Schuey

Opinions are all over on this so I'll also do a poll...

My initial plan is to do

(1) Primary bypass (saves ~30lbs weight and gives HP)
(2) CAT bypass

I will also be using a 911chips.com RS modified chipset...

what are your thoughts on this matter?

EDIT:

good points Marc...I want power, less wieght and a deeper sound...strictly street

Marc Shaw

I think that "best" varies as to what you want - power? sound? Do you track or race? Do you have noise limits to adhere to?

Marc

leosayer

I was told (when I bought my car) that I have primary and cat-bypass but I how can I check this?

Andy Roe

Leo,

The Primary By-Pass is a pipe that replaces the silencer which runs behind the rear bumper. Easy to see if you've just got the straight pipe fitted. The CAT by-pass is harder to tell as most CAT By-pass pipes are of a similar shape & size as the CAT anyway.

Andy

John Boggiano

I'll be in the minority but, much as I like the sound of some of the modified exhausts I've heard, somehow they just don't sound like a 964 should.

I really like the sound of the standard set up.

Naturally, I don't have a drilled air-box either...

Gary R.

I'm removing the stock Primary and secondary and putting on a dual-out Fabspeed. I'm also going to try their "Cup" airbox with stock filter, keeping the original handy rather than drill it out. I'll let you know how I like the sound. I believe I will be dropping over 50# off the rear with this mod.

Wachuko

I am going with what Tom W did...

Stock headers, fabspeed cat bypass, stock primary, secondary bypass (G-Pipe): 244 rwhp

I also have a drilled out air box

I need to find a good place (read $$$) to buy the cat-bypass... it is all I am missing from my desired setup...

H964

well how come no one is talking about this set up, cat bypass, primary bypass and stock secondary.
doesnanyone has this set up, and if so how does the car sound and feel
this was my plan in the near future.
thanks

Andy Roe

Mike,

That's the set up I've got & I like it!! Havn't noticed any seat of the pants difference though. I used to have a G-Pipe/Secondary by-pass on my old C4. That seemed to have a louder, deeper note. Prefer the Cat/Cup route.

Computamedic

That's exactly what I've done, along with the Dansk cat bypass. It sounds GREAT and I get many positive comments about the sound, like "We can hear you half a mile away!!"

If you plan on tracking the car, in the UK at least, you should forget it though. Mine was measured at Goodwood at 108dB which doesn't even come close to their allowable noise limit. I just love the sound though!! Quite a few Rennlisters have heard my car so independent authoratative views are available.

Regards


Dave

JasonAndreas

If I had to do it all over again I would buy a used airbox and cut it to match the cupcar style airbox and not bother with an aftermarket version. The aftermarket style are made from very thin plastic that have no sidewall ribs for stiffening I believe because the whole piece is vacuum formed. Anyway because of this "defect" the whole piece warps and won't seal properly.

garrett376

As Marc mentioned, it depends what your expectations are. On my cabrio, the stock exhaust system is best - even a G-pipe is too loud for tooling around town. As John B says, I like to listen to the air fan and the valves instead of the exhaust... on the cabrio.

On my coupe which is my "toy" - I like it loud: cut airbox (like the Cup style - done to save weight ), 2ndary bypass, cat bypass - this gives the best weight reduction I can get and still be reasonably quiet for a 4 hour drive to the race-track (maybe a 10 hour drive if I head to Laguna Seca next month...).

hjcarlin72

Replace stock exhaust with Fabspeed DUAL exhaust. Sounds awesome!!

puma1824

For those of you who are thinking about getting the FabSpeed Cup Airbox...I'm selling mine which is pretty much new. Fabspeed sells for $175...I'm selling mine for $150 shipped (Continental USA only). Only reason why I'm selling is WAF (Wife Acceptance Factor) Because my wife "allowed" me to get this car I'd have to honor the request in making the car quieter. Presently I have both the Fabspeed airbox and Fabspeed Primary bypass. The primary bypass will be up for sale shortly.

Tom W

Garrett: I drove from San Diego to my home (497 miles) in about 7 hours and Monterey is about 1.5 hours south of Half Moon Bay. I'd guess more like a 6 hour drive. You should come to Laguna Seca for the POC event so I have someone to play with (is your car KP too?). It is a wonderful track to drive. I think a double apex at turn 2 with a big throttle lift to rotate the rear end is the most fun turn on any track I've driven.

Gary: I've done the dual outlet Fabspeed exhaust to replace the primary. It gave 10 hp less than the cat bypass and secondary bypass. If you want power, save your money. If you want load (as in illegal in CA at 96+ db), it's your answer.

Leo: If the thing on your car has a heat shield attached to it, it's a stock cat. If there is no heat shield, it may be a cat bypass. If you do a search you'll find some pictures of the cat bypass.