The stock ratios of the T50 box are obviously not close.
Are you sure you can even get the close ratio gears for this box and if so
what cost (they will be straight cut)?
If you are thinking about whether the car will pull first gear or not you
need to think about the axle ratio in conjunction with the gear ratios.
Whether the engine in your car will pull overall ratio depends on the bottom
end torque the engine will produce.
Daniel1312
In a message dated 20/05/01 00:05:12 Pacific Daylight Time,
tob.sprite.landcruiser@home.com writes:
<< but the stock ratios of the T-50 gearbox are:
1st, 3.587
2nd, 2.022
3rd, 1.384
4th, 1
5th, 0.861
the close ratio kit ratios are:
1st 2.63
2nd 1.891
3rd 1.384
4th 1.0
5th .861
That's a mighty "high" 1st. Supposedly people have used these ratios on
street vehicles with much success. Unfortunately the ebay auction of said
gears seams to be getting out of hand.
I might just get it anyway, because with 200+hp in a light midget, my plans
for NOT racing may rapidly change as I lay my foot to the floor and take
off.
Hopefully the drive train will be sourced from one model Toyota, therefore
the components will already be matched to suit street driving. However with
the modified engine, delivering (more) power higher in the rpm range, the
close ratios might prove useful.
Very fun stuff indeed.
Oh and don't be put off by my grand far east plans. The "stock" British
Sprite still has priority over all this silliness. And yes the Datsun 5
speed run is scheduled for the first weekend in June.
Thanks
Toby
Toby,
I hope someone more knowledge and experience than me will answer... That
being said...
1. A close ratio gearbox will allow you to better get the performance out of
the engine- what happens is that the maximum torque/horsepower of the engine
can be taken advantage of by "better spaced" gearing. Provided the overall
gearing (transmission + axle) is high enough for the road (i.e. the engine
does not rev too high), a close ratio gearbox is good news for the street
too. The problem is that there may be no helical-cut gears available for the
Spridget. The only Spridgets close ratio gears I have seen for sale have
been straight-cut.
2. Straight-cut gears are desirable for racing (transmission is much
stronger than standard), but not for the street (way too noisy). Racers may
also use rear axles with low gearing (high numerical ratio) for maximum
acceleration, and the engine is at maximum revs in the long straights-
typically, racing engines will rev higher than what you will find in a
street car. That set up would be bad for the street as the engine would rev
too high for comfort on the highway.
I believe your comments about "fixed set of speed" and not being able "to
get me off a stoplight" in first gear apply to other forms of racing (not
road racing) and cars very different from our LBC... The highest
(numerically low) gear ratio I have seen for Spridgets is 2.5 (standard is
3.2 or above), and I don't think you would have a problem going in first
with that. Some of the five speed gearbox conversions start at 2.73 for
first gear... Did you think of a five speed conversion?... Now, that's an
altogether different topic!
Jacques Le Clainche
SCCA 1985 Mazda Spec RX-7 #44, San Diego region
VARA 1960 Austin-Healey Sprite #4, F Production
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