SeanR

Agreed Ed, we did another comparison today and both my '90 and '88 have smaller resonators, Richards '88 has large, Docs GT has the larger........It seems to be hit and miss on what was attached and no year seems to be specific. I think your '91 S4 had the smaller ones also.

I think I'll start making a list of what has what at the next gathering.

Mrmerlin

Well since my car also has a GT type rear muffler( 2 outlets instead of the one big oval) I took for granted that since it has the smaller resonators its like the GT resonators if thats what they are called , since all of the GT`s i have seen have had the smaller type resonators, and most of the S4 cars I have seen have the bigger ones.
I also forgot to add that Louie Ott, who was an early developer of the X to begin with has been working with Dave Lomas to develop the pipe that is MFG by Motorsport in Utah. I am running an X W/O cats

Ed Hughes

Usually in Texas, things are bigger, but it seems that most of the later S4's here have the small resonators.

Panzer9

I think I may have the smaller resonators, but I don't have any other comparison to base size differences. Does anyone have actual measurements- or can they be visually distinguished by some other characteristic?

SeanR

Small ones are approx 13x7x2 and the larger ones, well, are almost 2x that size in volume.

gslaberge

Those that run the X pipe--do you put the cats back on if your state has emissions testing? In Colorado at least for the short term we need this done every 2 years.
Thanks for the input
Gregg

Rod Handsfield

Your new 928 ('91 S4) owner needs some help here. The thrill of loud pipes left me when I turned 50. Do I understand that the X-pipe can be installed and the remainder of the exhast system left stock for a palpable (15 hp) gain in horsepower?

SeanR

You can run the X with cats, with everything else being stock and you will have noticeable gains. It will still be quite with the pumpkin muffler still on the rear.

soontobered84

My '89 has the x-pipe and a Flowmaster RMB and it's not too loud in the cabin but at WOT you can tell it's throaty and has a great rumble.

Rod Handsfield

thanks. Where do I get one (x-pipe)? How difficult is the installation?

David L. Lutz

928sRus
Call Roger at 817-430-2688
roger@928srus.com

Ed Hughes

Be green run high flow cats. We all need to do our part.

Ispeed

Y pipe / mid pipes / end pipe/muffler: / sound: / hp+:/loudness 1-10
stock / large resonator / S4 muffler / quiet / +0/1
stock / small resonator / S4 muffler / better / +0/2
stock / large resonator / RMB / pretty good / +0/3
stock / small resonator / RMB / very good / +0/5
X w/cats / large resonator / S4 muffler / quiet / +20/1.5
x w/cats /small resonator / S4 muffler / better / +20/2.5
x w/cats / small resonator / RMB / Very good / +20/6
x w/o cats / large resonator / RMB / VG, louder / +25/8
x w/o cats /small resonator / RMB / VG but LOUD / +25/10.0
x w/o cats / small resonator / '89 GT muffler / VG, stealthy / +25/4

I alternate between the last 2 options, I need some large resonators to try with RMB.

IcemanG17

Whats odd is every 928 sounds similar yet different.....I have the exact same exhaust setup (factory cats with small resonators and RMB) as Bills 89....but his sounds much better...much more burble than mine....the only difference is I have a Devek RMB and he has a 928GT rmb that has slightly larger pipes....hard to believe 1/4" in pipe diameter would make that much of a difference.....

SeanR

Same thing here, my '88 and Ang's '90 have the exact same exhaust config and the '88 has a much deeper rumble and at gas, is much louder.

Rog and I dropped off Richard K's '88 to his house Friday, he's running X w/ cats, large resonators and RMB and mine drowned his out. Weird how they each have a sound of their own. I have stock cats, small resonators and RMB. The only reason I've not jumped on the X pipe is I love the way mine sounds as is, and don't want to change that. I drove 2 X-pipe equipped cars this week and am amazed at how much quicker the car reponds to throttle input. It feels like the engine has a huge difference in flow. I'll get an X in a couple of months and doink around with the resonators to see if I can find a perfect fit for my ears.