David Borden

Tom, or anyone with firsthand experience... For a 2019 GT3, what file would you recommend for competitive autocross in SCCA SS class and Porsche Club Production class (200TW and 100TW tires)? I like a car that rotates well and we normally have fairly tight courses locally.

Im used to tuning with monotube shocks, Penske and currently Ohlins on a Cayman and am able to tune the car to do just what we like along with bar changes. Looking forward to learning how to tune via the laptop !

4 Point 0

What spring rates are you running? Stock GT3 are 45/120.

David Borden

Stock spring rates as far as I know.

Tom@TPC Racing

I would use the standard DSC file if its a 2021 unit. Let the g-force and DSC work for you. It works very well. If needed, I suggest making small adjustments(like +/-10%) in the Velocity table to the driver's input. The bigger impact changes have always been camber, toe, rake, and sway bar settings. For AutoX you generally want more rotation, full hard rear bar.

Tom@TPC Racing

Thanks for your feedback. Fair point, will try to do better with my available time and resource.
Always save the current file before making a change, in case an unfavorable change is made you can go back to previous.
After I read your post yesterday I experimented by changing offset from 30 to 100 on a new controller- if there's difference I didn't notice during a spirited street run. Not saying you should make that change, in fact I prefer that you didn't, I just did it because I was curious and didn't notice a change.

Tom@TPC Racing

Awesome to hear!

For the 200kmh flat out left kink, you could try increasing the Rear Hi-Speed Rebound by 10% in Velocity table. If that change is positive and you need more than add another 5%.

David Borden

Thank you Tom, I appreciate the help!

David

4 Point 0

All right, thanks for that. I'm going in. Wish me luck. There could be tears involved. I really don't want to mess with it. But since you went to the trouble of fixing the street map, I'll load that on, and then I'll try the 10% adjustment.

The track map is about 95% perfect for the street, which is outstanding. So the street map, doesn't need to be backed off very much at all to make it awesome.

I don't want to loose this new found grip at the track. It really feels like I am no longer driving the car hard enough anymore. If you have seen the condition of my Brembo GTS BBK calipers that have just been replaced, you wouldn't think that was even possible.

Will report back in a couple of hours with SOS messages if necessary.

4 Point 0

Ok, I'm off to a bad start. I opened the email where Tom sent me the new file and there is no attachment. Either I am incompetent (Very possible) or Tom sent the email and forgot to attach the file.
May I have it again please.

And this just adds to my fear of not messing with it.

enzotcat

Just did my 1st track day with the DSC controller and the stock GT3 Touring file. There is one "straight" where the entry to the straight is a slight right hander followed by a kink to the left. At the start of it there is a little bump, and it's taken at around 80-90mph under hard acceleration. When I was really on the gas, the chassis got unsettled a lot and wanted to skip sideways. No traction control intervention, but definitely a little unsettling to the chassis and the driver. There was also another corner - fast sweeping right hander - with a little bit of undulations, and a similar, but less noticeable problem occurred - I think @4 Point 0 described it well - a sideways step of the chassis. @Tom@TPC Racing - any thoughts on compensating actions to take with the suspension tuning there?

Tom@TPC Racing

It is difficult to provide custom tuning advice over social media, email, or even telephone, LOL, because of possible external factors(i.e. tire pressure, tire temp, tire condition, track surface condition, etc.), and I often don't know if the affect in question is caused by too soft or too stiff by the description. I also think that 4 Point 0 and enzorcat have vastly different setup cars so there is no universal answer, I am afraid. Anyway, just some guesses in different categories from behind a keyboard-

• DSC tuning- if feel too soft then increase % in Speed table at the relevant speed. Vice versa if feel too stiff.
• Rear Toe- could be the car needs more rear toe-in. Most stock 991 cars are set to 1.5mm rear toe-in per side. As speed increases more rear grip can be had be adding more toe-in.
• Driving technique- may be reduce duration of time with steering wheel turned.
• Sway bar- if equipped with adjustable sway bars try stiffen front bar one hole to swift more grip to rear.
• Rake- if equipped with coilovers try lowering the rear height (or raise front height) by, say about 3mm to swift more grip to rear.

enzotcat

Awesome, thanks. I should probably have bored that it didn't occur with the stock controller.

Tom@TPC Racing

Then I would try stiffening the rear on the guess that the high speed kink didn't produce enough lateral g-force to meet the threshold setting for more stiff command.
If this guess is correct, there are a number of different ways to stiffen with DSC software. Can use Speed value, or reduce the Speed G threshold, or Rear Shock Calibration.

enzotcat

Fantastic, thanks. I'll try that. And sorry for the "bored" typo - should have been "noted"

4 Point 0

Ok, Dr Frankenstein has been created. Muwahahahahaha.

I loaded up the new street map. It's much better. Then I had a play. I have added 10% to Hi speed rebound. Which takes it to 20%.

It was Lo 5% Med 10% and Hi 10%

Sport now is 5 - 10 -20.

So I also adjusted comfort to 5 - 10 -15 (Only adding 5% to Hi Speed)

I can't test it until next track day, as the sorts of speeds necessary are cornering at twice the highway speed limit. They tend to frown upon that in these parts.

I'm going to throw a Pro in the chair and have him give me feedback as to what he thinks needs more or less of and have a play at the track. Open Pit Lane.

What I will say is the car is sensational. It's by far the best it has ever been. It seems soft on the track. Maybe because I have been driving around on the street in full track stiffness. Or maybe because the suspesion is actaully working and moving up and down, rather than just skipping across bumps. Anyway, I am very pleased with the unprecedented levels of grip I have at present. Thank you TOM.

A quick question. I noticed front wheels are negative values. if I see -10% and I want to increase by 5% do I change it to -5% or to I change it to -15%?