diff ratio change for 3.4 V6 hilux

[mmaaxx]

G'day all,

My 3.4 V6 2003 model hilux has 4.1:1 diff ratios as it is a manual transmission and the autos have a 4.56:1 ratio.

Now, my query which I hope you all could help me with is, if I have 32" tyres fitted and the original size is 29", then to get the same performance in my hilux as the car had when the original 29" diameter tyres were fitted, I'd have to fit 4.56:1 diff ratios out of the auto hilux.....correct?

I worked this out by using ratios, correct me if Im wrong -

(4.1)/29" = 0.14137931
Thus 0.14137931 x 32" = 4.5241

Therefore I'd need a 4.5241:1 diff ratio to match the performance of the stock 29" diameter tyres.

So the 4.56:1 ratio will help my hilux accelerate as if on stock 29"tyres, and even thou I'd rev slightly higher at 100kph, I'd be using less throttle during acceleration so therefore my fuel economy around town should be lower, whilst on the highway it might be slightly higher?

Any feedback on this would be appreciated as I want to upgrade my 265/75x16 BFG AT's to 32/11.5x15 Wrangler MTR's and the trucks sluggish on take off now.

max.

[4sum4]

32`s will be fine with what your got

[mmaaxx]

THANX 4SUM4,

Im currently running BFG AT's 265/75x16 which are just under 32" diameter and the hilux is sluggish as hell off the line. Once it's rolling its OK, also doesnt crawl as good in low range four (first gear) as stock thou.


Thanks my reasoning in the possibility of diff ratio change.

[Dingo]

4.27 diffs would give you closer to origianal
4.56 diffs would give you better take off but slightly higher revs for 100kph than original and better engine braking