Need shock re-valving help/camber and such

[RoninLB]

i like 21/27 on the street
22/28 is unnecessary and to much street pounding if you eliminate the rubber t-bar bushings.. besides 22/28 in such a case will seem like cabin rattles are just 100 miles away

then figure if you get very good expensive street tires the side walls are stiffer than the cheaper ones

21/27, no rubber suspension bushings, good Bilsteins, and expensive tires make a trick 911 street car that can safely cruse 100 mph all day effortlessly on the back roads of Nevada

all above in my opinion

[michael pagano]

Actually 22/27 seems right considering 22 mm : 87.5 % more than the standard and 27 is 90%more...Plus Flieger has those so they must be good...
Any downsides to this or are stiffer in the percentage wise a better thing to do?

Sorry i know this has probably been talked about a hundred times, just want to get it right the first time.

Thanks in advance you guys are the best

[michael pagano]

Just read your post, posted at same time, i guess 21/27 is good too. What would stiffer fronts give me, more turn in?

[RoninLB]

i would tweak oversteer by going up a size in front sway bar instead of increasing front t-bars

i don't know enough to comment on unbalancing 21/27 or 22/28 besides above

[michael pagano]

ok ill do 21 27, thanks.

[RoninLB]

now you can worry about installing 930 brakes

[avr924]

Hi Micheal,
We are building a 76S for the track. We have boge struts, maybe you do too? I was about to contact Bilstein about it, will they rebuilt and revalve Boge struts? Anybody have ideas about rebuilding Boge struts?

[michael pagano]

no I have bilstien struts, so im not sure. Id ust give them a call.

[HarryD]

Originally Posted by avr924

Hi Micheal,
We are building a 76S for the track. We have boge struts, maybe you do too? I was about to contact Bilstein about it, will they rebuilt and revalve Boge struts? Anybody have ideas about rebuilding Boge struts?

You can get Bilstein inserts for Boge Strut housings. That is what I have.

Some reading:

Welcome to Rennsport Systems, Porsche Performance Products for the 21st Century

Welcome to Rennsport Systems, Porsche Performance Products for the 21st Century

[wswilburn]

Another vote for having Steve Weiner revalve the Bilsteins. Check out my post to see what I went with:

http://forums.pelicanparts.com/porsche-911-technical-forum/542740-results-suspension-upgrade.html

[michael pagano]

I just sent an email to rennsport, cant wait to feel the difference, thanks for all the advice.

[boyt911sc]

Michael,

When I first decided to up grade from stock 19/24 mm TB's for my SC, I believe it was sufficient to have a 21/26 mm combo. It was not too long before I changed to:

21/27 mm
21/28 mm
22/29 mm (this is where I'm now)
All the above had 22/21 mm Carrera sway bars
23/30 mm (spare TB's).

I like the feel of 21/27 or 21/28 for street and track uses. Bigger TB's after these combination seems too harsh for me for street driving. The 22/29 and bigger are definitely more suitable for track driving. And street driving unless you have roads similar to that of the Phoenix area where they have very nice roads. But here in the mid-Atlantic regions, you have to watch out for those bumps and potholes on the roads.




Experience how these different combinations suit your need. Some people have different tolerance and may enjoy driving a 23/30 in town. My two-cents.

Tony

[HarryD]

I find that in the rough streets around my house, the Turbo T-bars (21/27) are about all I would find acceptable. With my 205/55-16 street tires the ride is acceptable.

The harshness on the streets was especially noticable when I put on my 205/50-15 Toyo R888's to compete in Autocross this Sunday. On the other hand, even though we were very wet, the improvement in handling was immediately obvious on the AX Course.

[Flieger]

Eh... It is a highly subjective thing. I could do with much stiffer than 22/27 bars, at least for dive and squat. Roll is acceptable with the 22mm anti-sway bars front and rear, so I would probably leave that rate alone.

My car is just for fair weather canyon carving, though. More like a motorcycle type toy.

