Hey thanks for the link and the answer

 

Thank you all for the positive response to our GMG World Challenge header and cat systems for the GT3/RS 3.6 and 3.8.

A considerable amount of testing and development went into this system and like many of our other products it is a race proven design. We run these on our World Challenge GT Cup cars.


We do use a 200 cell German made sport catalyst that is specifically designed for the GT3/RS engine.

The headers are a direct replacement unit to the factory system as well.


Independent testing has been done by several tuners throughout the country, you will notice the dyno sheet on our website it was actually tested by RUF in Texas.

If you are in the area and are interested in the header and cat system we can also dyno your car before and after with or without software. GIAC does have a specific tune available for our GMG World Challenge header /cat system along with our GMG WC sport center section.

The software is not mandatory but does help power throughout the power band and does make a difference as the octane of fuel you are running goes up. So if you are running on the track and using 95 or higher octane there will be a difference.

If anyone has any further questions please do not hesitate to email the shop directly or give us a call.

If you want to check the parts out and are in the neighborhood please do not hesitate to stop by the shop.

I am sure you will find the workmanship,build quality and performance second to none.


The 4.0 version our of World Challenge header/cat system will have some changes to the design in order to take full advantage of the added displacement and breathing requirements of the 4.0.


More info on the system along with video can be found on our website or by clicking on the link below:

http://www.gmgracing.com/porsche_exh...72header.shtml

 

3.8= 400 cell cats
4.0= 300 cell cats w/special coating to make them work and pass emissions tests.

4.0 cat is less restrictive.

 

Thanks Pete.

 

Fabryce: will the sport header system pass emissions?

 

A little OT but I had a custom header made and deleted my cats. Copied a RSR system. Dyno before and after revealed I actually lost about 5 to 8 BHP on the peak. It was a painful experience. Good thing it wasn't expensive. I'm now back on stock.

 

Wonder why?...seeing race cars run no cats and free flowing systems.

 

Racecars also run restrictors and the exhaust is designed to maximize the engine in the car itself.

 

Just a quick follow up to a few comments above.....

-Headers have to be designed with specific dimensions in mind regarding the engine config, i.e. compression ratio, torque curve, fuel, etc.......

-Cats are needed for emissions but not needed for race cars.....

-We went through 4 header designs until we found the current one, it doesn't happen overnight but it does help when you test them on the race track, as our WC cars have been doing for years.

James
GMG

 

I thought so too.

I thought it was a no brainer to achieve some gains by eliminating the cats.

But the dyno proved me wrong.

Shame as the seen in the pics below - it looked pretty good.

Cheers

https://picasaweb.google.com/1164544...33459793560626

https://picasaweb.google.com/1164544...33496498410178

 

So does the Sport Header system pass emissions?

 

Yes, with the 200 cell cats, it will pass emissions.



James
GMG

 

i was wondering, do you get the same power gains if you are running a setup which has deleted mufflers? my car is running the equivalent of the sharkwerks track pipe - no side mifflers.

 

[QUOTE=silverboy;9076456]I thought so too.

I thought it was a no brainer to achieve some gains by eliminating the cats.

But the dyno proved me wrong.

Shame as the seen in the pics below - it looked pretty good.

Cheers

I have one question based on dyno experience with my gt3. Did you give your car enough time to adapt to the change? I say this because I myself posted some dyno results a few years ago when I trialed the FVD software and the Sharwerks rear delete exhaust. When I did did the exhaust and FVD software, the Car's computer quickly pulled the car into safer timing tables because it recognized 'something' had changed - the GT3 factory software has numerous timing tables to adjust for fuel type / temp / etc etc. After i ran the car for a few days - and specifically did a few WOT runs on the highway, when I re-dynoed the car, the car showed about a 5hp improvement - and no longer a 5 hp loss. When you look at the Factory A/F ratio it is spot on perfect for a NA engine - there are however timing tables that can be possibly further tweaked to benefit from higher Octane. I did my test on 94 Octane, and with the FVD software + Sharwerks rear exhaust + adaptation time = about 5hp at the wheels (that was my experience).

It is very possible your headers were not good, but no cats 'should' allow HP gains in the very high rpm range - but if the car is not above 6500 rpms all the time, the car may in fact be slower given the loss at the low end