Do I need an LSD?

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e30_Turbo
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Post Fri Jan 28, 2005 12:46 pm

Had a bit of a scare last night, decided to take a drive up a nice straight new stretch of road for a quick fix of speed, it was wet and dark but the road was empty and I use it as a gauge for mods, I can just about hit 90 normally before I hank on the brakes before hitting the roundabout. (Scene set)

Now I floored 1st, 2nd and then as 3rd was engaged I could feel a floating sensation from the back, I kept the foot down and then noticed the revs were really high, but not topping out. Then the back went and it was instant, I was looking outta the side window thinking, Ԛ“I aint had this before!Ԛâ€a. So I came off the power and the sideways motion stopped, but it wasnԚ't until I hit the gas again that the rear snapped back in.

Now I was towards 60mph when this happens and there was no spinning in 1st or 2nd as I had a rolling start.

Now is this a normal thing for a non-LSD car?

And would a LSD stop this happening?

On the way back I was given a standing applause by the group of lads walking by, it must have been cool to watch as the slide was a good few seconds and the snap back was very strong, still that wasnÔš't what I was thinking at the time!! LOL!!
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Post Fri Jan 28, 2005 1:00 pm

fozzymonster wrote: decided to take a drive up a nice straight new stretch of road for a quick fix of speed, it was wet.....
Doesn't this scenario tell you something? Wet road? Dark and presumably cold?
Ԛ“I aint had this before!Ԛâ€a. So I came off the power and the sideways motion stopped, but it wasnԚ't until I hit the gas again that the rear snapped back in.
Had you driven like a rally driver in less than favourable conditions before?
Now is this a normal thing for a non-LSD car?
I think that would be pretty much the case for most rear wheel drive cars given the grip conditions!
And would a LSD stop this happening?
Possibly. A cheaper option would be to drive a little slower in slippery conditions, a LSD can't overcome all of the laws of physics! :wink:
On the way back I was given a standing applause by the group of lads walking by,
Oh I think that was sardonic applause...but maybe they were impressed....

kp
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Post Fri Jan 28, 2005 1:05 pm

Not got any for a while kp?
Surely with the conditions 1st and 2nd would have span as well Sherlock.
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krazypaul
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Post Fri Jan 28, 2005 1:09 pm

Jimbob wrote:Not got any for a while kp?
Heh! Just pulling a leg...
Surely with the conditions 1st and 2nd would have span as well Sherlock.
Not necessarily. On a serious note for a mo, I'm doubting whether the differential would make the back twitchy at speed, probably more to do with the aerodynamics of the car and it being fairly lightweight.

Not that I'm an automotive expert.

kp
who did have some last weekend, ta :wink:
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Post Fri Jan 28, 2005 1:13 pm

I was just thinking about it - might've 'snatched' it into 3rd on what could've been a slippier road surface compared to the rest of road.
Maybe :mad:
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Post Fri Jan 28, 2005 1:19 pm

Jimbob wrote:I was just thinking about it - might've 'snatched' it into 3rd on what could've been a slippier road surface compared to the rest of road.
Maybe :mad:
Maybe....

I guess the point I was making is that fitting a LSD wouldn't be a panacea in those conditions, there are other factors to consider...cold wet tyres, suspension etc..

I was just trying to inject a bit of Friday afternoon humour :)

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Post Fri Jan 28, 2005 1:20 pm

Sounds like the symptoms of screwed rear subframe bushes.

An open diff wouldn't help though!
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Post Fri Jan 28, 2005 1:22 pm

KP,

Bearing in mind I've been driving rwd cars for 5yrs now, the current for nearly 2, I've only mentioned this as it's the first time it's ever stepped out like that.

If i was 17 or something I'd be happy to take your coments on board, but I'm 27 now.

EDIT: I'm not meaning to be off KP, just didn't add too mnay facts in my first post! :cool:

I'm fully aware of what my car will do in both wet and dry condions and can say with confidence I've taken her to the limit many times and what happened last night was just plain strange.


Jimbob,
I must have compensated for this without realising thinking about it, but I did have a rolling start. My first thought that the clutch had slipped, but once she clicked back in it was fine. The road is only a few months old and is very flat and smooth so I can only put it down to me may be leaving the revs up a bit high when I changed up.

My main question is wether the LSD would have given me more control, I suppose it will but was hopeing to get some feedback from members that run them!

Cheers.
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Post Fri Jan 28, 2005 1:30 pm

fozzymonster wrote:KP,

Bearing in mind I've been driving rwd cars for 5yrs now, the current for nearly 2, I've only mentioned this as it's the first time it's ever stepped out like that.

