joz8968

iTrader: (13)

Can anyone tell me roughly how many hours labour it'd take to remove my OEM FRONT open diff and replace it with a supplied Quaife LSD straight-swap replacement, in my 1993MY WRX saloon? I need to get an idea on the cost involved?...

Thanks, John

joz8968

iTrader: (13)

Anyone...?

911

As an estimate:

Remove gearbox from car = 2 hours (I assume the box will come off the engine)
Open gearbox/remove/replace/shim/finish off. = 2 hours.
Replace box, about 2 to 3 (always seems to take me longer to put mine back in that take out)

So, about a day of labour @ £30/hr = 250 + consumables?

Mine was done for me so why this is an estimate.

(API did mine)

joz8968

iTrader: (13)

Excellent, thanks for that 911

Did you too swap yours for a front LSD? If so, it surely must make the world of difference in terms of initial turn-in bite, lack of understeer... and, utimately, outright grip into, at and past the apex? ...

joz8968

iTrader: (13)

Sorry, just seen that you've converted your STi 4 to Type-R transmission spec, which definitely has a LSD front diff in it's set up, doesn't it? Is it a VC or mechanical (VC if memory serves)?...

911

No!
I took the Type R trans hoping it had a lsd but they were a (rare) option. I had API fit a plated lsd while they had it open to check the internals as I was suspicious...API fixed the one part that was worn.

I also put a plated rear diff into the car.

I hated the plated front diff! To me it drove terribly, the exits from the bends were full of torque steer and raggedness.

I had API remove it and refit the open front diff and the trasmission was sublime, just as it is today.

For me the front plated diff was a waste of time, no wonder the front diff option is rare!

joz8968

iTrader: (13)

Blimey, and there's me thinking that a VC front diff would be better than a normal open one - I feel smug with my WRX's std open diff now you've mentioned that!

Mind, front LSD's can be a little aggressive (have you ever driven a DC2 Integra Type R? - although that 's prob a mechanical LSD). Also, thinking about it, a front LSD would be 'wasting' some of the potential contribution from the rear of the Imp's 4WD, as the front side with little/no grip is transferring torque to the opposite front... if both fronts are spinning faster than road speed, surely it's only then that more than 50% torque would be directed rearwards, no?

Mark A

iTrader: (1)

He's old what does he know?

911

From the Old Man and to the wippersnapper above!

The diff I had was a plated one, set really 'light' but I hated it. Went fast by far with it out.
IMHO don't bother for road/tarmac tracks.

Now, let me have 20 winks....ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ

joz8968

iTrader: (13)

By 'plated', I take it this means a VC one with the interweaving plates that sheer through the viscous oil, blah, blah, etc, etc, etc... ?

911

No. I mean a true lsd with friction plates like a series of clutch plates compressed together by a series of springs that can be set to low or high compression (light or tight lsd)
Very different to a viscous diff I assure you in operation.

joz8968

iTrader: (13)

I'm with yer .

I know you're back to a open diff at the front and that you hated the plated front diff, but do you feel that a different type of front LSD would work okay with the Imp's 4WD set-up... For example, the option for Type R and RA is a front VC (I think) - how do these rate in your opinion? Also there're helical diffs and also the torsion diff (like the Ferguson one at the rear of Integrales) - do you have any comment on these types?

911

My only experience is open and that plated (Sti real works diff) unit.
Coming hard out of tight bends the car just wanted to keep turning and you would need to haul the thing out of a collision course. It cost me time everywhere on a flat-out hillclimb run.

now: some find these mods good, but not for me.
Took the diff out and back to open and the car steers fantastically, full of feel and control again.

The plated rear diff and dccd set CORRECTLY changes the car to a great race drive, but pointless onthe road under normal conditions. Set the dccd right for the conditions and let rip.

Just SO good. That dccd setting is very sensitive and the wheel position is very non linear but exponential in control. Took ages and a real expert to sort it out (John F on 22b, just the best chassis mapper I've known, but when the setting is right the car is away.

Rob Harriman on here has a helical front diff and he never moans about it, so there may be something there. Zen set his car up.

joz8968

iTrader: (13)

Cheers.

Re the Type R and RA's DCCD - what's the max amount of FORWARD torque distribution you can get away with (i.e. roughly what orange light on the dash) - on dry tarmac (obviously with bends in ) - without knackering it?

When the potentiometer is rear most, is it effectively distributing torque 65% rear / 35% front? What does it effectively change to when it's all the way forward (i.e. for use on ice and snow) - is it 50/50?

911

Yes, as good as fully locked so 50:50 really bad news in the dry!

For hillclimbing I use the dccd just over the first Green. Any more and the chassis gets twitchy, and I am no driving hero/god!

On the road and wet hillclimbs I set it to fully open and it is great.

You do need to experiment a bit which is tricky as you do need to drive hard to get 'into' the dccd effect.
It can have a pronounced effect on steering, esp understeer.

Although this vid is a bit misleading not how flat the car corners and how stable it looks (and was).
The car is doing about 90 mph at the bend:
DropShots.com

Same car, damp track, different venue:
DropShots.com

This one with too much dccd, the commentator says heavy braking, I had simply lifted off:
DropShots.com

The changes are quite small but in the car the car's attitude changes quite dramatically I assure you..