Lotus Elan

1973 +2 gearbox ratios?

PostPost by: HCA » Tue Jan 25, 2022 3:25 am

Will someone please give me the drive train ratios for a plus two five speed box as it left the factory?
I cannot find anything on the internet - plenty on the four speed, but not the five!

Thanks!
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PostPost by: hamm61 » Tue Jan 25, 2022 8:06 am

Yes,
1st 3.200 :1
2nd 2.010 :1
3rd 1.370 : 1
4th 1.000 :1
5th .800 :1
reverse 3.467 :1
Hope this helps , i have the +2 s130 handbook supplement , and the car
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PostPost by: HCA » Tue Jan 25, 2022 8:42 am

Peter, thanks so much! I really have trawled around for this and it just does not exist - so keep your book safe, it is valuable.

Leading on from this info, my next question is: how much difference in reality would a replacement box be noticed with

!st, 3.65
2nd, 1.97
3rd, 1.37
4th, 1
5th, 0.815

It is really the first gear that is wildly out. The car will only ever be used for touring and maybe with a 3.5 ration diff (there will be extra bhp to allow for a change in diff)
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PostPost by: HCA » Tue Jan 25, 2022 8:44 am

Actually, Peter - another question, what does your book say for the rear differential ratio? Is it 3.7 or 3.9?

Thanks
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PostPost by: mbell » Tue Jan 25, 2022 6:21 pm

I believe 3.7 was standard and 3.55 optional. My car has 5 speed + 3.55 which works well IMO.

I think the ratios would be ok, but not as ideal as the 5 speed ones. The short 1st gear probably isn't needed and I find the gap between 1st and second on the standard box as big as I'd want it at lower speeds. This one has bigger gap which I think may be annoying is traffic and car parks when trying to drive slowly (a 3.7 diff might counter that issue thou.).

Suspect you've found a possible alternative box? Want to comment on what it is?
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
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PostPost by: HCA » Tue Jan 25, 2022 6:42 pm

OK, yes. It all started with an offer we could not refuse on our house that meant I had to pack up the workshop quickly that would not allow me to separate the body from chassis to insert a Voigt T9 box. So the plan was, assuming I might be short of space at the next house, have the Lotus 5 speed recond.

However yesterday, the buyer admitted he could not get the money together and therefore we have decided to stay put for another two years. Yipee - I have my workshop back and the +2 is already poised on the two poster ready for separation :D

Voigt does not have any boxes on the shelf, but will have some in a few months as he needs new tail ends that might raise the price. He normally fits a 2.9 first gear, but he needs to finish one where he made a mistake and fitted the 3.6 gear. As it is not a very popular seller, I can have it for £2.5k. To me, this sounds ok in this day and age when you consider it is a complete unit with concentric release, clutch plate and gear lever. Hence the question above, is a 3.6 first ratio going to be hard to live with?

As my new engine will be a 1700 EFI, I will have a few bhp to allow me to go up to a 3.55 diff BUT Voigt is not happy with the batch of new 3.55 CW&Ps floating around the UK and will not use them after he had a failure after 83 miles on one. He suggests I look for an older 3.55 but the condition of course will not be known, but he thinks that for touring purposes on public roads a 3.7 on that box should be fine.

I thought the +2s had 3.9 as standard. If it is 3.7, then I am fine as I think mine might just need new seals.
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PostPost by: Donels » Tue Jan 25, 2022 7:15 pm

I think it depends on what you want from the car. I had a Westfield where I swapped the Ford 4 speed for a type 9 with exactly those ratio's and it was fine. It accelerated like a scalded cat but you have an early upshift.
In reality I quickly didn't notice it as in normal driving your using 3rd, 4th and 5th.
If you plan to go sprinting or hill climbing then it may be a bit low. In an ideal world it would be the 2.9 but in real use it probably won't matter.

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PostPost by: mbell » Tue Jan 25, 2022 8:24 pm

Donels wrote:I think it depends on what you want from the car.


I agree with this. My daily has quite a short 1st, its great when crawling in traffic and try to go slow. When setting of quickly you get through it very fast and can have traction issues. So comes down to person use and tastes.

I've never got a quote for rebuilding a Lotus 5 speed and I know its not a cheap one to do as parts are expensive. But are you going with Voights for reduced cost or is it more than that (e.g reliability)?

I suppose they is a bit of value for your current box, even if it is past its best, with the +2 specific castings that could be sold to offset the voights box. Which might make it the cheapest solution over all.
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
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PostPost by: stugilmour » Wed Jan 26, 2022 5:13 am

Those ratios look similar to my MT-75, which I think are….

one 3.61
two 2.08
three 1.36
four 1.00
five 0.82


I have a 3.54 final drive, the stock wheel & tire size, and CV shafts.

First does feel a bit low, but is handy in traffic. Suits the extra weight of the Plus 2 pretty well though. The gap between first and second is a bit more than I would like, looks like yours would be larger. The progression from second thru fifth is fine. The overdrive is perfect for modern highways, ~3,500 rpm at 80 mph.

There is a really good spreadsheet available on the forum that calculates all of the rpm/speed numbers and provides an overall figure of merit for the gearbox that you might find helpful.

HTH
Stu
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PostPost by: hamm61 » Wed Jan 26, 2022 7:10 am

Sorry , handbook says 3.55 :1 or 3.77 :1 I do not know what mine is, i suppose it may have some indication on it , my car is very much standard on motorwayss 3 000 rpm in fith is just under 70 mph .
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PostPost by: HCA » Wed Jan 26, 2022 9:18 am

Thanks again Peter. My car is on the two poster as I write, so later on when I have five minutes I will lift it and rotate the prop shaft to determine.

mbell, yes, my reasoning is the overall cost taking into account the resale value of my box, overall reliability, readily available parts, internal clutch release and hoping the gear lever might be better placed..

Thanks Dave for the comments. Voigt has given be a fixed price for a box that has a 2.9 that is only a couple of hundred more. As I am not in a hurry, I shall go with this.
Hal Adams

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Elan +2 - keeps me busy
Macan - hers
Felicia Pickup - my favourite
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PostPost by: Donels » Wed Jan 26, 2022 6:05 pm

Just one more comment. Alan Voights rebuilds Lotus 5 speed boxes for Paul Matty etc. You could ask him how much it would cost to rebuild your existing box.

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PostPost by: HCA » Wed Jan 26, 2022 7:34 pm

I have :shock:
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PostPost by: mbell » Wed Jan 26, 2022 9:02 pm

HCA wrote:mbell, yes, my reasoning is the overall cost taking into account the resale value of my box, overall reliability, readily available parts, internal clutch release and hoping the gear lever might be better placed..


Thanks. Having looked at prices for a few parts for my 5 speed box I can see the cost of the voights solution being lower and coming with other advantages.
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
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