exhaust set-up

[2fast_crolla]

i'm thinking of setting up a new exhaust but don't want to go full 2 1/2" piping, so i have a idea and would love some feed back.

the plan is to remove the cat all together, run 2 1/4" down to the axel and then go 2 1/2" from there to the muffler pan.

i just want some feed-back on what u all think the + and - r gonna be with such a exhaust.

[Jeff1018]

well if you remove the cat all to gether like you said and you get busted by the poe poe then you will be fined atleast $15k i heard and thats not worth it....

[Suprathai]

For the gains involved, which in such a modern day car is very close to zero, its really not worth it. Also what engine is this?? 1zzfe or 2zzge?

[bozurolla]

Recommend only using 2 1/4 tubing & cuple of stops or resistance points in between before ur own choice of muffler in the end,Using a 2 1/2 system from experience there was no back pressure & a noticable loss of power,Ide wouldnt remove the cat,By law its there for a reason & it also acts as resistance in flow,which is needed in a good exhaust system,the step up in sizes ive never seen been done before so no input for that..good luck

[2fast_crolla]

For the gains involved, which in such a modern day car is very close to zero, its really not worth it. Also what engine is this?? 1zzfe or 2zzge?

well it's a 05' runx z i got from japan.

fitted with the 2zz engine.

as for removing the cat, have been told not to.

the exhaust is made by rsr.

[CAP]

Where do you live ?

[2fast_crolla]

i'm in Jamaica.

1 note i 4got to mention, i'm gonna run thr pipe practically straight, with only 2-3 bends to stay in the channel, and to give the muffler that "kick" to the side.

will post pics as soon as it's done.

[selyaT]

well if you remove the cat all to gether like you said and you get busted by the poe poe then you will be fined atleast $15k i heard and thats not worth it....

Hahaha poe poe, love it :D

I wonder if the emissions laws are the same in Jamaica....?

[SILVABULLIT]

Go 2.5" from the cat back with about a 16" long resonator and a nice free flowing chambered muffler and you're in business. Good gains to be had but just be carefull of what muffler you use on the rear as that can affect power gains/loss a lot.

[51EKA]

bozurolla.... Who told you that cars need back pressure?

2zz-ge will benifit from 2.5" mandrel bent exhaust. As free flowing as possible, but that means it'll be really noisey too. What is hard is that, making it nice and simple, no crazy 90degree bends, no "u" bends. Basically as straight and as short as possible. If you have seen the trd kazuma race exhaust designed for 2zz celica. You'll understand what you need to get the most power from the exhaust.

No cat will gain you 2-3hp max. Does the runx have a secondary o2 sensor?

[2fast_crolla]

bozurolla.... Who told you that cars need back pressure?

2zz-ge will benifit from 2.5" mandrel bent exhaust. As free flowing as possible, but that means it'll be really noisey too. What is hard is that, making it nice and simple, no crazy 90degree bends, no "u" bends. Basically as straight and as short as possible. If you have seen the trd kazuma race exhaust designed for 2zz celica. You'll understand what you need to get the most power from the exhaust.

No cat will gain you 2-3hp max. Does the runx have a secondary o2 sensor?

no, only 1

[bozurolla]

bozurolla.... Who told you that cars need back pressure?

2zz-ge will benifit from 2.5" mandrel bent exhaust. As free flowing as possible, but that means it'll be really noisey too. What is hard is that, making it nice and simple, no crazy 90degree bends, no "u" bends. Basically as straight and as short as possible. If you have seen the trd kazuma race exhaust designed for 2zz celica. You'll understand what you need to get the most power from the exhaust.

No cat will gain you 2-3hp max. Does the runx have a secondary o2 sensor?

Im speaking in exhaust fitting terms lil fella sorry,Mines(1zz-fe)is custom made primarily(well was) made for semiracing specs ,as its still a daily driver ive kept the cat,ive personally made exhausts for 3SGTEs,V8s & WRXs,all differ from cat/No cats ,The point i was making its does need back pressure ,its not a huge amount enuff for u to feel the difference,but enuff to equalise itself pressure wise in the system,it does matter wat muffler u install in the rear ,a baffled or chambered muffler is recommended (cheers silva)

pls dont confuse

[CHA54]

if you want to see what happens when you have no backpressure on a NA car, take your exhaust off from the headers back and go for a drive.

You will probably be suprised at the MASSIVE loss of low to midrange power and torque.

[SILVABULLIT]

bozurolla.... Who told you that cars need back pressure?

2zz-ge will benifit from 2.5" mandrel bent exhaust. As free flowing as possible, but that means it'll be really noisey too. What is hard is that, making it nice and simple, no crazy 90degree bends, no "u" bends. Basically as straight and as short as possible. If you have seen the trd kazuma race exhaust designed for 2zz celica. You'll understand what you need to get the most power from the exhaust.

No cat will gain you 2-3hp max. Does the runx have a secondary o2 sensor?

Im speaking in exhaust fitting terms lil fella sorry,Mines(1zz-fe)is custom made primarily(well was) made for semiracing specs ,as its still a daily driver ive kept the cat,ive personally made exhausts for 3SGTEs,V8s & WRXs,all differ from cat/No cats ,The point i was making its does need back pressure ,its not a huge amount enuff for u to feel the difference,but enuff to equalise itself pressure wise in the system,it does matter wat muffler u install in the rear ,a baffled or chambered muffler is recommended (cheers silva)

pls dont confuse

Drop CES an email mate as they will be able to help you out with specifics. :D