Lotus Elan

5 speed box (Again!)

PostPost by: msd1107 » Thu Oct 29, 2015 3:29 am

No, you need a higher differential ratio. Even the the 3.55 ratio is too low.

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PostPost by: stugilmour » Thu Oct 29, 2015 4:14 pm

Point taken, and might just be a bit of confusion between lower vs numerically lower? Isn't 3.54 (11/39) / 3.55 (9/32) the 'tallest' commonly available ratio for the stock Lotus diff? Not sure what is available for the replacement Ford units the Zetec guys use.

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PostPost by: l10tus » Thu Oct 29, 2015 4:43 pm

Vince,

I think Stu is correct.

Seems the 3.54 is the highest available.

I too am searching for the Grail !

Lotus were obviously trying to address this issue by fitting the highest one available.

If it were available, would a higher ratio be restricted by physical size anyway (in the Ford unit)?

I wonder if we have to look elsewhere - perhaps other manufacturers?

Or is it the 4 speed box that is the overriding issue here?

Gearing is Just too low!

(Can't believe it has gone so many years without being addressed !)

Regards,

Phil.
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Sometimes my Lotus makes me cry.
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PostPost by: msd1107 » Thu Oct 29, 2015 5:53 pm

I vaguely remember 3.44 being homologated, but have never seen it. Probably for use at Le Mans.

Gary Anderson at one time proposed having a special diff ratio of around 3.2 made, which would give a top gear approximately the same as the T9 5th speed. This would require using the wide ratio 4 speed in order to be viable on the street.

Most of the 5 speed conversions have a 5th gear between .87 and .8 which is useful with the normal differential ratios of 3.55, 3.77, or 3.9 depending on whether you have a FHC, DHC and the state of engine tune and what revs you want at your normal cruising speed.

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PostPost by: elj221c » Thu Oct 29, 2015 9:22 pm

l10tus wrote:Gearing is Just too low!

(Can't believe it has gone so many years without being addressed !)



It's probably because you are probably the first to raise such a question except where motorway/freeway cruising is concerned.

Around 3750ish rpm at 70mph. Travelled all over at that and sometimes flat at 7k. :)

The gearing was suitable for the time and still is for most.

As someone else has intimated on the other thread, perhaps you are not the 'ideal' Classic Lotus owner.

To paraphrase: "Give it up".
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PostPost by: john.p.clegg » Thu Oct 29, 2015 10:23 pm

"Bring back the horse and cart",that's what I say.......

John :wink:
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PostPost by: l10tus » Mon Nov 02, 2015 2:00 pm

John,

They were often thrashed as well !
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