If i was 17 or something I'd be happy to take your coments on board, but I'm 27 now.
No need to get defensive, I was pulling your leg. Maybe E30Adam is onto something with the rear bushes. I think it would be disingenuous of contributors to say "yeah go ahead and fit a LSD" when it might not improve the situation.

My comments weren't meant to be patronising.

Edit: No offense taken and none meant. :wink:

kp
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Post Fri Jan 28, 2005 1:37 pm

KP,

No worries mate, ITS FRIDAY! I don't do agro on Fridays and I know you were only going through the facts, you've got a point, I was only trying to explain that it was the first time she had gone soooo sideways on a straight road with no steering input.

I've tried drifting, which in my car only destroys one tire! and have deliberatly got my arse out on rdbts and open corners, but never had her do it on a straight road.

I'll have a gandy at the rear subframe bushes, they are the ones that hold the rear suspension bar on right? The bushes are large round coke can sized rubber bushes with a lip at one end right?

I hope they're not shagged as I had them changed on my 318i and that was about Ԛ£400 including labour!!
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Post Fri Jan 28, 2005 1:40 pm

E30Adam wrote:Sounds like the symptoms of screwed rear subframe bushes.

An open diff wouldn't help though!
Seconded, they screw the control you have whilst cornering and accelerating hard right up. And open diff 325i's just spin up one wheel all day long in the wet its nothing out of the ordinary.

If you buy an LSD you'll find the back end will be much more lively and you'll end up sideways most of the time, albeit under greater control.
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Post Fri Jan 28, 2005 1:48 pm

You may well have hit a patch of oil, diesel or something aswell? Did you consider that?

I haven't had it happen in my 320 touring, but the same thing happened to me as I changed into third on a straight dual carriageway, the only thing which I can imagine made it happen, was the slight spin of the wheels on the wet tarmac, and the camber of the road, which made it the back end come out.

Maybe the bushes were dodgy? But it had an LSD and it was pretty controllable?

My Touring, with a 2.0 lump, and an open diff, is driftable, and controllable on the throttle. You can hang the arse out nicely at pretty much whatever angle you want on the throttle. If it's gonna get even more controllable when I put the LSD on then great! This is in the wet/damp by the way, no chance in the dry with about 100bhp!
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Post Fri Jan 28, 2005 1:59 pm

davetouring wrote: If it's gonna get even more controllable when I put the LSD on then great!
Big time, you'll love it :cool:
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Post Fri Jan 28, 2005 2:03 pm

The weird thing is, my touring with an open diff is more controllable in a drift/slide than my 2.5 Sport was. No sh1t.

Is it the extra weight over the back or what!?

Can't wait for the LSD. The only think is, I can't imagine it being that much more controllable!! I guess the real difference will be in the dry, because open/LSD diff will let you drift in the wet.

But why is the Touring open diffed easier to drift than the sport?

Or is it just the couple of years extra experience/practice which mean it's easier!?
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Post Fri Jan 28, 2005 3:16 pm

Is the touring a longer wheel base than the normal coupe or saloon?
Longer wheel base cars are less twitchy and alot easier to control in these circumstances.
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Gi
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Post Fri Jan 28, 2005 3:22 pm

If those bushes are perished it can lead to unpredictable handling...& MOT failure I found! I got the bushes but then realised it was a job I didnt have the tool for! Or the hydraulic lift!
They are the coke can size ones...

If you're anywhere near Hertfordshire, here's a plug -
J.N Tyre Services (Welwyn) LtdSwallow End, Welwyn Garden City, Hertfordshire AL7 1JA Tel: 01707 329181
There's a guy here who may be able to help with specialist jobs, he has the pulling tool for those rear bushes and he did mine for Ԛ£100 labour. this was last year - BMW were the next cheapest at Ԛ£260 labour, other places quoted >Ԛ£360!
Not many places do this job, you need the pulling tool which costs Ԛ£700 itself!!
Speak to Matt Thomas, tell 'em Gi sent ya.

I'm looking for a 3.91 LSD or someone who can re-condition mine if anyone can help?

It's Friday!!!
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Post Fri Jan 28, 2005 3:34 pm

davetouring wrote:The weird thing is, my touring with an open diff is more controllable in a drift/slide than my 2.5 Sport was. No sh1t.

Is it the extra weight over the back or what!?

Can't wait for the LSD. The only think is, I can't imagine it being that much more controllable!! I guess the real difference will be in the dry, because open/LSD diff will let you drift in the wet.

