RKAutowerks

Those with a 997 GT3 you can get a matching set! Also the dyno of our 997.1 3.6L set is at the below link.

https://rennlist.com/forums/997-gt2-...l#post12666867

911_RS

Nice work guys! Finally a long tube headers for the 991! ANy dyno charts? any loose of torque?

karimgt3

Flaps means stock exhaust button works?

Charles@dundonmotorsports

We finally located a PIWIS 2 tester so we can be able to dyno the cars now. Once in hand we will dyno away. Hopefully by end of next week

Yes, we were able to secure OEM quality exhaust flaps and I build a diverted bypass pipe around the flap in a much smaller diameter (same as stock size actually) and this kills most of the low rpm drone and annoying noises that your neighbors don't like. All of my 997 gt3 customers usually never even hit the sport button unless on track because the exhaust note is Seamless when the flaps transition from closed to open.

911_RS

I'm interested in this system… but worried about the CEL. For sure it will pop up every now and then. I will wait for GIAC to make the tune first for the RS (with CAT delete file), then I can get this exhaust

Charles@dundonmotorsports

When a CEL does Pop up in my systems it is almost always due to lugging the engine low load low speed lots of throttle. I.E. 996-997gt3 50mph in 6th trying to creep and be very quiet. Usually it doesn't even throw a p0420/430 cat efficiency fault, usually it throws an O2 sensor fault because of the irratic voltage the ecu sees due to high changes in load.

The test car here had several hundred miles put on it and no faults or changes in readiness. Stop and go driving or track use.

Everyone else that has one of my systems can vouch for me here. I think in 5+ years 2 people have had p0420/30 faults Pop up once. Clear and has not come back on. 4porsch (joe) probably has the most miles on any of my systems. PJS and MKK62 Mike Kim are right up there too.

RKAutowerks

I'll echo Charles (snickers) comments. The defouler does a fantastic job of getting the O2 sensor voltage into the correct range so the car doesn't "know" that a cat is gone. The ecu in the GT3/RS is a new bosch unit, hopefully GIAC, Cobb or others can crack it. If not you should still be fine. If you like wait a bit and see the feedback of a few others...

911_RS

I see... Well I got the GMG headers and rear bypass already for the RS, now it made me think in getting this too. Will wait for the GIAC tune first to be sure on the CEL and I don't want to loose any low end torque on the car.

Charles@dundonmotorsports

Most if not all of my setups make more everywhere. Even low end. Here is my 997.1 setup. Makes great low end power. Midrange is lost just because the DME is pulling timing out because it is exceeding the VE table.

911_RS

Very impressive power you made there... Is it with this type of exhaust only? Or with a custom ecu tune? I was told that I would loose low end torque if I remove my OEM side mufflers and with a cat delete setup. How many hp gains do you expect in a 991RS with this long tube headers exhaust?

Charles@dundonmotorsports

This is bolt on stock ECU no tuning. I have not done any tuning. If the ECU was tuned, the 5-6000 loss would not be there, but I think that is only on the dyno anyways as while the vehicle is driving the timing loss there is almost 0

I would guess my setup on a 991 GT3 3.8 is about 20-25whp and on an RS i would think atleast 25-30whp.

Most of the other exhaust setups lose power on those ways because they are retaining the cats and short primary pipe length. The 3" secondary pipe size makes more lower end power with my setup than a 2.5"-60mm does like factory, but that is in relation to my headers which are tuned for 8000-8400rpm

911_RS

+20-25hp?!?! keep us posted on the results! Interested in getting a set for my RS

Jon70

Any way to incorporate cats?

Charles@dundonmotorsports

I know how I could incorporate cats, but it would be at the expense of the muffler or the flaps or both. I THINK I know how I could add cats and include the flaps and keep the same mufflers but most likely the cost would increase $1500-2000 atleast.

RKAutowerks

PIWISII shipped today, we're scheduling the dyno time and time with SEAPAR (very gracious of you) to get the dyno data!