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What Diff shall I fit?
Jay k - 8/6/07 at 09:42 AM

Hi All, I am new to the kit car world so bear with me on this one.

I am building an MK indy with a 929 blade engine for summer road use.

I have the choice of 2 diffs to fit. Both are open 7" sierra diffs - ratio's 3.38 and 3.92.

I have been trying to find a gear calc that gives me accurate figures but with no great success. Can you tell me which would be the best diff to use and also if anyone has a link for a decent gear calc.

Thanks in advance
Jay K

graememk - 8/6/07 at 09:50 AM

3.38 imho

mookaloid - 8/6/07 at 09:50 AM

I think most of the BEC boys would fit the 3.38 for more relaxed cruising. The 3.92 would give you something like 70 mph at max revs in top - but would get there very quickly

Cheers

Mark

nitram38 - 8/6/07 at 09:53 AM

Doesn't that also depend on what wheels/tyres you are using?

Jay k - 8/6/07 at 09:55 AM

Going to fit 17"s

nitram38 - 8/6/07 at 09:58 AM

quote:
Originally posted by Jay k
Going to fit 17"s


And tyre profile?
It all affects the circumference and hence your speed.

goodall - 8/6/07 at 10:03 AM

gearcalc

thats a good one as far as i can see, takes into a count the wheels as well and gives compound gearratios

Jay k - 8/6/07 at 10:55 AM

3.38 it is then

goodall thanks for the gear calc - spot on!!

Cheers chaps