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Discussion Starter #1
I'm looking to replace an '06STI with an Elise. The STI has 3 diffs and is almost too easy to drive. My concern is that if I do go with a SC for more power, I'll need an LSD...especially on corner exit on the track.
Opinions?

Thanks,
TomK
 

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welcome to ET.

it's saturday day, so i'll play the welcome wagon. if you want to find out about LSD in the lotus (there are a couple of years' worth of LSD discussions) try an advanced search, titles only. use LSD* in the search field. enjoy.
 

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Well, we have a pair of aces. :D
 

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If you drive your car hard on the track you will want a limited slip. When I say drive hard I mean at least Time Attack level driving or SOLO.
 

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Discussion Starter #5
If you drive your car hard on the track you will want a limited slip. When I say drive hard I mean at least Time Attack level driving or SOLO.
Then I'm gonna be looking for a diff...

Thanks,
TomK
 

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Then I'm gonna be looking for a diff...

Thanks,
TomK
Making it easy for you:

You don't need the torsen lsd for track use.
Yes, this man really knows what he's talking about. I don't know of anyone who has more seat time on the track than Jack.

Autocrossing is another story :D
Jack is absolutely right. In fact, Lotus engineers will tell you flat out that they don't like the LSD because they set the car up right in the first place. It doesn't need it. The only reason to get it, and then its a matter of preference, is if you intend to auto-x. This is why it was offered in the first place. Outside of that, save your money for track fees.

If you do a quick search you will find back up to my statements from Lotus.
 

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But outside the world of Lotus engineers (who might not be unbiased), the consensus is that a limited slip diff is a very good thing. More than just a consensus -- you'll find that almost no one prefers an open diff.

One example is that when Porsche raced the 956 at LeMans in the early 1980s, there wasn't a limited slip unit available that would provide the reliability they needed. So their choice was open diff, or locked spool.

They chose locked spool. Given the disadvantages of a spool, that should tell you how unfavorably they looked upon the open diff.

Steve
 

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But outside the world of Lotus engineers (who might not be unbiased), the consensus is that a limited slip diff is a very good thing. More than just a consensus -- you'll find that almost no one prefers an open diff.

One example is that when Porsche raced the 956 at LeMans in the early 1980s, there wasn't a limited slip unit available that would provide the reliability they needed. So their choice was open diff, or locked spool.

They chose locked spool. Given the disadvantages of a spool, that should tell you how unfavorably they looked upon the open diff.

Steve
Hey Steve, I'm not saying your wrong when speaking of track cars in general, however, I believe that the Lotus engineers are unbiased. (Lotus could make a bunch more $$ selling LSD) That in fact, is their job, and as it applies to the Elise and Exige, the general consensus from the engineers who developed the car for the track, and those customers with considerable track experience - such as Jack - say no LSD.
 

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I know Enigma put an LSD into his Elise and really likes it. These are his early comments about Thunderhill

I have only had one track day on the car since I put the LSD in. Things to note.

The car is faster from T11 - T14. You get a much better run off of T11 as a result of the LSD. Its almost a 0.5s pickup since you carry that extra speed for a long time.

The tendancy to push out of turn 2 is gone. This means you can get on the power a little earlier but you need to be careful not to induce oversteer with the throttle.

No major diffrence in the rest of the turns.

The car should be faster with the LSD but the skill needed to extract the most out of the car is increased. Any 2nd gear turn is a good canidate for an improvement.
 

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wow, so another LSD thread, which is comprised largely of quotes of previous LSD threads. what a concept!
 

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Discussion Starter #11
I appreciate all the responses and opinions.

It's nice to know that some people believe that the car works well without a diff, and that it isn't "SCREAMING" that it wants a diff. With that said, thiscar isn't going to "stay as the designers intended"...it will have more power, be stiffer, run wider tires, and have more camber than was originally intended. If its still not screaming for a diff, and I'd be damn surprised if it wasn't, then I'll leave it be...

Thanks and be good,
TomK
 

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I would suggest driving the car for awhile on track with the open diff, and then you can make a determination whether or not you need an LSD. A lot of it comes down to driving style as well. On the flip side of the coin, one of the fastest drivers on here (Manley aka mlk f1) uses an LSD...
 

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GET LSD!

If you want the back end to slide out when you expect it to, then get LSD.
If you want to do single wheel peel outs, then leave it open diff.

for reference, here is double wheel (LSD) peel out : (notice the smile on his face, Thx LSD!)

