bryan767

iTrader: (6)

i got a sc300 with a 1jzgte not to long ago, i recently purchased a HKS hi power 170mm muffler. iv heard rumors that and stories supporting both sides of the question.

the question is:
is it safe to daily a 1jzgte - stock twins, stock boost - with a straight 3inch exhaust or does it need the back pressure from the cat?

some people say i need the cat to give back pressure to the turbos so i dont blow the seals. yet, i hear from other people (and personal knowledge) that since its a turbo car, the least amount of back pressure the better, which means straight exhaust and no cat.

im NOT worried about it being loud, nor emissions. im keeping my stock exhaust for a reason.

please support your vote with evidence, personal knowledge and experience! thanks!

One_jZ_SC3

iTrader: (2)

I can speak from personal experience on this subject. I also have a 1j stock twins, stock boost that I drive daily(~80 mi per day). When I first did my swap I was using the stock down pipe and stock exhaust system, The good was that the car was super quiet and I liked hearing the turbo spool

I then updgraded the exhaust to a full 3" mandrel bent with magnaflow race series mufflers and the difference was night and day! The car felt alot better as far as accelloration and tires spun out the hole. The boost went from 11 psi to around ~14 psi, I also put on a hi flow cat from Magnaflow so I dont think you have anything to worry about, I hear the back turbo normally goes anyways so I have another set laying around but after 1 year my turbos are still fine

Slow_Sc3

iTrader: (1)

no cats. trust me it wont be loud! and youll love how it sounds.

bryan767

iTrader: (6)

thanks for the quick responses guys! most likely im going to go catless. but more opinions would be awesome!

and should i keep the stock Downpipe or should i get one made at the same time i do my exhaust?

3000

Upgrade the downpipe. It'll unleash some more hp.

bryan767

iTrader: (6)

nice, i know someone who can make custom downpipes.. but hes sorta expensive. know of any brands or sites that have these off the top of your head? -im about to google search

edit: found a few on ebay.. but there to cheap to trust. and then theres 935motorsports which i saw in supramania.

Biggu

iTrader: (12)

do straight pipe. i did and i enjoy it. I think i picked up about 50 HP from just doing an exhaust alone. I can probably find the dyno sheet if you dont beleive me.


http://www.youtube.com/watch?v=4fTWfDhOOlY

GSXRMack

iTrader: (3)

Hey Biggu,

Do you have a new Y-pipe or how is yours set up?

bryan767

iTrader: (6)

nah i believe you.. the sc300 exhaust is sooo restrictive. and like sven said did you get a new y pipe?

SH_JZZ30

iTrader: (1)

I'm running no cats or resonators. 3" from the turbo back to where it splits then 2.5" piping to the mufflers. All mandrel bent. Sounds great and feels even better.

Biggu

iTrader: (12)

im running stock y pipe and down pipe still, from what Ive seen the ct12a turbos like the restrictive nature of the y pipe. From what Ive been noticing is that people that have replaced their y pipe with an aftermarket one blew their turbos 2-3 months later. with the stock y pipe and down pipe its more than enough power. Granted my car is running on an AEM EMS ive been making good power with them.

bryan767

iTrader: (6)

i think i might just do a Downpipe back exhaust.. i keep hearing that the ct12a's are sooo picky and what not, so im going to keep the stock y pipe and downpipe.. plus thats one less thing i gota buy hah.

OneJay

iTrader: (14)

I have 3" exhaust with one cat and I think it sounds and performs pretty decently. I did the 935 y pipe, and I didn't really notice too much of a difference on the butt dyno, but then again, I don't really drive my car too hard to begin with. I'm going on about 6 months with the y pipe, and my turbos seem to be holding up fine.

GSXRMack

iTrader: (3)

Cool deal, I will be on an Emanage Ultimate when I get back and a 3" all the way out, maybe a magnaflow or something.

Still debating on the Y-pipe. getting a spare turbo when I get back so might have to try it out. I do drive mine hard every so often but mostly a commuter.