floatfisher

So after reading many old posts from 2001 I have some questions. Does the JDM version make that much more power over the USDM version considering the JDM has a 2.5 inch collector and the USDM version has 2.3/8"?

Those of you who are running the JDM version which cat are you running? Obviously the stock one wont fit.

Im currently running a stock motor with mugen intake. Maybe in a few years I might do a mild motor build...MAYBE! So is it worth the hassel to go with the JDM version or should I just go with the USDM one?

Any suggestions or advice welcomed.

Thanks

Ultraspeed DC2

I have the USDM version and yes, the part where the Bpipe mates to the cat is very small. It does taper out towards the resonator and stays big behind that. I took the Mugen Bpipe, had it cut and mated to a GReddy SP2 Bpipe and made the world of difference. I recently picked up a T1R Bpipe, which everyone seems to like, but the donut gasket section by the axle back is way small. I don't understand the big deal with the T1R setup.

Dogginator

I have the JDM version with the JDM ITR cat and the Mugen Gymkhana 4-2-1 header with a 2.5"collector. There is no taper in the B-pipe before the resonator.

floatfisher

how does the exhaust bolt up with this setup? is it a perfect fit or some modification is still needed?

Dogginator

It is a perfect fit. I did have to get the JDM header hanger.

Edit: I did have to modify the cat slightly for the secondary O2 sensor. It had a tiny, non heated O2 sensor at the outlet. I opened the hole to accommodate welding a bung for the secondary O2 sensor.

floatfisher

since the JDM cat is hard to find would u suggest a different brand to go with? One that will fit just the same.

thanks

PYITR678

I say call Random Technology or CatCo and see if they offer a high flow cat in the JDM size. Also does the JDM or USDM Mugen exhaust have a resonator in the B pipe?

mugenracer

The piping on the JDM twin loop is 2.38" also, not 2.5". I have one and have measured it so i am positive about the piping size.

Ultraspeed DC2

It has like a huge 5-6inch diameter resonator that most people would scrape.

Dogginator

The resonator is large. However, I have a two finger gap but have not scraped it in over six years. Here is a track video of me passing look near 1:26. You can see the resonator hanging.

http://www.youtube.com/watch?v=Y11l_xQQNEI#t=1m26s