Drop Spindle Discussion

[Nikoror]

maybe that's because the rsr on top of the torsion bars acts as a progressive spring with the torsion bars (i guess stock 22mm) acting first and the springs from rsr starting to act only after the helper spring is totally compressed. this way you get a progressive spring from torsion bars to the rsr springs. maybe not

[Grant]

I thought that too. But Louis has his car set up so the spring is always loaded, which should reduce how progressive it feels. Basically, as soon as he's turning in for a car, he should be already on the higher spring rate. He said he tried it with the coils engaging later but it felt funky.

Also, the rear end feels just as compliant, and there are no other springs helping out in the back obviously.

[volpebob2]

Grant,

Maybe we can help each other. I've checked out a few pages of the posts related to drop spindles, and you seem to be struggling with understeer issues on your setup. If you still have a problem, I can give you a couple of setups that should work without much difficulty. I have a repair and performance shop that does, among other things, most of the Alfas in the Midwest, as well as SCCA race car and hi-performance chassis mods.

It seems like much of the advice/discussion on suspension setup is unrelated or is overly complicated and unnecessary to achieve the result that you need. I need to find some drop spindles with a 1/2" drop. You, I assume have a source.

It took me a lot of time, money, and track time to arrive at a winning setup for my GTV-6 race car, and the evolution of that final step was to utilize a professional race team's chassis program and the experts at Moog and Hunter Alignment to analyze the data and spit out some real setup specs that actually improved the car.

The change was huge. I now have 2 setups, a wet and a dry (stiff and too stiff). I'll be happy to give you the setup specs, but I need to know exactly what you're running at the moment (alignment F & R, wheels & tires, suspension & bushings, how low is the car, corner weights if you have them).

Regards,
Bob Volpe

[Grant]

Bob, I'm always curious to see what other people are running. So, you feel that a transaxle Alfa with some work can be a competetive chassis?

Do you have a website?

I'm not a dedicated racer, I've just gotten into time trialing. My car is also dual purpse; I use this car as my daily driver. There will be many differences between our cars then.

That being said, I'm using about 1 1/4 inch drop on my spindles (which nearly necessitates 16" wheels) and soft 27mm torsion bars and about 154lb/inch rear springs.

My car's handling is funky at the moment. I have no idea what the corner weights are, but it understeers on right turns and oversteers on left turns. I'm relocating the battery to the trunk to see if that will help with the understeer but I need corner weights to deal with the handling issues. Corner weighting a car with torsion bars is goign to be a %@$!^ I think. Actually, what's more upsetting is that I think the Milano is so flexible that my efforts to adjust the rear sway bar only seem to make that end lose or gain rear grip, instead of helping the front end gain or lose grip. I wish I could run a cage 24/7.

My alignment is about 2.4 degress negative camber, 0 toe (tire wear) and only 1.4 degrees of caster b/c of rubbing issues. I'm using 225/45/16 tires on 16X7.5 et37 wheels. Bushings are poly in the rear, and stock up front besides poly caster bushes.

Do you know of any other sources for torsion bars in the US besides AR Ricambi and Performatek? I'm looking for about a 30mm bar in the states.

[Nikoror]

Performatek have 30mm bars.

[Echo Leader]

Grant,

Nikoror is correct. Though to elaborate, they're not advertized. I was talking with Andy the other day and he was saying that he can order virtually any size T-bar you'd like. I'm not sure what the cost implication is when doing a small number of sets, but it would be worth giving him a call to find out. Might be easier then having something sent from Europe or elsewhere...

[Grant]

OK, I'll ask him how much it costs. He should really advertise that...

[Echo Leader]

Yeah, I think he's just overwhelmed and thus the website is a bit behind the times. It was a surprise to me as well... Hopefully not too expensive. I think he said something to me about the price, but I honestly can't remember and I'd hate to misquote him on something like that.

[volpebob2]

Grant,

The current setup I'm running for a dry track is 3 degrees neg. camber, 3.5 deg. pos. caster, almost zero toe FRONT; 1.75 deg. neg. camber, slight toe-in REAR (gotta bend the DeDion). 37mm hollow torsion bars from the English group 'A' race series, re-valved Koni yellows, custom rear springs matched to the front torsion bar rates (which are in the 800 lb range), stock front sway bar, and adjustable rear 1" bar. 15" x 7" wheels w/225/50 tires.

This setup is very stiff, and in the wet, very slow and twitchy. But my wet setup also has very compliant dry handling characteristics for bumpy tracks or road use, and has almost perfect suspension geometry. I use a version of this for some of my clients that want a high performance/neutral balance handling solution for the typical heavy understeer and UPS truck lean that all Alfas are blessed with.

For the record, you are spot-on; these cars have tons of cowl-shake and the moment I put a cage in my car it became a completely different animal. The only problem was it was so harsh, it was no fun to drive on the street anymore. I also run 16" x 7.5" wheels w/225/45 tires on my street car, only I run a more agressive offset @ 25mm, which sets the wheels pretty far out in the wheelwell. With your offset, try a hubcentric spacer and trim the plastic in the wheelwell for clearance.

