Dean,
The early (Mk 1-3) 3-rail gearboxes with non-synchro first had a
different ratio set, but the MkIV 3-rail shares the same ratio set with
the single rail gearbox. They are as follows:
Mk1-3 MkIV-1500
4th 1.00 1.00
3rd 1.454 1.394
2nd 2.460 2.158
1st 4.27 3.504
R 4.27 3.988
Regards,
Joe
(Data from Graham Robson)
Dean Dashwood wrote:
>
> I was under the impression (and I could be completely wrong here) that
> the ratios on the 3-rail gearbox supplied up to the Mk 4 were different
> to the single-rail supplied with the 1500, and that there was a much
> bigger difference between 3OD and 4 on the single rail. Certainly on my
> 1500 (which I presume has a single-rail gearbox, although I haven't
> (yet) had to take it apart to find out) I can definitely tell the
> difference between 3od and 4.
>
> (Ok, I'm sorry, this thread should probably be dead by now, but I've
> been away for a while, I'm trying to catch up, and I thought this
> sounded kinda interesting.....)
>
> Dean
> ------------------
>
> >----------
> >From: Donald H. Locker[SMTP:dhl@mrdog.msl.com]
> >Sent: 16 March 1999 02:38
> >To: Mostrom.Paul@principal.com
> >Cc: spitfires@autox.team.net
> >Subject: Re: FW: Mustang...Spitfire???
> >
> >
> >My original Mk-III had 1 2 3 3od 4 and 4od. Sure looks like 6
> >selectable forward gears.
> >
> >And for those who count 3od equivalent to 4, final drive ratios are as
> >follows and the ratios between gears show a reasonable progression.
> >Not quite as clean as a true close-ratio box, but much better than
> >many. And 4th/3od is only 11% from (what I would consider ideal) 0.80
> >
> >1 3.75 * 4.11 = 15.41
> >2nd/1st 2.16/3.75 = 0.58
> >2 2.16 * 4.11 = 8.88
> >3rd/2nd 1.40/2.16 = 0.66
> >3 1.40 * 4.11 = 5.75
> >3od/3rd 1.12/1.40 = 0.80
> >3od 1.12 * 4.11 = 4.60
> >4th/3od 1.00/1.12 = 0.89
> >4 1.00 * 4.11 = 4.11
> >4od/4th 0.80/1.00 = 0.80
> >4od 0.80 * 4.11 = 3.29
> >
> >OK. I'll switch back to lurking now.
> >Donald.
> >
> >> A Spit with six forward speeds????
> >
> >[bandwidth preservation act invoked; rest of message chain chomped.]
> >
--
"If you can't excel with talent, triumph with effort."
-- Dave Weinbaum in National Enquirer
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