Longhood Torsion Bar Specs - sway bars

[Shaun 69 E]

Years ago now I had an 84 Targa with 22/29s, Elephant bushings, Bilstein Sports, 17s w/ Victoracers, corner-balanced, lowered and so on. That car just flew through corners. Long gone, very fond memories.

Current car: 73 with anemic but "sporty" 69T motor, 19/26s, Heavy Duties all around, factory sway bars, 205/55 - 225/50 SO3s on 7x15 cookies, lowered and based on how well it handles, is corner-balanced by luck. Car goes through corners wonderfully, the SO3s stick like glue, but I'm getting more body roll through long sweepers than I would like -- 225s are riding up into the flare and rubbing. Ride is pretty darn comfortable both around town and day trips to NYC.

Should I go up in torsion bars? or beefier sway bars?

if torsion bars, what are some good combinations, especially against a future motor upgrade. Would love to take the Webers off my little 2.0 and stick them on a 3.0 with the exchangers and an M&K muffler, or go with a 3.2.

Thoughts?

[ttweed]

Thoughts?

My first thought would be "How fat is your wallet?"
Second question: "What is your primary purpose for the car?" Track days? Solely "spirited" street driving? You must begin with the end in mind, grasshopper....

I have seen a lot of stock-fendered early cars that fit 225s in the rear on standard 23mm-offset rims like yours and rub--not on the lip, but 2" above it at full bump, burning the paint. Sometimes on one side only--the other side is fine. Damn asymmetrical bodies...

There are a lot of things you can do, depending on how far you want to go down the slippery slope. Easiest and cheapest is to ditch the 225s and run 205s all around (or go to a 215 in the rear, or a shorter 225/45, if you just need that little extra bit of clearance). Don't like that idea? It gets more expensive from there.

You can get a pair of rims with more offset and try to space the tire ideally in the fender well. You might need more inside clearance mods to make this work. The Revolution 7x15" rims have been used by a lot of folks to avoid the hi-digit 911R Fuchs solution, for instance.

The next steps get more expensive. Of course you can hammer on the flares (or weld bigger ones on) to get more clearance, but then there's that pesky paint touchup running up the bill.

To prevent body roll, increasing spring rates and bigger ARBs are necessary. T-bar replacement will also entail a full alignment and corner balance job, not to mention re-valving your shocks, so add that to the cost. I liked a 22mm F and 30mm R combo in my street/track '73 w/ a heavier 3.4 engine in the rear. For full track duty, some people like to go as far as 23F and 33R, which is as high as you can go on spring rates without converting to coilovers. Include dentist bills in your overall budget (for possible filling replacements if you are going to drive the car on pot-holed streets in this configuration.)

Big ARBs alone can help provide roll resistance and keep the body flat in cornering, but only up to a point. Once they have transferred the cornering load from the outside wheel to the inside wheel and lift it off the ground, their effectiveness is finished, and you are back to being dependent on the T-bars for roll stiffness. Increased loading will still compress the outside suspension beyond that point (if the tires you are running have not already exceeded their max. grip level) and the tire may still contact the fender. If you are not running race tires, and not cornering at such an extreme level, you may be able to solve your problem w/ bigger ARBs alone, but they are best utilized for tuning handling balance.

This can still be quite expensive if you go with the hi-zoot adjustable bars available, but at least it doesn't require a new alignment job and re-valved shocks, so you may want to try it as an interim step. Don't forget the reinforced ARB consoles though, if you go this route--you may tear the stock ones out of the chassis. The WEVO consoles are nice! Kaaachiiing!

A cheaper alternative to the fancy adjustable bars is to fit the 21mm rear ARBs from the later Carreras. They can be adapted to the early cars and can be found quite cheaply from people who are upgrading to adjustables. They aren't even that expensive brand new from the factory. See this article for an explanation of how to do this. Combine this with a relatively cheap 18mm front bar salvaged from a '74-77 911S, or a cheap, used, adjustable Weltmeister or H&H 19 or 21 mm front bar, and you may have a "low-ball" solution, perhaps.

Then again, if you upgrade to a later, heavier motor down the line, you may be doing it all over....

YMMV,
TT

[304065]

My first piece of advice is be careful parking on Riverside Drive, particularly at night (Just kidding. Except for the night part)

22/28 was my first race suspension. It is WAY too hard for compromise street driving. 23/31 feels better but you realize why the factory went to coils in the early seventies, it's impossible to get enough rate in the tail with bars.

