Pros and cons of fitting LSD to turbo FWD car
Discussion
Car in question is an F56 JCW. I've already fitted smaller, lighter wheels and coilovers to lower it ~ 25 mm + geo. Big improvement in the handling so far, but I think there's more to give.
In winter conditions the car frequently struggles to put the power down on anything other than a feather light throttle input, and I want to feel more confident driving it when the roads are damp and slippy, which is quite often in the UK.
The tyres are good, so my next thought is an LSD. The car currently has an e-LSD which basically just applies the brakes when wheels lose traction. An LSD is an often recommended upgrade to this car.
It boils down to a Wavetrac or Quaife (as fitted to a JCW Challenge). The main difference seems to be the Wavetrac can provide power to the wheel with grip even when the other one is off the ground, whereas the Quaife will act as an open diff in that scenario.
Some people say the Wavetrac is much better (typically people who happen to be selling Wavetracs), some say there's little in it, and you would only see the difference between them in track driving as that is when you're more likely to get a wheel off the ground. Either way, is it safe to assume either is going to be a dramatic improvement over using the e-LSD?
There have been *some* suggestions of issues with the Wavetrac but none reported for the Quaife. The former is about double the price of the latter.
There's also the issue of whether I actually drive hard enough to justify one. I probably won't ever drive it above 7 or 8/10's at the most. I like to make progress but am a pretty chilled driver generally. There are defintely times when I feel like I could do with powering out of corners better though.
I have heard *some* people say the difference wasn't as noticeable as they were hoping for.
As an alternative (or even as an addition), it would appear that a slightly thicker ARB, and plates that will allow for more camber at the front might be a cheaper option to at least change the balance of the car to make it more confidence inspiring? I recognise that it is very much not the same, but it may be a favourable change for less money.
Any thoughts on any of the above?
In winter conditions the car frequently struggles to put the power down on anything other than a feather light throttle input, and I want to feel more confident driving it when the roads are damp and slippy, which is quite often in the UK.
The tyres are good, so my next thought is an LSD. The car currently has an e-LSD which basically just applies the brakes when wheels lose traction. An LSD is an often recommended upgrade to this car.
It boils down to a Wavetrac or Quaife (as fitted to a JCW Challenge). The main difference seems to be the Wavetrac can provide power to the wheel with grip even when the other one is off the ground, whereas the Quaife will act as an open diff in that scenario.
Some people say the Wavetrac is much better (typically people who happen to be selling Wavetracs), some say there's little in it, and you would only see the difference between them in track driving as that is when you're more likely to get a wheel off the ground. Either way, is it safe to assume either is going to be a dramatic improvement over using the e-LSD?
There have been *some* suggestions of issues with the Wavetrac but none reported for the Quaife. The former is about double the price of the latter.
There's also the issue of whether I actually drive hard enough to justify one. I probably won't ever drive it above 7 or 8/10's at the most. I like to make progress but am a pretty chilled driver generally. There are defintely times when I feel like I could do with powering out of corners better though.
I have heard *some* people say the difference wasn't as noticeable as they were hoping for.
As an alternative (or even as an addition), it would appear that a slightly thicker ARB, and plates that will allow for more camber at the front might be a cheaper option to at least change the balance of the car to make it more confidence inspiring? I recognise that it is very much not the same, but it may be a favourable change for less money.
Any thoughts on any of the above?
With my Fiesta ST, it made a huge difference.
On track, can just come out of a tight corner and plant your foot, where before you were trying to stop one wheel from spinning.
On a wet road I felt like that fella who used to ride an Ostrich puppet on telly (Lenny something ?) and didnt know where it was going to go, full throttle in second or third and it would try and change lanes, much more predictable now.
Dont get me wrong, 300 odd bhp through the front wheels is never going to be totally contained, but with decent tyres, considered mapping, an LSD and a suitably calibrated right foot, its so much better than you would expect, old FWD cars with half that power were a liability.
Trouble is, am about 16 grand deep into a car worth like four now
On track, can just come out of a tight corner and plant your foot, where before you were trying to stop one wheel from spinning.
On a wet road I felt like that fella who used to ride an Ostrich puppet on telly (Lenny something ?) and didnt know where it was going to go, full throttle in second or third and it would try and change lanes, much more predictable now.
Dont get me wrong, 300 odd bhp through the front wheels is never going to be totally contained, but with decent tyres, considered mapping, an LSD and a suitably calibrated right foot, its so much better than you would expect, old FWD cars with half that power were a liability.
Trouble is, am about 16 grand deep into a car worth like four now
J4CKO said:
With my Fiesta ST, it made a huge difference.
On track, can just come out of a tight corner and plant your foot, where before you were trying to stop one wheel from spinning.
On a wet road I felt like that fella who used to ride an Ostrich puppet on telly (Lenny something ?) and didnt know where it was going to go, full throttle in second or third and it would try and change lanes, much more predictable now.
