Those of you that have cut the stock pipe off the muffler and welded on a larger one. Doesn't that pipe run all the way through the muffler to the back where it's again welded? I'm just wondering how flow is increased when this pipes diameter can't easily be changed.
I'd like to get a 2-1/2" pipe welded on but I don't see the point if it's just going to be reduced to stock inside the muffler.

I'll take your 2 cents for a penny for your thoughts.

Thanks

 

does it add hp?

 

If done right I would think close or as much as any other aftermarket one. Also it's quieter and I already own it.

 

Getting a 2.5" exhaust and keeping your stock muffler is ideal. You'll gain power and keep your exhaust from droning. The stock mufflers are very very good. You'll lose 1-2 hp by not getting a straight through muffler.

 

I may just see if I can get one cheap enough from a junk yard to cut up and see if it's possible to run 2.5" all the way to the back of the thing.

 

It is possible

 

Although I have the HKS rear section running 2.5" axle back to the stock muffler is quite simple in my eyes. Basically remove the stock muffler assembly and take it to a shop to have them measure it out and get a look at what bends are involved. Once that is completed hack off the little 1.70" ID stock muffler piping and find a way to dremal the hole to a little under 2.5". The only other stel after that is welding a flange to one end to connect to the b pipe and having the other end welding the the 2.5" opening to the muffler. Hopefully this is understandable if not try getting in touch with .org member Larry b/c he is one that has done this mod.

Matt

 

So it seems that the majority of the noise from exhaust upgrades comes from the straight through muffler?
Do resonators hurt flow?
If the stock muffler's left in place, what's the best size piping for an N/A bolt-on car to keep it quiet. 2.25? 2.5?

thanks for any info