997gt3north

The usual range you see without driver:

Front 500-700 per corner
Rear 850-1150 per corner

Depends on whats in the car, how it is aligned, raked, etc.

Without going crazy gutting etc, DE cars are usually in the 3050-3300 range (light DE spec to heavy as delivered spec). Unfortunately, while your over all weight guess might be close knowing whats in the car, you corner weights really need to be measured to know what you have.

Your 3050# car looks like:
- light weight seats
- light weight 18" wheels
- gutted front trunk
- no cage
- pccbs
- lightened exhaust
- lwfw
- 1/2 tank of gas

+125#s for Typical DE Car (3175)
- add 1/2 cage
- fire exting
- iron rotors
- either no lwfw or gutted trunk or other

-100#s for the Stripper DE car at 2950#
- lw battery
- no carpets
- center consol delete
- glove box delete

997gt3north

I'm the guy with the 997 that just did this and had Ira fab up the new piece - glad to see that it will also work for 996gt3 owners.

Starting with the premise that there is no correct spring rates for a combo DE / street car setup, I would encourage you to consider very slightly higher spring rates as you wouldn't be doing this if this car was a a weekend cruiser only. As you may have seen, I went with a 620/900 setup and really like it. I would add, that to make the car even better, I think 700 (lets not even talk about higher for a moment) would make the car even better - I would thus suggest that you consider 700/900.

As I wrote in the 997 thread, the only thing I would change is adding slightly more front spring from my 620# (110N/mm) choice as it would hold up the front even better during braking. I can't say anything negative about the 900# rear - nothing - it is very good. It holds up the rear of the car well and in no way creates a twitchy too stiff rear. When you look at the fact that KW Clubsport Suspension has just gone from a 950# to 1050# rear spring (a setup used by many European Nurburgring drivers) I think this should give you comfort that the car is still streetable with 900 - 1000# spring in the rear as long as it has been re-valved properly.

I see in one of the posts in this thread that a poster is using a 800/1000 setup - to me, based on what I know now after my 1st drive after my re-valve, this setup would be an excellent Hoosier R6 type setup.


The other thing I wanted to mention is that, while you are in there, if I were you, I would consider doing the monoballs and solid caster pucks for the rear.

ninerguru

997gt3north... I found your article on the 997 forum and basically following your footsteps! Thanks! I have been exchanging email with Ira and will be testing it out on 6GT3s... Have been on the fence with the 700/900... I heard some good things with that combo... Thanks for your feedback...

Crazy Canuck

The 800/1000 setup is most excellent on slicks.

Works very well on Cups too. Tracks I normally drive are pretty smooth.

AudiOn19s

I think 600/800 is "better" if you do much street driving at all. Some of that will depend on how stiff the dampers are once they are re-valved.

I ran 450/900 in my old C2 on the same damper as the OEM GT3 units and it wasn't horrible but it was very stiff for street driving.

My GT3 has 600/750 but with triple adjustables and when you turn them all the way down it rides softer than it did stock. I've been thinking of the 800/1000 swap myself but not sure it's worth it. Car is such a joy to drive the way it is now that I'm not sure I feel the need esp when I drive it on the street as much as I still do.

ninerguru

700/900 it is! Shocks go out today... The waiting is the hardest part... Time to clean up and lube front monoballs and check rest of suspension while apart... Updates to follow as the project unfolds and parts start to come in...

MTB

You may consider this set up for rear mount. You can get both monoball mount and spring hat (for 60mm) from TRG.

v12man

I drove my car briefly on Friday after the initial setup and corner weights – the car is – surprisingly – nowhere near as stiff as I thought it would be – I might actually be able to persuade my wife to sit in it for short trips.

After the initial ride height and corner balance, we discovered we could not get the front passenger side (corner weights done with weight in drivers seat) low enough to get it where we want it without removing the helper springs, which I do not want to do, so we are waiting for new shorter springs (by 30mm) to arrive from Germany, and then we will finalise the setup.

I thought I would post – for interest – the shock dyno results – I cannot interpret the graphs, so please don’t ask . I also am not sure which are before and after – I think the before are the top 2, and the after the bottom 2, but might be badly wrong.

ninerguru

So, V12man... What length spring do you currently have? What is the length of the helper spring? Total compressed length? Your new shorter springs are just a bit over an inch shorter (30mm).

I will be ordering springs next weekend and wanted to know if 7" or 8" will be better in the front. 997GT3north used a 7" but said that an 8" would work better... I'm going with 700# up front and will not be using a helper spring. Thanks!

KOAN

Andy,

I was really impressed with how well your car felt at Mid Ohio. I have 800/1000 in mine with 2 way motons. I would leave yours as it is, especially you like the street feel. Mine is OK, but not great.

997gt3north

Another way to manage the street driving spring rate effect is to have a street tire with a softer sidewall - like the Pilot Super Sports - I was very surprised myself how much of an effect this can and does make with everyday driving - versus the OE+ cups on my 997gt3, it was like reducing the spring rates by 100-200#s in feel.

It was this very single fact that got me thinking a lot about how to setup a car and what Porsche from the factory could possibly do differently - ie, send the car's out with more track focused spring rates but deliver it on a tire more like the PSS. This would then allow a Hoosier R6 type tire to be better mated to a stock stiffer spring setup if desired for the track and yet add some tire sidewall spring effect with good rain channels to make it a better daily driver.

himself

I've got 700/900 with a re-valve and it's still very streetable. The real issue is rebound, especially when you go over road imprefections. The shocks won't extend fast enough and you will be airborn (or feel like it) for a very short time.

On the track, big rumble strips can upset the chassis, so you should be careful with them.

The time you will gain under braking, taking a set, and other transitiions is only a tenth or two per corner, but it adds up.

-td

ninerguru

Update... Rear monoball mounts and adapters came in today. Wife says they are to nice to install as they will get dirty... They seem very well made. Looks like 60mm adapters are now anodized in red. They will center in the protruding lip on the underside of the monoball mount. Shocks were delivered to Bilstein this afternoon... Front monoball mounts were inspected and lubed yesterday.

v12man

First - a word of caution - this setup is for a 996 Mk1 clubsport - I am not sure if there is a difference to a Mk2 GT3 - there is a difference in the original spring rates as manufactured, and documented in a thread by 911Slow which I can't find.

There is buried in another thread spring lengths of 8 and 9 inches for the mk2 when used without tender springs - although I believe in using the tender springs so that under droop, the spring stays seated in the hats - i.e when/if bumping off curbing or if the car is on a lift, it should help to keep the spring in place.

https://rennlist.com/forums/996-gt2-...s-quick-q.html Post #10


Final spring config will be:

Front 150mm (+-6 inches) 140nm/mm (798lb/in) 60mm internal diameter springs (this was originally 180mm, but we can't drop the car enough to get stock ride heights - fortunately my spring supplier will just swap them out at no cost)
Rear 180mm (+-7.2 inches) 180nm/mm (1026lb/in) 60mm ID springs

Both front and rear have a 5mm slider between main spring and tender (5mm is the height added to the spring stack by the slider)

Front and rear have a tender spring from H&R that is 15mm high when compressed, and 40mm high when uncompressed - so in normal use it will be completely compressed - in fact it is so soft I can compress it completely with my fingers.

ninerguru

Quick question... Do you have a single spring on your car or are you using helper springs? Do you know the front & rear spring lengths? Trying to determine if I need to get helper springs. Thanks!