Bilstein Valving

[bruboy]

Like a lot of the Guys on the board I use my SC for track and road. My cars is going in to the workshop over Xmas for the following up grades

26mm rear torsion bars
22mm front & 21mm rear anti roll bars
Revalved bilsteins

and Carrera 3.2 brakes with our hosts under A arm cooling kit. I listen to Bill V's advice!

I have been researching previous threads and talking to workshops in the UK about what settings to set the Bilsteins to and there seems to be quite a difference of opinion and I am unsure which way to go?

Any way here is a summary of the recommendations from various sources and a comparison with some previous Pelican threads. Interestingly the race shops still say the car will be OK for the road?

Race shops tend to recommend the RSR setup:

front 160/160 rear 200/180 ish

Compromise track road:

front 225/120 rear 325/150

And previous Pelican threads show around:

front 220/120 rear 360/140

Clearly the race set up is very different and I am tempted to go with this. does any one have experience of this set up on the raod?

thanks

[DW SD]

You may want to call a specialty tuner or the bilstein factory. I had a great experience with the shocks which were custom valved by Mirage International, here in San Diego. 858.581.1101 - ask for Jae, he's the owner.

Doug

[88 Club Sport]

I agree w/Doug...have them valved to your specific set-up/specs either by Bilstein or by a shop like Smart Racing. I'm planning on pulling my Sports this winter and having Smart Racing revalve them after I add larger sways. http://www.smartracingproducts.com.

Also, you may want to consider going with larger torsion. Many find a 22/28 combo a good street/track compromise. I went with 23/29 torsions and 22/21 sways with Bilstein Sports and while the ride is firm, I think it is ok for the street, especially if you have stock seats.

Just my 02 cents.

[lukeh]

I sent mine direct to Bilstein and had them done to their recommendations. They were very helpful and spent a lot on time with me on the phone. I believe the gentleman's last name was French. I'm sure a search under this topic would get you his name and number. I have been very happy and I seem to remember the cost was only $55 per

[KobaltBlau]

those are pretty wimpy torsions for SC at the track.

I would go:

22/29
23mm tarrett, srp or similar sways
elephant front bearings
elephant weather monoballs strut top and inner banana
rear Wevo SPS spring plates
Bilstein Sports. Don't know enough about custom valving numbers (but would like to)

[umgang]

Contact Steve Weiner at Rennsport Systems. He has all the formulas and expertise to recommend settings that will work with your particular car weight, suspension mods, tires...503.244.0990
Do it right the first time, with someone who is knowledgeable in this field.
Nick

[ttweed]

Originally posted by lukeh
I believe the gentleman's last name was French. I'm sure a search under this topic would get you his name and number. I have been very happy and I seem to remember the cost was only $55 per

That would be Jack French, at the West coast Bilstein Motorsports Headquarters in Poway, CA., 858-386-5900. They charge $70 per shock now for a straight revalve.

TT

[911-32]

I think you guys might be forgetting that this guy is in England - that's over the Atlantic ocean fellas. You know, the guys standing shoulder to shoulder with you in Iraq !

Its not easy, convenient or cheap to send shocks to the US. We get hit with postage and the revenue charges us VAT and duty on the return into the country despite the fact you owned them to start with.

I have also found that US specialists are very careful about letting their proprietary valving info get out. Now Rennnsport may be different but SRP will not help out. I think Bruce really wants a hand with the valving numbers so he can get a feel for who is BSing him on the ideal set-up. Given the range of opinions he has received I would also be wary.

If I was revalving my Bilsteins (and its one option I am considering right now in addition to Leda and SRP products), I would go to a shop that has a winning record in the PCGB Classic series. I have talked to JAZ (they did Craig Rapp's SC among other cars and have done all my work over the last 4 years) and Steve Winter told me, IIRC, the compression settings on the HDs and Sport Bilsteins are fairly close, but the Sports bump up the rebound a little. I think I recall the same info on Pelican. Steve's valving specs increase the rebound further still, but I am not sure what he does to compression. The going rate is £60-80 per shock. He is on 020 8903 1118 - tell him Richard Bernau sent you and he will explain in more detail why he changes the valving the way he does.

No doubt Parr Motorsport and others have good info as well.

I am pretty sure all the revalving in the UK is done centrally by Bilstein, but its the specs that are so secret. If you know your spring rates and corner weights Bilstein may be able to make a recommendation but IMHO, 911s are a curious car to set-up and I wager that real experience might work better than theory (but then what do I know!). I just like working with shops whose cars win races.

Given that anyone with a shock dyno can work out their competitors specs, I don't fully understand the reluctance to give advice of some shops, but that's life.

HTH
Richard

[911-32]

May have my numbers wrong as I saw this elsewhere:

HD's Rebound/Compression
Front 130/76
Rear 195/151

Sport Rebound/Compression
Front 194/150
Rear 311/160

[bruboy]

Richard, you are right I am trying just to get a comparison from the various figures I have been quoted. The revalving will be done in UK by Bilstein via the workshop I eventually give the overall suspension job to.

Like you I am surprised by the lack of data on revalving on the board as the three well know shops in the North Thames valley area were quite willing to give the specs they recommend over the telephone. The difficulty is they are all different so I need to get some real life comparisons to help with the decision. I messed up about 4 years ago buying what I thaught were Bilstein "Sports" for my original sport spec SC but later I found out they were HD's. dont want to repeat that error again!

