RKD in OKC

Glen... H vs X look at the letters, that is the difference. The X helps draw the exhaust out better without the exhaust pulse having to turn all the corners of the H.

SMTCapeCod

Give it a shot, but...I think we are angling in on the same desired outcome. I ran mine for a while with x, 100cpi, aftermarket mids and the stock rear muffler. It sounded decent but overall was still very quiet- the final muffler really does do a crazy job of stifling the sound.
I replaced the final muffler with an aftermarket akin to that in Roger's dual setup..and now it is too loud for my taste...just cats and final muffler might be one way to go, though I don't think the stock or my aftermarket mids are doing much to reduce dB/SPL.

Maybe some day Ken or someone else will get into surgery on the factory muffler and come up with 'three bears' options...no internals, no packing but baffles retained, and moderate strip out of packing only.

yardpro

i have x pipe, no cats and rmb...

the car sounds great.. you can hear it at highway speeds, but there is no droning, and it is not too loud by any means

megaelf

I have headers, X-pipe no Cats, stock mid GT-resonators and stock rear muffler.
Not too loud but a really great sound especially on higher RPM.
I tested with RMB but that was way too loud.

hb4

Yardpro,
I assume you have the large resonators as well?

yardpro

yes

rgs944

Here is my end result. I went with x-pipe, test pipe, single 3 in. mandrel bent pipe and flowmaster 40 muffler. Probably too loud for some but just right for my needs. I just love the reaction around here when people hear it. They can not believe its a Porsche. I also think it works with a 5 speed, I don't think an auto would be able to pull off being so loud.

gruffalo

do you have sound clips?

I have an '87 w/rmb, and it is dead quiet (almost...) I need to do something

Andy Kay

Last month my 87 S4 auto w/ large resonators got an X-pipe, new O2 sensor, cat delete and a stainless RMB. Slight droning effect at 2400 rpm but no big deal. Seems like the car "woke up".

After adding the 930 S steering wheel, motor mounts and Delrin rack bushings, the entire driving experience changed for the better. Feels like a much different car!

Bad oder on the first night due to the X-pipe coating being burned off. Neither my 79 911 SC or the 87 928 S4 have cats and neither have any exhaust odor.

Very happy with the results!

blown 87

I get the "How much trouble was it to put the Mustang engine in that Porsche?"
I think the X pipe, no cats, and RMB works well with a automatic as long as it has the big resonators on it, they are to loud with the small ones IMHO.
I agree that it does sound great with a 5 speed though.

rgs944

Yea, around here the muscle car sound is pretty popular but I also think it has a little of the exotic or European sound left. I am happy with the noise level for a weekend fun car.

RKD in OKC

If the Flowmaster gets too loud for you, Magnaflows are about 5 to 10 db quieter.

Speedtoys

You can hush up a single tube exhaust this way too. (FLowmaster in this example)


Helmholtz Chamber.


Before:


After:

Oli928

I was going to start my own post regarding my x-pipe experience, but this thread seemed like a good place to inject my thoughts and results.

Background: 1989 S4 Auto

I started with RMB kit about a year ago...sounded great. After recovering from other unplanned expenses (TT bearings, radiator, etc) I got back to the exhaust system. I still wanted a more aggressive tone and more HP. I went with an x-pipe from Roger and deleted the cats. I retained the small mid mufflers.

Within seconds of start-up, I realized this was way too loud for me...this from a guy who has a 1970 Barracuda w/340-6-pak, headers, turbo mufflers & 2.5" pipes all the way thru. I know "sound" is to each his own, I'm not criticizing anyone's taste...I just didn't personally like it (probably mostly due to the tiny mid-mufflers).

After some spirited searches online, I got some Borla "S" type round mufflers to replace the mid-mufflers. The sound definitely got deeper, but I had a bad rasp around 2100-2400 RPM. With my driving conditions/habits, this was my near/at shift point and HWY cruising RPM around town. The rasp was just too much for me.








Since the rear muffler was still in storage and easy to reinstall, I did. I LOVE the increased power (I'm guessing the engine liked the back pressure back). I like the deeper tone. I wish it had some more volume though. It is louder than stock and deeper rumble. It is quieter than stock w/RMB by 15%'ish...but lower tone.

The video at bottom shows my first two results. I didn't post the final sound (w/rear muffler) because the small mic on the iPhone 4S just couldn't capture the nice deep tone...everyone would wonder why I'm leaving rear muffler in.

Recap of my final (for now) exhaust I'm very happy with: X-pipe, Cat delete, Borla "S" type as intermediate mufflers & factory rear muffler.

My recommendation to those who comment that their exhaust was/is too loud after modifications: Reinstall the rear muffler...it takes less than an hour...if you don't like it, take it back out. My performance improved with it. I also got rid of small rattles in the car (engine runs smoother).

Oli928

Here is video link:

http://youtu.be/_vTG3iWkxOI