The 997TT in stock form is a wonderful car. I have owned many turbos and Porsches in general and the old saying holds true, Porsche makes them better with every new model. Coming out of a 996TT making well over 690 Wheel HP makes anything other than a jet seem slow. I was impressed and disappointed at the same time upon receiving my car. The ergonomics and little touches were correct this time, the ride, suspension, handling were great, stopping power is unreal. Heck, my last car the upgrade I used for brakes is now a standard in the TT today. Porsche clearly with the program.
The one thing I felt lacking, power. All the hype of no lag and big HP left me with a few clear impressions. The car had lag plain and simple. Nothing as bad as a K24, but when they boast no lag you expect instant power like the no lag a Harrier Jet uses to hover off and launch! You could clearly feel the car utilize the sport chrono and that extra 10 seconds of boost, but some how my watch never showed 10 seconds of over boost in any band. A blip often left me wondering if my car was not correct. As you stay in the power and reach near redline the car would almost feel like it was being held back, almost a stutter of sorts in the power band. In the upper ranges the car seemed to launch hard then nose off and then come back in to finish big. It is like a switch being flipped on and off then when that last big surge the ride was over, redline was present.

I have learned to enjoy the car as is. And with each new mod brings character and more importantly drivability.
Recapping the prior test all the dynos were run in-house on our 500SE AWD Mustang Dyno. Latest SAE correction, self reporting weather station and latest calibration done 1 week prior to runs. The bumper is removed, independent fans run on each intercooler, engine bay, under the car on the exhaust and the front radiators. Car is run in Sport mode, 91 octane in the tank.

In the exhaust test we found that the exhaust was a big cork. Carrying large back pressure kept the turbos from breathing and robbed HP. Where we left off was our exhaust test yielding an increase to 450HP and 457TQ to the wheels. This was up from the initial 429HP and 440TQ.

Our latest round of testing and development has turned to ECU tuning. It seems that the whole market has been requesting, waiting for this modification. After all, this is the reason I bought my TT the first time, the second time, and now this third generation of turbo. All of our programming is done with Garrett from GIAC. We all spend hours upon hours of testing and development with Garrett and Todd. There have been two big priorities that have added time to this R&D process and the final release. First, exhaust gas temperatures (EGTs) are important and they needed to be monitored with the proper tool. These new turbos are incredibly sensitive to heat. Second, there are anti-tuning functions within the 997TT DME detectable by this factory scan tool. It has been a priority to make sure that the EGTs are happy and that the software is factory scan tool compatible to avoid factory service problems. One could modify only part of the DME program however it may raise red flags during a factory service. Not something we wanted. It was also imperative that the software be made to flash and we didn’t have to remove the physical chip like some tuners currently do. To add to this difficulty Garrett wrote proprietary software that is faster and more reliable than the factory PIWIS software. Along with this the few of us that were testing the software also received a propriety scan tool also written by Garrett. This allowed us to monitor EGTS, IATs and other critical data during testing.

The ECU must be flashed out of the car and done on a bench. We have been bench flashing for over a year and a half now so this is nothing new. Currently all flashes on the 997TT will have to be done out of the car and bench flashed. We use a partial harness with OBD2 port and simply plug into the ECU like it was in the car. Some tuners are soldering in chips like we did several years ago. We never open our the box, we do it all through software.
Now the good part. My car based 429/440. We removed the exhaust and placed the factory exhaust back on the car. Base line was established like the last runs, 8-10 runs until the numbers overlapped done another. Typically 5 minutes between runs to bring IAT and EGTs down to previous tested levels. Interesting enough our runs with the new software created less EGTs then the stock software. Something that is crtical in keeping the turbos alive. Our runs yields an increase to 480HP and 480TQ. Don’t let the numbers fool you. Yes, the gains are great. That is almost 50 HP to the wheels. But more importantly the car now does many different things. Running the car in sport mode, the 2-4K rpm range will blast 1.2 bar almost immediately. It does not flicker once, just solid until it settles in to 1.0-1.1 bar at redline. Additionally, the upper end dip that I felt is now gone. The boost is no longer all over the map and more linear. It is clear in the curve and drivability as well. The power under the curve as seen in the dyno is a huge improvement.


We then bolted the exhaust system back on the car and went for another round. Our results were a staggering 506RWHP and 516RWTQ!! Do what ever math you want to get crank HP. Looking at the dynos you will notice that the dip that is inherent in new TTs at 5200 is now gone. The new curve starts sooner, last longer, and makes more over all power--not only peak, but under the curve where it really matters. (Sounds like a Viagra commercial ) The best I can explain what the car feels like, is a stage 4 (in terms of power) but with the punch of the GT turbos used in the 700 package.

For comparison purposes I have attached a stage 4 car. Notice where full TQ occurs in comparison to the 997TT. It is at 5K compared to the 997TT at 4K. This is huge on the road.

The chip is offered in several configurations. 91 or 93 octane, stock rev limiter, 7000RPM rev limiter. Please email or call with questions.

 

Here is the dyno of our latest runs as of last night. We added a set of triangular merge headers that are tuned specifically for the VTG technology. I literally smell like exhaust as I write this. Here are the results, 522AWHP/531AWTQ

 

thats awesome! so much power from just a couple small mods. what about sport cats, are they next?

 

Stephen, why is bench flashing preferable to just flashing the ECU in the vehicle...is this related to the security features the dealer uses to detect these files. Thanks, kevin

 

Very nice, Stephen. Great job.

 

And is there no cost-effective way of using and programming
for the newer turbo on a 996tt?

 

Why would you want to? A good hybrid will get you as much or more TQ ... sooner as well. Kevin

 

One of the things that is very clear is the PIWIS has about a 40% failure rate when communicating with the CAN system. The baud rate that the system talks to the gateway is very slow and not stable. Garrett didn't like the protocol Porsche was using and we both have seen and heard of flashing failure from the dealer. There are some updated DME files and I know that when the dealer has failed flashing it with the PIWIS the ECU will not wake up. They order another one and replace it.

Garrett priority software flashes it with a different rate and protocol but it overlays all the address blocks like the factory does. It triple checks the blocks and does it in the 16th of a time.

For example a flash from the dealer can take 45 minutes to an hour. Garrett's software takes less than 5 minutes. The files are 2 MB as opposed to the 1 MB of the 996TT.

The ECU in these cars is much different.

 

The program for the 997TT is actually more than the 996TT. If you have an X50 or GT2 you will get similar numbers, but the TQ will still be later.

 

My car has HFC on them now. This is why the reduction of most of the back pressure!

 

Those numbers are very impressive for just a flash. Maybe there is some power left on the table...

 

Yes, there is some left on the table, but for now we are not going to push it harder.

 

Stephen,

Nice work. It seems like the 997tt is a great value and can extract good numbers with minmal parts. Look forward to the "packages". I will have to chase down Fred and get a ride to see what if feels like.

Do I now hear 997tt shotout??? Any reason to go to Las Vegas is fine with with me!

 

WOW, awesome review and information. You guy's really did your HW

 

That would be fun. I have recovered since the last one