todinlaw

I have spent considerable time reading all the posts of guys experimenting with spring rates and Dampers on there cars

1) does anyone know for sure what the OEM spring rates are for starters on the 997-3.
2) without going with new shocks and anyone increased the spring rates soften the sways to get the car more neutral if so please share what you have learned.

sasportas

I have tried all adjustments of the stock sway bars and can honestly say that setting the rear bar to full soft feels the best and keeps the car neutral. The front bar I keep between one from full stiff or in middle setting. I know that I'm completely different from how the factory delivers the car. Try it, you may like it.

FTS

According to Excellence's first report of the 3, fronts have 45 Nm and rears have 105 Nm springs.

Larry Cable

I'd recommend the cheap update to the GT2 rear swaybar (and matching bushings)

todinlaw

I am trying to figure out your response in lbs. to convert newton meters to lbs you multiply the nm x .7375622 and that seams real low unless i am doing something wrong.

Where I am going with all this is that I want to soften the rear sway to make the car less snappy when I am rotating the car in a corner. I would like to try increasing the spring rate say 2 to 400 lbs and soften the rear sway a bit. but I need to know what the current rate is. Plus I know the cup guys are experimenting all the time. so trying to get some cheap knowledge.

NJ-GT

250 (257) lbs/in Front and 600 lbs/in rear based on the 45/105 info from FlyingToaster/Excellence.

997gt3north

I don't have the answer to #1, but basically you are going in the correct direction - more spring with less sway. If you go to the kwsuspesion site and look at their posted spring rates that they put on a variety of 911s, their approach (not everyones) has always been to increase the rear spring rate substantially over the stock rates (i.e. 400-500 going up to 900) but only marginally increasing the front spring rates - their approach has also been that they believe in using the dampers (compression/rebound) to further increase the spring rate (others do not always share this approach)

More spring and less sway will allow each wheel to better handle the road surface that each tire is facing so as you know this is where the big adjustments should be made

Can't remember the name of the shop, but the 996gt3 guys sent off their stock dampers to be revalved if they wanted to increase the spring rates - a quick search should give you this information and this is the guy/shop that I would call.

I think the shop is Dan Jacobs in CT

Also, just saw this on the TRG website
http://www.theracersgroup.com/shop/997.php
Looks like their approach is to really up the front rate versus the rear (again, everyone does something different)

paul

todinlaw

Thanks Paul, I love to do my own work it gives me a sense of satisfaction to figure things out, If I can't hear, I will bite the bullet and hire a shop to set up the car up and share what we do and how well it works. I know that I am on the right track and have a good idea of what I would like to try to make the car better, unbelievable to me that P makes such a wonder and adjustable track car but gives you squat in terms of dynamic specks. I will keep pushing for answers.

997gt3north

- based on my post above , iirc, the KW guys bump the fronts upto around 285 but the rears goto around 950 - so again, much more rear of an increase

- i can understand doing both - i.e. more front spring to avoid the dive / rebound under braking but also more rear to help rotation and again to reduce squat

- i would guess the 500f/800r would work well (and still be streetable) - but what do i know (thus call one of the real shops)

todinlaw

Trust me, i do not have all the answers, in a rear engine car the proportion of the spring rate increase is important and favors going more in the rear. When you go get a set of motions as I understand it they don't suggest as huge differential between front and rear. The bottom line hear is if you can get the spring rates right where you do not need to rely on the sway to keep the car level in the corner without relying on the sway to do the work allows the inside tire to stay planted when cornering. As far as the front goes, I was going to start out leaving that rate stock, if I can and stiffen the front sway, to help me with understeer, I am not sure I can but by stiffening the rear, it by nature will help the front with body role.
What we need is a budget, and a **** load of track time and springs, but I believe the gt3 is and can be an incredible handling car it just does not come from the factory that way. Its set up to push like a pig, and gets snappy when you rotate it.

997gt3north

- with my current setup, i don't find it snappy when it rotates and i have dialled out the push
- that said, it currently is and was when stock snappy if you have a lot of stearing angle and you are in 2nd gear (if you are too throttle happy)
- i am very happy with the car now in all mid and high speed corners (very very slight overstear)
- i agree that the car could be better with more spring and less bar (especially if you wanted to run slicks) but i think you can get 95% out of the car with what you have to work with (and in my opinion the gt2 rear bar is a good fix if it works for your style of driving - i'm very smooth and have only seen the upside benefit when i added the bar)

- if an intermediate like me can get the car around Watkins Glen at 2:16 with stock tires and a good alignment, then a pro with Hoosiers would certainly be sub 2:10 - so the way I look at it when I can approach 2:10 with Hoosiers, then it will be the car that needs improvement and I will spend the money

just my thoughts

Paul

(but i do agree with what you are doing)

todinlaw

I don't know how they rate the stiffness of the sway, and I understand that when you go to the GT2 bar you move it back one notch, do you have any idea if that is a bit softer setting? and how that adjustment relates to moving the stock bar back one notch, just curious?

GT3 Chuck

moving the setting toward the bar is stiffer and away from the bar is softer...

todinlaw

I understand that, my question is as between the rates for the GT3 bar and the gt2 bar, we know gt2 bar is stiffer, (i assume) how do the quantify that, lbs or what, and how much stiffer is the GT2 bar??

C.J. Ichiban

gt2 bar is allegedly 30 or 40 % stiffer for a ballpark...


I've got the stock sway bar but am considering both motons and gt2 bar.

frank- what kind of ride height adjustment have you made?