J richard

Meh, no issue running all three bypasses. No issues with the motor and it does like less back pressure. The limitation is the factory header/heat exchanger. A good set of headders flow more/better than the cup parts. However WAY too loud for the street. My racecar blew a 106db on the track with all 3 BP, too loud for many tracks. If you want to stay with stock exchangers I like the sport silencer that replaces the cat with the primary and gpipe. Same sort of sound just livable (barely)

boxsey911

Here's the noise the straight pipes make:

StanUK951

So long neck G pipe or short neck??

RW964

Hey Stan do a search here and you will find picts and the like.
A lot of info on this subject, the G Pipe being the short version and the J Pipe being the longer pipe with a support attached.
I purchased this one becuase of this reason.
The G Pipe supports the tail pipe just using the clamps. But I have never heard of any one having problems with this setup. Works Great.
As for the sound and hp diff I have no idea .. Mine sounds really good with a J pipe and stock plumbing the rest of the way.
Starting the car sounds like music.. Everyone looks and kinda gives that H#!@ yea look..... Next is the cat bypass. I am sure what ever you get you will be happy with it

StanUK951

I have a G pipe and cat bypass. I like it but wondered if the longer neck pipe toned down the slightly 'rough edges' you get with the G pipe sound and was a bit better performance wise. Probably not exactly worth losing sleep over though!

Porsche964FP

I have the long neck with Catby side by side with Jim Howley's ex 964 with short neck and Catby it was louder

Straight Pipes - Loudest, drones, loss of performance/ no back pressure.

Cup Pipe & G-Pipe - 2nd Loudest, drones, raspy and deep.

Catby & G-Pipe - 3rd Loudest, no drone (IMO), deep, maintains back pressure, best performance gains.

Cup Pipe - Raspier note, no drone.

G-Pipe/ long neck G-Pipe - Deep/ deeper, no drone.

Gus

I installed a set of Billy Boat headers and muffler, the exhaust has a very positive tuned sound at various RPM ranges and there is a noticeable seat of pants increase in power. The problem that I have is that at cruising RPM on the Interstate the tuned exhaust sounds ( a base tone) becomes very annoying and I will shift into a lower gear just to change the tone.
Has anyone else run into this, and if so is there anything that you can do to change the tone at a certain RPM or keep the reverberation from coming int the cockpit. IDEAS????
It is so bad my wife now refuses to go for long rides ( read trips) in the car.

niche

Great thread... thinking of doing something with my exhaust... I had fabspeed supercups on my 993 and it droned way too much.

Is it a big deal to do a cat by pass and g pipe (sounds like best option) with stock DME?

Gus

No. Cat by pass is an easy unbolt / bolt on. The "g- pipe" is not as easy, but spends on if you remove the secondary muffler, which you should.
In both case you will want to remove both rear wheels to have good access to work area. Left wheel for CAT, right wheel for secondary. Main mont is just behind right rear shock up near starter area. The rest is clamps at junction.

freedman

? You cant fit a G pipe withoput removing the secondary

And its only a ten minute job, two nuts on the silencer otself and the two clamps

Ghengis

I currently have the cat bypass and cup pipe. A recent addition was a small split to the secondary muffler. It doesn't sound terrible not too noisy, in fact the lads I was out with today thought it sounded quite nice.

I have to say though after several hours driving today my head is buzzing still!

Gus

My bad, for some reason I was thinking there swas another pipe between the primary and secondary. But, there isn't. Yes, there are 2 nuts on the front to remove the secondary from the mount. But, if you want to remove the forward secondary mount there are 2 bolts at the top up by the starter that you have to remove to get the mount off.

niche

Just got a shop to take out my secondary muffler and they put a longer pipe than the Gpipe you see everywhere. Love it.

964Lovac

THanks for all the information here. This is really a great thread!

I may be putting the cart before the horse here, but I have been thinking of what exhaust set up to go with. Originally was thinking with a dual bypass, but after reading this thread I am thinking more of a seconday by pass with a free flowing cat. (Not too sure about running catless)!

Mr.Alex

Is there another high flow cat aside from the one fabspeed sells that has good fitment?