diff ratio?

[Elanconvert]

maybe for you, bill!! knowing me, I'd lose count and keep having to start over
what happens if one is hidden behind a lorry?
how accurate were they put in in the first place?
also, is it not illegal to drive with one finger on a stopwatch?!!!

think I'll stick with GPS.........
fred

[billwill]

Take a passenger to do the counting & stopwatch.


They have numbers like 17.3 , so you can correct if you miss seeing one.

Anyway there's plenty more on any typical motorway trip.

[bill308]

My S2 SE 26/5327 had a 3.55:1 when I bought it used over 30 years ago. My parts book shows part number 026 R 0703A for the 3.55:1 crown wheel and pinion, clearly a pre S3 part number. The 3.9:1 also shows as a pre S3 part, the 3.77:1 does not.

Bill

[Chancer]

Interesting to learn of the early vehicles being fitted with a 3.54 diff ratio, was it specially made for Lotus as I cant think of any Ford production vehicles of the time that could have handled such tall gearing, maybe something with little wheels

Corsair V4 perhaps?

[rgh0]

The 3.55 ratio was Lotus specific as far as I am aware. Ford brought out a 3.54 diff later with a different tooth count.

cheers
Rohan

[Quart Meg Miles]

The Workshop Manual October 1972 describes the 3.9 as being 43:9 (which should, of course, read 43:11). Mine is actually 39:10 so was 43:11 ever produced, it is just 0.23% different in ratio?

[msd1107]

The 3.556 differential ratio was 9:32. Lotus "homologated" a 3.44 differential ratio 9:31, but it does not seem to have made an appearance.

A 11:43 would be 3.91, close to the regular 3.9 ratio. You might look at the Sierra differential gears to see if such a combination is available, or could be put together.

The larger gears in the 11:43 might offer slightly less friction losses than the smaller 10:39, but probably not enough to be noticeable. If you are interested in friction reduction, have the ring and pinion REM treated, which is now widely available and not too costly. For even greater friction reduction, RF85 is available, but is quite a bit pricier.

The 3.55 ratio (9:32) was introduced fairly early on, probably in reaction to drivers taking out the rev limiter and driving their cars at 7500+ on the Autobahn. Even with the 3.55 ratio, the FHC would still get to 7000. The later 3.54 was 11:39.

David
1968 36/7988 with CR trans and 3.55