BTW: I think the X pipe is flow based, whereas the H pipe is sound/pressure wave based (like the S3/S4 intakes have).

I thinking about on putting another balance pipe just before the first bend of the rear exhaust, for sound. This would mean making a new clamp joint at the resonators.

Further on I would like to replace the stock 2¼" pipe from the X to the big resonators with 2½". (The resonators have ~2½" pipe through them.) The last bit of pipe doesn't really matter, as the gas has cooled and condensed. It may actually be better to go progressively smaller to keep the gas speed constant.

 

Now I have a '78 model with 4.5L engine. Any gains using a Y-pipe? The middle muffler is off the car and if I look into the muffler it looks like the two pipes join into one chamber before being muffled if you know what I mean. So what's the point of joining the two pipes into a Y-pipe before it enteres the muffler?

 

Anyone know off hand the price differences between the suppliers of the x pipe?

 

Good question.

But better question....what is the best quality x-pipe for the price. Is that what your looking for?

 

Uhhh, they all come from the same place...my shop. Roger and Carl are both resellers for us.

 

My car wont idle after X-Pipe rmb install also billows black smoke at idle Im thinking it is the O2 sensor causing the problem but would appreciate any advice on how to fix problem .Hope this is an appropriate place to ask this question.If not could someone please direct me to the proper fourm
Thanks

 

and

The answer is the either Roger or Carl??

 

If they both sell the same thing, from the same shop, why the price difference?

 

Tell me you are not surprised that there are shops that sell the same things at different prices... ?

Dan
'91 928GT S/C

 

This topic has been touched on many many times:

an X pipe is a great replacement for the OEM cats period. IM experience it improved power, free revving with a more pleasant exhaust tone.

I had already fitted an RMB prior to the X and found the noise level at above 4k rpms somewhat irritable to my 'old' Led Zeppelin ears. I went back and forward with the RMB and OEM RM and finally settled on the GT RM..................this is all with the GT or the smaller resonators.

I have one of Dave's originals which yes you can now buy from a couple of sources which I'd highly recommend. Devek did have a product but I don't believe is availbale anymore and 928 SP have a product but they can advise directly on availability with a simple phone call.

As far as quality product..................excellent!!!!!!!!!

 

Un hooked my ground strap and reattached after breakfast no more smoke and car runs perfectly. I am runing the motorsporsts xpipe no cats and RMB ,car sounds awsome especially over 3000 rpm.Benefit is freeer reving engine and tangible increase in power not overwhelming but a nice little increase
Thanks
Sean Finn
87 s4 5spd 60k miles

 

Good to hear Sean! Is the car louder with the x-pipe and RMB?

 

Yes car is defineitly louder but not obnoxious I am very happy with the sound.I was at the car wash this morning and a guy pulled in on a Harley V-rod , the bike was way louder than the 928 couldn't hear the car running with the bike in he next bay. So as I said its louder than stock but not too loud sounds like a V-8 sports car should sound especially over 3500rpm.
Sean

 

X pipe and RMB, in my opinion, is too loud even with 87 mufflers. My brother had that setup at one point. The drone at highway speeds was pretty irritating. To each their own, but my neighbors would probably egg my house if I rolled in with that setup at 2:00am a few times.

-Joel.

 

In my case just a 2500 rpm in 4th gear under load. After that, it quiets out pretty fast.
Or maybe that's just the Doppler-effect