What would you recomend

[1QuIcKsTrEeTcAr]

I was working with my friend on his project 97 eclipse rs and we're going to be replacing the entire exhaust (headers,catback,muffler) and he wants to buy the apexi n1 catback exhaust but i suggested getting the n1 muffler and 2 1/2" piping going to the cat, it also saves more money. But anyway, do you think the n1 with custom straight through piping will be significantly louder than the original apexi catback because this is something he's worried about. So any help would be appreciated thanks in advance.....also i forgot to mention that he does not plan on putting in a turbo if that makes a difference.

[JoeWagon]

Expensive Apexi 2.5 inch will sound the same as a custom 2.5 inch mandrel. If the muffler is just an 'N1 Style' it won't sound exactly like the brand name one.

[ashah000]

Make sure the custom piping is actually 2.5". Some shops press bend and say it is mandrel bent.

[turbo2nr]

i say 2.25" would be better for a n/a car b/c the exhaust system still needs to retain some back pressure for the motor to run efficently.. it is a n/a car not a turbo motor...
1

[ashah000]

I thought you dont want backpressure, you want exhaust gas velocity.

[turbo2nr]

n/a car need some backpressure in the exhaust to maintain their compression ratio..
1

[kjewer1]

False. Backpressure is never good. ashah000 got it right. You want velocity, to exploit the scavenging effect and pull more aif/fuel in during valve overlap. Smaller pipes increase velocity, thats physics. Increased backpressure is a sideeffect of smaller pipes. So unfortunately poeple confuse the two. Its also possible to increase velocity efficiently, meaning less increase in backpressure pre increase in velocity. Thats the whole trick... Ehxuast backpressure has no effect on comrpession ratio.

[ashah000]

http://forums.2gnt.com/dcboard.php?a...7337&mode=full
http://forums.2gnt.com/dcboard.php?a...7216&mode=full

Just a few that I found that say that backpressure is bad. I am not really sure on this. Can someone set this straight
Edit >>> Thanks Kevin.

[scottsee]

im my opinion, the only back pressure you should ever have is durring doggy style.. =)

[1QuIcKsTrEeTcAr]

So basically, getting a custom mandrel bent or just the factory N1 exhaust systems will sound the same? Also what is the diameter size for the factory N1 piping?...Thanks for the replies

[ashah000]

check on google... i think it is 2.5 for the NT exhaust.
Then the one for gst is 3" which will fit on the NT

[turbo2nr]

well i dont noe if back pressure is that bad i got my info from my friend with a 9sec track chevell.. with a big v-8 i dont know the displacement on it all i know is htat the car is fast and he built it him self and races it him self..
1

[1QuIcKsTrEeTcAr]

Isn't 3" piping for an NT eclipse pointless considering there's no turbo?

[Julioluko]

yeah buddy you dont need 3.0, go 2.25 or even 2.5, no higher in my opinion.