I don't currently have a T5 in the car, a T5 is one of the transmissions I'm considering. I have looked at 3 speeds, but I have yet to find one that has a 2nd gear that is close enough to 3rd. The whole idea of this thread is to see if someone knows of a reason why you can't change the overdrive gears out with some that will result in a ratio between what would start out as 3rd and 4th. Third would still be third, fifth would become fourth, and the new 5th would be 1:1 ('cause it's the old 4th). Yes, it will have an odd shift pattern. I would love a simpler, cheaper transmission that still has good gear spacing, but unless I can figure out how to run a bike box, it isn't looking promising.
83 to86 Toyota Supra. third gear is 1.275, fourth gear 1.00, fifth gear.861 And there are adapters available for a Chevy bellhousing pattern from Novak http://www.novak-adapt.com/catalog/engine_to_trans_adapters.htm
I know exactly what you are trying to do and I think it would work, just like the Toploader that was made into an O/D trans you want to do the opposite. I also know why you need to do it, we had the same problem in the "Brick" when we ran an E motor. We had a T-10 that had too big a gap between 3rd and 4th and just couldn't pick up once you went to 4th. I think you could do what you are talking about but as said before you would really have to have your shifting down or you would lose the rpm gain just trying to shift. I think the T-5 is also strong enough for the kind of HP you are looking at now and in the future, after all we are not drag racing and don't have the hard shifts. I'm running a T-5 and plan on 500 hp through it before I'm done. Of course I use it like a 4 speed, O/D is just there. Mac, yes the Supra is RWD but still an O/D trans so no good as the top gear even with a lower rear ratio would go through a counter shaft. More drag. BTW, is this the car of which we speek?
Yep, that's me. I have a plan to make the push vehicle able to push quicker, and that should help with initial acceleration, but that is still no help for the RPM drop between each gear change.
No, you are always spinning the Main shaft, on input and out...on both the left hand and right hand boxes... those boxes do not reverse the rotation..countershaft is for ratio
Trent, mostly research still but we have it narrowed down to a couple possibilities, one being the T5 as described earlier, the other is intriguing enough that I'm going to reserve revealing what we're up to till after we figure out if we can fit it in the car. R8odecay, i didn't mean the input shaft wasn't turning with the engine running and the clutch engaged. If the output (on the boxes the output comes out the other side) isn't turning the wrong way, that's great, any idea how to adapt one to an automotive style clutch, without a custom input shaft?
Yes the mainshaft exits the box on both ends... you are spinning the mainshaft w/ the clutch on input, and the mainshaft is spinning the rear drive on output. The countershaft is shall we say passive, it is not driven and does not drive, merely switches the ratios.
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