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I am finally putting the exhaust on my GT. I have read alot of threads about this and I was wondering 2 or 2 1/4? Muffler and resenators?Side pipes where can you get them and how well do they work?I have a 32/36,pacesetter header,and intake manifold hogged out.Also I belive I have performance cam.This is the last to do before I can paint.Any help would kick a$$.Thanks Tim
 

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Usually for a mostly stock engine it is best to use 2" exhaust pipe to a non-baffled non-louvered perforated muffler of that size with a 2.5" over axel pipe.
I guess side pipes work but it is suggested that only one is to be functional and the other for show becuase it would flow too freely.
 

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pipes, mufflers

GT Tim said:
I am finally putting the exhaust on my GT. I have read a lot of threads about this and I was wondering 2 or 2 1/4? Muffler and resonators? Side pipes where can you get them and how well do they work? I have a 32/36, pacesetter header, and intake manifold hogged out. Also I believe I have performance cam. This is the last 'to do' before I can paint. Any help would kick a$$. Thanks Tim
jordan said:
Usually for a mostly stock engine it is best to use 2" exhaust pipe to a non-baffled non-louvered perforated muffler of that size with a 2.5" over axel pipe.
I guess side pipes work but it is suggested that only one is to be functional and the other for show becuase it would flow too freely.
As Jordan said, you still have just a slightly modified engine here, driven primarily on the street. The goal is not "ultimate HP" production, but rather a nice broad band of usable torque. The idea here is to keep the exhaust velocity high to enhance torque.

2" pipe back from your header adapter and following the original exhaust pipe routing is your best bet to achieve this. For a front muffler, I would instead recommend a short 2" in/out "turbo" style muffler and then just continue with 2" pipe over the axle to either a twin pipe resonator or just straight out to twin tips.

JCW sells a really nice, 13" bodied "Turbo" muffler for about $20 with various in/out pipe sizes. I've used this setup on several of my GTs and it works! You can probably source something similar from your local muffler shop, though maybe not as cheaply.

Side pipes complicate routing and mounting tremendously and deter performance somewhat because of the circuitous pipe routing necessary. Unless you just absolutely "must have" them, I would recommend against it.
 

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tekenaar- can you supply me with a part number for the turbo muffler you use from JC Whitney? I'd appreciate it- Thanks, James.
 

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Discussion Starter · #5 ·
Thanks 2" it is.I also have monza tips that I will use.JCW has been good to me so far.Thanks for the advice Tim.
 

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I did 2" with a small cherry bomb then strait pipes to the tips. Nice sounding on acceleration and a great burble on down shifts.
 

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if you want to further reduce cabin noise have the whole system bent out of 14 gauge tubing instead of 16. it will reduce the sound level dramaticly but you still will get to hear it. having that header wrapped will help too. when i had it it was teribbly loud till i got thicker pipe. Summit also sels an 11" case muffler that fits the best about $50. i belive it was a DynoMax muffler. very nice i have one my self.
 

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Tim it's kinda funny timing wise. This week I'll go ahead with a sprint knock off for Mark with mating flanges and collector to fit a GT. 1.25 mains to 1 .78 collector to 2 inch out. All tucked up short to the body.
 

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JCW 13" case Turbo muffler

gtjames said:
tekenaar- can you supply me with a part number for the turbo muffler you use from JC Whitney? I'd appreciate it- Thanks, James.
The one I use is the 2" in/out, 13" case JCW Turbo muffler, has P/N SG226316Y and costs $19.99 in the most recent catalog. This muffler has a center in/out and an edge in/out pipe . . . it's reversible.
 

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Its the 2 or 2.25 stock resonator thats hard to get.
 

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Stock GT resonator . . .

nobody said:
Its the 2 or 2.25 stock resonator thats hard to get.
If I want to use a stock GT twin-pipe resonator, I cut the inlet pipe back to ~1" remaining and weld a 2.125" ID - 1.875" ID adapter to it. You can then merely insert your 2" over-axle pipe into it and secure it with a muffler clamp. No leaks, very effective.

Hmmm . . . come to think of it, there's no reason why you couldn't take a stock resonator to your muffler shop and have the inlet tube expanded to fit the 2" over-axle pipe! :eek: Now why didn't I think of that before?!! :rolleyes:
 

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Is there any type of filler or baffling in the stock resonator that would hinder performance? becuase I have an adapter welded on mine meeting up to the 2" over axel pipe.
 

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jordan said:
Is there any type of filler or baffling in the stock resonator that would hinder performance? becuase I have an adapter welded on mine meeting up to the 2" over axel pipe.
It's just a hollow metal can, that's all. The hinderance is the size of the tubing in and out of the resonator, and the fact that the exhaust has to find its own way out the tailpipes randomly.
 

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Bob, Jordan, on Willit? there were VW type baffles in the stingers coming out of the resonator. I used my handy dandy Dremel and removed them. It opened up the stinger ID by about 1/8"-1/4" and made the exhaust note a bit louder in the process. This was on the factory original exhaust. HTH.
 

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Discussion Starter · #16 ·
I still am not sure what to do.I might run the exaust like one of my old GT's except use single tips.I also was thinking of using a 1 in 2 out like a Camaro.The only problem is that the Camaro is 2 1/4 so maybe a Riviera.I think the old setup will look good and sound good.
 

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Tim, your really making progress! Keep up the good work. :D
 

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Discussion Starter · #18 ·
I decided to order monza single tips and the turbo muffler.I figure it will work.I will put up pics once it gets installed.Thanks for the advice Tim
 

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Ok I'll spill it frst. I've been plannng a sprint knock off for a while now. I'll debut and deliver it at the next meet. Probably with some parts to go with it. A bit better flow than a sprint but all in all good for the motor. Might be worth seeing since the owner has agreed no photos, come on out to Tim's house.
 

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hey Tim, I am in the process of gathering new exhaust componenets as well and I will be installing an 11" Dynomax muffler. You will find it at Summit Racing p/n WLK17702. the diminsions will allow your exhaust to tuck close to the car for a clean appearance. Good luck on the exhaust and look forward to seeing your GT and the meet. If everything goes as planned, my GT will be there as well.
 
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