gmgracing

Gents

Just wanted to chime in on this topic..

We have done extensive testing with the 996 Gt3 and it is without a doubt a mistake to remove the catalyst the cars not only loose horsepower but also torque.

I would not recommend removing the catalyst.

What I would recommend is going with a lightweight muffler option and retaining the stock catalyst or using a 200 cell sport catalyst .

We are working on a 200 cell sport catalyst option that will incorporate our X over center section.
This option will be a direct replacement set up to the stock catalyst and will work with mufflers that mount in stock configuration such as our WC-GT mufflers for the 996GT3.

This sport center section will also have provisions for a muffler bypass should you wish to eliminate the mufflers.


The system is going to be tested on SpeedGT's yellow 996 GT3 , stay tuned for before and after dyno results.


Just remember - Becuase its louder doesnt mean it makes more power.

DHI

^^^^^
Good stuff.
Looking forward to seeing the results of the new setup.

D-Uber Cars

Mike,
Since you are almost local. Perhaps you give Charles a call? He made a nice system for PJ and me when we had our 996 GT3's. I made good HP, was light, sounded great (was a little loud) but, it did pass WA state emissions (OBDII). No cats.

4porsh

Hi GMGRACING,

Will you be getting dyno numbers with mufflers and w/o?or any other config.
Does this system you are working on need ecu programing?
How much does the system weigh?

911SLOW

If you mean below 3K RPM I would say yes you might lose a little, but talking about max hp and torque that statement is absolutely wrong. : )

MTB

Daryl,
How are you be doing? The cup style exhaust is fantastic but its too loud for my liking!

mooty

^ ipod is your friend ;-)

HiWind

John do you recommend a straight thru pipe in place of cat? We have no EM standards at the track here (or road for that matter).

911SLOW

I love Africa! LOVE it!


Sure, go ahead, it's the cheapest way to open up the 6GT stock exhaust. You see, the 6GT3 headers are good, it's the diameter of the pipes and cats that need work. (In fact for any modern sportscar, cats are normally the place where the biggest exhaust restriction occurs)


Since you can get away with it legally there, shoot!

Remember to keep all sensors in reading. No lambdas in free air and stuff like that.
Add two extensions in after C to minimize check lights.



A full aftermarket quality exhaust in the appropriate diameter and length, with or without an X pipe, motorsport 100cell cats or 200cell cats, lighter straight through mufflers and equal length headers would be ideal , combined with a good DME upgrade for maximum gains and no CEL.

On the other hand, the price difference is so great that, I don't really know if it's worth it for a few more HP, few more Nm, a better/wider torque curve and perhaps better sound.

If I wasn't after minimum weight in a street legal setup I would have kept my bypasses, no doubt.. But, in order to balance engine efficiency and emission numbers you need sport cats.

roberga

I did Fabspeed from headers 200 cell and sport mufflers. It was a great set up. The only thing was having to watch db police at PIR. Quiet days as Pacific was fine. Dynoed with over 50,000 miles on the car was ~360 at the wheels. Do not know what it was before.

HiWind

Thanks again John - As ever invaluable for the thoughtful modder - I'll work on my plan. When you're tired of throwing poo at your politicians, you shd take a trip down here - lots of windy roads and loud exhausts. track tomorrow shd be excellent for season opener - 11 3s running, 5 cups/Gt2s and some door mats - will be sure to check out all the bypasses on show. May post some vid if all goes well.

MTB

+1. I ran bypass for 3 trackdays and loved it. If it was not too loud (over sound limit), I would not add the resonators.

Paseb

i was using fabspeed catbypass on my 4s and i coulnt pass the db limit a tremblant racetrack...

i wanted to do some exhaust mods on my about to purchase gt3 but i dont think its possible to stay in the db range....

FFaust

Seb, I have full Fabspeed, and am fine at both Calabogie and Tremblant.

Paseb

what???

are you running with any cats?

i had stock mufflers and catbypass and i was 93 and its 92 if i remember right.

now my other question is, is my father going to pass db limit with his cayman s

i installed him some catless headers and awe catless mufflers.

the car is mucho loud loll

more than my 4s used to be.