F355bob

As previously posted, I got a FVD tune on my 2017 base PDK Carrera about 6 weeks ago. In that time I put on over 500 miles on the tune and it was great except for one lingering problem. At highway speeds and around 2000 -2500rpm when I gave it a dose of throttle, the engine would "flutter" for about one second and then it was ok. It never did it at any other time, but on a 50 mile trip where you were doing 70mph in 7th, it happened fairly often to be a problem. FVD sent me a few files to fix it and I thought it had gone away but it came back and we could not resolve the problem without cutting more power in the tune. I liked the power and did not want to loose any so I asked for a refund which Theo gave me in full. FVD is a great company to deal with and it was unfortunate that in my car the tune was a problem. The FVD tune was very fast and the car was so responsive. You could see the boost gauge number climb when ever you touched the throttle and this gave a very responsive car but may have contributed to the problem I was having. I guess I could worked with them to keep trying to resolve the problem but was worried I was doing damage to the turbo or engine when I was getting this flutter. I loved everything about this tune except for this problem. Since once you have a tune, you will not be happy without one, I decided to get Softronic. I had talked to Scott several times when I was deciding which tune to get and he thought he knew why I was having this problem and he could resolve it. I got the Softronic tune and it is also very good. It is smooth and the power does not come on so suddenly as the FVD. I did some accelerations on a on ramp that with the FVD and I could reach 90mph at the end of the ramp and also did 90mmph with Softronic so I think the power is the same between both tunes. The difference is how the power comes on.. In the Softronic the boost comes on at higher throttle inputs than FVD so it does not "feel" as fast but the on ramp acceleration shows it is. I do not have the flutter with the Softronic that I had with FVD. Hopefully Scott will post with what he thinks was the problem and the fix.

911.

Glad to hear you got it sorted. Wonder if other user with FVD tune have had this issue. Curious to hear what it was from Scott.

Speed2k

I’m glad your problem has been resolved, albeit probably not the way you would’ve preferred. Please update us once you’ve gotten more seat time with the Softronic tune.Does your car have the Sport Chronos? Do they both eliminate the turbo lag? How is the fuel economy vs stock (for both tunes)?

F355bob

I have sport chorno. Not much lag. Car shifts down to lower gear immediately . I got better than stock mileage with the FVD. I got 30mpg vs 27mpg on highway. Have not put enough miles on the Softronic to tell fuel economy/

spdracerut

On turbo cars, highway cruising is often a load case where there is enough exhaust energy to have the turbos making positive pressure in front of the throttle plate. There is a transition point where the compressor bypass valve wants to close. The flutter happens when you linger at that load point where the bypass valve wants to close, but it's not enough load to really slam it shut. So the valve bounces between open and closed a bit causing the flutter. So you can tune it such that at these highway cruising speeds, there is less exhaust energy to spool up the turbo and you stay away from that bypass valve transition point. But it makes the car a little less responsive at these lower load conditions. Generalization of turbo engines. Not 911 specific.

Tier1Terrier

Glad you got this matter resolved but I'll admit that I'm disappointed in the outcome. I'm not ready yet to pull the trigger on a tune for my 991.2 C2S MT but I've been reading all the threads on tunes for about a year and was strongly leaning towards FVD despite that they were the one with seemingly the least amount of users.

F355bob

I think spdracerut describes the problem I was having very accurately. I was surprised that FVD could not fix it but . Scott seemed to know exactly what it was and why it was doing it. The FVD tune is very good . I know someone who has a GTS has Softronic and is posting some 1/4 mile times and others are saying Softronic is no better than stock. Well I have had two tunes, Softronic and FVD and the Softronic is so much better than stock. I don't need a dyno to tell the difference between stock and Softronic. I removed my tune to see if the stock file had the flutter, which it did not, and the car felt like a Toyota without the tune. It changes the car into a completely different car. If you are on the fence about getting a tune as I was, do it. It really changes the character of these turbo cars.

XLR82XS

I have FVD tune in my 2017 C2. It's fantastic and have not had any issues similar to the OP. Definitely the way the car should be from factory. Beyond the increased response and drivability - it's as fast as my old 996TT when it was 100% stock.

F355bob

Is your car PDK?

XLR82XS

Yes.

Omega4

In the Softronic the boost comes on at higher throttle inputs than FVD so it does not "feel" as fast but the on ramp acceleration shows it is. I do not have the flutter with the Softronic that I had with FVD. Hopefully Scott will post with what he thinks was the problem and the fix.[/QUOTE]

Thanks for posting the comparison between tunes. I recently switched from Cobb (v104 map) to Softronic and thought the exact same thing...that the power didn’t come on as quickly as the Cobb on my C2 initially. But when RPMs get to about 4000, it’s a magical moment. My 0-60 times are similar telling me it’s putting down similar power as the Cobb v104 map. I also noticed that the car felt more planted without getting “squirrely” when accelerating hard in a corner...more linear power delivery it seems with Softronic.

The only thing I’ve noticed now is I’ll get a P24D6 tank pressure sensor fault after several hard accelerations high in the RPM’s. I don’t think it’s related to the Softronic tune as I’ve heard these sensors go bad from time to time. I’m going to try to see if I can throw that code again without the tune and get it looked at.

Thanks again for sharing your insight!

enzotcat

These sensors do appear to go bad on the 2017 cars, and it does seem that the tunes - be they Softronic, FVD or APR - so really more the act of flashing the ECU *which could occur as a result of a dealer flashing an ECU update* - seem to tickle this a little.

Omega4

Great point...thank you!

Sir99

I was wondering if the tank pressure sensor fault is now resolved or do you still get it ?

Wujohn

I have no tune and have the same fault code so it is not related to the tune...at least in my case.