One option that I know would work ok with the car is the 87-89 carrera CS as my car is about the same weight, same anti roll and almost the same rear torsion bars. However getting the data and more importantly personal recommendations would really help

[ttweed]

My shocks were just done by Bilstein West, and they are 235/120 fronts and 360/140 rears. Car is a 2400 lb. '73 911E taken beyond RS specs, with a 3.4 race motor, 22F and 30R T-bars, 19mmF and 22mm rear ARBs, 8 & 9" Fuchs, 930 brakes, full cage, etc. It is street legal but sees more track time than street driving. Ride comfort was not a high priority for me.

TT

[johnsjmc]

I have a 1980 SC.Jack French at Bilstein revalved mine at 235/120 front and 360/140 rear. I have 23/30 torsions and 22/21 Carrera sways. The valving was described as similar to sport with a little less compression damping on the front. I believe the compression damping is partially replaced by the resistance of the stiffer T bars. I have not completed the install and am using the rear shocks with standard bars. The ride is very much more controlled but not actually harsh.

[911-32]

Well it seems like compared to the Sports, the rebound is being bumped up a bit and the compression lowered a fraction. So this seems pretty close to what Steve was suggesting to me

Like you, I also bought "Sports" and had them sent straight to the shop. Over a year later, I discovered they were HDs. When running std t-bars the HD are OK but with big t-bars they are noticeably under damped. They still work pretty well on smooth tracks but tracks are not always smooth!

[bruboy]

its interesting to note that most folk here go for much larger T bars and slightly softer bump setting. The UK shops seem to recommend staying with the std 19mm front bars putting in 26mm rears and "holding the car up" on the firmer bump rated RSR shocks. It was also mentioned that with the firmer T bars the car is much more difficult to set up with transition between over steer/understeer a fine line?

I think the RSR had 19 front and 26 rear t bars originally so it probably makes sense to copy the factory shock setting. I am going to revalve to these specs and see what its like, I have got a spare set of shocks to revalve so its easy to change back to the HD's if its really to hard for street.

[KobaltBlau]

yes, firmer bars make the transition finer but you get used to it.

Having driven several setups, I think that the increased compression damping (say from sports) has a greater effect on ride quality than the mid range bars, say 22/28.

Unless your car has seen massive weight reduction it is probably not wise to compare torsion bar size to the RSRs. Tires have changed a lot as well, will you be running 'R compounds'?

[gulf911]

I could tell you my custom valvings...but then I would have to kill you...

Actually, I know of several shops that won't give out those numbers unless you buy them from them. Which at first I thought wtf? But I was reminded that these guys spent lots of hours and trial and error for real world results to get those numbers and are entitled some return on their time.

my .02

[bruboy]

Andy, yes the overall suspension modifications are to enable the car to run on R compound tyre without " rolling off" the tread.

The car runs great as it is with stock with SO2's, aligned, lowered and corner weights, but having run the car in this configuration for some time I have defiantly reached the cars limit on track days!

So I figure try small changes first to see if its enough to keep me improving my driving and lap times, don't like the idea of oversteer tho, mild understeer at the limit is just fine for me so the decision to stay with small t bars looks fine

You say compression damping had a big effect on the ride , my cars weighs 2500lbs so I figure the settings for the RSR at say 2200lbs ish should be ok?

still don't understand this damper secrecy thing tho, no specialists does the same with cam timing or suspension geometry!

[randywebb]

shocks do nothing to 'hold the car up' or down -- except in the sense that they reduce the response rate to a transient in the Z direction...

It's hard to tell if that was just a way to communicate the above or the guy who told you that is completely out of it...

[Jeroen]

how did you come up with that torsionbar combo?

[911-32]

I would be interested to know which shop is advising you.

The set-up they recommend is what 9M, for example, calls a "fast road" set-up. I ran something kind of similar for about 3 years on my 89 car which came with the 1mm bigger rear torsion bars as std (25mm) and a smaller rear sway bar, which I replaced with a 22mm adjustable sway bar. Damping was Bilstein HD. It is a nice road car set-up that works ok on the track. I had fun with it for 3 years before getting bitten with a more hardcore track bug. I have also riden in and followed various 3.2 CS cars and an early 3.2 running the exact same set-up you are looking at - std front torsion bars and 26mm rears. My car runs 22/29mm torsion bars and is quicker than all of them - so far anyway. The car with the "fast road" set-up was running newish Michelin Cup tyres vs my very old Dunlop/Pirelli R compounds and simply couldn't match the corner speeds in steady state cornering. Too much roll and weight transfer and the tyres just didn't perform to their optimum.

IMHO, the fast road set-up is just that, a good road set-up that will let you have fun on the track. If you are using R compounds and have done any other mods - sounds like you have reduced weight - then I would strongly recommend you go to big t-bars. 22/28 is a popular combo but in my opinion is too understeer biased. I have my bigger rear sway set full hard with the 22/29s and still feel it has a safe understeer bias. I notice this particularly on wet tracks where balance is easier to feel and limits easier to explore.

It really depends what you want. I used to have to toss and catch my car to get it to rotate on some corners and on road tyres that was fun. Now on R compounds and much stiffer it just turns in and grips. It's still adjustable and getting up to the limit can be a scarier experience because you are going a lot faster but its really nice to be able to lap at a similar pace to the more modern cars. I have spent laps pinned to the rear bumper of MkII GT3s, 964RSs etc, which is fun with a capital F. I don't for a second claim my car is faster or even as fast as GT3. 964RS etc but on track days where the drinving standards vary so much, you can often keep up with much more impressive cars.

The RSR comparison is not a good one. Tyre technology has moved on 30 years since then and the RSRs are much lighter. A better comparison is to look at how much stiffer Porsche made the 964RS compared to the std 964. And the 964 Cupcar stiffer again.

Just my $0.02.

Richard