Suspension experts...Need some advice..., regarding torsion bars & A-arm bushings Options

[wbergtho]

Hi all,

I'd like to get some advice from you track guys to help me decide on which size torsion bars I should upgrade to. I have a similar question on A-arm bushings. I have a 930 front suspension (stock) and would like my car to handle the bigger road course tracks better. I'm thinking my stock front 18.8mm torsion bars are a bit wimpy and also thought of upgrading the stock rubber A-arm bushings to a stiffer set. Those two upgrades should help enormously. I have new Bilstein sports on all corners and 185 lb springs in the back. I suppose the spring rate should be higher for the track...maybe 250 or more. My car is V-8 powered and weighs about 2550lbs with spare tire, top on, tools, full gas, etc.

All advice welcomed!

Thanks,

Bill (IMG:style_emoticons/default/driving.gif)

[Aaron Cox]

roller bearings, 22mm bars, 250+ lb springs....

[Joseph Mills]

What Aaron says and I bet you can start that bar at a mid setting. If you run out of bar, then consider a step up on the t-bars.

Are the rubber bushings toast? If your car is street & track, and the rubber bushings are okay, try the other upgrades first before going to other bushing choices.

..

[wbergtho]

Hi Aaron,

Is there a readily available kit for the roller bearing set up you suggest? (brand name and what it might cost just for this upgrade?) Do you think a harder bushing would possibly do the trick and keep some comfort level? Thx

[Aaron Cox]

contact mueller and brad roberts....

if they arent made yet, or arent in stock.... polybronze bushings from elephant racing are a step down from bearings, and then weltsheister poly bushings( 2 varieties RACE and STREET hardness - i have street) are a step down from polybronze...

[wbergtho]

My bushings look ok...just a bit soft for the track (ideal for the street...no noises). I want to sharpen things up a bit...I have no rear bar and still haven't decided what to do there. Some say you don't need a rear bar...some say you must have one. Maybe I should just put one on and decide for myself...and report what I find. My V-8 car is heavier than most 914's for obvious reasons. Perhaps my set up would do better with one...I'm not sure until I do so. Weight distribution is 56% rear 44% front. I had it scaled...but no attempt to adjust the corner balances. The guy who was helping me said impatiently..."looks pretty good...I wouldn't touch a thing". I believe that it can be fine tuned a bit better. I'm just trying to leave nothing on the table if I can help it. All the other guys who take track racing seriously will leave nothing on the table.

thx,

Bill

[Eric_Shea]

I don't believe roller bearings are available any more. Elephant poly bronze or Weltmeister "race" are options.

If this is for a serious "Road Course" car then the 18.8's might be small. If it's a sometimes road course car/sometimes autocross car and lots of times street car then they are perfect in my book. Ever read the 911RS/GT3 comparison in Excellence last year. Some of the propfessional drivers still prefered the 911RS... 18.8 bars.

[wbergtho]

Thanks for the info Eric,

I will look into the Elephant Racing Polybronze bushings... Sounds like what I need. Any thoughts on a rear bar? YES/NO? If yes, what size?

Thanks for all the advice guys... (IMG:style_emoticons/default/beerchug.gif)

[Andyrew]

A rear bar will be a toss up. It will really just make one wheel lift... thus not giving you all the possible tracksion you need.... This is a BIG problem for those w/o LSD but I assume you have it...

I'd say for a T bar, 22mm and 250lb springs like AAron said would be a good choice.. But you'll need a decent size sway bar.. I'd say get as big a sway bar as you can get... and dial it in with the rear springs. Replace springs for 180's and tone down or take off a link on the front sway bar when cruzing...

Elephant polybronze are 1 step down from rollers, and would be my choice for your car.

Let me put it this way... You want a big bar up front so you can dial it in.. You want a variety of coil springs so you can ALSO dial it in. 21mm front sway might be enough. and 250lb springs might be enough, and 22mm t bars might be enough... BUT you need to be able to tighten up the back, tighten up the front, or loosen them if need be...

Your car is way different than mine, and im setting mine up for autox, max corner speed 65mph, not track, max corner speed 140+...


So my setup of
22mm T bars
roughly 22mm front sway
275lb rear bar,
roller bearings with koni's all 4 corners.....

will be different than what you need.

Hope this gibberish helps... You have a lot of options.

