Differentials

[Chassis 33]

Hey folks, been a while since I've been in these parts, can anyone refresh my memory - what ratio is the diff in the back of the S1 FHC's?

Regards
Iain

[Number 7]

According to Robson's book, the S1 V6 4 speed was 3.07:1, the S2 V6 5 speed was 3.54:1, as were the 350i's.

7.

[NTEL]

Chassis 33 said:

Hey folks, been a while since I've been in these parts, can anyone refresh my memory - what ratio is the diff in the back of the S1 FHC's?

Regards
Iain

Hi Iain, I have a spare HU 3.54:1 diff complete with Powerlok unit up for grabs if your in the market

[Chassis 33]

God Dave, don't say that.

Number 7 said:

According to Robson's book, the S1 V6 4 speed was 3.07:1, the S2 V6 5 speed was 3.54:1, as were the 350i's.

7.

Hmm 3.07 rings a bell from the dim and distant- I'm going to have to be careful
Regards
Iain

go on then Dave, how much?

Edited by Chassis 33 on Monday 1st February 17:40

[NTEL]

Iain, YHM

[grahamw48]

I'm sure my S1 280 owner's manual said 3.54:1 (4 speed), but a 3.07:1 sounds good if you've got the power to pull it....more sought after I'd have thought.

[Wedg1e]

Sure my S1 (chassis 36 ) ran a 3.54:1...

[Chassis 33]

hmmm - looks like I'm going to have to do my own homework. Bugger, was hoping to crib of someone more cleverer than me.
Regards
Isin

[NTEL]

Chassis 33 said:

hmmm - looks like I'm going to have to do my own homework. Bugger, was hoping to crib of someone more cleverer than me.
Regards
Isin

Iain, there are 3.77 and 4.01 diffs available but they are as rare as rocking horse poo. I have only just managed to find a powerlok to fit my 4.09 ratio. If you are short of any bits I can recommend AJS Engineering Services. He specialises in Jag diffs, is very approachable, and is a mine of information. http://www.ajsengineering.com/Services.html

Dave

[Chassis 33]

Cheers Dave, I'll have to crawl under and see what I've got - a 3.07 will be too long for the engine/gearbox combo I'm looking to use given the realistic weight of the car - ok with the factory claimed weight mind
Regards
Iain

[NTEL]

Chassis 33 said:

Cheers Dave, I'll have to crawl under and see what I've got - a 3.07 will be too long for the engine/gearbox combo I'm looking to use given the realistic weight of the car - ok with the factory claimed weight mind
Regards
Iain

Come on, spill the beans, fess up.......what are you up to?

[Chassis 33]

Nothing guv'nor - you know me
Regards
Iain

[MJG280]

I've found this

The ratio can be deduced from a small metal tag secured by one of the screws holding the diff. rear cover on – the two numbers stamped thereon indicate (large number) crown wheel teeth and (small number) pinion teeth. The ratio, of course, is one divided by the other.

If the small tag is there of course

[Chassis 33]

Cheers - I'll take a look next time I'm under there.
Regards
Iain

[350zwelgje]

If you can't find a tag, it is possible (but fiddly sp?) to mark the propshaft and a rear wheel: turn the wheel until one rotation and figure out the ratio as it is a fixed one....
Small snag: Limited slip differential helps as an open diff the other rear wheel will turn and mess up the measurement.

Rob

[grahamw48]

Also a good way of finding out if you have LSD.

[Chassis 33]

It's definately an open diff in there, checked that first time round, just can't remember what ratio it was!!! Probably got it written in a note book somewhere.
Regards
Iain

[singh350i]

NTEL said:

Chassis 33 said:

Hey folks, been a while since I've been in these parts, can anyone refresh my memory - what ratio is the diff in the back of the S1 FHC's?

Regards
Iain

Hi Iain, I have a spare HU 3.54:1 diff complete with Powerlok unit up for grabs if your in the market

hi dave i might b interested in that diff depending on how much u want 4 it?? will it fit my 350i?

[Wedg1e]

singh350i said:

NTEL said:

Chassis 33 said:

Hey folks, been a while since I've been in these parts, can anyone refresh my memory - what ratio is the diff in the back of the S1 FHC's?

Regards
Iain

Hi Iain, I have a spare HU 3.54:1 diff complete with Powerlok unit up for grabs if your in the market

hi dave i might b interested in that diff depending on how much u want 4 it?? will it fit my 350i?

Should bolt straight in. The friction clutches are internal to the diff so it looks like a standard one to all intents.

[Poledriver]

When I (eventually) get my new engine built I'll be looking at a lot more power than standard (350BHP).
With the 250(ish) that I currently have, 1st gear is almost redundant. What ratio does the 'team' suggest that I go for.
Hopefully changing to a more usable ratio will also help with fuel consumption on a long run.
Current diff is, I believe, standard 350i fitment.