What 8,000 RPM 997.1 Really Feels Like | 4.1L Test Drive

Added: 2026-05-30

[00:00:01][music] [music] Hey everyone, Brandon here with Slacker [music] Racing back for another test drive. This one was really pretty exciting. A customer bought this car sight unseen.

[00:00:24][music] It's a 2008 Carrera 997.1 3.6 a 6 L and he had it shipped directly to us for a 4.1 L upgrade for our modified head package including cams and headporting, but he also wanted to be our first 8K build. And so this one is built to rev to 8,000 RPMs. Today we're going to do a little testing, get some values, and go ahead and ease it on up into that 8K range and [music] just see how she feels. We've tested on the dyno. Here we go.

[00:01:02]Okay.

[00:01:21]Whoa, that is way up there.

[00:01:24]>> Oh, I already It did extend it out. Holy [laughter] >> Wow.

[00:01:31]>> Wow.

[00:01:32]>> Everything looked really good. [music] And now it's time to see how it looks and feels in the car. Come along.

[00:01:38][music] And here we go. [music] This car feels pretty tight. Has good suspension on it.

[00:02:00][music] And going to cruise along about 4,4500 RPMs. Just trying to get a little more heat into the engine. Uh, we've got the coolant temperature up, but since I'm going to be pushing it pretty hard, I want to let it stay there for a minute and get the oil temps up a little as well.

[00:02:22][music] [music] Even at park throttle, she's pretty peppy. This one, this one's going to run out pretty good.

[00:02:57]Now then, when building an 8K engine, there are two key things that we're looking at in those springs. One is the resonance frequency of them. So the size and the shape of the spring and the style of the spring, those are all going to contribute to what is known as the resonance frequency of that spring. And that's where it's going to become unstable as you increase the revs more and more. Now then, these specific springs are designed for about 10,000 RPMs on the resonance frequency. So I know we're not going to be anywhere near that. and they're plenty safe. The other thing we worry about is valve float, not having enough spring to be able to control the valves at the higher RPMs.

[00:03:43]And so for that, we go up a little bit on the seat pressure. So we added just under 20 lbs of seat pressure on the spring rate over the stock. You don't want to do too much because all that extra energy of the spring, if you've got more than you need, that is still energy [music] in the system that has to be dealt with. And so you want just enough more to make sure you can comfortably control it. And once again, these springs are probably good up to about 9500, which there's some other limitations in the engine that will need to be addressed first before we can go go that high with them.

[00:04:26]Easing our way up. Starting to get some temp into the oil.

[00:04:57]All right. So, that's a pull to 7,000 RPM right there. And it is nice and peppy. We're going to ease our way in there. Make sure we're not feeling anything we wouldn't expect. And that seemed all pretty normal.

[00:05:13]Now then, the only downside to the 8K spring package is the extra seat pressure did look like it cost us a few RPM at the top end. And I'm when I say a few, about [music] three or four less uh horsepower than what we would have expected from this engine with stock springs. However, I believe the uh the trade-off is going to be well worth it.

[00:05:38]Okay, so we've got her warmed up. We've done a 7K pull. Everything feels normal as expected. Let's push her on up there and see how she does.

[00:05:49]I'm excited about this.

[00:05:54]So, we'll start our pull off at about 2500.

[00:06:05]Whoa.

[00:06:09]All right.

[00:06:10]That looked like [music] it was right below the rev limiter. She never quit pulling the entire time. That feels amazing.

[00:06:22]Let's do it again. Now then, one thing I do want to test is go ahead and bounce off the rev limiter. make sure one it's doing what it's supposed to be doing, but also that I don't hear anything or feel anything abnormal or unexpected. Now then, it's not uncommon in, you know, the race cars to have them not only hit the rev limiter, but even maybe bounce off of them for a second if they're at the end of a straight. And that's where the increased rev limiter and the increased RPMs really come in handy on this one.

[00:07:04]Whoa.

[00:07:09]Wow. Okay. All right. So, looks like the rev limiter did kick in. We felt all of that. Kicked in about 8,000 RPMs, just as expected. Holy cow, that thing was moving.

[00:07:24]Woo!

[00:07:25]This car flies.

[00:07:27]This is fun.

[00:07:44]Ah, that's kind of addictive. Holy cow. I'm not going to lie.

[00:07:53]I like being able to hold the gear a little bit longer. That is fun.

[00:07:59]All right, we'll do one more. I do want to hit the rev limiter one more time.

[00:08:04]Just get a couple of checks on it. Make sure it's functioning properly.

[00:08:23]And it is.

[00:08:25]Holy cow.

[00:08:27]This car freaking scoots.

[00:08:38][music] So, this slacker 4.1 L engine made 419 horsepower on the dyno at the crank and 363 ft-lbs of torque. When you give it the beans, it carries that power all the way to the top to 8,000 RPMs. And it's just an absolute pleasure to drive. This build was definitely a success and sets a new mark for us going forward on what we're capable of doing. We set this goal at the beginning to have an 8K build. To finally get here feels amazing and not just get to 8K, but have it pulling all the way through the power band. Really excited about this. Porsche sets the standard for us with the GT3, and it's always our goal to meet or exceed those standards, and I feel like this is a big step forward towards doing it. We appreciate you all joining us for this test drive. If you liked it, like, subscribe, leave comments, tell us what you think, and tune in for more to come.

[00:09:52]Cheers.

[00:09:56]I'm Philip. Thanks for watching. If you want to check out another video, check it out right there.