Hey guys.
swapped a 1.9td aaz into my samurai, with a k24 turbo and a giles pump tuned to deliver enough fuel for 25+/- psi. I'm running stock boost and not much fuel right now, its alright but I want to eventually take advantage of my ip. After doing a bit of research I'm worried I'm going to destroy my transmission if I get much beyond the power I'm currently making.
After playing with some gear calculators I've came up with this and I was wondering on peoples opinions on gear sizes and the power band/ cruise efficiency of the engine. I also think it would be good to have this information on hand to make it easier for people in similar situations.
Right now I'm thinking
Toyota w56 transmission and transfer case with a Sidekick rear axle 4.625 and swapping 4.625 gears into my front 3rd running 31" tires
This combo would give me:
2600rpm in 5th = 61mph / 98kmh
3000rpm in 4th = 60mph / 96kmh
4000rpm in 4th = 80mph / 128kmh
3200rpm in 5th = 75mph / 120kmh
low range would end up giving me slightly larger gears then I have now which would be a nice benefit.
While being light the samurai is basically a brick wall on wheels and wind resistance is huge at high speeds so the power needed beyond 50mph increases substantially with speed. Would dropping the gear to 4th at 3000rpm put me in a good spot on the power band to make passes on the highway or should I be looking for slightly larger gears.
Next size up 5.125 diff gears:
2850rpm in 5th = 60mph / 96kmh
3350rpm in 4th = 60mph / 96kmh
4000rpm in 4th = 72mph / 115kmh
3550rpm in 5th = 75mph / 120kmh
I think these would be too large and not worth pushing the rpm's so high on high speed cruises. My typical highway cruise speeds would be between 60-75mph, however the increase in low range gearing would be a nice benefit. Increasing my tire size to 33" would drop the rpm about 200rpm but would then be starting to push the strength of the axles.