My advice is to change all the bushings if you haven't already. Get some SC adjustable spring blades for the back. If you really want to get kinky and spend some money, check out Chuck's camber-compensating spring blade system. Smart racing front bar. WEVO camberking up front, but don't go crazy on the negative camber because it's a street car and you need braking performance. Monoballs for the forward banana pivots.

You don't need big tires. 205/50 on Flat Six Fuchs will fit fine, not rub and have the advantage of being LIGHT which helps in all phases of the handling regime.

The goal is to keep the contact patches on the road, and to tune out all the weird handing glitches caused by stiction, weird kinematics, and bizarre dynamic toe changes.

A little roll is OK for a street car as is suspension movement. . . search here for the German dude with the RSR. . . very lightly sprung compared to what we do, but the handling works incredibly well.

Good luck and send me a PM next time you're on the far west side. . .

[Flieger]

Stiffer torsion bars are the "proper" way. If your anti-roll bars are too stiff in comparison to your torsion bars, you will notice that the ride is very harsh and jarring over sharp bumps in the road because the one wheel transfers the bump to the other. You will also still have lots of dive and squat.

If you have stiffer torsion bars, it helps control body motion in all performance aspects. The benefit of sway bars is when they are adjustable. You can have just one rear anti-sway bar, adjustable, and that will tune the transient (chicane turn-in) handling feel. The over/understeer tuning comes at the expense of ultimate, steady state grip when you move away from the natural balance.

A soft front and stiff rear adjustable anti-sway bar combo is a good way to go if you are just looking for a little more performance and less roll. It will make turn-in sharper and the car will handle well around the tight twisties.

[kenikh]

I think you could get waht you want with 19mm or 22mm sways and adjustable shocks set on hard. Cheaper than going full guns IMO.

[Tom F.]

Hi Shaun.

My experience with 19/26 torsion bars was that it didn't work for me. Too tail happy. 19/24.1s seems to be working pretty well. I have an 18 mm factory rear sway bar and Koni reds. If you get Konis, don't set them on full hard. You need to be a 1/4 turn away from full hard, or thereabouts.

With your 2 liter, probably 19/23s are fine. Also, be sure your ride height is high enough for the stock suspension pieces.

If I were in a mood to spend real money, I'd buy a bunch of the Elephant Racing stuff, a set of raised spindle struts and some big, fat Sanders hollow torsion bars (front and rear). I haven't tried it, but everything I see and read points in that direction.

Tom

[Shaun 69 E]

Thanks Everyone for the good advice all around. Great link on the sway bar Tom, thanks. Of course I just spent Saturday re-bushing the rear bar, but that just would make for an easy sale now.


To recap, my goal is to run flatter through long corners, see pic below. car already sticks greater than my driving skill and since I'm on public roads, I drive "conservatively fast with no traffic around." Some time at Lime Rock this summer will be a big help. I can safely run through the curve below at about 60; been practicing it for weeks.

here are my priorities:
1. Keep the car on the road. any changes during driving season must fit within a weekend. Every component of the suspension was recently pulled and freshened with the addition of the 19/26s, Bilstein's and adj. springplates (have nice rubber). If I gathered the new bars (both types) and later front A-arms, I could do the swap in a day for about $500, with my sources. Alignment is $80. Firestone wouldn't give me the lifetime alignment deal of $130 when they realized I might be back a few times per year.

2. Keep the 225 rear SO3s until I see cords. These tires are addictive and I believe (rightfully or not) that they are a critical component to how the car handles now.

3. Preserve the early car look. I do have a set of SC flares and RS bumper quarters and can see 7x8x16s on the car someday, but I want to keep it narrow for as long as I can. It's non-numbers matching 73T with good but patchy rust repair. I won't be desecrating anything by adding the flares, but appreciate the graceful early lines. Tom T, the nice thing about this car is that it's a barnfind anti-restoration. It had quite a lot of surface rust here and there, quickly taken care of with black POR15. I can weld on the flares myself. If funds were short for a respray, I'd just cover the arc with POR and drive it. Still deciding on whether to go back to original Gemini Blue or keep it black or do a custom blue-green-gray so dark that it looks black. In the end, this car is only about driving. Cosmetics are not even tertiary.


My sense is that I can inexpensively go to 22/28 torsion bars and 86 A-arms and sway bars on the car in the near term and then do a full Elephant upgrade this winter if funds allow.

Good plan?

[Shaun 69 E]

bend I've been using for testing the car.

[Shaun 69 E]

Good luck and send me a PM next time you're on the far west side. . .

Will do John, may even be down this Thursday or Friday. Hoping to move to Brooklyn in 11.

[John Straub]

Has anyone done 21/26 or 22/26 torsion bars on a SWB car for street driving?

John