I'm building a locost with an s2000 engine and gearbox. I want to use the cossie lsd but without spending around £700 on a 4.1 crownwheel and
pinion for it I have decided to go for small wheels (13"
and try and find a 3.92 ratio.
I have found a 7.5" diff with the 3.92 ratio, and I am of the belief I have a 7" (a way of checking this would be nice if known) but I would
like to know whether the crownwheel and pinion for the 7.5" is usable in the 7" too.
Hi, basically if you measure across the top mount holes its aprox 7.5" on a 7.5" diff and 7" on a 7" diff I dont think you can
interchange the crownwheel and pinion but am happy to be corrected
also do you really need an lsd there has been some debate on this before and the car is so light people say you dont need one unless its for serious
competition
Ray
Well the car is going to be taking a caning when I get it on track. I also have the ability to gain free race tuition so it'll be at the limit a lot when used in anger
ok cool but i dont think theres a cheap way to get an lsd in there talk to rs cosworth breakers about a diff
TEL:02392 379000 or 07968005319
[Edited on 8/11/09 by RAYLEE29]
I've got the diff. But it's the wrong ratio. The standard s2000 final drive is 4.1, hence me going for smaller wheels (than the s2000's
16" and a 3.9 ratio, if possible
maybe fit the diff in the 7.5" housing with the 3.9 cwp?
maybe a case of take both apart and try
just a thought but is it for short circuit use then? as id have thought youd want a taller diff with smaller wheels?
It's road and circuit when i can. I want to be as close to the ratio of the final drive of the s2000 as possible. I don't wanna be doing silly speeds in first
What's your existing 'cossie' LSD? There's a 3.92 7" LSD available as standard fitted to the 2.0 DOHC XR4x4 so maybe worth
looking for one of those. Or you should be able to source an open 7" 3.92 fairly easily and create one from your existing 3.62 7" (assuming
that's what you have). I dont think you can mix and match bits from 7" and 7.5" diffs.
Liam
you'll have to turn the diff upside down to run with the s2000 as it turns the opposite way. you can get a 7" 3:9 lsd diff too if thats what you need. the 7.5" crown and pinion wont fit in a 7" casing either as its too big.
quote:
Originally posted by steveyb
you'll have to turn the diff upside down to run with the s2000 as it turns the opposite way.
quote:
Originally posted by Liam
quote:
Originally posted by steveyb
you'll have to turn the diff upside down to run with the s2000 as it turns the opposite way.
No it don't
You're thinking of the Pre 2005 K20 (civic Type R) and preludes. Thanks for the input though
The size of the Sierra diff relates to the diameter of the crown wheel, so the parts are not interchangeable between 7" and 7.5" variants. It's just happy coincidence that the casing is approximately the same measurement.
quote:
Originally posted by steveyb
quote:
Originally posted by Liam
quote:
Originally posted by steveyb
you'll have to turn the diff upside down to run with the s2000 as it turns the opposite way.
No it don't
are you sure? i thought it did?
the B16A and B18A engines ran the other way round - the F20A runs in the coventional direction, as proved by numerous Westies
and AE86s running them.
Just a thought a ford scorpio 7.5 diff is available in a 4.27 ratio non lsd .