But why is the Touring open diffed easier to drift than the sport?

Or is it just the couple of years extra experience/practice which mean it's easier!?
Sport would be more twitchy, the extra weight of the touring would make it easier to keep the back end out using the weight of the car. You need an LSD to do a proper long drift though as you need both wheels spinning which an open diff won't give you.
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Post Fri Jan 28, 2005 3:36 pm

Gi wrote: Not many places do this job, you need the pulling tool which costs Ԛ£700 itself!!
Speak to Matt Thomas, tell 'em Gi sent ya.

You can also use a torch and a bar, saves buying the tool but take a bit longer, my local place charged me Ԛ£120 and they don't have the tool.

And also yay it's friday!! :beer:
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Post Fri Jan 28, 2005 4:10 pm

Tourings are near 50/50 weight distribution which makes them great for drifting.

The tool for subframe mounts isn't Ԛ£700 so I don't know where you got that from. It is expensive though at Ԛ£250 but can still be a pig of a job.

Anywhere that quotes more than Ԛ£120 for doing the subframe mounts are having a laugh with you, they probably don't want the work because it's such a shitty job and if you do happen to accept their rediculously high quote then they'll be making a nice packet out of it.
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Post Fri Jan 28, 2005 4:12 pm

I booked my car in for the next day at a local garage who charged me Ԛ£80. (S & B Motors on the Nuffield Estate, Adam)

Back to the actual topic lol, I remember mine would make squeeky noises, surely he can hear this?
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Post Fri Jan 28, 2005 4:20 pm

If only I knew about these forums a year ago!!
I think it was a workshop that didnt have the tool that said it was Ԛ£700...thought that was excessive!
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Post Fri Jan 28, 2005 4:22 pm

Jimbob wrote:I booked my car in for the next day at a local garage who charged me Ԛ£80. (S & B Motors on the Nuffield Estate, Adam)

Back to the actual topic lol, I remember mine would make squeeky noises, surely he can hear this?
They don't always squeak mate, yours must have been proper knackered :lol:

I think mine are okay but I have new ones so will probably take mine to that place on the Nuffield to get them done, total bargain!
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Post Fri Jan 28, 2005 4:48 pm

dave my sport drifts well but only with the lsd, without it when u went in it, it would just slide then catch grip again, it couldnt hang out all day long like it does now :cool:
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Post Fri Jan 28, 2005 5:41 pm

yep. an LSD just makes it more predictable, you have a much better idea whether or not it's going to spin up the wheels, and what will happen when you do.

with an open diff if you put your foot down it might grip both wheels, or spin up one wheel, or spin both wheels - and this can change instantly mid-slide if one wheel hits grippier tarmac. so trying to slide smoothly is bloody difficult because you're having to guess what the car is going to do next.
an LSD will make you go sideways more often (with an open diff you can sometimes spin up one wheel but keep going straight) but it either spins both wheels or grips both wheels so it's much easier to control.
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Post Fri Jan 28, 2005 6:33 pm

I know the principles and reasons behind an LSD working, I was just saying that in the wet, you can you round and round a roundabout as many times as you want with the arse out. Until you make a little mistake. Thats with an open diff. The only reason for this is because there is little grip, both wheels spin, in the dry it would be a different story, the inside wheel would spin, and it wouldn't drift.

I think the wheelbase is the same on a saloon as the Touring, it's just the extra weight over the rear which makes it more controllable. The sport is lighter at the back, and hence more difficult to keep dead on drifting, with uneven road surfaces etc.

All good fun and games.
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Post Fri Jan 28, 2005 7:26 pm

Just got new subframe bushes fitted on my 318is, the difference is incredible, I don't know how I drove it before! it was all over the place at every opportunity.

One was really bad.
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Post Sun Jan 30, 2005 1:51 pm

i dont have a lsd, but my car drifts so easy i wouldt bother with one. the camber on my back wheels is so much cos of the 60mm drop theres hardly any tyre on the road most of the time so i think this is why it slides so much.
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Post Sun Jan 30, 2005 2:24 pm

Mark you'll have to pop down and try my SE, the LSD will improve traction for sure but as has been stated its not the be all and end all when it comes to control. try slamdad and see how he compares m8, plenty of r/bouts here too :wink:


while you're driving mine I'll take a gander @ your sub bushes if ya like ?

oh, theres a 2wd cossie I/C on ebay @ the mo... cheap too M8 :cool:
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Post Sun Jan 30, 2005 10:14 pm

lsds are the bestest thing ever!!!!! :cool:

GET one!!!!