Drop Spindle Discussion

[Potenziato]

You can read the beginning of this thread on the at the end of page 16 and continued to page 17. 2nd 3.7 Litre 24 Valve Milano Project!

Grant, I've tried various combos and I like the RS kit better with the stock spindles. I also took the old suspension from the 24V and moved it to the Verde. The old suspension consisted of Koni Reds, Sparco springs, stock torsion bars, and a 26mm front swaybar. The car understeers with this setup and it understeered withe the drop spindles. I took the front bar off and the car would oversteer quite a bit. I haven't tried a stock 24mm bar.

The RS kit worked better for me with the stock spindles. I had tried prior the RS kit without spindles with and without the front bar. The car definitely felt most balanced with the front bar. However, if I had softer spring rates, I'm not sure the 28mm front bar would work the same.

Looking at some of the factory specials provides no help either. The 75 turbo used a stock front swaybar but uses a huge rear sway bar. The SZ, used drop sindles in the front but had no rear swaybar.

Grant, I'll sell you my spindles and than you can find out first hand.

[Grant]

"The car understeers with this setup and it understeered withe the drop spindles. I took the front bar off and the car would oversteer quite a bit. I haven't tried a stock 24mm bar."

You mean the car with Sparco springs and no front sway bar oversteered a lot right? And you haven't tried that stup with a stock bar yet right?

I had basically that setup on my gold, I had shankle SS rear springs, stock torsion bars, and the puny 22mm sway bar. I was just fooling around at the time, as I knew what th eend result would be: snap oversteer.

With the ex-Larry suspension, you're saying that drop spindles didn't help understeer at all? Because that pretty much would be the situation where I would have thought drop spindles would have helped (not having excessive spring rates, allowing the car to roll a bit and utilizing more negative camber when cornering hard).

I'm really curious, you've pretty much tried the drop spindles with a lot of setups....what DID they do? You felt something change, right?

So, I wast talking about switching sway bars around with the drop spindles. If you'll humor me, I can take a 24mm bar to Infinion and inbetween track sessions (there are 4-5 and the gaps can be up to 45 minutes inbetween our driving sessions) and swap out the two bars for one session, and you could go out and see how it is. I was thinking this should make the car understeer less, but there's no real way for me to know. If this sounds like too much hassle for you, that's OK too.

[Grant]

O, and I sent you a PM.

[Grant]

I'm not sure I understand your question?

I'm fully aware that spending more money on tires, or going to a driver's school (thanks jj) will net me faster lap times, for less effort.

This still won't satisfy my urge to tinker with things though, and I find doing things myself very rewarding.

[75evo]

I have drop spindles too.

I don't see how it can affect the handling negatively. Like Grant mentioned earlier, it reduces camber loss during turns, which can't be that bad....

But I find that, compared to others, I'm not too sensitive to the car's handling characteristics, so maybe I'm not the best of judge. Some drivers can tell you exactly what he or she feels vis-a-vis the car's handling characteristics. I on the other hand can't give much more than "it understeers/oversteers/a little tail happy".

[gtv27]

An interesting discussion. I am not familiar with the use of 'drop spindles' in 116s, but assume it is to change the front roll centre and dynamic camber change - not sure if you are tring to raise or lower?

Can somebody give a quick outline of what is trying to be achieved with drop spindles?

In our 105 we used spacers under the top ball joint (also called knuckle risers) to give it more camber gain from a raised front roll centre (also gained droop travel which helps keep the inside wheel on the ground). That's all good, but it does introduce bump steer, which is not so nice (compromises....).

I am playing around with springs and bars on my GTV6 at the moment to make it a bit better on the track (but don't want to go super stiff out of respect for the shell and not wanting to make it awful on the road). So would be interested in things that work with relatively low rate springing.

[Grant]

So it's like the spacer that the 105 series chassis use, but it goes below the spindle. When you have a car that's really low (like mine) the LCA get's angled way up when the car is just sitting there. If it's that bad at rest, I can only imagine how bad it would be when I'm cornering hard.

As the LCA rises higher and higher, it's bringing the bottom of the wheel in more and more towards the chassis of the car (the upper control arm is doing the same, but to less degree) the end result is a *loss of negative camber going around the turn and toe out at that wheel (the tie-rod is at a high upwards angle too). I think drop spindles should lessen bump steer too, but I'm not so familiar with bump steer. It doesn't seem to as big of a deal for as the roll steer is.

