996TT_STEVO

You must have the louder version! I have the quiet version and it's great!

The must have fitted a different system when you were not looking, because I have no resonance!

Anyone else coment on the Fabspeed!!!

santicua

I had the B&B and it was WAY too loud for my liking. Lot of drone from 2.5K-3K RPMs which drove me insane. Switched to the Cargraphic and couldnt be any happier!

Charlie360

I was thinking of going down the enlarged diameter header route - why do you lose torque, surely there is less back pressure with these and the turbos will spin up more quickly. I'm not clever enough to disagree, just interested in the reply!

1999Porsche911

The more you reduce back pressure at low RPM's, the more power you lose at those low rpm's. The reason for this is that when the exhaust valves open to release the spent gases to the exhaust system, having to much flow through the exhaust will reduce the compression of the engine at this time. At higher RPM's, because of the speed that the gases what to excape at, the exhaust is no longer holding the gases back from escaping, but the physical size of the exhaust ports are. Therefore, you do not lose compression due to execesive exhaust flow at high engine revolutions.

Bottom line is that all combusion engines MUST have back pressure in order to operate. Even the fuel dragsters have back pressure.

I hope I made sense.

Kevin

Well NA engine need backpressure... Turbo engines do not like backpressure.. The turbochargers as a whole create backpressure.. The less baskpressure the better.. However is you increase the size of the primaries you slow the velocity down, this creates more lag and sluggish low RPM throttle response.. FYI the new Chile pepper creates up to 3bars back pressure with it's exhaust and turbo system...

The factory spend thousand of dollars on the factory header.. IT is engineered for this engine.. every other aftermarket system lengthins the primaries.. Turbo engines want short primaries and free flowing collectors.. This is what you get with the factory header..

Charlie check out my DIY header mod, and spend the time removing the metal at the inside welds to smooth the transition of air flow.. Save your money and put it into a Europipe or suspension..

NC Bob

I've had the B&B on for two years. Did not get the headers. 45hp is bunk. The only thing I noticed was a lot better sound. Very little performance improvement. Also no resonance. Very acceptable bang for the buck though.

1999Porsche911

The same engine, whether NA or turbo needs the same amount of back pressure at low RPM's to get the same torque. You have to remember that the amount of back pressure is determined by the length of the exhaust flow, how many bends are in the system, but most imporatantly by the smallest diameter that is in the exhaust path. So you can install 6 inch pipes throughout the system and if you have a 2 inch diameter tailpipe, your back pressure is determined by the tailpipe and not the 6 inch pipes. An engine will not operate without back pressure. Increasing flow of the exhaust on any engine, turbo or otherwise will always reduce power at low RPM's..

Kevin

The VE of the two engine are going to be roughly the same.. Yes, you need backpressure on the cylinder's to promote combustion.. Again I stress that a turbocharged engine has enough inherant backpressure built into the system.. The turbochargers put more backpressure on an engine than a well designed header system on a NA engine. Basically you aren't comparing apples to apples and you can't install the same camshafts into a turbocharged engine and you can't run the same duration, as in a NA engine..

On the 930 engine if you install equal length headers with the same diameter primaries you lose torque and you increase lag... vs shorty headers..

On a Porsche turbocharged engine the turbocharger A/R and turbine wheel determines the backpressure.. Most of us realize that if you were to funnel the 4" diameter turbine housing on the Pcar turbo to a 1" pipe that would be similar to shoving a potato in the tailpipe... Car wouldn't run well.. You have to be practical and use documented designs.. On the 993TT and 996TT is you run no mufflers and straight pipes just like the 935-GT1's and GT2 EVO.. You will make more power due to that reduction of backpressure.. Thus my comment turbocharged engines do not like backpressure, they make more power without it..

vyper340

Which Cargraphic and how much? Where did you get it?

vyper340

Anyone else have comments on the Fabspeed?

prg

I have a fabspeed quiet (sport). It sounds great at WOT and decreased the lag in my previously mildly laggy X-50. The resonance is annoying from about 1900 to 2800 rpm.

JS

Fabspeed Sport here and happy with the product and service, nice change from stock.

ebaker

The way I understand it you want the exhaust gases to be as hot and moving as fast as possible when they hit the hot side impeller. More of the exhaust gas energy goes to make boost. This gives maximum boost and the least lag. Relatively small, short, straight, double wall tube headers accomplish this. This benefit outweighs the airflow restriction of the smaller header tubes.
There is a restrictive looking area in the collector of the stock header that should benefit from some grinding.
Probably at somewhere around 650 HP(?) you will benefit from larger header tubes.

Kevin

This is the final result of many hours with porting tools and polishing cones..

sharkster

And good photoshoppin' by Joan Ah brings back memories!

Just a word of advice if you have stock turbos or GT1s etc... these headers work really great. It also works out cheaper than buying 2.5K headers (usually of the long tube nature which isn't what you want). They do reduce lag by at least 200-300 from my testing.Plus the coating helps too

PS Do you still have that GT3R Oil Pump for sale? Even though I'm not planning on increasing rhe redline a lot I doubt I'd need the extra pick up but since I'm in there.....