Esprit gearbox
Discussion
There's a Sport 300 transaxle for sale at this site:
www.findit.co.uk/cars/lotus/parts/170884.htm
Not sure what the differences are between a V8 and Sport300... Sp300 DOES however include a LSD.
Just another idea - why not try to find a renault box? The lotus uses a box out of a renault 25 i think. Lotus probably do some strengthening, so it may not be a long term solution, but it would certainly get you mobile again. Oh, and you can buy a complete renault 25 for about £300!
Cheers
Rob.
www.findit.co.uk/cars/lotus/parts/170884.htm
Not sure what the differences are between a V8 and Sport300... Sp300 DOES however include a LSD.
Just another idea - why not try to find a renault box? The lotus uses a box out of a renault 25 i think. Lotus probably do some strengthening, so it may not be a long term solution, but it would certainly get you mobile again. Oh, and you can buy a complete renault 25 for about £300!
Cheers
Rob.
Hi There,
You need to be very aware that even though the Renault box will probably fit that is not the entire story. Last year whilst I was awaiting gearbox parts for my S4s (broken 2nd gear & new syncros) researched this possibility and found out the following info:
1: Lotus Cars UK confirmed to me that the box used in the Esprit has its entire contents strengthened and subjected to various processes which allow it to cope with the additional torque the Esprit produces (not that you'd notice when so many people have problems with it!!). The V8/SP350 even have their ECU's modified to give minimal torque in the first 3 gears to preserve the box.
2: If you fit a Std Renault box then chances are it will fail at some time and this could be very dangerous if you are travelling at high speed and something breaks internally causing the rear wheels to lock up.
When my gearbox was in pieces I had a good look at all the components and have come to the conclusion that there is nothing you can do to further strenghten it as the aged design is the problem. Some of the teeth on the gear cogs/syncro ring shafts are only a few mm when new and it only takes a few crunched gearchanges to shear these resulting in new parts being required. My advice to you would be either buy a Quaife or Hewland box or make do with the std one (many people have had no problems with the std box and yet others I know have had several new gearboxes. Lifespan seems to be related to driving style/pure luck). There does not appear to be any other option at present as very few boxes fit into the space available. Some guys in the USA are currently researching putting a Porsche G50 transaxle in but I suspect this will be as costly as a new Quaife when you add up all the associated costs.
Regards
PS: To give you an idea of just how much torque even an S4s produces it is something like 277lb, a Ferrari 360 only produces about 286lb. The V8/SP350 Esprit's produce 295lb. I suspect if the Esprit ECU was modified to give less torque and more top-mid end grunt the gearbox would not be such an issue.
You need to be very aware that even though the Renault box will probably fit that is not the entire story. Last year whilst I was awaiting gearbox parts for my S4s (broken 2nd gear & new syncros) researched this possibility and found out the following info:
1: Lotus Cars UK confirmed to me that the box used in the Esprit has its entire contents strengthened and subjected to various processes which allow it to cope with the additional torque the Esprit produces (not that you'd notice when so many people have problems with it!!). The V8/SP350 even have their ECU's modified to give minimal torque in the first 3 gears to preserve the box.
2: If you fit a Std Renault box then chances are it will fail at some time and this could be very dangerous if you are travelling at high speed and something breaks internally causing the rear wheels to lock up.
When my gearbox was in pieces I had a good look at all the components and have come to the conclusion that there is nothing you can do to further strenghten it as the aged design is the problem. Some of the teeth on the gear cogs/syncro ring shafts are only a few mm when new and it only takes a few crunched gearchanges to shear these resulting in new parts being required. My advice to you would be either buy a Quaife or Hewland box or make do with the std one (many people have had no problems with the std box and yet others I know have had several new gearboxes. Lifespan seems to be related to driving style/pure luck). There does not appear to be any other option at present as very few boxes fit into the space available. Some guys in the USA are currently researching putting a Porsche G50 transaxle in but I suspect this will be as costly as a new Quaife when you add up all the associated costs.
Regards
PS: To give you an idea of just how much torque even an S4s produces it is something like 277lb, a Ferrari 360 only produces about 286lb. The V8/SP350 Esprit's produce 295lb. I suspect if the Esprit ECU was modified to give less torque and more top-mid end grunt the gearbox would not be such an issue.
