My H/C C5 put down 395/376 yesterday on the dyno. They said my injectors and exhaust is a big restriction, so I need some help from you guys with the exhaust. Here's the setup right now:

- TPIS headers that are 2.75in out with the same diameter flange
- They bolt into a 2.5in flange on the midsection
- No cats but a 2.5in magnaflow xpipe next to the headers
- A 2.5in pipe goes to my Z06 exhaust.

I am going to keep my headers, and I'd rather keep my z06 exhaust since it sounds exotic. But it looks like I'm going to end up with some Borla Stingers since they flow the best. I don't like how they sound, though.

My friend built a custom exhaust for his firebird and went full 3in all the way. I've been looking at muffler solutions for vettes and I can't find out the size of the over-axle pipes on any of them? I want to go with a 3in midsection since that would give me room to grow with my headers; plus 3in xpipes are easier to come by:

- TPIS headers 2.75in flange that bolts into a
- 3in flange with a 3in pipe that's welded to a
- MTI 3in xpipe that's close to the headers
- Then a 3in pipe with a 3in flange that's bolted to the catback over-axle pipe
- what exhaust???!?

Wouldn't this be a waste if I had a 2.5in over axle pipe? It's fine if it's a 2.75 inch.

Are the stingers 2.75in?
How about the z06 exhaust?
What do you guys think about the 2.75 header out to a 3in midsection?

 

with 400 RWHP I really doubt the exhaust is restricting you. I ran 514 through stock mufflers

 

Going to a 3 inch catback is not going to help. What was the duty cycle on the injectors, and what size are they?

 

Im running 625 RWHP through Borla Stingers....Sound a little louder than I wanted but Im ok........If you are looking to go to a 3 inch all the way, expect to be louder than Borlas for sure

 

So I guess the title of this post is dictating the responses I've been getting. I didn't ask for a 3in catback, I said 3in custom exhaust and what are the pipe sizes for the z06 and borla stinger systems?

90 droptop: Stock is 26lb and duty cycle was over 100%... I want to say 115%. I'm thinking at least 32lb injectors, and maybe bigger since I plan to spray a 100-125 wet shot later.

HurricaneZ you're running a nearly 3" exhaust up to your stock catback so you've opened things up quite a bit. Mine is 2.5" so that's a restriction right there. I see gains of 10rwhp with stingers over the stock exhaust all the time on this board.

mikes99corvette: I am a little worried about the sound level with the stingers, but it's not a daily driver so it might be okay.

So the question still is how big are the over axle pipes on the stinger and z06 exhaust?

 

Bigger inj. have nothing to do with running a wet shot. I think the point we are trying to convey is that a bigger exhaust is not going to help at the power level you are at.