Hello,

I am planning to put a 3.8 litre VS engine and auto in a mini bus (Toyota Coaster). I know it has been done before but I can not find any information on the best diff ratio to aim for.

The bus is pretty small, it would be about the same drag on the highway as a large 4WD (it is about the same weight, and although the windage is higher, the rolling resistance is very low.) I would like it to be able to cruise comfortably at about 90km/h but have something left to overtake or do 100km/h if the fuel budget permits.

My question is, what engine revs do you think I should aim for? I'd like the engine to be revving freely, not lugging, but I don't want it to be thrashing either.

Thanks in advance,

Matthew