The V8 Owners Forum -

In the search for quicker 1/4s, I have decided to see if I could upgrade the back axle with better gearing, Im running 3.7 CWP at the moment,
Trouble is, the axle I use is a Celica LSD type F, strong as fook, with bigger shafts than a 9" @32mm, gears are available at £600 a set!!!!!, with a bit of research I have found the axle is common to a few of Toyomotors, but the chance of finding what I want is virtually nill,
Bit more asking around and It seems the Supra indi rear has the same internals as my live axle , both classed as "F" type either Indi or live, so far so good, then to throw a spanner in the works, my axle is a front loader, and the supra is a rear loader, part numbers cant tell me if the gears are interchangable as they have different ratios, But the supra does run better ratios, 4.3 and 4.1, which ratio do I want, I think I would prefer the 4.1, but somebody has offered me a diff with 4.3 gears less the LSD for the price of postage, trouble is they are in the Netherlands,

Is it worth going for the 4.3s and trying them in my spare diff to see if they fit or do we think as a collective, 4.3 is too short.??????

Hi Ian, if you run the 4.3 you could run larger diamiter rear tyres (if they can be fitted under the rear arches, this would surly give you a better launch, and you could get ones that "grow" more as they spin delaying the need to change up (yes I am probably telling Granny hao to suck eggs ). My concern would be that if you gear too low you end up with 1st to low and you have to change up before you have got going, and 2nd still too high to launch without bogging down. The other alternative is to put in a high first and second in the gear box and use the low rear diff and you end up with all the gears too close and you are in 5th 30 yrds off the line trying to climb onto peak torque and getting there 20 yards after you crossed it. Personally if you cant use bigger tyres then I would recommend the 4.1 ratio.
What speed do first and 4th work out at max revs with and each of the alternative ratios you have? (assuming 4th is straight through on that box)
Best regards
Mike

What speed, gear and rpm are you currently crossing the line at ?

Such a long tims since I had a good run up the strip, My fear is its going to be a too short 1st gear, but I have a problem with 2nd-3rd ratios being a bit too far away ratio wise you almost feel the engine start to struggle for a couple of secs before it comes on cam again,
Steve, from memory, its about 107 @5kish in 4th

Hi Ian
if its 5K ish in 4 th then the then the 4.3 would give you 5.8 k for the same speed. If your red line is 7 to 7.5 and peak power is about 6.5k then if you can launch as quickly and cover the first half of the track as quickly then you should see an improvment, shouldn't you? Gearing down should make the gap between 1st and 2nd less of a problem but idealy you need to find a higher first. I still think you may find the 4.1 the best bet if you can't sort a higher first gear.
Mike

My 60fts are good, @ 1.59 on street tires, so if I can keep it around there I would be more than happy, Gearkits for the Gearbox seem pretty unobtainable, which does make me wonder if the Supra box althouth robust, is the right box to have, T5 maybe?
Im still thinkg about the 4,6 and what to do with that, high comp engine with a shot of gas, super tought bottom end, chevy rods and forged pistons, or build a forced induction motor, theidea of 2 small low mounted superchargers have their appeal,

I still think it should have a 302 in it, it's a ford damn it!
302 ford, 2X turbos, a T5 and gear vendors "gear splitter" over-drive unit. should go quite quickly
Mike

ian.stewart wrote:My 60fts are good, @ 1.59 on street tires

Good ? Thats f'in brilliant lol