tCjosh

iTrader: (8)

Sorry if this is a stupid nu-b question, but is there any midpiping system (w/ high flow cat and/or resonator) out there that would bolt on to the trd axle-back exhaust??? Even though I know that the trd axle-back exhaust doesn't give any hp gains, I just don't want to get rid of it if I can get a midpiping system that could bolt on to it...I have searched and found nothing...



Thanx!!!

Josh

05TXFM

iTrader: (1)

http://cgi.ebay.com/ebaymotors/SCION...spagenameZWDVW

Found this on Ebay

They also have other ones
http://stores.ebay.com/TruBendz-Tech...QQftidZ2QQtZkm

mr_speedvision

I contacted Josh at Trubendz heres a link to his reply https://www.scionlife.com/forums/viewtopic.php?t=133037

TCpete

if your going n/a i suggest 2.25 and not 2.5. something ive learned from alot of experience with pipe size.

sp0t

^i was suggested the same... more airflow but the whole backpressure thing comes into place. 2.5 is really for F/I cars... maybe im just talkin out of my a$$ but that's what i was told. that's probaby why our cars gets so raspy

senseiturtle

It has less to do with backpressure as it has to do with velocity.

Smaller piping = faster exhaust velocity, but if you get too small, the engine has to push it through, robbing you of power.

larger piping = easier for engine to "push", but velocity goes down very quickly. The gas has time to cool off in the piping, getting more dense, and again, making the engine push.

Perfect sizing would allow evacuation at a constant velocity from the time it leaves the chamber to the time it leaves the piping. 2.25 is fine for N/A small-engines... 2.5-2.75 for V8's... and 3-inches for 18+ psi turbo motors.

pimptc

i might be wrong on this, but isnt stock exhaust already 2.25? i have 2.5 but do you reccommend going to 2.25, i have the megan header and s-pipe dont know if that matters

mr_speedvision

Well I contacted Josh at Trubendz about 2.25" exhaust. He said that he has not had any requests for anything other than 2.5". He went on to say that he would need to make new jigs. The only way he can substantiate the cost of a new fixture is if he was garaunteed to sell 20+ of the 2.25" system. So here is my question. With a cold air intake and header will I increase the airflow through my engine to the point where 2.5" would be the best choice? From the info I could find optimal exhaust piping for a 2.4 liter is 60-70mm. 60-70mm is 2.36"-2.76". Now granted I don't drive a 240hp 10k reving drag car. Stock exhaust is right at 2.13" up to the mufler and 2.45" to the tip. So just over 2 1/8" and just under 2 1/2". So an increase of roughly .375" in diameter is 1.36 cubic inch per inch of tube. And an increase of .125" would be .43 cubic inch per inch of tube. So ugh yeah... I guess i need to look at this more and see the cfm gain... I have to go to work now...

senseiturtle

I think 2.5 inches would be fine.

- We do have 2.4 litres of displacement, which is a good amount more than a lot of 1.6-1.8L civics who run 2.5 inch piping.

- The power differences between "perfect" sizing and "pretty damn close to perfect" are simply not enough to justify too much heartache. I'd just buy what you're comfortable with.