Hi all. Re the Gearbox for your S4. I have had experience with the Renault boxes for some years now and have been using them on Chevrolet V8's with great success. A current car I have with a 350 Chev unit produces 267 kw (356 hp) at the rear wheels. I havent broken a gearbox with this power yet. Have a look at this website www.merthyr.ac.uk/gt40/technics.htm and go to Renault Transaxle data. All the gear ratios of the models in the same casing as Lotus are there. You will see that the Lotus unit uses the same ratios as them. The internal strenthening can only be perhaps a hardening, but this is done at the factory (Renault) - it always sounds good for the salesman at Lotus to say its a strengthened one and not a 'standard' unit - after all they have a reputation to uphold !!!! If you take apart say a Renault 30 gearbox and put it aside a 21 Turbo gearbox, there is a great difference in strength. I havent had a Lotus spec box apart but the ratios are the same as the 30 as is the final drive. The 21Turbo is definatly stronger. The crownwheel is wider as is the teeth, the pinion gear almost 10mm diameter larger and the gear teeth are also larger and this is just the naked eye differences. Only thing is the 30 models have a 4 spider differential. The 21 turbo unit is a 2 spider unit. Unbolt it from the crownwheel and take it to a good engineering firm and tell them to put in the extra 2 gears. I know of one company which does this. I also found the early Renault 20's had the diff unit ready machined for 4 spiders. Perhaps you could pick up one of these for about 30 quid and take out the diff unit for the spider gears, alternativly just find a 30 box and swap the diffs over. You will need to change over the rear housing on the gearbox because of different gearleaver inputs but this is no problem. I also found a change of oil helped. I have been running Redline synthetic oil for sometime. Being at the rear of the car the box heats up alot and obviously the oil!! - too hot - oil breaks down - teeth contact gearbox wears out or goes 'pop' - check it out could be worth something. None of these boxes are expensive in the UK - about 100 pounds for a 21 turbo is the going rate privately - about the same for the 30 if you can find one. See how you go.
Thanks alot for the advice Lawrence! Do you think the final drive difference of 3.44 to 3.89 will change preformance much, maybe a higher top speed!!Does the box that lotus use have two or four spiders? also the gear selector mechanism on the rear of my original box is beyond repair is it possible to modify the 21turbo selector with some of the parts from the original lotus unit?
Hi again. Well when I used the 3.89 box my top speed was 250 kph. The 3.44 gave me 270, but you will have to have the power to pull it though. Acceleration may be a tad slower, but once again comes down to how much power you have. I dont know if the Lotus unit has 2 or 4 spiders. You will have to check that or perhaps someone here could enlighten us. The rear gear selector levers will be able to be adapted to suit. I hope you are handy with tools, welding and some fabrication techniques. You can still use the same flexable push/pull rods. Its quite a simple task if you study it. ...
Actually I just grabbed a handful of Lotus books and ran to the workshop to check out the gearchange housing on the 21Turbo box. and thanks to some wonderful photography I can 99% confirm that the rear gearchange housing is that of a 21 Turbo. Sounds like it could be easier than we think here !! Im using the 30 housingon my 21T because its what I started out with and fabricated linkages appropriately. All Ive done is bolt on the 30 housing to the 21T box !
Have a go and see how you get on.
Actually I just grabbed a handful of Lotus books and ran to the workshop to check out the gearchange housing on the 21Turbo box. and thanks to some wonderful photography I can 99% confirm that the rear gearchange housing is that of a 21 Turbo. Sounds like it could be easier than we think here !! Im using the 30 housingon my 21T because its what I started out with and fabricated linkages appropriately. All Ive done is bolt on the 30 housing to the 21T box !
Have a go and see how you get on.
hi. I had a look at the lotus box and the 21 turbo box
side by side and it seems that the only difference apart from the final drive having a lower ratio is that the boys at lotus have put in larger/stronger bearings all round. In your experience do you think
it is worth swaping the bearings around, have you had problems with to much torque breaking a bearing in the standard unit attached to your v8? by the way what car is your chevy v8 in?
regards.
side by side and it seems that the only difference apart from the final drive having a lower ratio is that the boys at lotus have put in larger/stronger bearings all round. In your experience do you think
it is worth swaping the bearings around, have you had problems with to much torque breaking a bearing in the standard unit attached to your v8? by the way what car is your chevy v8 in?
regards.
Hmmm they must have had to machine the case to put in larger bearings. I have seen that the earlier boxes (Renault20's of the 1970's have smaller bearings and wouldnt be suitable). Wouldnt be such a good move to turn down the input/output shafts to do it! You would have to disassemble the shafts to do the bearings if this is the case. I havent broken a box at all. My dyno readings for the engine are 458hp @ 6000 rpm and 464 ft/lb @ 4500 rpm. Email me your phone number and we'll have a yap. Regards. activ@xtra.co.nz
Sharon
lyk2no used the word "affordable" in his original post.
Although the Quaife unit is undoubtedly an excellent product its a bit pricey.
As a general point, i'm sure that quaife would find a whole load of customers who would buy an reliable 6 speed transmission for their v8 esprit (that could take 450+bhp) if the price was more reasonable.
Rob
98 V8-GT
lyk2no used the word "affordable" in his original post.
Although the Quaife unit is undoubtedly an excellent product its a bit pricey.
As a general point, i'm sure that quaife would find a whole load of customers who would buy an reliable 6 speed transmission for their v8 esprit (that could take 450+bhp) if the price was more reasonable.
Rob
98 V8-GT
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