With winter approaching the high country, my track season ended yesterday and I'm already thinking about "stuff" that could be done to improve things next year. Specifically, I would like to make the car run "flatter" thru the corners. Currently there is quite a bit of body roll even with the H&R sways set full stiff fore and aft. After talking with fellow track rats and reviewing parts of Cannga's most excellent thread on turbo suspensions (which is about as long as War and Peace), I think the logical place to begin is with coilover springs preferably to replace the stock units that come with the Bilstein Damptronics. According to Cannga, these are 340# front and 565# rear. His have been bumped to 448# and 600# although I haven't combed the thread to find who manufactures them. So, questions:

1. Who makes replacement springs and how stiff can you go before having to re-valve the dampers or is that not a consideration? I think some of the local track guys are running spring rates well in excess of 1000# although not on a Damptronic unit.
2. If I were to consider changing the entire coilover and went to something like a Moton that is not designed to work with PASM, would it also affect Sport Mode that works in conjunction with PASM? I need to retain Sport Mode functionality as it increases turbo boost from about 18 psi to 23 psi via the Evoms tuned ECU, plus the more aggressive throttle mapping, more tolerant PSM settings, etc.
3. In going to a stiffer spring, can the sway bar settings be better optimized?
4. Similarly, would it affect alignment which is now -2.5' camber, 1.0 mm total toe in front, 6.0 mm total toe out rear?
4. At what point does the car basically become "unstreetable" due to subjective ride considerations?
What else do I need to know before starting to talk with the shop pros? TIA

 

I know it's not an answer to the questions above but I would recommend trying the TPC Racing DSC Module.

I have changed everything on my car from the shocks to the sways, LCA's etc etc and the DSC module.

Today I fitted a module to a stock car and it made a huge difference and I would do that before anything as th car just feels so much more planted now and has better bump control.

 

War and peace - I resemble that remark.

1. For Bilstein, the possible increase of spring rate before re-valving needed is at most 200 above stock and not more, meaning around 550/750. *In general* around 400/600 is considered to be the start of a more track oriented car, and of course 800/1000 for the hard core advanced drivers (not me!). No question that by 800/1000 you need track Ohlins/JRZ/Moton stuffs.
There are two places you could get springs that fit Bilstein: Hypercoil and Swift Springs. The springs you want to look for is 70mm ID, 6 inches long front, 8 inches long rear. The process is very easy and cheap - labor should be around 300-400 per axle.
Swift Springs: http://www.swiftsprings.net/products...r-springs.html
Hyperco: http://www.hypercoils.com/PDF/70mm.pdf
Currently my car is set at 448 front/600 rear - versus Bilstein's 336/560.

2. Good question and VID997 and other pro's/experts here could tell you for sure, but AFAIK you should be ok. You simply disable the PASM part of Sport mode, and not the rest.

3. Again VID997 would know well here but IMHO the H&R sway should be fine, neither better or worse, depending on where you drive, road condition, etc., etc. In fact you may find that the stiffer spring allows you to ease off on the hard setting of the sway bar. Unless you are extremely hard core at track, the stiff setting of sway bar is not necessarily the best way to control body lean; in other words, if you find your setting of sway bar is Stiff front/Stiff rear, IMHO it's a sign that you need stiffer spring. Body roll could be controlled with stiffer spring, then fine tuned with sway bar.

4. AFAIK should not.

5. When becoming un-streetable? Totally depending on how long the daily street drive is, how old and who you are, what tires you are using, what else is in the car (drop links), etc. Very very roughly speaking, I would say around 400/600 spring rate is the cut-off between a street car, and a more track oriented car. The tire makes a HUGE difference, both R comps and the Bridgestone RE11 are noticelably stiffer side-walled than Michelin PSS and make car more sporty, less comfy. In my case, daily drives of 17 miles, Bridgestone RE11, rate of 450/600 is the most that I could tolerate. Hope this helps and best of luck whatever you decide to do. If you *are* driving car to work and belong to the 50 plus crowd, I would strongly suggest to try the stiffer spring and stiffer tire before changing the whole coilver. It is relatively cheap, totally adjustable, and with a good tuner, all you do is hand him the key and a copy of that post about spring in my Bilstein thread. :-)

Alright alright I *get* the War and Peace part. LOL

 

Nick I suspect Steamboat is way way beyond help :-) as far as just DSC module. And if he's going for Ohlins/JRZ/Moton without PASM, then the DSC module would be money wasted because it won't work anymore.

In other words, the DSC is a great product but only the first step (electronic manipulation of damper setting), next step is lower springs (DSC module cannot do the job of lowering stiffer spring), then coilover; Steamboat is *beyond* this last step . The TPC web site actually shows these different stages, all the way to hard core track stuffs AFAIK.

 

Yes I totally agree with but it is a clever product and something he can fit himself in 20mins and will be shocked at the difference.

