English Axle CWP
Discussion
Thanks, Guys!
I'd tried the usual suspects (Burton, Rally Spares etc.)... no problem getting a very short CWP (5:1 would be easy, if I fancied a top speed of 60mph!), but they tended to just get confused when I asked for tall ratios, 'cos they couldn;t understand why anyone would want one!
Mitchel Cotts is a good call, though - they're not too far from me, and I understand that they make the Caterham 6-speed that is the other element in my Big Plan... I'm thinking about converting my Elan to a 6 speed box - to keep the close ratios and hence the acceleration, but combined with a nice, tall diff to give relaxed long-distance cruising for continental trips.
I'd tried the usual suspects (Burton, Rally Spares etc.)... no problem getting a very short CWP (5:1 would be easy, if I fancied a top speed of 60mph!), but they tended to just get confused when I asked for tall ratios, 'cos they couldn;t understand why anyone would want one!
Mitchel Cotts is a good call, though - they're not too far from me, and I understand that they make the Caterham 6-speed that is the other element in my Big Plan... I'm thinking about converting my Elan to a 6 speed box - to keep the close ratios and hence the acceleration, but combined with a nice, tall diff to give relaxed long-distance cruising for continental trips.
Sam_68 said:
I'm thinking about converting my Elan to a 6 speed box - to keep the close ratios and hence the acceleration, but combined with a nice, tall diff to give relaxed long-distance cruising for continental trips.
But a tall diff ratio will slow your acceleration. Sounds like what you really want is a tall top gear. Think some of the 'repmobile' type Sierras had a high 5th for economical motorway cruising.If you really do want a higher final drive than Ford's highest 3.54:1 then why not just fit larger diameter wheels? Mind you, on an Elan you'd probably have to modifiy the wheel arches to do it.
I'm not too worried about acceleration off the line - I don't tend to do drag starts in the Elan, anyway, 'cos it's still running rubber rotoflex couplings.
In any case, it's the overall gearing in any gear that counts (ie. gearbox ratio x final drive ratio), so a six speed box with the right ratios needn't sacrifice too much... I'd lose something away from the lights, unless I fitted a stupidly low first, but as I said, that wouldn't bother me too much. Once I was rolling, the rev drop between gears ought to be enough to keep the engine on the boil (though the Lotus Twin Cam is surprisingly torquey compared to modern 16V units).
The idea is to get similar overall gearing in top to an overdriven 5-speed box (the Caterham box is direct drive, 1:1, in top, hence the need for a taller final drive), but to fill in the gaps at sensible road speeds (20-100mph) with the smaller steps between ratios.
There's also the technical appeal of having a 6 speed (possibly a sequential Quaiffe, if the ratios in the Caterham box don't calculate out right) rather than just a boring Ford 5-speed, I must admit!
In any case, it's the overall gearing in any gear that counts (ie. gearbox ratio x final drive ratio), so a six speed box with the right ratios needn't sacrifice too much... I'd lose something away from the lights, unless I fitted a stupidly low first, but as I said, that wouldn't bother me too much. Once I was rolling, the rev drop between gears ought to be enough to keep the engine on the boil (though the Lotus Twin Cam is surprisingly torquey compared to modern 16V units).
The idea is to get similar overall gearing in top to an overdriven 5-speed box (the Caterham box is direct drive, 1:1, in top, hence the need for a taller final drive), but to fill in the gaps at sensible road speeds (20-100mph) with the smaller steps between ratios.
There's also the technical appeal of having a 6 speed (possibly a sequential Quaiffe, if the ratios in the Caterham box don't calculate out right) rather than just a boring Ford 5-speed, I must admit!
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