So here's my suggestions:
I assume you're using the drop spindles to lower the car instead of lowering with the torsion bars. I think this is part of your problem. The distance between the upper control arm and lower control arm has been altered, and thus the geometry. The bump steer is affected by the arcs of both the upper and lower control arms. By the numbers, the factory stock steering geometry calculates out perfectly with about a 1/2" drop of the lower ball joint, so the factory dimensions are almost perfect, if the car is lowered a bit.

To check your results, if you remove the torsion bars and run the spindle up and down thru its full vertical arc of travel (still connected to the upper and lower control arms AND the steering rack), you should see the spindle move in camber and toe change as it goes thru its vertical travel. The amount of movement or "steer" of the spindle as it moves vertically is the bump steer. The closer to zero, the more predictable the handling. My guess is that you're going to see a lot of bump steer which is contributing to your understeer/oversteer scenario.

The second issue is, I've read several posts related to your handling issues (although not all of them). No increase in spring rates are going to give you a dramatic increase in roll stiffness. Use sway bars for that (Rears only). Spring function is primarily to keep tires in contact with the pavement. Shocks do the same. Keep these functions separate and simple.

Third issue is you've GOT to have the correct alignment settings. Everything sounds good on your alignment EXCEPT........you need 3 or more degrees of positive caster. When you turn the wheel, steering geometry causes the wheels to go to positive camber, and the tighter the lock the more positive camber is dialed-in. That's the reason we use so much static neg. camber to begin with, because in turning the wheel we lose a lot of camber and through G-force flex of the suspension bushings we lose the rest to arrive at zero camber in a turn (hopefully). Positive caster counteracts the effects of camber loss when turning the wheels. The more pos. caster, the less pos. camber gain upon turning the steering wheel.

Also, and equally important, pos. caster self-centers the wheel after turning it, so w/zero caster, let go of the wheel and it won't center itself--not a happy moment when you are tail-out opposite-lock expecting the car to right itself.

The best setup to regain control of your handling should be:

Keep the Bilsteins
Stock front sway bar
Ricambi rear sway bar
NO LARGER THAN 27mm front torsion bars. (remember, larger won't help your roll stiffness measurably unless you go super high, and then you'll have terminal understeer)
Rear springs that calculate out to be al least 35% stiffer than stock.
Lower the front end 1" - 1.5" by torsion bar method; in any case make sure front end is lower than rear.
Lose the drop spindles unless you can confirm that they DON'T affect bump steer negatively.
Make sure alignment is correct.

If the frame is not bent and the car is straight, it WILL be neutral or a little tail-happy,--trim with tire pressures. Run tires at full pressure and drop pressure on the end of the car that you want to have less grip. It may not be the most exotic solution, but it works.

I hope you find this info helpful.

Bob

[Grant]

Hi Bob, thanks for your input.

I have found a few things that are a little bit contradictory so far, however I am no expert on the matter.

I'm trying to catch you before you sign off, but here it goes:

I've lowered my car a lot. With out the dropped spindles, my LCA's angle was VERY sharp, which should make me loose negative camber as I roll, correct? This has been discussed earlier on in the thread.

The dropped spindles also raise my roll center, making my front end more roll stiff, which I noticed.

The dropped spindles I have have a little bump steer correection (steering arms are bent downwards) but not quite enough. I want to convert to heim joints and spacers to get the tie rods level again.

Also, after moving to the dropped spindles I noticed:

More front end grip, less squealing of the outside edge of the tire as I was maintaining more negative camber, and LESS bump steer.

And, I have lowered the car with torsion bars, if you were saying that I didn't for some reason.

If I shouldn't increase the spring rates by very much, how can I elliminate roll? With a 26mm rear sway bar, it already feels like I'm stressing the mounting points. I've torn my dedion sway bar mounting points twice and had to get it re-welded.

Anyhow, I hope you see this in time.

PS, Ron Simons coilovers from the Netherlands (Intrax kit) runs up to about 700 lb/in springs up front, in addition to the stock torsion bar (progressive). Rear is something like 300lb/in. This kit is very good, if a little on the firm side. I think higher spring rates was the way to elliminate the roll.

[Grant]

Looks like I missed you, but the above is the approximate ride height.

Even with the raised roll center, 28mm and 26mm sway bars, the car still rolls a fair amount. I think the only way to go is to increase the spring rates further.

How did you have the dedion bent? I want to look into that soon.

[Nikoror]

There's always the option to: increase track width, reduce weight, lower CG.

[75evo]

Hey Grant,

Why not try a different approach.

Get hubcentric spacers, 25mm?, $50 each
Have a shop who can modify the fender to accommodate the extra track width
Euro bumpers, or lighter bumpers (you have these already right?)

As you said, this is a dual purpose car, so you have to make some compromises. Also, have you moved the battery to the back?

[Grant]

Yeah, I think the track on these cars are too narrow to be of much use. But, I'd be increasing the track to gain grip right, and not to reduce roll?

Things are going slow. I have the battery cable and everything run, but I'm an electrical n00b. I don't have a clue where to buy the right adapters to mate a large battery cable with the stock positive cable. I have an idea for now, but I'm still trying to find the parts I need.

Also, moving the battery to the back is a good thing. However, my problem lies somewhere else. I think rear battery would make the car understeer less on right turns, but oversteer more on left turns if I mount it in th back right!

[75evo]

How about mounting it in the center? Your trunk will be totally useless. But it was already so small to begin with.