Drop Spindle Discussion

[slyalfa]

I think if you put a adjustable link on one side of the rear sway bar you can make it so it will be the same right vs left.

[Nikoror]

Here's something to think about:
LF 678 RF 742
LR 646 RR 605
With battery in RR. Total 2671

With someone in the driver seat:
LF 752 RF 754
LR 698 RR 629
Total 2833

[slyalfa]

hmm I never had scales but I did shorten my right back sway link. which should have that affect.
it seemed to make it the way I liked but I also do mostly only hard rights on the street.
it just seemd like that is what was needed I did not think much about it at the time.
but now you bring it up I get it.

[volpebob2]

Grant,

Sorry for the delayed response...I work a lot and log on infrequently.

OK, so, I read all of the responses subsequent to our conversations, and here are my thoughts:

Relocating the battery to the trunk is a good Idea to help with the understeer, although RR seems to be the smart choice, as w/driver, LF should be the heavy side. It's weight is nominal, so it's not critical side to side any way. Don't worry about understeer one way, oversteer the other way---which leads me to th next issue;

If this problem is occurring, you need to find the reason. The base car is NOT this unstable, unless it has been bent, something is broken, or some mod has been severely miscalculated. Look at the rear springs/sway bar clearance. Is it possible that they are making contact on one side? Do you have a broken/leaking shock? Take a prybar and try to move (front -to-back) your upper control arm where it goes into the body. If the inner bushing is bad, it can cause handling issues. The other thing that I've run into is the caster adjustment rod nuts (in the engine bay) coming loose.

Pre-loading the swaybar with a shorter link like one guy suggested is asking for more problems and more unpredictable results. You are essentially loading an undamped spring and causing a jacking effect on the rear suspension.

Wheel spacers, especially on the front to put the track out 1/2" or 12mm per side are a great idea to gain front end grip and lose some of that understeer. But spend the money on hubcentric spacers. Your wheels don't center on the lug nuts, they center on the bore holes in the center that rest on the lip around the wheel bearing cup. H & R, Eibach, and a few others make hubcentric spacers for Alfas in 6, 12, and 25mm sizes that will give you a more aggressive stance, and more front end grip, taking your 37mm offset wheels to the max recommended 25mm offset (w/the 12mm spacers).

I'll say it again, bigger torsion bars in front will only increase your understeer, but if you must, then put rear springs with a rate commensurate with the fronts to balance the chassis for neutral handling. After all, it's not the roll you want to cure, it's the handling issue, right?
******Try this exercise if you have a large front sway bar on the car (I think you mentioned 28mm front); disconnect the link on ONE SIDE of the sway bar (this renders the sway bar inoperative). Drive the car. Does the understeer go away? Then the front end is too roll stiff.

Finally, on the contradictory information, reducing the distance between the roll center height and the CG height will reduce the roll angle, which leads many racers to want to raise the roll center. Essentially this is what you have done, and you have noticed a reduced amount of roll as a result. But in most cases a higher roll center causes jacking effects and erratic suspension movements. In some cases, raising the roll center can also reduce camber gain. Most successful race cars have the roll center 1.00" below ground to 3.00" above ground.

On the issue of lower control arm angles, it is the relationship to the upper control arm that is important. If the LCA and the UCA move in the correct arc in relation to each other, the spindle will suffer no camber loss. The suspension geometry has to be right.

With respect to bump steer, you seem to have that solved. The steering rack is the 3rd link in that puzzle. You probably have less bump steer if your drop spindles have been corrected for this issue. My bump steer is an issue that I have to live with as a result of steering rack/tie rod angles. Oh well!

I can't believe that you've damaged the DeDion with your setup--it's stiffer than normal but not mega-hard! I've been racing my current chassis since '98 and I've never had an issue, and my suspension is MUCH stiffer. Maybe I should ask how much HP you have??? Did you only rip the sway bar body mounts?

Everything I've given you here is racing science and pure physics--I didn't invent it, I just use it. I hope some of this helps you. I'm positive that if you follow the diagnostic steps and sort the car properly, you'll get the result that you are looking for. I always do.

I'd still be interested in a contact for the drop spindles.

Best of Luck,
Bob

[volpebob2]

Grant,

Forgot to mention, if you decide to weight-jack the car for different corner weights, the correct way to do it is with ride height adjustments, not sway bar link-pin tricks. Just drop or raise one corner of the car, and you'll get instant weight transfer at both diagonal corners (i.e., drop front left 1/10", RR will raise by a similar measurement).

This will put more weight transfer on the corner that was dropped, and consequently, more grip in corners. Big caveat though; I wouldn't use this as a band-aid to solve your current handling inequities. First solve the problem, then use this to dial-in the balance as the last step in chassis tuning.

