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Do you have a Limited Slip Differential?


Darth G-F

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I am looking to buy a Caterham 7 from http://www.super7cars.com/ they sell left hand drive SV with an Hayabusa engine. This car has about the same power to weight ratio as a R400. They even got an offcial 3.25 sec 0-60mph with that car.

 

However, the LSD is an option and the seller tells me I don't need a LSD in this car and that it even makes the car dangerous! Well I have a turbo Miata with a power to weight of about 300bhp/ton and I know for a fact that the LSD saves my butt more than anything. It does it's job very well at "limiting the slip". So I don't see why a Caterham would be dangerous with a LSD while the Miata is much safer with it.

 

So what kind of diff do you guys have? Should I get the LSD for my Caterham? What is standard on the R300-400-500?

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It can make it a bit all or nothing in the wet which can be interesting i.e. if you break traction mid corner it's both wheels and all the grip is gone.

 

Open diff's only tend to light up the one wheel which makes the breakaway more progressive as one wheel is still nailed.

 

It just gives the car a different charachter which you may or may not like for road use.

 

Preload on plate type diffs should be setup for a lightweight car rather than a large (heavy) saloon.

 

Probably worth checking if the bike engined guys in Canada are sourcing the diff or caterham are supplying as there are various types available.

 

Ian

 

Green and Silver Roadsport 😬

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The LSD makes the Miata safer because it keeps the rear end planted when going out of a corner. Without the LSD the tail is way too loose and you can't apply power to get the reat in line. With an open diff, applying power will only result in more spin. With the LSD more power will transfer weight to the rear and the slide will stop. Much safer IMHO.

 

I will inquire what is the LSD this company has for the 7. If it is a Caterham LSD I will go for it, no way should a LSD can be more dangerous. I checked Caterham web site and the R400 and R500 both have the LSD as standard equipment.

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A correctly set up LSD should stop the tail from kicking out when you make an abrupt "confidence" lift half way through a bend.

 

If a diff is set to almost lock you could suffer a little more understeer but I wouldn't describe that characteristic as dangerous.

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I've got an R300 and I originally had a standard diff. After 6 months or so I upgraded to an LSD and the difference is really noticeable. I much prefer the LSD - there's more grip at the rear of the car and as a result you can give it more welly coming out of slow corners / roundabouts. It does feel a tiny bit less progressive when it finally loses grip but it's still easy to catch...

 

 

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I did have a nasty moment in my old M3 which I put down to the LSD - I was in a bit of a hurry to get to Heathrow and coming off one of the big roundabouts, I got a bit of spin on the inner wheel, the lsd ramped up, transfered the torque to the other wheel which promptly broke traction as well, sending me into a big slide.

It caught me totally by surprise and I knew I couldn't lift off or it would have spun. It all worked out OK but I learnt another little lesson - namely to be bloody careful in the wet when you've got an LSD. It is different to driving an open diff'd car which would just have spun the inner wheel in this situation.

Something else I noticed in the wet was on bigger roundabouts where you slowed, gave way, and accelerated through them from (e.g. Milton Keynes). In the wet the transition between the diff locking and unlocking gave some strange feelings - from bad understeer to snap oversteer.

 

 

J351 TPE . . . battered old X/Flow

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The car will be much better under extreme trail braking.

Better out of tight corners as the power has somewhere to go and is of course essential for doughnuts!

 

Firm respect with the right foot is called for at all times in the 7. i found mine no worse in this dept with an LSD.

 

If you get a unit aftermarket and have it fitted get some one who know's what they are doing like

Road and Race Transmissions to set it up for a 7. (I have no connection with them other than happy customer).

 

Hants (North) and Berkshire Area club site here

My racing info site

here

 

 

 

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Adam

 

Was that an E36 M3? Lovely engine: shame about the chassis!

 

After some 280k miles in 3 examples and 2 real nasty "moments" I decided to swop mine for an E46 330Ci Sport - just a little slower, a lot quieter (I don't know why this is a positive in my Beemer and a negative in my 7) but a nice chassis.

 

Silver SV SSR

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BigYin: It was an E30 M3 Cabrio - one of 786 ever made . . . . . . there's one less now ☹️

I preferred the E30 to the E36, but you're right about the engine, fantastic! I've never tried the latest M3 - don't really fancy it though.

I've gone off BMs now - they're too practical, too safe, and they bring out the worst in my driving ! That's a bad combination.

 

J351 TPE . . . battered old X/Flow

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Adam

 

E30 - a truly great car. Respect!

 

Not sure I'm ready to give up BM's yet though:

 

1 - 'cos mines black, I do seem to be able to drive round Sarf Lunon with relative impunity

 

2 - I had the misfortune to put the BM into the bodyshop for a week or so to get some vandal damage fixed and got a Volvo S60 2.0t in exchange. Nothing against Volvos (I've also got a V70), but the S60 is a truly nasty car PLUS you get treated differently when you drive one. Following the same driving routine that would have resulted in an untroubled week in the Beemer, had me squeezed by buses, cut up by Cabs, brake tested by white vans, raced by spotty yoofs in MaxPower Corsas, held up by Grannies in Skodas and waved at by sad, pipesmoking old gits driving S60's, wearing overcoats, hats and gloves and listening to Magic FM...............................................

 

Never been so glad to get back in a BM!

 

Silver SV SSR

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