Marcus S.

Hi,
I'm planning to do some modifications to my exhaust system on my 996 GT3 MK1. I have been told that the 997.1 GT3 header will fit, and after this you custom built mufflers and tips.

Anyone here at Rennlist who has done this? Anything to think about

All tips are welcome

BuckeyeDrew

I just did this (well, kinda). I just installed a complete 997 gt3 system on my 6gt3. While I did not use any oem exhaust parts, the process was pretty much the same. I had an issue getting the 7gt3 headers to seat properly. I had to remove the bracket that bolts to the block and holds the stock 6gt3 muffler. Once that was out the headers went on very easily. Also had an issue with getting the o2 sensor wires to reach sensors now that they were in different spots. I had to just run the existing wires in a new route (would be nice to get longer wires). Although you can probably re-use gaskets and bolts, I purchased new ones as the costs were very minimal. It was a very fun process and surprisingly easy.

Rovman

Sharkwerks built a custom exhaust for there 996 GT3, albeit it was for the .2 GT3 as well as a center exit. I would assume the two cars would be similar. I think it is documented on their website.

Raven 666

I would love to hear this set up if there are any video,s ................

mmuller

I would highly recommend a 997 system (complete) on a 996. Once you see how the two a designed, you will see there is is hp to be had. I had changed my car to a set of 7GT3RS headers and 7GT3RS center box with Supersprint side mufflers delete pipes. Saved around 70lbs of weight and made 18hp+ at the rear wheels. Somewhat louder than stock 6GT3 but not terrible and was still able to run Lime Rock with turn downs only (88db limit).

If just changed this to a set of 7GT3 SCarGo Catless headers and a 7GT3 rear center box (titanium vs metal. Didn't want to burn a hole in the Ti box) and it's now making more like 30hp at the rear wheels. It's almost cup car loud now, but not quite

The only downside of doing a 7GT3 exhaust is that you either need to cut center exit holes in your current rear bar, or switch to a 6Cup rear bar with the center exit already in it. The 6Cup rear bumper does also improve the air exiting the rear of the car due to it being cut a little higher the a street car. They are cheap enough as a replica that it's worth it.

I don't have any roadside sound clip, but if you can hear the exhaust from the in car in my YouTube videos. Search user "mrmmuller".

cfjan

Will your catless headers + stock center box setup pass Lime Rock w/ the turn down?! LRP has such a strict sound level limit.. !

mmuller

I doubt it will pass. I could swap the headers back if I choose to run there again, it's not that hard to do and I can do both sides in about 45 minutes. I generally only do LRP twice a year, one DE and one race in the SPB, so it's a choice I have been avoiding the last year.

I think I would run it with the Catless headers and wait to get meat balled and then come in and switch the headers.

Marcus S.

Great! Seams pretty much straight forward I will start the search immediately...anyone know if the headers are the same for 997.1 GT3 and 997.2 GT3 ?

Marcus S.

Yepp, found it This will help a lot

http://sharkwerks.com/porsche/996-ca...40-wheels.html

Marcus S.

I'm on the same side Much HP to find in the 997 exhaust design. My idea is not to make a center exit, I will try to do a x-pipe solution with some small mufflers and then do some nice tips at the existing holes in the bumper, prefer original look.

mmuller

I had originally planned to do the same. When I started to ask around about the custom work required to achieve it, the cost was high enough that it made the bumper cost (painted) only $400 less than the full 7GT3 solution. Decided I wanted to be OEM like and went that route. Either way, the magic is the better header design so you will be making gains either way.

kk2

plus it's much easier to find oem parts if something needs replacement.

GreatWhiteNorth

Here is another visual. Bumper is from Getty

Marcus S.

Anyone know if it's any difference between 997.1 headers to 997.2 headers? Had found a pair of 997.2 headers here in Sweden but don't know if they will fit.

Please reply

mmuller

Both will fit. 997.2 are better because of the newer cat age.