Kevin Michael

Dave , if they(x-pipes) go on sale soon, please let me know! I want one.
Kevin

ROG100

Malcom,
It certainly sounded better but still to loud for me.
The GT resonators are so smal I do not see them attenuating any noise.
Roger

H2

On my '85, I have a cat back RMB with stock cats. My wife doesn't like the sound but I love it. However, the X pipe should give more power...but I still want good (relatively loud) sound and, preferably, the weight loss of getting rid of the heavy stock muffler. Maybe my hearing's going?

Harvey

the flyin' scotsman

Which resonators does your '88 have?

H2

I don't know the specifics on my '88 yet since it's to be delivered here by the end of January. I'm just planning and budgeting for all the things I'll be doing to it. Some things I won't be able to order until after it arrives. First job is a Tbelt/WP/new Rollers/new front crank seal, and other while I''m in there stuff.

Harvey

the flyin' scotsman

ok understood..............in my experience the X, GT resonators and RMB is too loud when the engine is get beyond 5k rpm as well as for longer trips. Loud enough to set off parked cars alarms.

I had the RMB before the X but once the X was installed there was no way it was coming out...........it made such a huge diff.

The RMB was changed out for the stock but I didn't like that; look or noise level. Thats when the GT rear muffler was attained and installed............good to go!

PorKen

The 86.5-87 resonators are the largest/quietest of the bunch.

redpathtribe

Roger,
Are you saying that if you use the X-pipe with new cats that you don't need the air pump anymore? Or is it without cats that you don't need the air pump?

danglerb

New OBDII style cats don't require air injection, but that may not mean anything to your smog inspection guy.

I think some years the air injection goes in the head or something too?

touque

Rick - doesn't matter - with or without the cats (and the new X-pipe), you don't need the air pump. Just cut the belt on your '90 and it will be 'disabled'. Of course, you could completely remove it and the piping as well to save on weight as Roger stated...

the flyin' scotsman

Install the X and use the air pump for a boat anchor as well as all the associated plumbing.

SMTCapeCod

I routed it such that one of the hoses from the diverter valve pumps into the heads (of course, most 928 heads aren't set up to accept that) and the other uses a stock hose I found in pet to go into one of bosses on the bottom half of the air cleaner assembly... I do have my $50 Euro idler wheel around somehwere waiting install too though...

the flyin' scotsman

The resonators did change through the years:



Now I'm curious as to how a stock '87 S4 with the larger resonators would compare to a stock '89 S4 with the smaller GT resonators.

Did Porsche publish noise levels?

Ketchmi

I put 87' mufflers on the white supercharged 89' in place of the smaller resonators, he thought it was too loud with an RMB and cats. It's more than acceptable now, X with cats and RMB and early mufflers. There is a large difference in sound.

SteveG

I know I am in a minority here and I mean no disrespect to Dave or the product, I'm not trying to start a fire. I believe Dave when he says I am the first to ever return his x pipe and cats. I remain concerned about the band connectors with webbing provided and no provision for the air pump connector and the position of the O2 sensors, one on each side, not centrally located. If you are of a mind to remove the pump or at least not connect the pipe from the pump I'm sure you will be happy with the quality of the cats and the pipe. He did mention the option of welding when I ordered; if you do not understand exactly what you are getting, you should ask. I had an emissions problem (rich) and that was my primary concern. So when I saw his set up in person, I felt it was not for me. We suspected the old cat was at least part of the the problem; it was not til after it was removed that we noted they had been gutted. Sometimes it is just not possible to know everything. I went with the original set up and new cats. The standard restocking fee at most supply houses is 15% which gets pricey as the $$ goes up.