But yes changing other parts for a more track orientated setup is necessary.


Have you tried one yet Cannga?

 

No, and there is a reason. The primary problem is of course the stock PASM programming: it's either too soft or too hard. So there are 3 ways to change this:
1. Stock springs and TPC DSC (no doubt a great product)
2. Lowering springs and TPC DSC
3. Bilstein Damptronic coilover

Why did I not put TPC DSC next to number 3? The Bilstein coilover comes with a different programming from stock PASM *already*. The Bilstein hard setting is a huge improvement over stock PASM, stiff but not jittery, and very much useable.

You *could* add the DSC to Bilstein, but purely personal taste (no right or wrong); I feel fine without it. At a thousand dollars it is not cheap and you might have noticed cost for number 2 (lowering spring + DSC) comes a touch closer to number 3 (Bilstein). But again no right or wrong, different choices for different people.

 

Cannga & GTRNick, Thanks for your responses! And, as Can points out, I am waaay beyond help.

Cannga, I like the idea of taking the spring rates to the Damptronic max.; probably 560# fr and 784# rear from Swift, and seeing how that works as a cost effective solution. It would be nice not to have to throw a $10,000 bill at this by way of purchasing new coilovers. Chris Cervelli has also opened a shop in Denver and I plan to get his thoughts and help when the time arrives. Thanks again!

 

Thought you were staying for the weekend? Snow in the forecast for the pass?

 

Yea, I was advised as I was leaving the track yesterday that NOAA upped the precipitation forecast over Loveland and Rabbit Ears so I decided to beat feet and go home. R-888's ain't what you want in a slush storm over the pass! My motto is "Better to be up here wishing I was down there instead of being down there and wishing I was up here"....or something like that.....which I 'm sure you've heard before. But I did have a really good time yesterday and it was a nice way to end this season.

 

As soon as I saw your post's title I knew you've passed the point of no return .

Regarding spring rates, you might want to consider even lower like 500 front/700 rear. I mean 200 above Bilstein stock is absolute max, but 150 above is a better match for the Damptronic's damper and also safer as far as not causing damper failure (leaking of the valve), which as you could imagine is an absolute pain in the derriere. Car totally incapacitated while shock is being re-valved.

I had 560 front in my car in the past; while that rate is nothing for a track car, it was very very stiff for street driving. Also not sure about this but I felt that my car understeered, because of the lower speed of my daily drives. In other words, I suspect such stiff front is fine for the track because the MUCH higher cornering speed there, but understeers for street driving's lower speed because car doesn't lean enough and the front neg camber tire remains tilted in neg camber state with less bite/traction.

 

Yeah no probs matey


I guess I should have thought about it more when you started talking about the spring rates

 

Hey Steamboat,


I rode in pwdrhounds car early this spring on the street right after he installed his JRZ suspension set at the lowest setting. His car was felt smoother than my stock 997 (at the time) with pasm off. At the track, his car was solid at a higher spring rate (not sure what he had it set to, I think 800 at the time.) You may want to have a chat with him.


I don't like the idea of having the sways set to their stiffest setting. I like the car to have a balanced weight transfer giving weight to the corner that needs it especially at higher speeds.


I would take your car to Chris and have him take a look at your current setup. You may just need different arms and an alignment.


My car has the monoball cup arms and hr lowering springs. The cup arms are a little noisy on the street but, I think you run the same brake pad as me and that noise is much worse.

 

When you rode in my car this spring I had 1100F/1200R springs on my JRZ Pros. I had compression set full soft when you rode in it. I can say that on the street the car rode better than any suspension I have ever run and that includes RUF Bilstein PSS9s and H&R coilovers. This set up would be fantastic on the street but was a bit soft on track. I think it would make a great 50/50 street/track set up. I replaced the springs after one weekend. I'm currently at 1400/1500 but for an optimum track set up Chris calculated the rates at 1700/1800. I will probably go to that this winter but that will necessitate JRZ Tripples which will allow you to tune out the harmonics of the tire compression as well at those rates. My car weighs 3180 ready to run without driver. Keep in mind a 997 Cup weighs 800lbs less than a 997TT and rides on 1458/1458 springs. Bottom line is, quality Motorsport shocks are the key, there is no way around that. You will never be able to replicate the performance with the Damptronics. With the compression turned way down, my JRZ Pros at 1400/1500 ride better than my old JRZ RS1s did with 700/800. With good shocks you don't need to be scared of high spring rates. Art's Cayman is on 1000lb springs with JRZ Pros and he says hands down the car rides better than stock. He puts a lot of street miles on it. As far as sways go, if you are having to run overly stiff sways, you are basically putting a band aid on poorly set up under sprung suspension. Sways are a fine tuning tool as ideally you want the suspension to do the job on its own. Later...

 

Much to consider and learn. Very little is as straightforward and inexpensive in this sport as I tend to hope it might be....

Thanks for everyone's input!