Lately Ive been looking into the mugen twin loop, but I have a few questions? Does Mugen still make a USDM spec ITR exhaust (2.25 diameter) if so I definitely want to avoid that. The one that IPS Racing and Kingmotorsports sells is the one that will work with jdm 4-1 header and the carsound cat which I already have (this would be the 60.5mm version which bolts up pretty close in diameter to the 2.5 in. carsound cat)...
Ive looked at all the archived posts and noticed people talking about differences in B-pipe length...If I ordered the twin loop from IPS would it work with this setup?

 

There is no USDM spec diameter or JDM spec diamter. They are all 2.3x" in diameter.

The difference in USDM spec vs JDM spec is that USDM one has shorter b-pipe length, where as JDM spec one is a bit longer.

With your setup (JDM 4-1, ITR carsound cat), USDM one will just fine, as long as your ITR carsound cat was designed for a U.S. application.

-Sean

p.s. see sig.

 

it will work, but i believe the mugen twinloop is 2.25"

 

If you click on the pic at Kingmotorsports website it says that its 60.5mm, which is 2 3/8 correct?

 

Correct. 60.5mm. I haven't measured it though.

 

60.5mm is 2.38"

 

Isn't the Mugen smaller for the length of the tubing before the resonator? I've been told it stays pretty small until it finally becomes 60.5mm once it exits the resonator. Any confirmation?

 

The pipe leading to the resonator is smaller - just over 2". This is to assist in warming the catalytic converter and to provide some backpressure.

The Mugen exhaust is good for over 200 whp btw. Of the exhaust that sound great, it's probably the quietest.

 

Why would they want it to produce backpressure on purpose? Is it just an emissions thing?

 

I'm pretty sure the only difference is the B pipe length

Its a great setup for a high horsepower NA application

JP


[Modified by HondaJon, 3:36 PM 1/28/2003]

 

This is why I had my Twin Loop modified. I replaced this section with a new 2-1/4" section and opened the resonator to accept the larger pipe. The other end was opened up to 2-1/2" for a perfect fit to my hi-flow cat.

The Twin Loop also has a tapered section right before the cat with an I.D. less then 2".

Still, without modification the Twin Loop is still up to some serious power.

 

Are you all saying that the Mugen twin loop + 4-1 header will get me a little more than the 168 "weak sauce" whp I have at the moment? Now that I've decided to keep the ITR in favor of the M3, this seems like a pricey, but worthy power alternative without sacrificing reliability.

 

I got 185ish whp with intake, header, exhaust, timing and more fuel (via fuel pressure riser)

 

Nice numbers! Which intake?

 

I can't remember - it was around the time I switched from AEM to Mugen. But I think it was with the AEM CAI.

 

Yeah...okay...lost ~15whp midrange and over 10 whp peak on a 2.0L with the Mugen exhaust.

 

Depends on your definition of "high horsepower"... Like BPR said, the Mugen exhaust is good for over 200 whp. If you have a 2.0L, then no, you wouldn't want the Mugen.

 

i have a 2.0 (B20+PR3)...i was planing to get a Mugen TwinLoop SI backaxle and custom 2.25 mandrel bent...this would not be good..??????

 

You're better off with a 2.5" system from header back

 

Does the twinloop have any bottlenecks out of the box?

Why not go with a 2.5 bottleneck free system like SMSP?

JP

 

See above...

 

Good question, but SMSP's not JDM y0!

 

Correction:

It's not JDM
It's not <u>quiet</u> (at least not compared to the Mugen).
The exhaust you choose isn't going to have a big effect unless you are making over 200 whp.

If your car is only mildly tuned/modded, you are better of basing an exhaust purchase on characteristics such as quality, fitment, ground clearance, and sound since they all perform so similarly. Get whatever floats your boat.

 

The pipe just after the cat and before the resonator is 54 mm. OD.
Replace it with a 60.5 mm (2.36 incs) OD and will be fine for 200/210 whp application.
But for a 2.0 lt. go for a full 2.5 exaust.

 

I beg to differ, a 2.5" full exhaust system made a pretty good improvement on the dyno on my otherwise stock R over my old 2.5" header/2.25" exhaust system. About 5-10whp over the entire powerband without any tuning. I'm not making 200whp yet.

I'm a believer in that parts should be chosen to work correctly with one another. With 2.5" headers on Type R's I have never seen an instance where a 2.5" exhaust wasn't beneficial over a smaller 2.25"-60mm exhaust.

Of course there are other factors but as far as performance is concerned when mating an exhaust up to a 2.5" collector header and cat I'd definitely have to give a nod to the SMSP full 2.5" system.


[Modified by SurferX, 8:21 PM 1/28/2003]