Dont get me wrong, 300 odd bhp through the front wheels is never going to be totally contained, but with decent tyres, considered mapping, an LSD and a suitably calibrated right foot, its so much better than you would expect, old FWD cars with half that power were a liability.
Trouble is, am about 16 grand deep into a car worth like four now
It sounds like I have to get one then. Particularly as most feedback I've had seems positive On track, can just come out of a tight corner and plant your foot, where before you were trying to stop one wheel from spinning.
On a wet road I felt like that fella who used to ride an Ostrich puppet on telly (Lenny something ?) and didnt know where it was going to go, full throttle in second or third and it would try and change lanes, much more predictable now.
Dont get me wrong, 300 odd bhp through the front wheels is never going to be totally contained, but with decent tyres, considered mapping, an LSD and a suitably calibrated right foot, its so much better than you would expect, old FWD cars with half that power were a liability.
Trouble is, am about 16 grand deep into a car worth like four now
I know exactly where you're coming from on cost though, I almost envisage doing the clutch and maybe a light flywheel, and the bill is probably going to be around £3k, so I wanted to be certain about it 
Top pup said:
I ran an R53 facelift cooper S for a while, and I was always extremely impressed with how it put the power down to the point I suspected it may have a LSD. I did a check on the spec and it had the factory LSD fitted. Whatever type of LSD the factory fits it had no obvious downside.
Yeah I've had an r53 as well and that had the LSD, and I remember it clinging on well, although it had a lot less torque than my f56 JCW especially at low revs. Had one in the DC2 as well but that was very low torque, and I have to say I'm not really sure I noticed its presence in that.
I have a Wavetrac on a RWD car and think it is great. Can't comment on quaife as I've not tried one. But I find the Wavetrac coped very well with bumpy uphill driving (bad road surface, not huge potholes etc). With the open diff (pre-Wavetrac), the TC would be killing power due to momentary wheel spin, this is completely gone with the Wavetrac, and the car just launches up the hill.
I think you'll find either is a great improvement, and the Wavetrac has a slight edge due to the wheel-off-ground thing.
Definitely the best mod I've done, but definitely not the best value as it is expensive.
I am getting another Wavetrac fitted during Feb.
I think you'll find either is a great improvement, and the Wavetrac has a slight edge due to the wheel-off-ground thing.
Definitely the best mod I've done, but definitely not the best value as it is expensive.
I am getting another Wavetrac fitted during Feb.
Top pup said:
I ran an R53 facelift cooper S for a while, and I was always extremely impressed with how it put the power down to the point I suspected it may have a LSD. I did a check on the spec and it had the factory LSD fitted. Whatever type of LSD the factory fits it had no obvious downside.
The R53 Cooper S LSD was a torque biasing type with a low bias ratio of about 2:1 - made by GKN ( GKN Super LSD ) and was the same type as used on the Mazda 3 MPS DickyC said:
Why doesn't the traction control sort out the wheel spin?
It does, by applying the brakes and backing off the power, but it can’t distribute power equally, it just quells wheelspin.I turn off the traction control most of the time anyway as can feel it killing the power, prefer to modulate it myself, it will on a damp/cold road let you spin the fronts to the rev limiter in second and sometimes third, on a dry road when it’s reasonably warm no wheel spin whatsoever, once moving anyway.
Did consider a played diff like a Kaaz but more expensive and not really fit and forget, Torsten Mfactory one cost me about £1450 two years ago, that and the EBC brakes bring it together as a viable package, rather than just a sort of overpowered Fiesta.
TameRacingDriver said:
plenty said:
If you drive hard enough to notice traction problems, you'll notice an LSD.
More camber won't solve the problem, and a thicker front ARB will just promote understeer.
Rear ARB.More camber won't solve the problem, and a thicker front ARB will just promote understeer.
Not tried it on track yet but it seems to have improved grip and made the rear a little more mobile.
I had a geo setup as well but thinking of ordering some coilovers, going to get something else soon so can go a bit more track focused, its easy to ruin a car as a daily, only thing I have done thats too much is the bloody mongoose exhaust, even after I added an extra silencer in.
Increasing (negative) camber on a FWD car which doesn't have an LSD will make traction worse on corner exit because it will add grip to the loaded outside wheel at the expense of grip on the unloaded inside one. You'll also be exiting corners faster because of that extra grip on the outside front wheel which will further unload the inside wheel.
Stiffening the rear in roll will help but it has its limits; even if you come somehow completely eliminate body-roll you'll still get weight transfer and hence uneven contact pressure across the car. Stiffening the rear will also have other effects, both negative and positive, so make sure you know what you're getting.
