Exhaust Comparison
 

While taking some measurements of my cat back exhaust today (I have a modification in mind), I notice that the inlet and out diameters on the mufflers seemed quite large compared to most of the other aftermarket mufflers that I've come across - 3.5 inches (inlet) and 4.5 inches (outlet). I am curious to know this compares with some of the other aftermarket exhausts on the forum .

JD
p.s. Despite my penchant to be bawdy, this is not a "size matters" competition. :)

Yeah, besides its about girth, not length anyway. At least thats what the spam emails I get say... :p

What car are we talking about? 3 1/2" inlet? 41/2 outlet ? I'm all about bigger but that size is good for diesel trucks

An '02 S - 3.2 .

the 02 S stock exhaust inlets are 1 3/4" and the outs are 1 7/8" with the stainless steel exhaust tips (ornamental pipes as Porsche calls them) are 3 1/2" so on my car I went to 2" pipes coming from the headers back with 2 1/2" out plus ornamental tips. I'm a little confused with what you have there or what you want to do with it, but it sounds like it's going to be toooooo big. The new engine I'm installing in my box now (3.8 dfi S) will have 2 1/2 pipes going back with 3" coming out.

My "plumbing" runs 2.25 from the headers (no secondary cats) to the muffler inlet that gradually necks up from 3' to 3.5 at the inlet . The exit diameter from the muffler is 4.5 and it gradually necks down to about 4' at the tips . What can I say, this is how the crazy dudes at 9ff designed it. Since, they have set the top speed record for a production vehicle 2 or 3 times now, I have to defer to their judgement. The exhaust sounds great, but I'm considering ways to make it sound more aggressive. With that said, what I am trying to do is reduce the size of the mufflers by installing ones that are smaller in size and diameter. The problem that I am encountering is finding something that is compatible with the inlet and outlet diameters. If I decide to eliminate them altogether and weld in some straight pipes, I'm afraid I'll end up with something that requires me to radio Cape Canaveral before I head out on a drive !

a 3.8 S DFI motor eh? how much did that run you, and what year box do you have?

I can imagine how loud it is or would be with straight pipes. I never heard of anyone doing pipes like that. Very interesting. did you get any dyno numbers before and aft? If they are available I would like to see them. If you want more volume why don't you replace the mufflers with aftermarket glasspacks or whatever they pack them with now or maxflow race mufflers. You can get those in almost all different confiurations.

Well it was kind of a special one time deal that most likely will never be able to dublicate again. The motore was 10.5k but it's what I got with the motor that counts. all the elecronics including wire harness. I've also sunk another 4k in parts for the conversion and most likely will need another 2k-4k (if I'm lucky) to finish the project. I'm putting it in my 04 S 986 Boxster. I have a thread started over on rennlist with some pictures but I'm really just getting started (3 months) Unfortunately work interferes with my fun. :ah: Sorry Jonny for sidetracking your thread.

Believe me, I've been searching ad infinitum for a set of universal aftermarket mufflers that will fit. So far I haven't been able to find anything that matches up to the inlet and outlet diameters of my exhaust . Past dyno numbers have been positive . However, now that I've completed quite a few more mods I'm due for another visit .

How long are the transitions? It sounds like you could have them cut off, and weld on new transitions to whatever size muffler you decide to use. Without a picture, it's hard to give good advice. (hint,hint)

The transition pipes incorporate both the exhaust flanges, as well as the tips. The tips of my exhaust are not removable, but rather they are welded directly to the end of the exit pipes. With that said, it would make more sense to build an exhaust from scratch or purchase something already made. Like the Fabspeed race exhaust for example.

p.s. This is not my exact exhaust. Rather it's a file photo from 9ff. My exhaust actually has larger inlet and outlet diameters .

Yeah, I agree, either a "custom" exhaust, or buy a kit. It may be that they went to a larger core on the muffler to reduce any restriction, since they are a primary backpressure source, along with Cat's.

I am seriously considering having a skilled exhaust fabricator remove the mufflers and weld in some straight pipes in place of them . If the sound is too aggressive I can always go back .

It would be a piece of cake to fabricate a pipe to replace the pieces shown in your picture. They could replace from the flanges on, or just cut out the muffler and weld in a straight pipe to replace it, though that would make putting them back on more costly.

I still like the idea of a full size bypass pipe, with an electric "cut-out" like they use on Hot Rods. You could choose quite or loud, depending on your mood. Though they would add cost, complexity & some weight.

Any thoughts on how it might sound with straight pipes ? :eek:

Geez where is a vegan cafe when you need one.

Ya Johnny - LOUD !!! A friend of mine did just that but drives it at the track here is a link to the utube. He is the one in front I could not hear my exhaust over his.
Sounded good actually. Wait I don't have it on utube . let me edit it and post it quick and I will get back to you.

Ok here it is boxste s no mufflers no cats

http://www.youtube.com/watch?v=NVs4nGA7uAE

Wow ! That sound is ripping . Nice driving by the way. You're not the Stig are you ?