2.5 or 3" exhaust, what muffler?

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CanadianR

Member
A friend works at an exhaust shop, and has said that he can fabricate an exhaust setup in either 2.5" or 3" from right off the turbo.

Would be straight through off the turbo, until the muffler at the back.

questions would be, what size piping would be good, and what muffler would you guys reccomend? not to be loud as hell, but to be a decently low rumble.

Stock GTiR, stock everything. anything important about the o2 sensor around the cat converter? (wont be having a cat in this setup).
 
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CanadianR

Member
so 2.5" is good without a tune. 3" almost "requires" a tune then? Just building it to make it as efficient as possible.
 
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a11ova

Guest
I run 3" elbow, downpipe, and full system with de-cat on mine. Also have tubular manifold which all seems to work a treat
 
O

oap-r

I love Rob xxx
Jeddeh said:
not to be loud as hell, but to be a decently low rumble.
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Then you need to buy a car with a V8 :lol:

Turbo'd inline fours sound $hit no matter what size of exhaust you put on.
 
C

CanadianR

Member
update. got quotes again from muffler shops as my friend is just too busy to do mine supposedly. got quoted 1800 bucks canadian to do from the turbo to the cat.:der:
That was from the shop that would even quote me. The second shop I went to took one look at it, said, "that car didnt come here in North America" (obviously not since it was imported from Japan ya bonehead:doh:) and then said that he couldn't get me a quote, just straight time and parts.

So I'm wondering what other members have on their cars for exhausts. Any brand name stuff like Mongoose or 5Zigen or anything? Or do most people go custom exhaust? what have you guys used?
 
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youngsyp

New Member
JPWard is doing a group buy on 3" elbows and downpipes at the moment. You could go for one of these and get the shop to fabricate a downpipe back system. That would be extremely simple and shouldn't be too expensive.

As for box design, a transverse rear box with the tail pipe exiting on the other side to stock would give you decent sound levels.

You could try what I have and that's a silenced decat pipe (fairly large silencer, about as big as the cat was) and a small inline rear silencer. The noise level is not to bad but, it's pretty un-restrictive.

To get the low/deep tone, you'll need a resonator or 2 in the pipe run. The resonator in my system is just before the pipe goes over the rear subframe.

As for sizing, I have a 3" elbow and downpipe narrowing to a 2.5" system after the flexi joint (a custom job). This works very well and gives excellent turbo spool up and throttle response too.
 
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youngsyp

New Member
Jeddeh said:
what is a transverse box?
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Like the OE exhaust, a back box (muffler) across the back of the car, parallel with the rear bumper.
This would follow the lines of the original exhaust but, exit on the passenger side rear, instead of looping back round and entering on the drivers side, like the OE system does.

Look for Campbellju's exhaust pics, that's the design I'm refering too.

It basically gives you as large a rear box (muffler) as you could get, to help keep sound levels down.
 
Trondelond

Trondelond

Active Member
youngsyp said:
As for sizing, I have a 3" elbow and downpipe narrowing to a 2.5" system after the flexi joint (a custom job). This works very well and gives excellent turbo spool up and throttle response too.
Click to expand...
Revival of old threads! I was wondering about this, since I've now got a 2.5" pretty much straight pipe from the elbow back. I've ordered the 3" elbow/downpipe, and I'm thinking to myself that the exhaust gases will cool off through the 3" pipes, thus reducing the need for 3" all the way? If I lag the 3" exhaust as well, would I really be needing the 3" exhaust all the way?
 
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