exhausting question :p

I want to get an exhaust on my car. there are no slp or whatever exhaust systems available here on the market so basically i'm gonna get a shop to do all the piping and just add a flowmaster muffler and cat on it. Now, is a 3.00 inch exhaust just as good as a 3.5 inch exhaust for my stock z28 or will there be much difference?
Also, the biggest diameter performance muffler i can find is a 3.00inch from the flowmaster 80series, so if i put on a 3.5inch exhaust and had it going into a 3inch muffler at the back will this restrict or cut horsepower or would it be better than just having a 3 inch exhaust all the way through?

I want more power and more noise out of the exhaust basically. Thanks for the help in advance. Oh, and will the power gain be noticeable down low in the 0-100kms range or will it be mainly more noticeable on higher speeds on the highway? thanks again.

going from 3.5 to 3 will restrict the flow more than if you just had 3" all the way back...

what about going from 3 to 3.5, but yea i say go 3 in all the way, or after the muffler go with 3.5

Going from 3 to 3.5 would only reduce the velocity of the exhaust and thats not what you want. Put on 3" all the way back to keep your velocity and flow consistant, 3.5" is too large for a stock z anyways you would only lose power with it.

yup, contrary to popular belief you do need a little backpressure in the exhaust, dont believe me, have an engine dyno'd without any exhaust on it, then dyno it with headers, pipes, and mufflers, youll pick up more torque and a few more ponies. but my suggestion, especially for a stock engien, is the 2.75 - 3in piping. i wouldnt go more than 3in, no need to, unless you drop a 572cid engine in there running a huffer, then there is a 4in system you can buy, but its pretty unnessesary ni my opinion.

yea, i agree, small block rely on backpressure, 4in is huge, they have those 4in kits for the desiels

now i have a question since i plan on getting a crate 350 crate motor would 3.5" straight back be good sionce im gonna be pushing 420 hp and 450 foot pounds of TQ?

3in would still handle that just fine, i mean if you really want 3.5 i dont think that would hurt you or anything, but 3in is about as big as anyone driving a street car would need. but thats just my two cents, maybe drop flowmaster or someone like that a line and get their two cents on the matter.

thanks for all the replies guys. I'll go with the 3 inch then. I'm surprised though that you say if it goes any bigger than 3 inch it could actually lose hp. i thought the less restrictive the better, but i understand that for a street car 3inches is all that is necessary. thanks for all the help.

Oh by the way, will it be much louder than it is now? I currently just have the stock exhaust with a flowmaster muffler, but what i'm getting is the 3inch exhaust with the 80series flowmaster. will it be noticeably different? oh and will it give me power i can feel low down or just extra power on the higher speeds? thanks guys.

o yea it will sound louder, i think the loudest muffler flowmaster has is the 40 series, im puttin it on mybronco, i jus put some mustang headers on it yesterday, now i gotta get a y pipe and tail pipes made, you could go with 3 1/2 in tips, me im going with chrome 3 1/2 in or 4 in tips

you guys ever seen those restored late 40s early 50s hot rods that have like 1" tips. now thats what i call back pressure!!

haha, hondas have them

yeah but they great for flamethrowers, nice blue torches with them little tips, bigger tips make fireballs :)