I'd like some LSD.

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tbourner

Active Member
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Mar 19, 2018
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Location
Havant
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AMG A45
How do I know if I've got an LSD? It's not on the original options list, but I've never had a problem with traction - although I usually leave the t/c on so I wouldn't know.
 
Turn off the traction control fully by holding it down until it says off.

Find a quiet space and hold the brakes on gently.

Floor it in manual mode for a few seconds.

Get out and see if there are 2 tyre marks or one.

Two = LSD
 
Turn off the traction control fully by holding it down until it says off.

Find a quiet space and hold the brakes on gently.

Floor it in manual mode for a few seconds.

Get out and see if there are 2 tyre marks or one.

Two = LSD

Totally wrong, you can still do elevens without an LSD.

The best way is to put up your reg plate and someone can use the checker to see what specs your car came with. Otherwise you will have to jack the rear of the car up and see if one wheel turns or both.
 
Also totally wrong.

Might have one fitted aftermarket and a Quaife is the most popular where the wheels still turn in opposite directions.

I know you can do 11s with an open differential but I actually described a burnout. That is far more likely to result in just one wheel spinning because with an open differential as soon as one wheel spins more power goes to that spinning wheel and the brake will hold the other wheel still. ;)
 
Surely if you were the kind of driver who might need an LSD then you would also be the sort of driver who could tell by the way that the car drives?
 
Surely if you were the kind of driver who might need an LSD then you would also be the sort of driver who could tell by the way that the car drives?

Not really, I've never driven anything like this before, so have no frame of reference for how well it should drive. It seems to keep traction very well in corners, even in the wet - it doesn't feel like it needs an LSD added, so maybe it does have one, but it wasn't on the option list so I was just wondering if there was an easy way to tell.
 
This might be slightly confused by clever traction control applying the brakes to keep the driven axle planted.

The definite answer is to take the cover off the diff housing and look, but that's probably not worth the effort. As suggested above, put it on a hoist and turn one wheel and see if the other side spins with it, or in the opposite direction?
 
The spin the wheel off the ground test only confirms if you have a clutch type LSD. There could be a geared torque biasing differential (strictly speaking not actually an LSD) that still spins the wheels in opposite directions.

More likely it hasn't got one. You don't need one as the TC does its job well but you'll get more thrust off the line and out of slow corners because the TC will be cutting in less.
 
Also totally wrong.

Might have one fitted aftermarket and a Quaife is the most popular where the wheels still turn in opposite directions.

I know you can do 11s with an open differential but I actually described a burnout. That is far more likely to result in just one wheel spinning because with an open differential as soon as one wheel spins more power goes to that spinning wheel and the brake will hold the other wheel still. ;)

Your still wrong too if you think you cant do a two wheel burnout without an LSD. Wow look my non lsd below, only looks like one mark ;)

69CAC74E-03A7-46C7-9AEF-2B211AE9B29B_zpsg4gj2tkf.jpg


Plus I was correct then as I was assuming he was asking if he had one fitted from standard when the car was new.
 
If you're not getting blinded by the traction control light flashing at you when you drive "enthusiastically" then you probably have a lsd or don't need/ wouldn't benefit from one.
 
Your still wrong too if you think you cant do a two wheel burnout without an LSD. Wow look my non lsd below, only looks like one mark ;)

69CAC74E-03A7-46C7-9AEF-2B211AE9B29B_zpsg4gj2tkf.jpg


Plus I was correct then as I was assuming he was asking if he had one fitted from standard when the car was new.
The question was do I have an LSD and he'd already said it's not on the options list so I tried to answer all possibilities. It's actually quite difficult to confirm for sure as debated here.

You're still missing my point though, I described a stationary burnout as I'm well aware you can still do an 11 with an open differential as already stated. :p

NB: The stationary burnout isn't completely foolproof but do 3 in a row in different places and it'll be almost certain that at least one will leave a one tyre mark if it's open. To do a double with an open both tyres need to lose traction at exactly the same moment (which is rare).
 
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The spin the wheel off the ground test only confirms if you have a clutch type LSD. There could be a geared torque biasing differential (strictly speaking not actually an LSD) that still spins the wheels in opposite directions.
In my experience of owning Biturbo E63's with an open diff. a Quaife Torque Biasing diff. and an AMG Locking diff (the clutch type), it's easy to tell if you have the clutch-type LSD as you will feel the inside rear wheel pushing / scrubbing in tight low-speed turns.
More likely it hasn't got one. You don't need one as the TC does its job well but you'll get more thrust off the line and out of slow corners because the TC will be cutting in less.
When I swapped the open diff. for a Quaife the most obvious difference was exactly that: more thrust off the line and out of slow corners, but without the pushing / scrubbing in tight low-speed turns. If you're drag racing then a locking diff. is better, but for use on the road I definitely prefer the Quaife, which is also less prone to causing snap oversteer when you're - ahem - driving enthusiastically.
 
I liked the Quaife for road driving too, it's very unintrusive. I ran one on my Z4 Coupe and it could also be felt in faster corners when you get that lovely feeling of your right foot being more directly linked to the angle of the rear when powering out.

The C63 with an open differential feels sloppy when it spins the inside wheel under power on corner exit.
 
I'm surprised AMG don't install some electronically controlled variable diff that automatically tightens the lock in <Sport+> and backs right off in <Comfort>. - Yes, it would probably cost a shed-load to service... but AMG.
 
Do C63’s without an LSD flash the traction light all of the time? I rarely see mine on unless I’ve been really naughty, but I have an LSD.
 
My CLS63 very rarely comes on, except when it was wet. It appears to allow a fair bit of slip and doesn't cut in harshly either, quite impressive T/C really.
 
My CLS63 very rarely comes on
When I ran my current E63 on an open diff I didn’t see much of the TC warning lamp either, but swapping to a Quaife diff the improved thrust when I floored the throttle showed me quite how much low-level “silent” intervention it had been making.




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It would be interesting ( to me at least) to try mine with a quaiffe and compare before and after - hard to judge otherwise isn’t it? Unless you’re constantly driving to try to put your car sideways ...
 

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