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Milano LSD: Worth the time and $$ to convert, or not...?

Posted: Mon Aug 29, 2005 10:54 pm
by MilanoMan
My Milano Platinum had the transaxle replaced by previous owner with a NON-LSD 4:10 unit from a Milano Gold. Bummer! I've recently replaced the 2.5 with a totally rebuilt 3.0 and S cams. Now that I have gobs more torque, I can pretty easily break the inside wheel loose when accelerating hard out of a corner. Makes me wonder if it would be worth it to find an LSD transaxle and replace mine?

The car is used only on the street...no track events are planned. Rims are original Alfa 15" and tires are Falken Ziex...not Azenis, much less sticky, so they are merely average in performance.

Looking for opinions...would it be better for me to just invest in better tires, assuming they will provide enough grip to keep a street driver happy? Or, does the LSD make a substantial improvement to the car? Tires are a lot cheaper and much less hassle than replacement of the transaxle...

Thanks,
MilanoMan

Posted: Tue Aug 30, 2005 2:15 am
by Mezevenf
After tightening my suspension at the rear, I spun the inside wheel all the time on my stock 2.5L V6 on Falken Azenis rubber ST115.

Just thought I'd let you know, doesnt seem that the rubber would help all that much. Go for the LSD ;)

Posted: Tue Aug 30, 2005 10:54 am
by MerrilGordon
I'm sure grippier tires would help MiloMan, but I have the same problem. A mild stock cammed 3L GTV6, stock FI, open differential, and ok 205/50-15s. On a number of occasions when I've really put the power to the pavement the lighter loaded tire spun. That tended to upset the car requiring counter steering and letting off the throttle. Also, this was not in tight corners but ones with minimal curve. I figure with a good LSD that wouldn't have happened and I could have kept the power on.

I think with the extra power you have you'll keep running into the same problem. With a limited slip you could put down substantially more power before traction is broken again. Especially with high grip tires. Might be safer as well.

How much LSD grip is another question. A good rebuilt unit at stock 25% grip may do the job. Extra shims gets less slip between the axles, but I don't know if that is better when highways get damp. A friend of mine has a Milano with extra shims and it's quite squirly when the roads get slick. I guess it's a judgement call there.

Merril

Posted: Tue Aug 30, 2005 5:21 pm
by Mezevenf
I'll be running 75% soon, I'll let you know how that goes.

Posted: Wed Aug 31, 2005 1:13 pm
by MD
Mezevenf

Just a quick note. I run 47% and it pushes like the proverbial so I suppose the key question is, where do you want to use it? If it is for street, I would not suggest using more.

Posted: Wed Aug 31, 2005 2:52 pm
by Mezevenf
It is for street and light track.

Mind you, what I class as street is not exactly street driving. Its a weekend car used solely for driving fast (and legal, of course), not as any kind of transport.

I expect the outside wheel to drag, we'll see how it is. Thanks for the warning though, but its already in the car.

Posted: Thu Sep 01, 2005 12:45 am
by Mats
I have only the std setup on my cars and have never slipped the inside on the street and only minor slippage in one turn at one track in the season. Rather have that then understeer going into the turn or during power-on.

Who likes understeer?

Posted: Thu Sep 01, 2005 4:33 am
by gtv11636
MD wrote:Mezevenf

Just a quick note. I run 47% and it pushes like the proverbial so I suppose the key question is, where do you want to use it? If it is for street, I would not suggest using more.
MD
Why would it be too much for street use ? Do you mean it will be too much on wet roads or also on dry ?

Posted: Thu Sep 01, 2005 1:38 pm
by MD
gtv11636

If you caught Mats comment earlier, it is not just a throw away line. And no, I wasn't just talking about conditions in the wet.

What happens when you push too hard from the rear is that somehow you have to get the front to stick equally as well otherwise you get so much understeer that it pushes the car through the corner apex and onto the other side instead of around the corner. (if that makes sense).

Of course this depends on to some extent on how much power you have to do the pushing and other factors like your suspension set up which may help counter the problem (but not eliminate it)

The problem with open diffs is that you cannot ultimately push hard enough because the inside wheel lifts off and you lose drive so you get around the corner by inertia. So in theory, your ultimate speed is to some extend limited by this. Nowhere is this more aparent than really hard driving in the mountains.

So at the end of the day, life is a compromise...

Posted: Thu Sep 01, 2005 11:17 pm
by Mats
Actually if you have LOADS of power you can get powerful oversteer without sliding...
It fries the tires quick enough though, here's how it works.

Normally if you have too much braking in the diff the wheels want's to roll the same amounts of turns, but since the diff is there to take care of the fact that the inside wheel rolls a shorter distance through the turn a braking diff will try to make the car go straight or force one wheel to slip, usually the inside because the load is less there. This means that you have to break traction on the inner wheel before the car will turn, massive understeer... BUT!
If you at the same time in a turn press the gas pedal, the force applied will almost only go into the outside rear (the inside is slipping, remember?) and this will give a kind of torque-steer since the force is not through the center of the car. Therefore - oversteer.
Weird huh?

This means however that the inside will always slip and that you will have to be very brutal at turn-in. Expect to buy lots of tires...

The easiest solution will of course be to run a std 25% diff without preload. Don't assume that the designers of the car are stupid, they usually know what they are doing. ;)