:shift:
 

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I bought a LSD shortly after I bought my Elise thinking I woud need one too. Since then I've superhargered the car and done 17 tracks days. The LSD is still sitting in the box. I'll install it the first indication I think I need it. To date, that has not happened.
 

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LSD to be or not to be

I sold my 05 STI which I Autocrossed and purchased an 06 Elise NA w/o LSD. If you are driving hard on a tight course at any time you will want the LSD, on any quick transition you will spin the inside tire, period!

Its much easier to start with an LSD and if you should find it un-useful, its an easily swap to some Elise driver who would love it. Diff for diff and cash.
I just spent big bucks buying another complete tranny with LSD so I could be competitive to the thousandth!
 

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For autocross it makes sense (and that's why Lotus intro'd it). There are no tracks that I know of where LSD is advantageous (read: yields better laptimes). Yes, it is easy to spin the rear inside wheel on very tight turns where you cannot carry speed and are forced to accelerate hard. But those are rare turns. For all the others, the correct way to turn this car IMO is to trail brake to plant the nose, then get up onto the throttle pretty hard to plant the rear. When you do the latter, LSD can overload the outside tire and cause it to slide which is really just scrubs speed (even if it feels and looks cool). It's also a good way to loose the rear end (which looks really stupid).

You need to drive the Lotus proficiently before you, and only you, can determine whether LSD is the right thing for your driving style. Sounds like you want to jump in with two feet and totally mod a car that really defies everyones attemps to improve dramatically on what Lotus engineers have created. But you'll find that out for yourself I suppose. Just keep in mind that this car has a very small engine that is pretty max'd out in power so the name of the game is keep it light, low Cd, and not too much tire. Power, stiff springs, LSD, big tires, body kits - they seem to slow the car down or create drivability idiosyncracies on the track from what I've seen.

Lotus engrs got it right without LSD, stiff springs, electronics driver aids and 4wd. It's not popular thinking in todays world - but it's the best road going track car on the planet in terms of feel, fun and performance. And it has no similarity to an STi or all those 'other' cars that demand mucho mods to work right.
 

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I know we're orbiting about the same points in many posts...but.

It's absolutely true that you want to get on the power early and get weight to the back.

With an open diff, if you apply too much power, you will just spin the inside (unloaded tire).

With an LSD you will put power to the loaded tire as well, and you work direct the power to the inside wheel to spin it helplessly.

And it's very true that if you are going to overpower the rear end with power, spinning the unloaded wheel will result in more predictable handling since you will actually lose drive to the loaded wheel and it can focus on grip.

However, if you are using this at all as a method of "saving" yourself -- I have to strongly, strongly suggest you back your overall pace down, because it sounds like you aren't actually recognizing the vehicle dynamics and seeing it coming. (that generally comes with experience).

With an LSD you should be feeling a bit of yaw as you approach the limits of putting power down on exit.

Jason Plato, the 5th Gear presenter (and former British Touring Car Champion) reviewed the Elise SC on this weeks show (I bet it's on youtube now) and demonstrated how much the open diff impacts performance pretty well. Admittedly, he provokes it for the point of demonstration, but it shows exactly where the open diff kills you on exit.

Steve
 

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Jason Plato, the 5th Gear presenter (and former British Touring Car Champion) reviewed the Elise SC on this weeks show (I bet it's on youtube now) and demonstrated how much the open diff impacts performance pretty well. Admittedly, he provokes it for the point of demonstration, but it shows exactly where the open diff kills you on exit.

Steve
Yep, posted here: http://www.lotustalk.com/forums/showthread.php?t=53918
 

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Discussion Starter #19
Again, great posts and I appreciate your help.

Yep, I'm looking to jump in with both feet...that's me. Body kits?...that's not me.
I have some experience with small, underpowered, open-diff, mid-engined cars... ran a MR-S for 3 years with local CSP championships, so I'm no stranger to the dynamics of this "type" of car. When I test drove it, it brought me right back to the best handling car I've ever driven and wihout a doubt, the most enjoyable car I've ever had the pleasure to drive....I expect the Elise will take that position in my "mental-ranking".

It is good to hear that the car doesn't immediately call for an LSD, I'm quite surprised that there is such a continual debate over the subject...but I suspect that the more developed track cars will use them with good effect.

In time...I'll see how itgoes and go from there.

Thanks again,
TomK
 

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