997gt3north

R888 is better on the track - if only because it has no tread blocks to move around under load. I also found it a good tire from the 1st corner out of pit lane. The tire has a very stiff sidewall so it needs less camber - do not over camber this tire. The R888s in 18s have a 255 which makes for a perfect front tire - ie maximum width. The R888s need to be run at lower temps than originally stated by the manufacturer to have good grip - ie around 31/33f, can't remember the rear temp I liked. One word or caution on this tire, when the rears start to go, they can and do lose grip levels extremely quickly - as in, you are doing 1.2G corners and then all of a sudden your rear comes around at .6G - you have to keep this at the back of your mind so that you don't cause yourself a car wreck - if the tire is going, it will go very quickly.

997gt3north

Another mini update

When I was driving to Mosport for the car's first shakedown, I was noting on the highway that I thought the front's were slightly under dampened in Normal mode but basically spot on in Firm mode - it was Firm mode I used on track that day.

Well, guess what, the shop mistakenly re-used my front 450# valved shocks with the 618# springs instead of putting on the shocks that were re-valved for 600#s with the 618# springs. Obviously I plan on changing this shortly.

Why I thought I would mention this is that it is a little case study that may be useful to others. And that is, the Firm setting basically increased the damping rate enough that it perfectly (in my opinion) dampened a spring that was 168#s higher than the rate that the shocks were valved for.

What this likely means is that a stock valved car can most likely change out the stock springs to a 375/750 setup and just run the car in firm mode and the valving should be pretty close to optimal. I personally would go the extra mile and re-valve them and would recommend a 700/900 setup but it is useful data from my shop's mistake.


The other possibility is to use this data to design your own PASM setup / spring rate given your local tracks that you run. Let's say for example you run bumpy Sebring and smooth other. Given such, send out your shocks and have them valved for Front = 600#s and rear =800#s. Install 700/900 spring. For Sebring bumpy track, run the car in Normal Soft mode and then for other track, run the car in Firm mode. The spring rates 700/900 give you the better spring rates than stock, and then PASM allows you to run bumpy or smooth tracks - very much like Porsche intended - this is what I will be doing.

Mvez

+1.....I thought the 392# front spring was perfect in sport mode with my stock valving, and thought the rear could use more spring and a softer rear bar setting. I think the 672# or 728# rear will be just about perfect for stock valving.

I should have everything installed and ready for a shakedown on Oct. 22nd, after I get back from Oktoberfest with the M3.

997gt3north

A few pictures to finish off this thread.

Somewhere between 2007 and 2008 model years, the rear shock bodies went from being fully threaded to only have the lower third of the shock threaded. For anyone that may go through a re-valve, if you have a fully threaded shock, you can probably use 5-6" springs with helpers - if you have the partially threaded shock body, 7" for the rear with tender, is likely a better fit - this all depends on ride height.

The picture you see below is from a rear shock with only the lower third being threaded - it has a 898# spring with a 168# tender (0.9 inch block height / 60mm free length) and the car has been lower approximately 10mm.

If you look closely, you can see that when you look through the main blue spring, there is no threaded portion.

<-------------- you can see how this is different than in my picture poster that has a fully threaded shock body (if you look closely)

997gt3north

This should be the last 2 pictures for this thread.

Below is two different pictures of my front setup.
The spring is a 7" Swift 616# spring
The Tender is a Swift 45# 70mm free length with 0.94 inch Block Height

The car has been lowered about 10mm - to be exact, the ground to fender on the front axle is 25.5 inches - the rear is 25.6 inches.

The uncompressed tender spring shows how much a 616# front spring has to be 'tendered' at full droop.

Ur20v

Old thread but trying to find out how to access the rear shock top mounts with a oem half cage and trim fitted?

Cheers
Jay

CRex

It's all the same. Remove rear shelf carpeting. You'll find the base of the half-cage mounted on top of rear shock tops. The screws from the shock absorbers come through the tub and through the drill holes in the base of the cage, secured by hex nuts on the cabin side. Remove nuts as you would normally and the shock can be removed from underneath.

Ur20v

Cheers CRex. So just squeeze my 120kg 6'3 frame in between the cage then to access the bolts lol!

Jay

Ur20v

Its good to know I don't have to remove the cage, seats and other trim...

F1CrazyDriver

Bumping this thread up.I have gone ahead and taken OP advise, per this thread and ordered swift spring set: Z60-203-060 Z60-203-060 I pinged Tom at TPC informing him that I purchased Swift springs to try reduce the amount of nose dive in the front of the car, if anything can be done via DSC – Tom immediately replied back asking a few questions regarding my DSC unit and swaybar. Next thing I know boom I had a DSC file to upload to my unit.Very cool that you can do this type of stuff with DSC. Obviously the DSC was not available with the OP started this thread, therefore lets call this round 2.As for the rear springs, anyone know what are the best options available today? If not I can make something however I rather just get something off the shelf. I see that Tarret’s product sometimes hits the swift spring. Has this been addressed and a revised product design ? Or did I misunderstand. Goal : Less nose dive, faster turn in at front and i dislike understeer.

Tom@TPC Racing

Using the DSC tuning software I increased the Default Rate(that's the minimum damping value) by 8% in Sport mode to complement the stiffer spring rate.



997.1 GT3 and .2 GT3 do not have universal-shaped racing springs on the rear like the fronts do. The OEM rear spring is proprietary-shaped conical springs that mates to the OEM rubber bushing top mount. There's no different spring rate selection that's a direct fit, that I'm aware of. Probably because upping the rear spring rate is not good for the OEM rubber bushing top mount. The spring "bends"during suspension travel since there's no articulating ball bearing in the OEM rear top mounts.
We do have a kit to convert the rear top mounts to monoball with motorsport style hats that makes universal-shaped racing spring compatible on OEM PASM rear shocks.
Link here- http://www.tpcracing.com/997-gt2-rear-top-kit.html



Since you increased the front spring rates to reduce dive, you'll need 700-800 lbs springs in the rear to balance the car. The stiffer rear springs will help transfer the weight to the front.

F1CrazyDriver

^ Thank you Tom. I'll definitely look into your kit after some real seat time on the car.
Finally got around installing the front springs, yesterday. It took me about ~6 hours that said, 4 hours was mostly cleaning front fender well area. Driving around it feels much better then oem. I will write a detail write up after a few weeks of driving. Thus far, massive thumbs up.
Thank you to the OP.

TRAKCAR

F1CrazyDriver

Peter, interesting approach. I have yet to track the car on this setup, just finished it Saturday. I went one notch softer up front swaybar. I do have a massive front spliter. Maybe the 335 up front will not be enough ?
Do you happen to know what 16RS spring rate is up front and weight on each corner ? I'm curious.

F1CrazyDriver

Anyone happen to know GT2 RS (997) or GT3 RS 4.0 (997) Rear spring rate ?