Some general GTM questions

[ohmygosuness]

So, I was having a pretty good day today. Getting ready to install the firewall until I realized the bottom of it is interfering with the intake manifold.

My good day suddenly became just okay.

Here's my question: is the top part of the manifold just a hunk of solid plastic and can I just cut a chunk off?

[Shoeless]

Let's make your day a little easier. You most certainly need to trim that to fit. The intake manifold is just a plastic cover, Dremel tool and small cutoff wheel and you are good to go.

I swapped my intake cover for a full carbon fiber one, yup, immediately got the cutoff wheel treatment and it looks perfect.

https://i.imgur.com/8qfE0wd.jpeg

https://i.imgur.com/hm6eWLk.jpeg

https://i.imgur.com/H3eD646.jpeg

[ohmygosuness]

Okay, that's not too bad then. I'll get trimming.

By the way, what's that black stuff coating your firewall? Is it heat insulations or paint?

[VRaptor SpeedWorks, LLC]

Well.....It depends on what engine you have. If it is an LS3, and like the one in Shoeless's photos.....that very top part is a just a plastic sound deadener cover with foam under it to cover the top of the intake manifold. Yes, you can just trim the part of the cover off that is interfering with the aluminum panel. If you have an LS7.....no, you can't just trim that. That is the actual intake manifold. You will have to trim the alum to clear the manifold. In the past, I have been lucky enough to only have to trim a small piece....just out of the aluminum for clearance....and then NOT having to trim anything out of the "waterfall" interior cover that fits between the seats. Just removing the thickness of the aluminum panel provided the clearance I needed.

[ohmygosuness]

Well.....It depends on what engine you have. If it is an LS3, and like the one in Shoeless's photos.....that very top part is a just a plastic sound deadener cover with foam under it to cover the top of the intake manifold. Yes, you can just trim the part of the cover off that is interfering with the aluminum panel. If you have an LS7.....no, you can't just trim that. That is the actual intake manifold. You will have to trim the alum to clear the manifold. In the past, I have been lucky enough to only have to trim a small piece....just out of the aluminum for clearance....and then NOT having to trim anything out of the "waterfall" interior cover that fits between the seats. Just removing the thickness of the aluminum panel provided the clearance I needed.

I have the LS2. I would assume it's similar to LS3 because they're both Gen IV. It looks identical to the one in Shoeless' photo (minus the shiny carbon fiber appearance). Also, it looks like I'd have to trim about 1/2" for the firewall to sit vertical against the car frame.

[Shoeless]

I have the LS2. I would assume it's similar to LS3 because they're both Gen IV. It looks identical to the one in Shoeless' photo (minus the shiny carbon fiber appearance). Also, it looks like I'd have to trim about 1/2" for the firewall to sit vertical against the car frame.

Go ahead and just try removing it from the engine. If similar to the LS3 it comes right off with a handful of bolts.

The black coating on the firewall you see there is a combination of Lizard Skin Sound Deadening, Heat Blocking, and then their Top Coat (just to have a gloss finish). I used this 3 step process in areas that made sense, used only the Sound Deadening where I wanted it, and then some panels just got spray on bed liner simply to be black and match.

[crash]

My recommendation...cut on the cover all you want. DO NOT cut on the intake manifold itself.

As Shoeless said, take the cover off, fit the engine, then cut the cover to fit the bulkhead.

I believe the cover acts to both insulate the driver/passenger from sound and also to block some heat from getting to the top of the manifold. I run the cover on the race car for the potential heat blocking effect.

[ohmygosuness]

My recommendation...cut on the cover all you want. DO NOT cut on the intake manifold itself.

As Shoeless said, take the cover off, fit the engine, then cut the cover to fit the bulkhead.

I believe the cover acts to both insulate the driver/passenger from sound and also to block some heat from getting to the top of the manifold. I run the cover on the race car for the potential heat blocking effect.

When you say cover, I'm assuming you're talking about the black plastic part on the very top where Shoeless have it in carbon fiber (that looks like rolls of bread).

[ohmygosuness]

So, upon further investigation. The top part of this engine that interferes with firewall is the actual manifold, not a cover. Here I thought all LS intake manifolds are the same. Thanks guys for pointing that out. That means for the engine I have, I may need to trim the fire wall.

But few more things came up.

1) One of the bolt holes on the plastic manifold is warped/stripped and I'm unable to tighten it down. Will be looking into getting a new intake manifold.

2) I was thinking about getting an LS3 manifold (so I can be like Shoeless). But from research, it seems incompatible with the LS2 since LS2 (being the oddball of Gen IV LS series) has Gen III cathedral ported heads while the rest of Gen IV all has rectangular ported heads.

3) I'm thinking about getting an aluminum intake manifold. But issue with that is louder noise and MAYBE higher engine bay temp (I'm sure Crash will have something to say about that :D).

I've also never seen a GTM using an aluminum intake. So, I'm a bit skeptical.

[crash]

I would say to run whatever intake manifold fits, as interference issues are priority #1. If you decide on a particular intake manifold for whatever reason and then have to trim/modify the firewall, so be it. Within reason of course.

[ohmygosuness]

I would say to run whatever intake manifold fits, as interference issues are priority #1. If you decide on a particular intake manifold for whatever reason and then have to trim/modify the firewall, so be it. Within reason of course.

I was a bit concerned about hood clearance with the aluminum one I've been looking at that sits 0.75" above the OEM plastic one. But after seeing this guy's ITB setup (pic below), I think I should be okay.

217976

Also, I don't have my transaxle yet. My engine is still being propped up on the rear end with a jack stand and is tilted at an angle. I won't know how much to trim until Mendeola delivers.

[crash]

I was a bit concerned about hood clearance with the aluminum one I've been looking at that sits 0.75" above the OEM plastic one. But after seeing this guys' ITB setup (pic below), I think I should be okay.

217976

Also, I don't have my transaxle yet. My engine is still being propped up on the rear end with a jack stand and is tilted at an angle. I won't know how much to trim until Mendeola delivers.

This is a significant issue. Highly recommend that you do not do any cutting until your engine and transaxle are mounted in final position. This may mean that you have no issue at all.