Mike Rainbird

iTrader: (3)

No, I said pick the one YOU like (after testing both) . I just said I liked the way an ATB drove .

markk

iTrader: (2)

Porkie, one thing you have to remember when asking about things like this on a forum, particularly PF, is that how many of them have used all of the types listed on here, ATB/Viscous and plated.

I would say, off the top of my head, me, AG, Tim finch, have i exhausted the lot now ??

The ATB is just too, well weak for an LSD you dont even need to have a wheel in the air for it to send all your power into oblivion.
The only problem with a viscous is heat, if it gets too hot it will lock, hence we use coolers, the plated is the best of all worlds for power and cornering and brakeing imo.
Mine on my new car is an uprated 9" viscous though ! .

WD Pro

Just read this with interest.

When picking a diff for the rush (yb) I came to the conclusion that a ATB was the best option - I was advised to consider the 'push on' effect of a plated diff - especially when you factor in the lack of weight in a 7 style car.

I also think there is a ATB option for the 7" that doesnt need the new input shafts ?

WD

markk

iTrader: (2)

you wouldnt have any ' push on effect' if you pick the correct ramp angles

WD Pro

Yep - got told that to, another thing to think about

Have a mate with a 'race' R400 and he runs the plated option but is going to remove the plated one from his 'road' rush and replace it with a pumped up VC - is it just that one type suits one car type / suspension type better ? (rush is de dion)

markk

iTrader: (2)

you have to be careful with the viscous as well, you have preload and fluid viscosity measured in nm/s acroos the vc unit. the vc unit and preload needs to be set according to the cars weight and use, otherwise it will just burn itself out in no time with excess heat.

The plate with the ramps to suit your application is the best thing Ive ever used. so controllable, so reliable.

R5FORD

iTrader: (1)

iv got a ATB quaife diff for my cossie, havnt got the car yet so not fitted.

Have no idea how it will feel to drive etc just hope it lasts.

JohnnyB

I can say I have driven all 3.

But the ATB was on a front wheel drive. I loved the Plated Diff in my MK1 escort.

Porkie

iTrader: (1)

I think I will also get a Gripper.... the wheel in the air is just not an issue though at all.

andrewg

i would hardly class a atb as an lsd! they are good replacement from standard strenght wise.highly recomended for front of 4x4



also just spoke to charlie that has my old focus and he has been speaking with a guy that specialise's in race set up and wants less under steer and he just told him plated is the best for less understeer,,

andrewg

doesn't need to be in the air ,, just less weight than the other

Mike1

Good info - I guess someone like Bara know all about the right settings for VCs on Cosworths.....I'd say the thing with all these uprated types ( VC or plated ) is knowing the correct preload/fluid viscosity/ramps ( as applicable ) to suit your application. The trouble is they're not the sort of things you can "try out" easily if you're Joe Average.

How often do plated diffs need maintenance? Is there extra noise, low speed manoevrability issues or anything else to factor in that makes the VC with a cooler a completely redundant option?

Porkie

iTrader: (1)

oh shit. I'm going to need a proper fat cunt to sit in the passenger seat at all times!!!

ooohh... I think I have just thought of a cunning way Brom can pay me back the mony he owes me!

GARETH T

lee im suprised you havent gone for a active diff PMSL more things for stu to fit

Porkie

iTrader: (1)

nah... I'll buy this one first. More work for him that way!

ian sibbert

I have driven all three and all in competition, I have also driven 4 x 4 sierra and subaru's with spool diffs.

ATB are brilliant in FWD cars where rear wheel loss is no issue, in a RWD like the westy you need to be continuously progressive to keep them activated, if you drive on and off the throttle or get the car out of shape after the apex, they do become very wooley and unpredictable and as has been said when they loose traction you can struggle...on a circuit car with decent suspension setup I can't see you having any problems with an ATB and they are very reliable.

Viscous Diff's are again ok and much more forgiving than an ATB, you'll be very familiar with the way they drive, the issue with heat wont be as prevelant on the westy as say a sierra or an escort and obviously size matters, the little 7" diff cant be made as tight a the 7.5 or 9", with decent oil and only shortish durations of competetion use they do perform very well...some rally drivers I know do prefer a rear VC on tar as opposed to the plated......you can fit external coolers to help with the heat dissipation and I have used a 9" rear on my original escort with no troubles at all...bara can take the 9" to IIRC 900nm as a max, I think mine was set to 520 nm...

