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pauli

UN1 gearbox question

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I have come across a UN1 gearbox with the code UN1-016. As far as i am aware these were fitted to the early X180`s ?

What is the difference in the gear ratio`s between this box and the 026 box?

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no difference at all. Both seem to go the same, although both are off the road at the moment, As the 88 i am having the chassis blasted and coated. And the 92 i can`t really decide what to do with it yet. As the car has only covered 12500 miles but has no history.

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As the car has only covered 12500 miles but has no history.

Ouch! That's very frustrating.

I get people emailing me asking when the production of the Esprit Turbo finished. There's much literature stating it finishing production in 1990, but there were 9 cars built in 1991 and 1 car built in 1992. And quite a few registered in 1992. Good to know you've got one of them.

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yes looked at Mr Bells site on many occasion, and must say is very usefull. But i can find nowhere that lists the difference between the Lotus boxes, gears etc...

The 91 model i have was registered in the March of 91 so would be one of the first that year i should imagine.

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some way through the S4, they changed to right hand gearshift on the rear cover. early ones 016 or some such, late ones 026/7? iirc. this makes the change better/different. thats all interchangeable.

all V8's I am led to believe had a higher Renault 25 v6turbo 5th gear ratio. I have done this to my SE. easy job.

later V8's had a synchronizer on reverse that seems to wear out a bit as it is always rotating, unless your in reverse that is!. this seemingly comes with longer straight teeth on the shaft too.

all had the 3.889 diff ratio, 21 turbo ratio is a goer, but a bit of a waste on a 4cylinder car. i am building a whole box with this in, but i doubt it'll see the back of the car, just doing it for something to do. high diff and high 5th gives 218mph iirc, if it could pull it.

very late ones are speedo off the abs/speed sensor etc, not mechanical speedo. shows that in the book.

only S300 had a LSD, (unless very late v8's had em) a mega expensive lotus only gear type part. other options are Quaife ATB or the uber rare 5 Turbo rally car diff.

seemingly they are no-lotus only spec parts in the esprit box, no matter what most people tell you. some bits have lotus engraved into them, but under test, they are the same as std parts.

if u want a mega-uber knowledgeable chat about UN1s, they man to talk to is Kevin Jones at GTO Eng.

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thanks Pete, so really the only difference between the early Lotus box and the 21 turbo is the diff ratio?

At the moment i have a 026, 016, and 2 013 boxes, and was wanting to play with the 013`s to come up with a nice box for my 88 turbo, when i first purchased my car the last owner (i pressume) had put in an 013 box (naughty trick, so beware potencial owners). But hey ho i bought the car and didn`t know at the time, although i have run my car up till this day with the same 013 box (since 1990) and no probs except speeeeeed :P .

So when i bring her out next it would be nice to get the correct or even better gearing from the box.

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only S300 had a LSD, (unless very late v8's had em) a mega expensive lotus only gear type part. other options are Quaife ATB or the uber rare 5 Turbo rally car diff.

Sport 300 had a helical geared LSD,

and the '91 X180-R had ZF clutch type LSD (the 20 street cars for the USA)

No other street Esprits had LSD from the factory, no V8's


Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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thanks Pete, so really the only difference between the early Lotus box and the 21 turbo is the diff ratio?

At the moment i have a 026, 016, and 2 013 boxes, and was wanting to play with the 013`s to come up with a nice box for my 88 turbo, when i first purchased my car the last owner (i pressume) had put in an 013 box (naughty trick, so beware potencial owners). But hey ho i bought the car and didn`t know at the time, although i have run my car up till this day with the same 013 box (since 1990) and no probs except speeeeeed :ermm: .

So when i bring her out next it would be nice to get the correct or even better gearing from the box.

potential prob with a 21 turbo one is the weaker std renualt 2 pinion diff, instead of the lotus 4 pinion one. but, 21 turbos are quiet pokey heavy froggy cars, so maybe one fitted in a std esprit turbo, they might last the distance, but in a v8 or a charge cooled car, they wont last as long. i know others have done it and they are still going, but the four gear diff, or an LSD of course is best it seems.

apart from some really early 25's, theres no other UN1 with the mechanical speedo output other than the 21 turbo and the esprits. this comes with different coloured and ratio speedo gears too to suit the 3.44:1 ratio, fitting the crownwheel and pinion or in fact the whole 21 box to our cars needs those gears fitted too, to make the speedo read right. i have all the bits for several boxes and was going to build a high diff one with the high 5th too, but its a bit pointless unless you have 500hp and do road races in America. have done a spare 3.889:1 one instead, in case of breakage in mine.

good luck

Sport 300 had a helical geared LSD,

and the '91 X180-R had ZF clutch type LSD (the 20 street cars for the USA)

No other street Esprits had LSD from the factory, no V8's

so they do travis, I always forget about X-180s, as we dont have them here!.

i'd love one though

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Hi Pete and all,

sorry for longgggg delay in replying. Could you tell me what i would need to change in the box (un13) to bring up to Lotus spec? The crown wheel and pinion would be one item, but what cogs-gears would i need to change?

Gearbox`s are a new thing for me and i am looking forward to taking one apart and building it back up, and just want to make the best i can and bring one up to spec.

thanks

Pauli

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