> Tom
> From the comments about rear end gearing and my calculations based on a 15%
> speedometer error I suspect that I have a 4:38 differential in my SU 2L.
> When I got the car running I had not driven a Datsun 2000 for about 29
> years. Even with that time span I noticed the difference from the stock
> differentials in the 68 and 70 models I drove years before. I thought that
> the engine had been played with at first, but now I think it is all in the
> differential gearing.
>
> This car is a lot of fun to drive, especially if you like to accelerate
> quickly. I am still trying to figure out whether the suspension has been
> played with, or if the gearing is helping the handling as well. It seems to
> handle better than I remember. But that it may be my imagination because I
> don't see fancy shocks. In fact the car had new factory original shocks in
> front when I got it. It may have a slightly thicker sway bar, but I need
> compare my sway bar with a known standard bar to be sure.
Ought to be a simple way to figure your ratio out. Certainly one short of
marking the driveshaft and tire, then crawling under the car on a creeper,
hanging on and counting the number of driveshaft revolutions for each tire
revolution! Sorry couldn't resist. Can plead that I'm still feeling the
"happy juice" from another visit to the dentist.
I'd think you could get a ballpark idea if you ran steady with another
roadster with known tranny and rear gear ratios and then compared revs at a
given speed in either 4th or 5th. You could calculate the RPM difference as
a percentage and compare that difference to the difference, also in percent,
between the 3.7, 3.9, 4.11 and 4.38. Unless you're running the same tires or
at least tires with the same height there'll be some variation but this
should give you a pretty good idea of what gears you have in your car.
For that matter there's probably an easier way to figure it out. Hopefully
someone will toss it out and we can all add it to our bag of tricks.
FWIW,
Ron
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