The 4.0TT Is Officially Mounted in Our B9 S4

Added: 2026-05-24

[00:00:03][music] >> This is for braking.

[00:00:08]>> [music] [music] >> All right.

[00:00:37]>> [music] >> What?

[00:00:40]I'm going to go check that one.

[00:00:43]What?

[00:00:44]>> [laughter] >> Tyler [ __ ] his pants.

[00:00:48]>> [music] [music] >> We have to do this to the RS5, too.

[00:01:08]Unfortunately.

[00:01:12]>> [music] [music] [music] [music] [music] >> Sorry.

[00:01:57]>> [music] >> Oh my god.

[00:02:06]If you're probably wondering why this just happened. This is a non-sport diff and let me the two manual S6s we have Wavetrac LSDs in the rear cuz the Wavetrac is actually better than the sport diff. Jay from JXB thinks that these are welded. It's the same issue with the front Wavetrac that or not Wavetrac the front custom LSD that's in the black manual S6.

[00:02:33]You have to machine off the ring gear to make the ring gear bolt in just so the ring gear is part of this.

[00:02:41]So I'm seeing if these are bolted kind of like the C7s were.

[00:02:46]I have a feeling it's not but one way to find out and I can it's got 200,000 mi on it so I can see like the how it is. If it is welded we probably will cut the ring gear off and then try to find an LSD that will fit in here because I wanted an LSD over the sport diff.

[00:03:03]Yeah, so now we're going to split this open.

[00:03:07]Oh [laughter] my god.

[00:03:15]DID IT?

[00:03:16]>> [screaming] [laughter] >> THE PRY BAR OR AN EXTENSION.

[00:03:26]RARE EARTH MAGNETS.

[00:03:28]Stick it in there.

[00:03:38]Where is it?

[00:03:40]Oh my god.

[00:03:46]10 hours later.

[00:03:49]You You to be joking me.

[00:03:55]Where Oh, it's been on it THE WHOLE TIME.

[00:03:58]>> [laughter] >> GOD DAMN IT.

[00:04:05]>> [laughter] >> IF THERE SWEAR TO God if that bucket was there It's good he moved it.

[00:04:25]I said I'm working on it. Right, no kidding. Good thing I moved it.

[00:04:42]What was that? Was that chunk of the concrete?

[00:04:45]>> Watch back. That would have went into the bucket, too.

[00:05:01][ __ ] remind me of >> This is tall stupid. Back and numb.

[00:05:08]Yeah, that's how you do it.

[00:05:15]Cool.

[00:05:17]>> [music] >> You're [ __ ] up. No, but it ain't going to be smooth.

[00:05:23]Make your [ __ ] head.

[00:05:29]This hurt.

[00:05:37]>> [music] >> [ __ ] There's literally nothing you can even do. There's not even a back surface on here to even drill holes into.

[00:06:19]Hey, what's up? Hey, um I have this diff apart.

[00:06:23]And did you take apart the one that you have there at all? Which diff are we talking Uh for the B9.

[00:06:29]Yeah, once upon a time I took it apart.

[00:06:32]Yeah, so this one it doesn't even have like a flat surface to remotely even put bolt holes in.

[00:06:41]Do you know if you can just buy ring gears?

[00:06:46]Uh likely not the kind that you're going to want cuz the problem is it's got to mate with that pinion gear.

[00:06:51]Yeah. Um this one it it bolts in. It literally shapes down to the curvature of the ring gear.

[00:06:59]There's not even a flat surface to even put bolts in.

[00:07:04]Could you machine a flat surface to insert a speed? No, here I'll text you a picture quick. Yeah, that'd be way helpful.

[00:07:12]On the previous generations like the C7 the ring gear on the rear diff is bolted in so you can actually bolt it with the JXB kits to a Wavetrac.

[00:07:24]That is not the case for the new generation because the ring gear itself is welded. So both the front and the rear are at JXB and we're going to be machining those off and hopefully trying to make a LSD for the front and the rear. Now we don't know if there's enough material because on the back of the ring gear there's a big bevel where you would bolt to if there's enough material. I'm hoping this we can get this to work otherwise I'm going to figure it out because this car has open diffs front and rear. I didn't have a sport diff. I don't want a sport diff and I'd rather just go with an LSD especially for this one for weight and don't have to deal with all the super weak sport diff.

[00:08:03]That's if we can get it to work. Um there's only one way to find out.

[00:08:50]>> [music] [music] >> All right, so one thing that we I didn't even realize is the car was missing the starter harness. So the harness is its own thing.

