I honestly can't decide what exhaust system and header/downpipe setup I should buy. They're all so expensive and I've never worked with a supercharged car before so I don't know if it would be better to have a 2.5" or 3"

Right now, I only have the Stage 2 kit, an intake and a port n polish done on the intake mani and the supercharger. I have an appointment to get my car dyno tuned in a month and i wanted to put the exhaust and header in before I got the tune done.

Does anyone have any kind of advice as to which system would net me the biggest gains or which header/dp + catback system would work best with one another?

Even after searching through pages and pages of search criteria, I can't find any definite answers. Cant anyone give me a little advice? I'm looking for performance over sound and I want something that wont kill my wallet

 

A 2.5" catback is really the best for the SS/SC. I would only recommend a 3" if you are planning on big power (TVS or Turbo). The 2.5" will maintain excellent exhaust gas velocity while flowing very well. The best is when kids on this site put 3" catbacks on stock/near stock SS/SC's. Remember bigger isnt always better.

 

thats what I was assuming haha. Ricer tech = fail

thanks for that!

 

Here check this graph out ....

 

These cars sound pretty crappy with the wrong exhaust on them. IMO keep the cat and make sure you have a good muffler and resonator or it will sound very raspy. Get on youtube and search exhaust clips too.

 

They sure do !

 

I'm pretty sure this article is written more for naturally aspirated cars where the effects of Scavenging are more important (whereas with our engine scavenging doesn't happen). We're blown - generally speaking the bigger the exhaust pipe the better (within reason of course). I'd go with a 3" if you plan on running smaller than a 2.8" pulley, but if you're going to stay with the stage kit a 2.5 should be plenty.

My 3" catless exhaust sounds just fine (I have a magnaflow resonator and muffler). It'll only sound like **** if you go cheap and buy a crappy brand.

 

Anyone have a Megan Racing cat-back? I've been listening to tons of youtube vids, and it sounds pretty decent over my crap speakers, but wanted to get some real world opinions.

 

I have the megan racing cat back, I like it alot. I went from a 3a muffler to it, good change.

It is loud though, but it comes with a silencer.

http://www.youtube.com/watch?v=2oGMN7pbbfU

 

Does the silencer quieten it down a good bit? Restrictive?

It doesn't sound raspy at all from what I can tell on the vids.

 

Some people think the megan exhaust is ricey, but I like the sound.

About the silencer, I actually dont know, never used it before.

 

Haha, I hear ya. Thanks for the info man!

 

No problem.

 

Definatly gonna keep my eye on this post. I'm in the same boat. I want exhaust thats gonna make power but don't want it loud and to sound like crap. I would rather hear supercharger whine over exhaust anyday.

 

I want free flowing without too much noise as well. One thing I haven't seen anyone do so far is run two mufflers (other than GMPP). As long as they are straight through style mufflers, they will reduce noise without restricting flow. Anyone tried this? I've been thinking about a non-offset in place of the resonater, and an off set for the rear muffler. Thoughts?

 

i have a megan racing cat-back and i love it, the silencer makes it almost silent. pretty much how the stock cat-back sounds imo. With my mods i decided on a 2.5 inch and i couldnt be happier. but the megan racing cat-back is one of the loudest out there. be careful if you do get it, Got 2 exhaust warnings in my town for it =p

 

Nah .... that graph pertains to all types.

Supercharged cars are not as sensitive to exhaust backpressure as turbocharged cars. You really do not need a huge exhaust on a supercharged car. The blower just forces the air through the motor and out the exhaust. Which I'm sure you already knew. A 2.5" catback is really an ideal size for the SS/SC. It provides excellent flow/exhaust gas velocity, and supports good power levels. People really do not start to benefit from a 3" exhaust until they start making higher power levels (300+ Whp).

 

you could never go wrong with a magnaflow

 

well as of now I think I'm gonna go with a 2.5" setup from mandrelexhaustsystems with the maganflow muffler and 18" resonator but I still dont know which header + dp to use!

 

That chart isn't right for all applications, else it is suggesting that the ideal exhaust for our car is 2" (or 2 1/4" if you're looking at 300). I'm pretty sure a blower shifts that graph to the left, if the chart is even correct in the first place - 2 1/2" single pipe supporting 500 WHP? 3" single pipe for 700? Seriously?

But say what you will. Few people are trapping as high as I am without meth/nitrous, TVS/Turbo or cold ambient temps. I did it when it was 90* outside with high humidity. Obviously there's no way to tell if it's due to the exhaust or another factor unless I dyno my car, swap exhausts and dyno it again, but I'm pretty sure you're overestimating the amount of airflow necessary before a 3" shows gains over a 2.5" setup.

 

I never said it was ....

All I was getting at is the 2.5" has the best of both worlds interms of flow & velocity, and is more suitable for 90% of the SS/SC's on this site.

By the way that graph isn't stating it's for N/A or F/I cars. It is a graph dictating exhaust pipe flow for specific output of an engine. I never said to live by that graph, but it does show that a huge exhaust is not always needed.

 

Primarily because 90% of the SCed cars on this site don't run smaller than a 2.9". As I said in my original post, a 2.5" is adequate for most cars, but if you plan on running the smallest pulleys available a 3" will see some gains. Your posts seem to be giving the impression that you won't see gains from a 3" until you go aftermarket boost, which isn't true.

The point I'm making is that the sizes indicated by the graph aren't even close to those run in reality for ideal power. If anything it's more of a bare minimum than an ideal size, tbh.

 

Then you are reading them wrong. What I'm trying to explain to people is that a 3" on a stock/mildly modded SS/SC is over kill, and that a 2.5" will be more suitable. A stock/mildly modded SS/SC will not flow enough air to take advantage of the 3" exhaust, and in turn create eddies/backpressure thus decreasing potential power output. I really don't care anymore what people think is best on this site. Everyone always has in their heads that bigger is better without looking at the engineering aspects of flow & velocity. I can guarentee if you took your 3" exhaust off and replaced it with a 2.5" system you wouldn't feel a loss in power even though you are below a "2.9" pulley.

 

awesome thread man!

been wondering bout this myself. anyone no the size of a stock ss/sc catback?

 

2.5" O.D. piping for the most part. It necks down to 2.25" O.D. piping over the rear axle to the muffler.