Plated diff with highish ramp angles would be my diff of choice... 40/65 on the gripper or higher i.e. 45/90 if you can get them (dont know which diff your running). The best all round type of LSD in my opinion, what we run on all the rally cars we have/service for, a little bit more expensive to maintain than any of the others but well worth it....

Spool diffs are excellent on 4WD cars on both gravel and tar, subaru WRC used them extensively in the 90's early 2000's, and I do know of a couple of escort wrc's running 9" spool diffs. They are little hairy on a RWD car, ok for drifting but not really ideal for circuits....

Porkie

iTrader: (1)

Thanks Ian.... so say I hadn't just ordered the ATB... what would you have bought?

Plated yes? and had it set up right?

I don't like the sound of the 'unpredictable' nature if you getting it out of shape after the apex....

because thats pretty much how I like to drive!

doh! think I have mucked up here!

ian sibbert

Lee,

A little less sophisticated than the westy, one of the sunbeams (2.0 N/A Zetec) we built came with an ATB in and I took it round trawsfyned (test venue we use in mid wales), it was ok as long as you anticipated the snatch back after initally stepping out (if that makes sense) but it was very unnerving when comparing it to the plated salisbury diff we put in for him the cars behaviour was night and day different...like I say in a FWD car and especially if you left foot brake and keep the power in the ATB seems good, its when you subject them to sudden force changes that they become unpredictable....

To me it's all about driving style, most people (even people who do track days) dont really push the boundaries of a diff and for those people ATB's are fit for purpose (not for a minute suggesting Sean B doesn't push his car lol) and i'm suprised he recommended an ATB TBH, but most (rally) drivers i know who push a car hard would I think agree that the ATB is not ideal in a RWD format.....

As I said above, i personally would have gone either plated with highish ramp angles or a VC, dont know which size diff you have in.....

Porkie

iTrader: (1)

its just a little 7' Ian.

I've ordered it through CTS as they have the flanges and everywhere else including Quaife is out of stock...

I have until lunch time tomorrow which is when they are sending it out to decide as I can pay a handling charge and send the ATB back to Quaife...

god dam it... swaying back now!

Martin just sent me an email saying this in huge letters!

Per……… Lated

markk

iTrader: (2)

Porkie - 'stick wi yer dad'

Once you have run the two together you will see just how good a plated is, I personally will never ever run an ATB, not even in a fwd after a FWD experiance I had in one, though after we sent it back to quaife, who said there was nothing wrong with it, I refitted it and miraculously it was acceptable.

Mike1

Is that what happened with the Mk1 Focus RS - they changed them subtly after the first batch and press reviews - hence why when the press have tested later production versions they're supposedly less wayward? Or was it really all down to suspension geometry......

JohnnyB

Porkie when I was 21, I moved back to zimbabwe as my brother-in-law wanted me to work for him. He had a massive haulage company and was making a fortune.

A friend of his was into rallying and was getting a little passed it and I started helping out and driving his Nissian Stanza, but being from england we build a MK1 bubble arched escort running a 2.0 nissan rally engine out of the Stanza.

it had a Atlas Axel and Plated diffs, they just feel so progressive you just know what they are going to do and it adds confidance.

GO PLATED

markk

iTrader: (2)

and funnily enough this was in a MT75 box as well about 2002/2003.

wide ka

jesus, good job i didnt ask on here and just get a plated diff! like picking what to have for a birthday!

Mike1

Sounds like a decent Bara VC diff with a cooler would be OK for a fast road car (that's not often launched hard then) as a lot of the fast cars seem to run a 9" version

JamesH

iTrader: (21)

scoooby slayer

iTrader: (4)

got a plated in my saph. there awesome very predictable when sideways.

Mike1

Be interesting to see how yours compared to CossieRich's set-up

GARETH T

apart from maintenance, is there any downsides to a plated diff?

