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USDM Manifold with twin loop

Posted: Wed Feb 19, 2020 1:01 pm
by JZMotorsport
It's been forever since I did my exhaust. I have an RMF header with test pipe and full catback mugen twin loop. I'd like to keep the twin loop catback setup but was hoping to restore stock manifold and replace the RMF setup. Is this possible? It would be nice to have a cat back on the car as well but not sure about spacing.

Any info would be appreciated.

Re: USDM Manifold with twin loop

Posted: Wed Feb 19, 2020 1:05 pm
by aklackner
Assuming Mugen twin-loop and you're looking at keeping the Mugen b-pipe, I think you need a custom cat to make that work. IIRC the USDM cat. would be a few inches short of connecting up to the Mugen b-pipe.

An alternative would be to modify the Mugen b-pipe with larger pipe before the resonator and then you can match the b-pipe to the USDM cat length.

Re: USDM Manifold with twin loop

Posted: Mon Feb 24, 2020 9:47 am
by coolhandluke
I previously ran a Mugen TL with a JDM 4 to 1. I will try to confirm the setup details. The key items will be the cat/testpipe length, which varies off JDM and USDM configurations (header, cat, and Mugen TL.)

Re: USDM Manifold with twin loop

Posted: Mon Feb 24, 2020 4:21 pm
by jayhaire
On my old GS-R, I had a JDM 98-spec 4-1 header, JDM ITR cat, and Mugen twin loop. The b-pipe was JDM length. You'll need to confirm what length b-pipe you have.

Re: USDM Manifold with twin loop

Posted: Mon Feb 24, 2020 5:32 pm
by Stin1
This thread explains it all. Take note the 2 flange and 3 flange are larger on the jdm cat / b pipe. The photobucket pictures are distorted, but you can still see them.


http://www.ozhonda.com/forum/showthread ... ifferences