diff strength

[ever88]

hello all

 

Anyone got a good idea as to how strong the sierra lsd diff is?

 

I have one of those Xr4i lsd diffs but haven't a great deal of experience with them. I wonder what sort of horses they can cope with and just how fierce an lsd they are.

 

anyone got an opinion here.

 

I hear lots of cosworths boosting and boosting without much mention of rear end work and I presume the cossie lsd can only be the same as the xr4i.

 

if you know please pass a comment but no guesses please if that doesn't seem too rude.

[tim]

dont know much about them but i dont know they take alot of work to work well in an escort

[Onyx Dave]

Xr4 diffs are not the same as Cosy diffs, they not so strong.

What sort of power are you talking about as have put over 250 bhp through english diffs all the time and have not broken 1 for many years in racing.

[Retromotorsport]

The Sierra based diffs are useless.. yes theres loads of talk of 400ftlb going through them, but thats in 4th gear so just the diff doing the multiplying so around 1200 ft/lb being applied gently to the rear while strapped down to provide the grip.

 

On the road the sierras rear suspension dosnt really apply itself to putting power down, the rear wheels gain too much camber to acctually keep the tyre footprint on the ground. They spin up really easily as its only the inside edge in contact.

And cars using the standard Cossie center section that have grip break them all day long

 

The Motorsport center sections have a 9" CWP instead of 7" (i think) but these are around £4000.

 

Its never power that breaks transmission parts ..its grip ...........

 

Take a x-flow powered car with skinny wheels and standard suspension and put 100bhp through it .. its will spin up

take a huge engine with a 1000bhp and it will still spin up at the same power point as the x-flow spun up. and thats below the breaking point.

 

Now put just 250 bhp though it but change the suspension and tyre width, and you'll be breaking everything

[Onyx Dave]

My old xe mk1 had around 250bhp and has never broken anything on road or track yet.

It has a standard type 9 5 speed box, one piece prop, 3:77 diff with plate LSD, 1 inch blocks and decambered single leafs, spax shocks, no tramp bars or link setup just bog standard! Using 185/60x13 Yokos 032rs.

[ever88]

I spoke to fostek today who build rear axles for rally (based in Cramlington)

 

His comments were the sierra based diffs are pretty strong and strong enough for my intentions.

 

My intentions with this will be mostly road but the occasional 1/4 mile.

 

it's a 3.0 twin turbo with 300bhp or there abouts and I was told by many that my English axle lsd would be out of it's depth here unless some money was threw at it.

 

as for the camber issue. I have noticed that the rears of sierras are quite severe in this region.

 

is there a way of relieving this?

 

thanks for comments

[Retromotorsport]

yeah fit a live axle ..

 

To be honest you can re-locate the mounts a bit, like the rs500, when we ran Sierras the static ride height at the rear was quite high.. verging on postive camber with the camber comp plates in there, it was good round the track, but crap on the starts..the camber still came into play