The Lotus Grand Tourers

It used to be that "top" gear was the one which enabled you to reach the car's top speed. In overdrive the car could not reach the same speed as the engine speed was too low. If you were to plot the engine power vs. the road speed for each gear and the power needed to push the car along at that speed, top speed is achieved when the engine power matches the power needed. Say the maximum engine power is 160bhp and you need 165bhp to achieve 135mph. If, in 4th, the engine reaches max power revs when the car reaches 135 mph, that will set the car's max speed. If, at the same road speed in 5th, the revs are lower, and, therefore, the engine power is lower, the top speed in 5th will be less. The car is being overdriven to reach max speed.

https://www.ebay.co.uk/itm/Original-Lot ... Sw9tFeszBm
Ebay.co.uk has a couple of knobs on currently.
By the time you've had one made and 3D printed an insert it might be worth considering.
I found this by searching on "elan + 2"

Tony

This from my Eclat. It doesn’t have an overdrive

That's a different pattern. My Elite (maxi based) and to my knowledge all earlier cars are a double H layout ( reverse below O/D).
Did later Excels with Toyota parts have a changed layout?
Tony

Is that the Getrag change pattern Don?

Pete

My Excel came with a horrible wooden goose-neck job so I replaced it with a Toyota one eBay 122077958539 as it's not unlike an original.

It has the correct pattern for the Toyota 'box, i.e. reverse under 5th, and being Toyota it has the correct thread form.

Andy

Pete Boole wrote: Sat May 09, 2020 08:11 Is that the Getrag change pattern Don?

Pete

Yes, Pete


I had on the Lady installed this one, which has a similar shape and is really a good feel in your palm

Did they fit the Getrag dogleg box to the Elite/Eclat? That's a new one on me, in the 80s I had an E12 with one of those boxes. I somehow assumed it was a bit of a rarity, just fitted to some of the bigger BMWs. Sounds like it was more popular than I thought.

I think all the series 2 cars (Elites/Eclats) got the Getrag box. I'm fitting one to my series 1 because it's much stronger than the Lotus box.

Pete

Complete hijack but I got mine off a BMW

And a good job you made of it!

Pete

To explain overdrive I find it easier to think purely in mechanical terms. Gears 1-3 involve a smaller gear on the gearbox input shaft driving a larger gear on the output shaft. Gear 4 (in almost all cars) involves the same sized gear on the input and output shaft or 1:1. Gear 5 or overdrive involves a larger input gear driving a slightly smaller output gear, perhaps a ratio of 0.8. Result, more speed for less engine revs.

For Robert, to be pedantic, fourth gear is a direct drive through the mainshaft, the laygear has 1st, 2nd and 3rd gears only.
For Trevor, the road speed (mph) per 1000 rpm in 4th gear is 16.6 (Owners Handbook), and 135 mph comes up at 8132 rpm.
In overdrive/5th, at 21.2 revs/1000 rpm at 135 mph engine speed is 6367 rpm.

Gearknob gear position. Elite Handbook shows 5 above R(reverse) and strangely the Lotus badge in the centre of the Knob.
Elite Handbook Techical Data refers to Overdrive (5th), incidentally at 0.8:1
Excel Handbook shows O/D above R (reverse) with the knob centre the same.

Gertag gearboxes apparently carried a dog-leg lever position to enhance 2nd to 3rd gearchange (Wikipedia).


Dave the cog.

The dog-leg Getrags weren't fitted to the Elite/Eclat - conventional pattern. I think the dog-leg boxes were on the BMWs and possibly others of the same period.

Pete

It's worth remembering that at the time the Elite and Eclat were launched, there were hardly any 5 speed boxes available. The Maxi box was a great innovation when it was introduced, and became the internals for the +2S 130/5 box, then the Elite and Eclat. Alfa had a 5 speed at the time I believe, and very few others. Overdrive was very popular on more powerful RWD cars using conventional 4 speed boxes to give relaxed cruising - where top gear, as Trevor says, was often set to match max power revs with top speed. Overdrive was also an extra cost option - so marking 5th gear as O/D was probably a (justifiable) ploy to warrant a higher price for the car.

Apart from autos, the Elite/Eclat S2.2 all had Getrag boxes, and Excels all had Toyota boxes. No idea about the differences in gear pattern though!

Cheers, Richard