My viscodrive is having trouble coping, unless the road is VERY smooth it slips with a big clunky bang when boosting. I'm on lowered springs much harder, and about 270bhp at a guess, is it just something I'll have to live with or is there any other option? do the guys with big BHP have a solution to this or is it just to take it easy on anything but a perfect road surface?

could it be that the viscous fluid in mine has deteriorated and a new one of the same type would be better?

also, what are the consequences if it actually breaks? is there a chance of this?

Thanks.

AFAIK you can`t actually break it ( I certainly haven`t heard of anybody breaking one anyway ). What state are your wishbones in? I don`t think you should be hearing any bangs either possibly a knackered gearbox mounting .

Baz

new front wishbones, it was doing it before and after. just got it back from motormech with everything sorted out that it needed.

huh hum i have!!

lol holds head down!





i was showing off doing some wheels spins and i decided to turn the wheel and go for some circles! one of my mates said one wheel stoped spining, locked and the all you heard was bang!

carlt laughed at me! too!

might be the balancing of your tyres aswell if its stugling for grip and jumping/banging!

I agree, you can break it

http://img441.imageshack.us/img441/7916/photo015jh2.jpg
http://img212.imageshack.us/img212/9376/photo017dw7.jpg
http://img207.imageshack.us/img207/4214/photo016pp9.jpg

oops


is there exists a quaiffe or a kazz diff i would certainly be interested but haven't found one so far

Does sound like it might be a different suspension problem.

Yes they do break but it is an all or nothing thing typically, ie. you end up with no drive at all.

I wouldn't want to change it I think the viscodrive diff is ideal for a FWD car as it isn't too aggressive.

If you have the 6 speed box then the Quaife ATB diff for Alfa 156 V6 can be made to fit. If you've only got 5 gears then you are not so catered for

Then of course you have the fun of making up something to replace the ViscoDrive as you certainly don't want both in place

Trevor what is the benefit of the alfa diff?? Can you not just go without the Visco drive?

I have a 5 speed box. I dont know what to do about it

How easy is it to change the diff, so I can get another identical one and see if that fixes it? Sometimes it even slips on a smooth surface, especially when cold.

are you sure it is the diff and not your clutch? If it is actually slipping and you're not accelerating very fast then it probably isn't the viscodrive

The knocking can also be your driveshafts if they are worn BTW. I had to get recon ones at 120k as mine were in a state.

John

It's definitely not a clutch slip, it's a bang / clunk / 2 rapid clunks accompanied by a jolt which makes the smallest little bump or dip in the road surface feel like i hit a massive pot hole when on boost, or like i had hit the dashboard with a sledge hammer. thats the best way I can describe it really. other people who have been in the car said it feels and sounds like the viscous coupling slips. I thought it was engine mount at first but its the road surface that triggers it, not the load on the engine. I will research the effects of knackered driveshaft to see if it could be that, also sounds a possibility. apart from what i have described above there is nothing else wrong and it drives perfectly at all other times.

Cheers

The Quaife ATB copes a lot better than the ViscoDrive can, still can't stop wheelspin with nearly 600bhp of course, but it does get the power down earlier

bad road surface can cause engine mount judder - my top mount used to bang and clunk a LOT on my daily commute over the battlefield also known as the Coventry ring road

easy to check - get a piece of exhaust rubber (the stuff used for bracket hangers) and wedge it between the alloy engine mount and the steel tie-bar at the back left corner of the engine bay

I ran for over a year with bits of rubber stuffed in the gas before I bought a Barbz special insert

EDIT - viscodrives can cope with lots of power, as long as they're not abused - as soon as you have one wheel spinning freely, you'll kill the viscodrive in a very short space of time.

but if you have a lot of power you'll soon have at least one wheel spinning! certainly on track the kappa could spin its wheels anywhere - even exiting Paddock at Brands in 4th

I found a shredded tyre outside my house the other day, will that do? I'll try wedging it up and see if that cures it!

I thought the Viscodrive prevented one wheel spinning (as in a normal diff) it allows both wheels to spin instead as it juggles the power across the diff.

Viscodrive will delay the onset of the inside wheel spinning up, but it won't prevent it.

I'm still struggling to see why so many people have traction problems - I'm with JohnS on this one, after 1st gear, I don't have any traction problems in the dry and on a decent surface, it rarely even spins up in 2nd in the wet.

I disagree with this as the visco is one of the most reliable parts on a drivetrain.
I have never known one fail,unless the gear end to the box shears off.
They work using Plates and Fluid hence ''Visco''.Putting large amounts of torque through them is what there designed to do.
This works by limiting the spin on the o/s wheel.If you allow the power to be transfered to the o/s visco then the n/s wheel will transfer little power,and no loss of traction.The differential will always spin the wheel with the least resistance.
With this in mind you only need one visco.
Commonly found on 4wd systems theres very few models with it fitted to a 2wd.
Using a good diff and binning the visco should improve launches and cornering imo.

i have many problems of wheel spning in second gear... and in track days.... in the third gears also lose many traction..

I used to before fitting the traction control.
Even in the wet now i can pull off with all the power down and have no loss of traction.
Well worth the money.

Talking of diffs - the ones fitted to the Focus RS & new Meganne R32 are supposed to take handling to another level ~ what is different about these diffs compared to the Coops ?

Talking of diffs - the ones fitted to the Focus RS & new Meganne R32 are supposed to take handling to another level ~ what is different about these diffs compared to the Coops ?

Did you write that in a tunnel Mike, seems to be a bit of an echo

I think the Focus uses the Quaife torque biasing diff and not a snatchy plate type diff. I had one on my pug and it did totally transform the car, you could floor it all the way round a roundabout and it would just grip all the way where it used to spin the inside wheel.

I think a propper torque biasing diff would work well on the coupe but it would take too much time and money to develop.
The visco coupling is nearly as good and much simpler in operation.

on some cars people uprate the viscous coupling but increasing the pressure of the fluid (I think that's how they do it anyway), that might be a possibility for us.

I don't think ours tend to fail int he way described on that Wikipedia page
John

I have the Quaife ATB in the kappa, its the same as the Focus RS uses (not the same fitment of course). Can be made to fit the 6 speed 20vt gearbox

How easily can it be made to fit.

Guys at extreme had a focus in with an uprated diff from quaiffe and by all accounts it was very much a handful on the road but on track it would have come into it's own.

Trevor i take it the ATB is the one from the Alfa?

Its the Alfa 156 V6 ATB in the kappa. IIRC it needed some mod to the casing to get it to fit, and a sleeve made up to replace the ViscoDrive

Keith at Auto Integrale would be able to sort the job for you, bound to have been other work I didn't get to hear about to make it fit, plus of course I'm running the Alfa gears as well

I guess it would then also work in a late 5 speed ( mid 98 onwards) as they're basically the same box