errr, is this right? gearing calc question

[justinc]

right, it is late and i have had a long day, i am in the process of working out some gearing / revs etc, if i have a non overdrive auto trans with no lockup converter, and a slip % of about 3%, should i be using a figure of 1.03 instead of 1 for top gear?

jc

[isuzurover]

right, it is late and i have had a long day, i am in the process of working out some gearing / revs etc, if i have a non overdrive auto trans with no lockup converter, and a slip % of about 3%, should i be using a figure of 1.03 instead of 1 for top gear?

jc

Yes. The ratio would be 1.03:1 if your auto has a final drive of 1:1 and you estimate 3% TC slip.

But where is the 3% figure from???

[justinc]

just plucked it:D. what would you consider a 3.5 v8 rrc tf727 to slip at on normal cruise? i seem to rmemember that 3% was close?

jc

[Blknight.aus]

3-5% from memory temperature and oil quality mauled a difference, use ratio*1.03 for all ratios to calculate optimal theoretical ratios.