Fudgey

iTrader: (4)

depends on what diff, a 2 way will creak and sound like its fucked at low speeds, and could also scrub the inside wheel on slow speed cornering, like a welded diff etc if its ramped up.

Lee, do you still need a spare 7" casing?

i might have one you could use, its from a GL sirerra that has the splined driveshafts go into the diff, but i dont know if the casing is any different to a cossie flaged item. if you can find out and still need it, its yours

cossyking

i got a quaife atb diff in my 3 door and quaife told me that you wont get enough power out of a cossy engine to kill 1 so they must be quite confident. it does seem a really good diff aswell

markk

iTrader: (2)

the only maintenace is like plate changes every 2-3 years of competition use, which would be more like 10 years on a road car.

the road going/fast road ramp angles are not noisey at all once run in, the plates need to bed to the friction washers once that has happend there is no noises (maybe the smallest if your really listening for it ! ) and defo no scrubbing of tyres at all.

I think some people have either been mis-informed or been using some really shit diffs, or wrong set up for application perhaps.

Big Will_

Tried and tested

mk3cosworth

7 1/2 rear gripper plated for me with atb and thick wall front diff

GARETH T

i know what has to be done to them, as i've had a few apart to replace the plates, but i cant think of any other downsides

Mike1

Ian

Have those chaps ever said why they prefer a Viscous one over a plated type on tarmac?

Seems interesting that most of the big power cars on here run a Viscous 9" type

Porkie

iTrader: (1)

Mike1 you REALLY want a Viscous one don't you!

Mike Rainbird

iTrader: (3)

As I said, it is SO subjective, IMO - TRY BOTH! Make it so everything can be swapped over (same drive shafts) and then go and test at Bedford. Takes even the likes of me (by myself) 45mins to swap a diff over. Stu should be able to do it with help in around 30 mins .

However, DO NOT let him tell you which diff is on, so you are testing blind and only judging by what it feels like to you, with no bias (in the same way Redline tested the tyres at Bedford).

Mike1

Well, like you, I'd really like to try them all as Mike says! However, there is little chance of me having the resources to do that.........but I like to hear people's opinions on stuff. I've tried a Quaife ATB and a standard clutch type ( both on BMWs ) and also have experience of the standard tired old Viscous type on a 2wd Sapphire......but I'd like to hear what the re-rated Viscous ones are like on a road car as well.
I'm sure there's a couple of guys ( Ronnie Amis(?), CossieRich ) running the Bara type ones - it would be good if they had tried a Gripper one to make a comparison.
Obviously Ford went for a very mild locking action with their own VC set-up and I remember reading how Rod Mansfield said it had advantages and disadvantages over a Torsen ( ATB ) type when the car was being developed.
To be honest, I love threads like these on vehicle dynamics and even though I have little/no knowledge I like to hear from people who do

ian sibbert

Mike,

Its still subjective when you talk about VC's, one size does not fit all....

The 9" ford diff is particularly suited to a VC as it doesn't suffer as badly with reliablity and overheating issues as the 7.5 and 7" and like I said the level to which a 9" diff can be set is considerably higher IIRC (320nm - 900nm)than the 7 or 7.5" diffs.

Certainly on the escort group a car and wrc car the usual rule of thumb was a plated rear in an aluminium case for gravel and a magnesium cased VC for tarmac, although some people did make an exception and swapped and changed, my own car has a mag cased plated diff in it....

To have a forgiving diff on a rally car is always a bonus as the driver (whether its clubman or WRC) is not fighting the car when entering or exiting corners (not forgetting we dont usually operate on a totally smooth surface), a vicous delivers the drive in a very smooth way and gives a driver confidence to press on a little harder and ultimately improve their stage/lap times.

If you look at the wider spectrum, although you might find on this particular forum some of the higher powered cars run VC's, the disciplines they are operated dont warrant anything more sophisticated than a VC and they are a nice safe (from a drivers perspective) option. In other more intense forms of motorsport (rallycross, rallying etc) and definately on gravel the majority of cars do have plated diffs in them.

My recomendation in this case is based on the fact that I assumed Lee would be running either a 7" or 7.5" in the westy, both of which perform better IMO with a plated diff in.