canelo pr

I have a 90 gs and the previous owner install a custom exhaust (2 3/4)inch and im looking for a new exhaust but i want one looks like factory. I know tanabe and rs-r have one but is 60mm .my question is which one is better and if i go ls/vtec the size of the pipping will it affect the performance or i should make a custom 2.5 .thanks h-t

dschenke

i would say 2.25" if daily driver n not very built, but if built 2.50" to big exhaust wuld hurt u

be18see1

what? you guys really don't know how hard it is to read these posts. I have a 2.5" on my gsr and it lost some bottom end power but it really opened up the top where my stock 2" exhaust had restricted it.

dschenke

reason it loss lowend power cuz there wasnt enough back pressure

majinsoftware

Lol back pressure.

Any kind of back pressure on NA is bad. Real reason it lost power is because theirs not enough exhaust velocity.

When building a tuned exhaust you want to aim to keep the velocity of the exhaust gasses up while keeping the back pressure down.

I cant tell you the correct size with out having your car on a dyno and flow meter.
But generally 2.25' is a good size for 1.6L-1.8L with power range between 5-7K rpm.

If your revving to 10k id suggest you go for 2.5' as that will keep good power from 7-9k.

But for daily driving and auto cross 2' will be the best and keeping power around the 3-6K which is your main driving revs.

These are with properly designed exhaust systems tho. Not just some backyard best guess or to fit job.
And if its just a cat back system your making dont even bother. Get the whole thing done and done right the first time.

tilegend

i can't believe the whole backpressure thing is still being thrown around...

jesterjess

MS really knows his $hit... I agree with him 100%, it seems that I just read that yesterday in a great Honda Horsepower book.... Good work!

+1 2" - 2 1/4"

racebum

this is true and 2.25" will support a 1.8 above 7k as long as it isn't crimped bringing it back below. i can't believe people still talk about backpressure LOL. think that through. has would pressure the motor has to work against in any way create power?

majinsoftware

Yeah it works above 7K but flow velocity wont be optimum. You would be losing at most 1HP over the 2.5' but its worth it to have the extra power down low where your likely to use and need it.

sirbikealot7

finally someone knows thier ****. back pressure doesnt matter, you need to keep velocity up to maintain power

canelo pr

so who makes a 2.5 exhaust and $$$ or i should make a custom 2.5 because the problem that i have right now is the exhaust is too loud its almost 3 inches and im looking for one that looks factory and which one is better tanabe or rs-r. im sorry im new on da's and i notice they don't make that many parts for us . but thanks h-t