So after doing some reading, it seems like the way to get these 116 cars to grip like glue is to make the spring rates really stiff. What a shame!!

I'd like to think the Alfa suspension is superior to that of a swing axle Bug, but we're taking the same route to get these cars to handle (the bug having swing-arm rear suspensino, that has a terrible camber curve....you lessen this problem by making the spring rates ultra stiff, and lessening your overall suspension travel). If you look around, other cars don't need 28 or 30 mm front sway bars in a performance application...a hot E30 bar is 25mm, hardly larger than a stock verde bar. A medium hot performance bar on the same BMW is aroudn 23mm! I know this also has to do with where the sway bar mounts on the suspension, but bear with me.

I noticed something had to be wrong with the geometry after going to 27.3 mm t-bars and 154 lb/in springs -- the car rolled just about as much as with the stock spring rates! This was after lowering it considerabley, so I thought I messed something up with the suspension, and after taking a guess where the front and rear roll centers were, I can see that I lowered the front RC a ton! That would partially explain why the car rolls so badly. I'm hoping the drop spindles will also lessen the amount my car rolls with the 28mm bars.

The super huge sway bars that these cars run really seem like a band-aid to messed up suspension geometry.

[Grant]

75evo, how long have you had your drop spindles on your car?

[gtv27]

Grant

Maybe it is too low at the front, putting the roll centre below ground and causing lots of roll despite the stiff springs and bars (just a guess, haven't done the measurements to confirm)?

I was told once by an old bloke who used to rally these that the lower wishbone needs to be parallel to the ground at rest. Also cautioned against using big anti-roll bars (as per your thoughts).

Despite rolling a lot, how does it handle with those specs?

[Grant]

Well, w/o the roll bars, it understeered very strongly, and the grip just wasn't there.

I have my sway bars mounted and out on a WIDE private road, I had the car handling almost nuetral at high speeds, with understeer in the sharper corners. It was finally "acceptable" but then my rear sway bar mount broke (where the end link connects to the dedion -- it sheared it righ toff) and I need to get that fixed before I can make any more conclusions.

[Grant]

Another thing is, my sunroof Milano is going to roll more with the same setup that you have, due to a lot of weight being higher up on my car. So you might not be in that bad of shape after all.

In fact, I drove a friends GTV6 3.0 one time with full shankle (t-bars, shankle SS, 27mm front, 25.4mm rear) and that car felt very nuetral in the short time I was driving it. It was also very low to the ground. I think if you just picked up some shankle sway bars, you might be quite happy.

[gtv27]

Mine is very mild and runs standard front TBs, variable rate rear springs (Kings - I believe are ultimately about 20% stiffer than standard, but don't have the specs), standard rear bar, 24mm front bar and koni yellow.

On the road it has mild understeer. On the track it has chronic understeer. Still quite quick and drivable, but constantly having the ease on the steering and feed in the power to avoid toasting the front tyres (which is a real culture shock for me coming from 105 which has the exact opposite problem).

I am now trying a 22mm front bar, but have yet to take it to the track (next event not until June ). Feels a bit more pointy on the road so hopefully will be better on track. Worry is that increased roll will cause front tyres to fall off their contact patches (we'll see).

If that happens, plan B is to re-fit the 24mm front bar and put on a rear bar from a 75 (bit bigger). However, plan C could be a roll centre adjustment - either front or rear...

[Grant]

When your car is as stock as yours is, you shoudl be running as large of sway bars as you can find. The 24mm might feel like it understeers a lot, but I'm rpetty sure the speed aroudn the track will be faster than with the 22mm bar...just because there's more ultimate grip.

You should get some larger front t-bars in the front for starters, they're not too hard to get in OZ are they?

Pile on the negative front camber. I've been told -2.5 degrees is a good place to START.

I'm off to class!

[gtv27]

Thanks for the tips.

Bigger anti-roll bars are certainly my plan B. Bigger torsion bars are not part of the plan - want to keep it supple. Negative is -1.5 a the moment but think I may need go as high as -2 to -3 (although that's a lot for a road car).

[Potenziato]

Quote:

Originally Posted by Grant " With the ex-Larry suspension, you're saying that drop spindles didn't help understeer at all? Because that pretty much would be the situation where I would have thought drop spindles would have helped (not having excessive spring rates, allowing the car to roll a bit and utilizing more negative camber when cornering hard).