[wbergtho]

I'm not sure what size a stock 930 front sway bar is...but that's what I have. It is an under body type and I'm pretty sure I can't get a "through body" style front sway bar into my car do to the radiator hosing and other junk I have currently in the way. Maybe I can move things around. Have you seen any trick aftermarket front sway bars for the 930/914 that are still mounted below like the stock one? I suppose I could cut & massage the stock one with adjustable drop links...but it would be far easier to buy an aftermarket one that fits right in.

Yes...the car has LSD

[Aaron Cox]

the thru body bar goes UNDER the gas tank... you should have plenty of room....

a 930 underbody, i want to say was 18 or 19mm...

BTW - you should also upgrade to threaded perches in the rear to take advantage of the chepaer racer springs

[Dr. Roger]

ride quality is not an issue, right?

those 23mm front tortion bars are something to experience on the street. how's your back? =-)

i believe it's all about the drivers preferances.
some go big on the springs and light on the sways.
some go light on the springs and big on the sways.

with my limited experience at at high speeds i do know big springs help with porpoising and diving which is a big plus on the track.

23's will make your car feel like a go-kart. =-) 1 1/2" of wheel travel.

[JPB]

Correct me if I'm wrong but isen't the length of the bellcrank or horisontal part of the TBkit responsible for the bar's twist? My stock unit is 19mm and kinda week but shortening the lenth of that member would make it harder for the bar to be twisted since now 5"C:C is twice as much torsion force as would 2.5" C:C would be. The only problem would be relocating the bar 2 1/2" closer to the drop link's vertical center.


(IMG:style_emoticons/default/confused24.gif) Less weight, same parts?

[Brett W]

When I first got my car I cut the arm on the sway bar shorter, but the problem you have is the linkage can get to short and will bind so you can only go so short without increasing the bar diameter.

AS far as T-bars go. Do not go to big on the springs. Your Bilstiens will not be able to control the spring rates. They don't have enough dampening to properly control your heavy springs. You can however step up to some 20mm bars or some 21s and use a bigger front bar. If you are going to drive this car on the street I would suggest softer spring setup and a bigger sway bar setup. The car will be much more predictable and controllable on a bouncy street corner or smooth race corners.

You might call Shine Racing and see if they still do their roller bearing setup. If not you could make your own.

[Eric_Shea]

My stock unit is 19mm and kinda week

The only stock through body 19mm bar was a 1976 930 bar. They are available and scarce. I have them on both the teener and the 911RS clone. Love them. If it's a stock teener or 911 bar it's 15mm

(IMG:style_emoticons/default/agree.gif) with Brett. Keep the T-bars light if not stock and work with the anti-sway bar to dial in your needs. I think 23's absolutely ruin a street or autocross car.

[wbergtho]

My radiator hoses go right under the gas tank and cannot be relocated easily. I'm pretty much stuck with the stock front under body 930 sway bar. Have any of you racers seen a stock bar cut & modified to accept adjustable drop links (on either a 911, 930 or 914)? I wonder if anyone makes such a kit. I'm guessing not. Perhaps I should modify them and use better bushings there as well. It's hard to relieve preload with a stock non adjustable bar...know what I mean?

Bill

[Eric_Shea]

A stock "underbody" bar? (IMG:style_emoticons/default/confused24.gif)

[Dr. Roger]

all i know is having an "over the suspension" sway bar allows for great adjustability/flexibility. tons of bar options. IMHO well worth the cooling hose re-route.
the sway bar goes right up against the fuel tank and the firewall. it may be a non-issue with your coolant hoses as i'm guessing they are at floor pan level. ???

if you start cutting and driling that stock sway, be sure to keep the temps cool... =-)

[wbergtho]

I ran my hoses on the right side longitudinal and ran one through the old heat tube and the other on the outside of the longitudinal. They both swing into the passenger side floor (a bit) and poke through the lower bulkhead...under the gas tank...through the trunk bulkead and to the radiator. Next time I get my gas tank out...I'll see if they can't be re-routed somehow. It actually will be a PITA. Maybe I'll try to modify the stock sway bar. Good idea...don't heat up the stock bar during fabrication..otherwise you'll mess up the temper of the steel...not a goog thing to do to a sway bar.

Thanks

[Eric_Shea]

I would seriously contemplate getting a through-body set-up. (IMG:style_emoticons/default/wink.gif)