Porsche 991 Turbo S with Akrapovic Cobb Tuning BMC and More

So we are definitely partial to the Porsche world. Having owned the 991 Turbo as a Project Car, we have developed some pretty nice products for this platform. We have also had the chance to test and compare others tuning and performance products as seen here. So when it comes to making power on the Porsche 991 Turbo, the formula is simply like many other Porsche Turbos or turbocharged cars, more air in, and more air out with the help of tuning. The Porsche 991 Turbo S already comes with 560hp, stronger than the 520hp 991 Turbo. The main difference between the 991 Turbo and Turbo S is simply the mapping. The rest of the performance parts are the same. So this means that the gains of the 991 Turbo S will be slightly less where both cars will achieve the same end goal performance number. This customer wanted to have the top level products on his vehicle. When it comes to our exhaust systems, our Agency Power products are nice, but Akrapovic is jewerly. At about 4 times the price, it better be! The titanium muffler works inconjunction with the stock cat pipes or the aftermarket titanium high flow cats this customer purchased. The exhaust does not retain the factory tips but includes new oval tips with integrated carbon fiber exhaust surrounds. To take it up a notch, you can then get the full Akrapovic carbon fiber diffuser to make the full rear underside carbon fiber. The fit and finish of Akrapovic exhaust products has always been top quality and the carbon fiber work is 2 levels higher.

For more horsepower and faster turbo spool, we did a set of Fabspeed high flow headers. The headers are done as a 3 into 1 merged collector which are specific for the left and right bank of the engine. The new design is much improved over the factory “clam shell” design. The way each runner is designed is what helps the turbos spool up quicker. Headers are usually known for improving low end torque on the Porsche Turbos rather than top end power. Though the exhaust makes more noise and maybe around 20-25 horsepower, the turbos are nothing without some tuning. The Cobb Accessport has been a great upgrade for the Porsche 991 Turbo community using their OBDII port tool which allows you to load tuned maps, stage upgrade maps, get custom tuning, and even revert back to your original file. The Cobb AP3 even does datalogging and code clearing. The off the shelf Stage 1 and 2 maps are great for the 991 Turbo and Turbo S providing an increase of power as well as handling the high flow cat pipes. For some extra performance and air flow improvements, we also upgraded the stock air filter to a BMC Italian high flow air filter. This retains the factory box and lasts the lifetime of the car. Its filter element flows better while catching more bad particles. For style points, the car was lowered with H&R Springs much like we did on our Project 991 Turbo here.

So to see where the performance was on this 991 Turbo S, we did a baseline and after mod comparison as well as compared it to our other Cobb Accessport Turbo S and our VR Tuned Tuning Box 991 Turbo. The baseline test, just a couple days prior, in similar conditions, on our Mustang AWD Dyno yielded 462 awhp and 440 ft/lbs of torque. The Mustang Dyno reads low with about a 20-25% drivetrain loss. At about 20% loss, this puts us pretty close to the factory 560 horsepower mark. After the mods we had massive gains in torque and strong gains in horsepower throughout the curve up until 6000 rpm. Torque went up nearly 110 ft/lbs over stock at 3700 rpm which is a tremendous increase. I would guess about 20 of that was from the headers. The horsepower did fall off at 6000 which could be do to heat even though the ambient temp was in the 60’sF and there was a mix to 93octane. Fans were a blazing on the intercoolers so it seems the top end could use a little custom adjustment. Horsepower gains was almost 80awhp at 4100rpm and kept to about a 60awhp gain till 6200rpm where it was about a 25awhp gain. The overall wheel horsepower numbers were 485awhp and 554ft/lbs of torque.

To validate these findings, we compared the results as we mentioned above in the 2nd dyno graph below. The Cobb Accessport was pretty consistant between the 2 Turbo S cars we tried. The pervious Turbo S as featured here, had the Agency Power Y-Pipe and Intake Kit along with a set of Agency Power headers. It also had high flow cats and just muffler deletes by another company. Its numbers were pretty on par with 474awhp and 536ft/lbs. However looking at the test you could see the power and torque came in sooner with both tests being started at 2500rpm. The 3rd dotted line is our original Project 991 Turbo with stock cats, AP exhaust, AP Headers, AP Intake and Y-Pipe, along with the VR Tuned. We use this as a comparison all the time as this car ran very strong. Its peak torque was slightly less at 548ft/lbs but had a slightly higher peak horsespower of 495awhp. The big difference 4100 to 5800rpm where the VR Tuned has a slight advantage. We know this as we raced our own car in the McLaren here!

Stayed tuned as we will be sharing another two Turbo S builds with one having the same mods as this car and the other as our Project 991 Turbo. Enjoy the video and make sure to shop for all your Porsche parts at our Porsche Performance Store Here or call our specialists for Performance advice 1.480.966.3040.