452gt3

Has anyone had good results on track from changing spring rates on 991.1 gt3?

Cay_PI

Yes. .2 RS Springs works fine with standard dampers and PASM Dport mode.

452gt3

Thanks for the feedback!

Seth Thomas

Yes there is a lot of benefit from changing the spring rates on the 991.1 cars to a stiffer spring. If you have some time before you are ready to make this modification stay tuned as currently there is an amazing suspension package that is in development that is going to make the 991.1 cars an amazing car all around.

DK7

only springs? change plug&play?

kblask

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Stay tuned to what?

452gt3

Thanks again, I also have mono ball and recently added a DSC controller, drop links so springs is as far as I plan to go.

A/S

^^^if you have monoballs, and the DSC, the car only needs a nearly twice as stiff front spring, and rear ones can be left alone.

Going with stiffer springs in the rear, which need more than twice stiffer springs in the front moves the spring rates into 991.2 GT3RS territory, a car that is already too stiff sprung for most U.S. racetracks. The PASM stock shocks in the 991.1 and 991.2 GT3 and 991.1 GT3RS are not calibrated for the much stiffer springs in the .2RS, and the OEM program for the DSC box is already running deep into the 500mA current (full stiffness) on the front shocks using the stock soft 256# springs, so the much stiffer front springs would be out of range for the ideal valving they need. On the OEM DSC Sport 991.1 GT3 maps, the front shocks go to full stiff at 80% of their g-meter table, and that's practically any element causing 0.8g or higher g-forces. DSC compensates the soft front springs with a stiffer shock setting in the front axle, then adding the stiffer front spring allows the DSC table to be adjusted, but there is not enough adjustment to keep the same shocks and run a 550# or 650# front spring. Around 450# front springs with the DSC Sport program you can still use the stock shocks.

Now, if you venture into much better shocks than the decent PASM, there are two super nice options: Manthey Racing KW 3-way and they already come with matching springs, or Ohlins TTX with matching springs as well, between these two I prefer Ohlins, but it seems that Manthey has more data setup for our use.

I'm near the end of optimization on the stock PASM shocks, after many iterations of DSC sport custom maps, my limitation now is the shocks, this is where I think these cars would benefit the most for lap times (not power mods, or brake mods, but suspension mods). My .2RS is already on monoballs and proper springs, so shocks are the next ideal mod.

In the meantime, I would love to know more about what is coming soon from Pro-Driver Seth, it must be goooooood.

452gt3

A/S thank you sounds like great information, I like doing the front and if I want to try adjusting the rear later I have data to test against. I'm trying to sty away from adjustable shocks I tried them on a 04 gt3 and felt I was not good with the engineering to get the best out of the car and I was better off with custom vavled stock shocks.

Thanks Mike

Cay_PI

Depends on the productuion year. If its ab GT3 built before 2016 you need:

-> front helper springs
-> spacers
-> front "federteller" (don't know the english word (otherwise the car comes to high)
-> rear main spring (stock spacers and helper spring are allready the same parts as .2 RS)

If its a .2 GT3 or .1 RS you don't need the new "federteller" but the rear helper spring and spacers (because these cars don't have the helper spring on the rear like the .1 GT3 and .2 RS)

Thats it. fits plug an play. It runs fine with the OEM dampers. With PASM normal (which is perfectly adapted to the OEM springs) it becomes a bit underdamped, good for comfort. On PASM Sport (which is way overdamped with the OEM springs) it becomes nearly perfect. Stiff but way more reactive on rebound than stock. Feels more comfortable than stock on PASM sport and is way more stable. Especially under braking / turn in. Car feels 200kg lighter in tight corners. And its not underdamped, not on the (stiff) front and not on the rear.

Not so much different than what porsche did with the new RS. Dampers are not that different than people think...

Send me a board message if you want to know more.

PS: my DSC V3 sport controller is for sale because of this, I don't need it anymore and I'm not able to make better maps than stock PASM sport
PPS: Öhlins or KW V3 are even better for sure, but thats another thing

KOAN

I'm very happy with BBI springs.

452gt3

I like BBI products but what did their springs do for you performance wise?

KOAN

I found the car very planted, balanced and communicative. They claim that their spring rates are within the range of the stock shocks. They increase the rear a little and they approximately double the front spring rate. I left the height unchanged. For context, I am coming from a 996 GT3 with 800/1000# springs and Moton Clubsports with all rubber removed from suspension, and Pirelli take offs. The BBI springs were good for a sub 2:00 VIR time on stock size Hoosiers and minimal alignment, otherwise stock 991.1 GT3.

452gt3

Thank you for the followup that's what I'm looking for seems like the front springs are the big problem and I may start there and do the rear later.

Stealth 993

Anyone got all the part number for the swap?