll buy that.

[01:05:07]Okay, so that was good camshaft theory part two. I just want to mention some data that we know from past episodes on exhaust testing just cuz I think it's interesting versus this. So, we tested a big block Chevy with both 3-in and 2 and 1/2-in exhaust with straight-through mufflers on it a long time ago and the difference there in peak horsepower was only 13. So, it's 600 horsepower, a 2 and 1/2-in exhaust only killed 13 horsepower. You would think it'd be more than that, for sure.

[01:05:41]>> So, store that in mind when I get to conclusions. Now, we also tested a MagnaFlow straight-through muffler versus the worst turbo muffler we could find, which happened to be the Thrush, and that we only did it on a 340 horsepower engine and the difference between those two was only 14 horsepower between the straight-through muffler and the uh super turbo. But, what's important is we did the same thing, same two mufflers, on a 600 horsepower engine and the turbo killed 78 horsepower, which begins to tell you why I estimated that it was going to kill 50 on this. But, isn't that interesting?

[01:06:22]We killed 14 horsepower on a 344 horsepower engine. We killed 78 on a 600 horsepower engine. And that could go to your camshaft theory. It can also go to the fact that we're making not quite as much as double the exhaust flow, but a significant more exhaust flow at 600 horsepower. I'm starting to believe it's both, not just a power number, but it's actually camshaft and power numbers.

[01:06:46]Right. Right. Cuz if I remember right, we tested that on the Cleveland, Yes.

[01:06:51]which had a big solid roller.

[01:06:53]And it's on a 108.

[01:06:54]>> Yeah. Yeah, so it's got a lot of overlap. So, you know, by bench racing theory, that begins to give credence to your cam thoughts.

[01:07:02]>> Yeah, there's just a lot involved, a lot of nuances to getting the right exhaust system for your car. You've got to consider what you have to begin with. So, with that in mind, we know that the results that we saw here really just apply to this engine on this day. I think it's indicative and I'm going to go through the stuff that I learned from doing this. First of all, that Dynomax muffler is great.

[01:07:28]>> Yeah, it is. And I don't understand it.

[01:07:30]It makes an S turn with the exhaust. It makes no sense.

[01:07:34]>> S. Yeah, a smooth S and it makes power and it's quiet. I would actually use that muffler now.

[01:07:41]The next thing is we talked about a lot, back pressure makes power. That's bogus.

[01:07:45]We increased back pressure and never really saw that it made that difference.

[01:07:50]The next thing is I got to believe that even with a different camshaft, 2 and 1/2-in exhaust is good enough for 500 horsepower. In most cases, yeah, it sure should sure looks that way. Yeah. I would agree. You agree with that?

[01:08:04]>> I'm at that decision point myself with my '67 Cougar and I was kind of fretting over the 2 and 1/2-in stuff that I have.

[01:08:13]But now, man, I'm totally okay with >> That makes 470.

[01:08:16]>> I know. Yeah, just throw it in. And the last one, which is the point of the whole episode about mandrel versus crunch bent, is mandrel must do something because it reduced back pressure versus the crunch bent, but the engine didn't care.

[01:08:30]>> [music] >> This engine didn't care, but it showed us something in the data as far as back pressure. So, there's something there.

[01:08:36]The problem is is that this is leaving more questions than ever. We have to do the same test on something with a lot of overlap that makes the same horsepower and compare it and that would prove your cam theory. Oh, we would see for sure.

[01:08:50]Man, there's more questions than answers every single time, but it's still awesome every single time on Engine Masters.