A stock Solex car doesn't have quite the bottom-end response that an SU car
does, so it won't mind a little help. The hp and torque curves of the Solex
and SU cross at 4000 rpm. However, an SU car with the same 3.9 will still be
quicker.
Yes, you'll notice the difference. Usually when I switched from a 3.7 to a
3.9 it wasn't too obvious on first drive, but it became obvious as I drove
it more (only a 5% difference). Going to a 4.11, on the other hand, was
really obvious right from the first drive (11% difference).
As for top end, the cars are way over-geared in 5th with either diff. I
doubt if top end will suffer. After all, isn't 124 mph in a roadster fast
enough?
Using 185/70-14 tires, 6000 rpm (the rated hp peak) in 5th would be 137 mph
with the stock 3.70 diff. The engine doesn't have enough hp to get there.
The Solex cars were rated 124 mph. Using a 3.9 diff would be 130 mph at 6000
rpm.
> -----Original Message-----
> From: owner-datsun-roadsters@Autox.Team.Net
> [mailto:owner-datsun-roadsters@Autox.Team.Net]On Behalf Of
> Beamonk@aol.com
> Sent: Wednesday, November 17, 2004 10:34 AM
> To: datsun-roadsters@Autox.Team.Net
> Subject: Re: Differential help
>
>
> What if one were to put a 3.9 diff in a Solex car? What is the
> effect? Faster
> acceleration, less topend? Is it a noticeable difference in a Solex car?
>
> Thanks,
> john Brasfield
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