Lotus Elan

limited slip diff.

PostPost by: jimj » Mon Oct 18, 2010 11:50 am

What are the downsides, apart from price, of running an lsd in a road Elan?
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PostPost by: summerinmaine » Mon Oct 18, 2010 4:16 pm

Axle conversion or do-nuts?
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PostPost by: jimj » Mon Oct 18, 2010 4:55 pm

CVs
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PostPost by: summerinmaine » Mon Oct 18, 2010 6:28 pm

Then I may be wrong, but I can't see how there would be any downside.

I have cv axles and an LSD in my 2002Tii, and it works like a charm.

I was thinking that an LSD might create additional stress on do-nuts as it locks and unlocks.
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PostPost by: Roy Gillett » Mon Oct 18, 2010 7:32 pm

Jim,

How can we possibly hope to keep up with you round North Wales if you fit an LSD? I see your 3 Castles entry has been posted. Look forward to seeing you and Carol there. BTW I am pretty sure that Graham Walker has always run a Quaife LSD in his Sprint so he might be worth asking.

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PostPost by: jimj » Mon Oct 18, 2010 10:33 pm

Roy, that`s the idea, innit? A bit more power oversteer around the cones is just what I fancy. I thought I had a problem with the existing diff. and what with Christmas coming I`m always stuck for something to buy Carole..........As it happens my existing diff. is fine so she will just have to settle for something boring. Why is that it`s Ok for ladies to buy blokes tools but not Ok for blokes to buy ladies useful items?
Yes we`re pleased to see you`re on the 3 Castles list too as are many familiar names, I`d particularly like to be familiar with Kim Porter!
I`m still intrigued as to the pros and cons of lsd in a road Elan if anyone else has experience.
Jim
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PostPost by: rgh0 » Tue Oct 19, 2010 7:18 am

A quaiffe lsd has no sudden engagement effect and never gives total lock up so it does not upset the handling at all in my experience on the road or track. I just helps you get out of tight corners qucker by enabling more thottle use earlier in the corner exit without spinning the inside rear wheel. Also helps in long fast accelerating corners for the same reason. Also helps with those drop the clutch starts as you dont sit their just spinning one wheel.

On the road in corners in a standard car the softness of the rear suspension and lack of ability to generate much body roll with standard road tyres makes it useful really only in the wet as its hard to loose traction in other circumstances. If you stiffen up the car and use stickier tyres it helps more in road use in corners in the dry.

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PostPost by: stuartgb100 » Tue Oct 19, 2010 11:37 am

Hi Rohan,

Does the behaviour of a Salisbury plate-type, versus a Quaiffe lsd differ then for a road car ?
How does track behaviour compare ?

Thanks,
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PostPost by: gerrym » Tue Oct 19, 2010 12:52 pm

Stuart, the answer is really in the name. The Quaiffe unit is not actually a limited slip diff at all: it's a automatic Torque Biasing Differential. The bias is a built-in property of the gearing design chosen (not adjustable at all) unlike a limited slip diff.

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PostPost by: bcmc33 » Tue Oct 19, 2010 2:21 pm

summerinmaine wrote:Then I may be wrong, but I can't see how there would be any downside.

I have cv axles and an LSD in my 2002Tii, and it works like a charm.

I was thinking that an LSD might create additional stress on do-nuts as it locks and unlocks.

Jim,
Gerry is correct.
I guess your 2002Tii has a genuine LSD (Salisbury type) that we used to use on Cortinas and Escorts in the good old days. A genuine LSD has the advatage/disadvantage of being heard or felt at each time it operated in reaction to some slip caused by the differential speeds of the driveshafts.
The Quaife "LSD" is different and is in fact a TBD (Torque Biasing Differential) which reacts seamlessly when there is an applied torque differential between the driveshafts.
The Quaife unit will be much better in the Elan than a genuine type LSD.
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PostPost by: summerinmaine » Tue Oct 19, 2010 3:10 pm

bcmc33 wrote:
summerinmaine wrote:Then I may be wrong, but I can't see how there would be any downside.

I have cv axles and an LSD in my 2002Tii, and it works like a charm.

I was thinking that an LSD might create additional stress on do-nuts as it locks and unlocks.

Jim,
Gerry is correct.
I guess your 2002Tii has a genuine LSD (Salisbury type) that we used to use on Cortinas and Escorts in the good old days. A genuine LSD has the advatage/disadvantage of being heard or felt at each time it operated in reaction to some slip caused by the differential speeds of the driveshafts.
The Quaife "LSD" is different and is in fact a TBD (Torque Biasing Differential) which reacts seamlessly when there is an applied torque differential between the driveshafts.
The Quaife unit will be much better in the Elan than a genuine type LSD.



Thanks Brian.

Mine is a 3.91 from a later BMW with a 25% locking factor. And it was the lock-ups that I was thinking about when I speculated that it might not be as good on a do-nut rear axle.
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PostPost by: fjbm » Wed Oct 20, 2010 11:41 am

summerinmaine wrote:Axle conversion or do-nuts?


Hi

Are there any problems when using a LSD with donuts?

Thanks
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PostPost by: Elan45 » Wed Oct 20, 2010 1:21 pm

I have a Salisbury type LSD in my AE86 type rear wheel drive
Corolla. I don't notice it at all in normal driving but it gets chattery in low speed tight turns, such as a left turn from stopped at a traffic light in the US, or same but right turn in UK. This is because it tends to act as a locked axle in that situation where an open diff is at its best.

I also have a Quaife in my Lotus Eleven and I've been in situations on track where one rear wheel gets unloaded in a negative camber turn, the track is getting sloppy late in the race and the quaife doesn't help the situation much at all (inside rear wheel spin). If you want this diff to help in autocross or sprint situations, I think you need to consider the LSD over the TBD. For normal street driving, I think I'd prefer the quaife.

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PostPost by: curly type 26 » Wed Oct 20, 2010 5:27 pm

Dont use roto flexes with LSD you need one of the solid rear systems ( quoted in chris harveys ) elan book page 208, :D Curly
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PostPost by: bcmc33 » Wed Oct 20, 2010 5:38 pm

curly type 26 wrote:Dont use roto flexes with LSD you need one of the solid rear systems ( quoted in chris harveys ) elan book page 208, :D Curly

Giving it a little more thought - would not roto flexes confuse both the LSD & TBD?
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