Bob

[Alfar7]

Quote:

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.

[Grant]

Hey Richard, real quick, if I you were to make your street cam regrinds for a V6, does it matter which camshafts get sent to you - 2.5,3.0,S...?

[Hit an Apex]

Quote:

Originally Posted by Grant 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.

[volpebob2]

Richard,

Thanks for your input, but I think we're on the same page on most points. My setup is working very well on my race car, and employs more or less your philosophies, if you review my post on my initial setup for the benefit of Grant and his handling issues.

I've seen some of your posts in the past, and liked most of what I've read. I've no issues with the car except for brake overheating, but on the handling side the car is very neutral w/a slight tendancy towards oversteer in throttle-on fast sweepers, as I set it up that way per the chassis program we used initially, and I have to say, it was good right out of the gate. The setup range was 100 (understeer) to 110 (oversteer), 105 being neutral, and I set it up at 106 percent.

You are correct, the car is heavy, but with a stiff setup such as mine it feels 500 lbs. lighter, and although it is not as lithe in the twisty bits as an Elise or a Honda, it is extemely stable in fast sweepers, where I can make-up time on twichier or shorter wheelbase cars.

According to my setup program, the ideal numbers would include a lower ball joint location 1/2" lower than present, which prompted my search for drop spindles.

I cannot enclose a photo of the car in action as the file is too big, but if you would like to see it (if you think you may be able to gain some insight to the level of success of the setup), send me your E-mail and I'll forward. Always looking for the competitive advantage. Tire temps really tell the story--after a session they are even across the board.

I welcome any suggestions you may have.

Thanks, Bob

[AR4me]

Bob,
If you email me the pic I can re-size it and post it for you - PMed you my email address.
Jes

[Alfar7]

Quote:

Hey Richard, real quick, if I you were to make your street cam regrinds for a V6, does it matter which camshafts get sent to you - 2.5,3.0,S...?

[AR4me]

Here is a pic of Bob's race car.
Jes

[Bane]

This has been most informative thread, one of the best on this forum.

I'm convinced that drop spindles are very usefull in improving handling of lowered car.
Another opinion is that stiff springs control body roll and that it almost eliminate geometry issues.


This debate was based on dry track conditions. Nobody here seem to compete in hillclimb events.
In hillclimb there is normal road, with all it's shortcomings and very different conditions. Rough surface, all kind of weather.

What about wet conditions?
Or rough road surfaces?

How superior is soft springed dropped spindle solution for wet roads, and can no-roll stiff springing compete against that?

[Echo Leader]

Interesting angle. I don't know that hillclimbs are as popular in the USA as they seem to be elsewhere in the world. Maybe I'm just out of the loop, but it sure seems like I see more mention of them outside of our borders.

I would think that you would want to have a softer suspension for wet and/or rough surfaces. As you've noted, lower spring and anti-roll bar rates can be used if the geometry itself reduces the overall tendency for the vehicle to roll. To me, these types of conditions would be even more suited to a drop-spindle implementation than would a smooth and consistant racetrack.

[Grant]

I was very interested in utilizing soft spring rates instead of the weld-it-stiff approach of roll-camber control as I used to flog my car on bumpy back roads, as well as daily drive it, as well as take it to competitive events.

On a bumpy surface, obviously, the soft spring approach will be best, as you can maintain contact with the road (and not destroy your car, hopefully).

On a wet road, softer is usually better, although the importance of dropped spindles is probably less here, part of the reason for installing them was to induce camber gain, but when there's 50% as much grip, the car rolls less, requiring less camber gain, which then negates most of the reason for the dropped spindles. The roll center is better, true, but with less body roll due to less grip, there isn't as much need to fix the roll center that drops further and further as the A-arm compresses.

Since going through the process of participating in this lengthy discussion, I learned a lot. I also learned that I was wasting my time. After installing the dropped spindles, it helped the handling a good amount (worth my purchase price of $180 and some time to install), but I never saw staggering amounts of grip until I adapted front coilovers (RSR actually) and tried to match the spring rates in the rear with some custom springs. Even with the dropped spindles and huge sway bars and torsion bars, I was still rolling like a pig on tight turns. While the camber gain was fine, the center of gravity would shift so far onto the outside wheels, it would overload them and I would lose grip prematurely. After increasing the spring rates 2-3X over my old setup ( and 4-6X over stock!) I was finally happy.

These cars are really narrow. Unless you have custom control arms made and a widebody, they will always be limited by that fact. Might as well do the best you can, for me it was combining dropped spindles and RSR coilovers (not a bolt on, mind you!