[00:09:10]Now because this obviously didn't come in a B9 I didn't figure that out or plan for it.

[00:09:18]So it was kind of a shot in the wind.

[00:09:20]Now ironically we had the starter harness on the 3-liter that came out of the car and just fiddling around it literally bolts right up. So we have a 4-liter starter with a 3-liter harness. It bolts up identical, the clips are identical.

[00:09:40]This literally plugs right into Oh.

[00:09:43]This one plugs right into the alternator.

[00:09:46]The stud that goes into the alternator also plugs into the alternator.

[00:09:51]And it was just all going to work.

[00:09:54]How we got super lucky on that, I have no idea.

[00:09:57]But, I'm not going to complain about it. So, now we just basically got to get the starter in, put the motor mounts on, and then we're going to hook up the transmission, and then essentially just bolt this into the car.

[00:10:53]>> [music] >> Okay.

[00:10:54]Yeah.

[00:11:06]>> [music] >> I think this is all right.

[00:11:16]>> [music] [music] [music] [music] >> Oh, that ball went and all.

[00:12:11]This bolt Yeah.

[00:12:14]Where was that? My pocket. You [ __ ] [ __ ] good it fell.

[00:12:18]>> [laughter] >> It fell into my this pocket. It went like that. That's funny.

[00:12:36]>> [music] >> I'm going to have to cut this inside [music] of the car.

[00:12:44]Because the motor mount bracket covers this.

[00:12:50]All right, so on the 4-liter, they actually route the harness, the engine harness.

[00:12:55]I like it on the 4-liter better. They actually route it underneath the car. On the newer ones, they route it over and it's completely in the way.

[00:13:04]But now it's in the way in the B9. Um the because of how the different subframes are, the power steering rack actually cannot go all the way up. It is actually hitting the harness and the shield.

[00:13:16]When we mounted the motor mount brackets that we made, it actually brackets over the bracket that we need to remove. So, I'm just going to cut it off cuz we're just going to shove the harness up and out of the way.

[00:13:30]Yeah. Um foresight that we definitely didn't see.

[00:13:34]But there's a lot of different things that they changed for this platform in this chassis, so we're going to kind of just wing it as we go.

[00:13:48]What are you doing?

[00:13:55]>> [music] [music] [music] [music] [music] [music] >> So, as you saw in the video, we had to cut some brackets for the power steering rack. Now, on the B9s, they have the numerous different subframes. There's technically three of them.

[00:15:42]On everything else, there is literally one. You just have a front subframe and your rear subframe.

[00:15:48]Not the case in the B9.

[00:15:50]Now, because of that, the 4-liter is from the previous generation. So, we've got the motor mounts and everything in the motor mount brackets, which we made in this video, installed, but as you can see, a lot of the stuff we had to finagle to get installed. Now, I don't know if there's a specific procedure when they're assembling stuff. Like, do they just take like the lower subframe, put the steering rack on it, then put the motor mount brackets on it, take that, and then bolt all that to the motor itself.

[00:16:20]There are going to be some things that I'm probably going to want to change. Uh one, sway bar will not fit. It will hit the oil pan of the 4-liter. I have an idea on how to get around that where I can probably modify the one subframe, notch it out, and then make a custom bent sway bar that'll kind of come down and go around and clear the oil pan. I'm hoping that is the route we have to go for that. Otherwise, I have to make like another oil pan with a clearance.

[00:16:46]And I don't know if there's any room in the pan itself to do that. I think the next steps that we are going to do is I want to get the car off the lift cuz it's just in the way. Um it just It's been sitting on the lift, and the problem is is because of the three subframes, it's not like you can just remove the subframe and you're good to remove the motor. You have to do one, which is the suspension, then to do this, and then all the other just to get to even get at the bottom of the motor.

[00:17:13]So, what we're going to do now is we're going to get the all the suspension components back together. I have a new rear subframe because it was hit on or whatever he ran over. It hit the rear uh mount. So, I have a new subframe. We have coil-overs we want to install.

[00:17:30]Um I have all the mountable sphericals that I want to get installed at the same time and then just get it off the lift.

[00:17:37]Because then from there, then we can basically start working on the wiring, where figuring out the wiring diagram.

[00:17:43]There's like 15 wires that I just have to splice into to hopefully get it to fire and communicate. First off, like fuel pump, uh ABS module. From there, we'll probably have to do like a whole CAN emulation like we did on the manual swaps just because this generation has a lot of flex ray versus the C7 does not.