[ivangene]

this is so distrurbing as I had a set of 28 rears and looked long and hard fpor 22 fronts and thought I was lucky to get a set of 23's.... then was told 23/28 was going to push and I should find the 22's... I asked what about 23/30 and got "the nod" so sold the 28's and got some 30's.....

now I am worried its going to be too much cowbell....I also dont know what anti-sway bars I have but I would bet 100% they are stock based on the car history....

At this point I am fairly commited to going forward....I will re-valve the shocks while its apart.

thoughts on the 23/30 match?

[wswilburn]

I have 22/29 and feel it is jut fine for the street. I would probably be OK with 23/30 also.

[Flieger]

I very rarely hear of people changing to smaller torsion bars. Usually they start out looking for a sporty street car for an occasional autocross. Mission creep sets in and they end up liking racing and track days, so they go bigger and better on springs and sways. Cheaper in the long run to save up and get the good stuff the first time.

Monoballs and the Rebel Racing A-arm bushings also make the torsion bars feel softer and smoother since the rubber bushing's torsional spring rate is removed or, in my case, the terrible stiction/friction of the poly urethane bushings is gone.

[Chuck Moreland]

To the OP, you might want to check out our capabilities at Elephant Racing.

We build and modify shocks in-house. We rebuild, custom valve, and recharge sealed nitrogen gas Bilstein shocks. We also shorten and lengthen shocks.

We have Jack French's valving specs, which he shared back in his day. Now We design our own valve stacks. We choose individual valve shims to achieve the force/velocity curve we want. We match these to the torsion bars/spring rate and planned use of the car.

We have a Roerhig computer shock dyno, which we use to test every single shock we work on. This costly piece of equipment is indispensable for shock modifications. Without it, you are shooting blind. From experience, I would never put modified shocks on a car unless they've been dyno tested and proven to perform in-spec.

If we can help with your setup and selection, give me a call.

[175K911]

Originally Posted by ivangene

this is so distrurbing as I had a set of 28 rears and looked long and hard fpor 22 fronts and thought I was lucky to get a set of 23's.... then was told 23/28 was going to push and I should find the 22's... I asked what about 23/30 and got "the nod" so sold the 28's and got some 30's.....

now I am worried its going to be too much cowbell....I also dont know what anti-sway bars I have but I would bet 100% they are stock based on the car history....

At this point I am fairly commited to going forward....I will re-valve the shocks while its apart.

thoughts on the 23/30 match?

Years (decades?) ago I ran 21/28 on an SC I had, soon switched to 22/29. Also had H&H sway bars (how's that for dredging up some history), 22mm adjustable at each end. That was OK for street and track, and anything stiffer would likely have just caused too much flex in the Targa chassis.

My next SC, a coupe, I started with the 22/29 with Weltmeister sways and was never happy on the track but it was quite nice on the street.

Fast forward to the late 80's and an '86 Carrera I had. 22/29 was just too soft in that heavier car, so I tried the 23/30 route. Way too much understeer. so I settled on 23/31 with custom valved Bilsteins, Jack French valving specs.

Current Carrera, started with 23/31 and stock Bilsteins. Boy it was uncomfortable, and not as much fun as I'd remembered from my previous 911. Sent the Bilsteins to be rebuilt and revalved to the specs I had from 10 years earlier. What a difference, but still too much understeer at the track. Moved to 23/33, had the rears revalved to match, and that's what I've run for years now. Beautifully balanced car on the track, custom valving actually helped the ride quality because the shocks could control the torsion bars.

So ultimately, it's a personal choice. And there's always a compromise between street and track. But the real lesson I learned more than 20 years ago when I first discovered Bilstein's revalving service is that once you move much beyond stock torsion bars, stock Bilstein valving is less than ideal. Can probably get away with Sport Bilsteins with 22/28's but past that and you really need to get the shocks valved to match your torsion bars, car weight, intended use, etc. It's worth the investment, and you will be amazed at how it works.

[Flieger]

That is exactly what I was talking about.

Mission creep = bigger bars.