Need shock re-valving help/camber and such

[michael pagano]

I have read up a lot about rebuilding the bisteins, and its about time for mine. I called today looking for the Jack French, the man who knows how to valve them, to get the numbers, and he apparently he doesn't work there anymore. The guy I talked to had no idea really, told me to write down what i wanted.

Well I'm hoping you guys can help me out. I ahve a 76 911s(mag cases), with a 2.7, and yoko s-drives on 7 inch fuchs. I have taken some weight, but not much, out of the car(AC and lighter battery). I drive the car aggressively on the street, will do a auto x or two this summer, and maybe even a track day. The car has stiffer torsion bars, I'm not sure how stiff though. Supposedly they are the turbo torsion bars?? Is there such a thing? They are definitely stiffer than stock but not ridiculous. So what kind of shock numbers should i have mine set at?

Also when i get my car corner balanced and such what should i set my alignment and castor/camber at?

Basically looking for a pretty aggressive street setup, preferring handling over ride for a narrow body 911.

Thanks in advance, the car is coming along great, just put in monoballs, stainless brake lines, and fixed a header leak today.

[Flieger]

Torsion bar (and anti-sway bar) sizes are a crucial piece of information. You need to find a receipt or measure the bars to find out what you have. The spring rate and the car weight are the 2 most important parameters for determining damper valving.

[michael pagano]

Im guessing there is not an easy way to check this...?

[michael pagano]

Can i take the "caps" off the rear swing arms/take the cap/bar piece off the fronts. I have the struts out now and have to raise the steering rack anyway. Just dont want to get into all the indexing stuff if i accidentally slip one out...they have been in there for 20 years. \

EDIT
now i think im confused about tbar indexing. I guess i can take them out and measure and put back in without trouble. Ill have a go tomorrow. Thanks.

[ivangene]

did they quote you a price for the rebuild?

[michael pagano]

No but there is a chart with the prices on the bilstein website.

[RoninLB]

if re-valving good Bilsteins wasn't a waste of time on a street car I would have done it

But if Bilsteins have 100,000 miles on them sending them in instead of buying new makes sense. I think costs are close to same


and a wild guess on what T-bar upgrades are in the car. Bruce Anderson's tech books and articles along with Porsche's Up-Fixin books has long wrote about upgrading to 21/27 or 22/28 T-bars. They're the opinion leaders and every 911 wrench I know has bought into it. Heavy track bars is another story

stock turbo front were same as non turbo at 18.8 mm

stock turbo rear
1976-88 26 mm
1989 27 mm

[ivangene]

Originally Posted by michael pagano

No but there is a chart with the prices on the bilstein website.

thanks - here is the link for anyone else...

Service

[175K911]

Jack French passed away a few years ago, and his wealth of knowledge went with him.

Valving a Bilstein is a bit of an art, and as others here have suggested it's critical that you know what you have- torsion bar sizes, car weight etc. Get it wrong and the car will be squirrely. Get it right and it's a joy to drive. In other words, every car and suspension combination is going to be different. Some years ago I gave Jack a set of specs, and I was off on the front rebound spec. Worked fine on smooth track surfaces but made threshhold braking in bumpy braking zones horrible. Pulled the inserts, overnighted them back to Bilstein and had the rebound changed and the car was perfect.

My recommendation is that rather than taking a guess at it and making a mess of your car's handling, go through well known sources like Steve Weiner at Rennsport or Chuck Moreland at Elephant Racing. They know what works and what doesn't.

[Superman]

Consider me another vote for Steve Weiner. That guy has forgotten more about 911 handling than I will ever learn. He has settled on some proprietary shock valving specs that he believes will maximize handling. I have a great amount of confidence in his judgment. At least, when it comes to 911 handling.

I wouldn't have installed monoballs on a street car, FWIW. I would however, install stiffer torsion bars and anti-sway bars. I am very happy with my late-Carrera sways and 22/29 T-bars.

[HarryD]

Hi Michael:

Where are you located? Please add it to your profile as it will help us steer to to appropriate local resources.

As noted above, Steve Weiner is a great resource.

If you truly have "turbo torsion bars" then you have 26 mm rear and 19 mm fronts. Some folks use 21 mm fronts as well. These are all "street friendly" selections and the standard Bilstein setting should be ok for you. As a data point, my car weights about 2700 lbs and has 26 mm rear/21 mm fronts with Bilstein HD fronts and Sport rears (they have not been revalved). The car has been lowered and corner balanced as well by Rothsport road and Race. The car handles great.

From what I understand, you need to revalve if you have a more radical change in T-bars or you have a significnat change in vehicle weight. Steve and others do do this for a living can speak with authority on these topics.

[Flieger]

Clint at Rebel Racing re-valves Bilsteins as well, but he and everyone else will wnat your car weight and torsion bar sizes at a minimum to ensure that the valving give handling somewhat close to what you want. Otherwise it is a guess- valve for stock 19/23 and possibly be underdamped in the rear (if you have Turbo torsion bars), leading to a rear end that bounces around more than the front- not what you want. That means quick understeer to oversteer snap spins/tank slappers on a racetrack.

[michael pagano]

I opened up the front today and found white sway-away hollow bars. They said (18 21) on the end, and measured 21mm, but ill make sure with a better gauge tomorrow. I am completely redoing the front because the torsions were worn on teh botttom because teh bushing are worn out, so I will replacing both.

I am in East Hampton, long island, new york.

Any idea about my valving off those front numbers?

Thanks

[Flieger]

If you are going to use the same size fronts, then those measurements help. I take it that is 21mm OD, 18mm ID so that probably works out to the stock rate.

The front and rear work together, however. You need all the spring rates or else just stick to the stock Bilstein valving.

[michael pagano]

I am going to order new bars all around, 22/28 sound good?

[michael pagano]

Or should i go a little softer?

[Flieger]

There you go. Now just call one of the guys like Clint and give them that info plus the car weight.

[Flieger]

22/28 would be fine by me. It would be sporty for a street car. If you like a firm ride, go ahead with 22/28.

[michael pagano]

sounds good, thanks

[michael pagano]

Do you think 21/27 would be a little more sensible for the streets without sacrificing a lot of stiffness?

keep in mind i have stock sways