An LSD is the "correct" solution (well, I suppose RWD 4WD is the correct solution, but an LSD is next on the list); you just need to pick carefully. If you get the wrong diff, or it is set up wrong, it may start to lock before the inside wheel starts to slip (simply due to the different path lengths taken by the two wheels) you'll end up with god-awful under-steer. Obviously there is a trade-off here between having the diff start to lock and generate under-steer in really tight corners vs having it stay open too long when a wheel loses traction and hence spin away some of your power. This is why high performance cars these days tend to use active diffs which take input from things like steering angle sensors to decide when and how much to lock.
Stiffening the rear in roll will help but it has its limits; even if you come somehow completely eliminate body-roll you'll still get weight transfer and hence uneven contact pressure across the car. Stiffening the rear will also have other effects, both negative and positive, so make sure you know what you're getting.
An LSD is the "correct" solution (well, I suppose RWD 4WD is the correct solution, but an LSD is next on the list); you just need to pick carefully. If you get the wrong diff, or it is set up wrong, it may start to lock before the inside wheel starts to slip (simply due to the different path lengths taken by the two wheels) you'll end up with god-awful under-steer. Obviously there is a trade-off here between having the diff start to lock and generate under-steer in really tight corners vs having it stay open too long when a wheel loses traction and hence spin away some of your power. This is why high performance cars these days tend to use active diffs which take input from things like steering angle sensors to decide when and how much to lock.
Edited by kambites on Thursday 30th January 09:30
Thanks everyone this has been very helpful, and clearly it's a bit of a mine field to say the very least.
Based on the comments I'll consider giving the rear ARB a go but leave the camber as is given the possible other issues that might introduce.
I have the money to do this but I just don't want to waste it if there's not going to be much benefit.
I also get that a RWD car would be more optimal overall, but the only RWD cars I'd see as more fun than my mini given the budget that I would have are mostly all 2 seaters, or have basically unusable back seats. A BMW would be the other answer, but I've always found the 3 series I've had (both 328s) a little dull in the past, and I'd still end up wanting coilovers and a diff on those, and I can't really stretch to a proper M car.
If I had space I'd just buy another MX5 or MR2 or even an Elise if I was feeling very flush, but I'm not.
Based on the comments I'll consider giving the rear ARB a go but leave the camber as is given the possible other issues that might introduce.
I have the money to do this but I just don't want to waste it if there's not going to be much benefit.
I also get that a RWD car would be more optimal overall, but the only RWD cars I'd see as more fun than my mini given the budget that I would have are mostly all 2 seaters, or have basically unusable back seats. A BMW would be the other answer, but I've always found the 3 series I've had (both 328s) a little dull in the past, and I'd still end up wanting coilovers and a diff on those, and I can't really stretch to a proper M car.
If I had space I'd just buy another MX5 or MR2 or even an Elise if I was feeling very flush, but I'm not.
TameRacingDriver said:
It boils down to a Wavetrac or Quaife (as fitted to a JCW Challenge). The main difference seems to be the Wavetrac can provide power to the wheel with grip even when the other one is off the ground, whereas the Quaife will act as an open diff in that scenario.
This may be their claim but it is not reality.I have a Wavetrac, rwd car, and in tight turns etc etc, I can easily get lots of one wheel wheelspin, absolutely no difference than the previous Torsen it had before of another brand.
But their diffs are very well made, so no issues there. But I've seen no evidence on my own car that their setup prevents it behaving like an open diff when one wheel goes light.
But I'm sure any LSD will be a good benefit in general, assuming of course the e-LSD you refer to doesn't interfere with things
stevieturbo said:
This may be their claim but it is not reality.
I have a Wavetrac, rwd car, and in tight turns etc etc, I can easily get lots of one wheel wheelspin, absolutely no difference than the previous Torsen it had before of another brand.
But their diffs are very well made, so no issues there. But I've seen no evidence on my own car that their setup prevents it behaving like an open diff when one wheel goes light.
But I'm sure any LSD will be a good benefit in general, assuming of course the e-LSD you refer to doesn't interfere with things
Yeah they claim it's a wave technology which is apparently what seperates it from all the others.I have a Wavetrac, rwd car, and in tight turns etc etc, I can easily get lots of one wheel wheelspin, absolutely no difference than the previous Torsen it had before of another brand.
But their diffs are very well made, so no issues there. But I've seen no evidence on my own car that their setup prevents it behaving like an open diff when one wheel goes light.
But I'm sure any LSD will be a good benefit in general, assuming of course the e-LSD you refer to doesn't interfere with things
On the F56 group I'm on, most seem to swear its a lot better, but its always difficult getting opinions from people who've spent more money because they're always going to want to consider their purchase the best, but even people who are selling both seem to think it's a lot better...
But then there's your experience...
Bloody minefield
TameRacingDriver said:
It boils down to a Wavetrac or Quaife (as fitted to a JCW Challenge).
If it's good enough for JCW Challenge cars (pretty serious race cars) then I'd go Quaife without hesitation. And as I previously owned a JCW, I agree, a road going JCW really does need a front locking diff.Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff