Exhaust Banging

[Kozeyekan]

Hey everyone

I've installed a 3 inch turbo back HKS silent system, and going downhill, it's all sweet, but uphill it bangs against the chassis just near the B pillar. Just wondering if anyone else has had this issue, I was thinking of getting a brace fabricated somehow, but am not sure where to attach it. I might need to go to a workshop and have them do it, but I was just wondering if anyone else has come across this, or is it just one of those things?

[Godzilla32]

Hey everyone

I've installed a 3 inch turbo back HKS silent system, and going downhill, it's all sweet, but uphill it bangs against the chassis just near the B pillar. Just wondering if anyone else has had this issue, I was thinking of getting a brace fabricated somehow, but am not sure where to attach it. I might need to go to a workshop and have them do it, but I was just wondering if anyone else has come across this, or is it just one of those things?

Why does it make a difference if your going up or down a hill? The exhaust hangers/rubbers should be holding it secure enough that it doesnt move so much to hit any part of the car. Id be checking that you have hooked all them up first and all the rubbers are in good condition before making any mods to the 'bolt on exhaust'...

Deren

[cowie165]

Are you sure the exhaust bolts are still tight? If they weren't torqued correctly perhaps one or two have loosened enough so that there is a little play in the dump->front section? On downhill it rests against itself but uphill it is just hanging and banging around as the car goes over bumps etc.?

I'd doublecheck that everything is tightened, and as Deren said, hangers are on and ok, before coughing up your hard earned for a brace. If it is on right, it shouldn't need an extra brace.

[RANDY]

Might want to check that whoever fitted it used the factory hangar for the cat. There is an upside-down U shape that is bolted around the B-pillar. That goes on the outside of the cat, and the bolts that hold the cat to the dump/front pipe run through the holes in this hangar. It takes the weight of the dump/front pipe off the turbo, so if it's swinging around then i'd guess that it's not there, or not done up.

Check it, cause without it you can warp or crack your turbo flange or exhaust manifold. (whichever breaks first I guess)

[Kozeyekan]

Hey guys, thanks for the advice, but:

The bolts are tight. Damn tight.

All the rubbers are in, the two at the rear, and the one on the side. The brace near the cat is on, and I might be able to adjust it enough to clear the b pillar brace. I'm giving it a go tomorrow.

The problem is that the b pillar area is a fair way from the cat. I was really hoping I'd missed a mounting point somewhere around that area that would bring it down about 2 cm, but apparantly not.

[MANWHORE]

yep, happened on my car.

I just got the exhaust shop to make a cut in the pipe and bend it, then reweld it. Problem solved. You should have about 10mm between the exhaust and all other things, otherwise it will hit.

[Godzilla32]

I wouldnt be modifying an exhaust that is mean't to fit perfectly without any changes myself. Defeats the whole purpose of buying the bolt on exhaust option in the first place... There has to be another explanation for why its knocking on the cross member or watever its hitting.. It can be hard to see without a hoist and getting under it properly and checking from all angles.

[Kozeyekan]

I wouldnt be modifying an exhaust that is mean't to fit perfectly without any changes myself. Defeats the whole purpose of buying the bolt on exhaust option in the first place... There has to be another explanation for why its knocking on the cross member or watever its hitting.. It can be hard to see without a hoist and getting under it properly and checking from all angles.

Yeah, I jacked it up and checked it all out.

The cat brace is kosher, the problem seems to be the rubbers.

They are about 2 inches long, and should be about 3. This would allow the exhaust to drop a bit lower, but the solid rubber would prevent the rebound which is causing the knock.

I'll check out some suppliers and see if I can organise these, Has anyone else had anything like this before?

[mad082]

i have the problem with the exhaust hitting on the tub when i go around right hand corners. i found it was the front pipe twisting on the dump. also the fact that it is a 3.5".

[Kozeyekan]

i have the problem with the exhaust hitting on the tub when i go around right hand corners. i found it was the front pipe twisting on the dump. also the fact that it is a 3.5".

I've got a solid front/dump pipe in one.

It does seem like it could move to the drivers side though. I'm going to try the rubbers, if that does not work, I'm going to have to cut a wedge out of the pipe and reweld to improve the angle.

[mad082]

is it banging sideways or up and down?

i also just remembered that we cut a bit out of some of the other mounts under that car (not the ones that hold the exhaust) so that the centre muffler wouldn't hit.

[MANWHORE]

It's not as simple as you said. Of course the catback is supposed to bolt straight on. Mine did.

But when you start changing things upstream, like the cat, dump/front pipe, they can move the position of the catback slightly.

It moved mine about 1cm. If you think about it, the slightest difference in angle can move the catback quite a bit, since the catback is so long.

That 1cm was enough for it to bang.

In a perfect world, yes, everythign bolt on won't require mods. But, as i'm sure you're aware if you try and install things yourself, nothing ever 'bolts straight on' e.g. take a fmic kit as an example.

Cheers

[Kozeyekan]

It's banging up and down, so I can either make up a bracket to keep it low (I already have about 2 cm clearance) or get newer, stiffer rubbers that are a little longer.

[Godzilla32]

It's not as simple as you said. Of course the catback is supposed to bolt straight on. Mine did.

But when you start changing things upstream, like the cat, dump/front pipe, they can move the position of the catback slightly.

It moved mine about 1cm. If you think about it, the slightest difference in angle can move the catback quite a bit, since the catback is so long.

That 1cm was enough for it to bang.

In a perfect world, yes, everythign bolt on won't require mods. But, as i'm sure you're aware if you try and install things yourself, nothing ever 'bolts straight on' e.g. take a fmic kit as an example.

Cheers

Yeah clearly it comes down to compatibilty of various parts made by different companies.

Deren

[Kozeyekan]

Well, the cat back is an HKS hipower silent, made specifically for the HNR?HCR-32, but the front/dump and cat were from BOS group buy. It seems all sweet, but I guess it's out by a few mm. Not that I'm complaining, the pipe looks fantastic, and is well made, it just means I'll have to fabricate a bracket, or find some way to make it work.