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transexual curiousity?


yankeedoodoo

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Some one in the club must have tried this! OOooopps.....Wait, I detect a small error: Freudian slip OR dyslexic moment? Well, anyway, I am attempting to express my curiousity about transaxles in sevens. Has anyone ever tried fitting one such as that from a 944, or the odd old hewland gathering dust in the corner of the garage? Am interested in results, thoughts about the effect on overall weight, weight distribution, shiftability, drivability and any other attendant problems. Should this query be considered in the realm of idiotic lunatic demented mental meanderings of a possibly hungover colonial caterham neophyte (me)? Please fell free not to respond if my query is not worthy of your time/thoughts. Thank you. Most of you would have loved the Lotus club tour of Symbolic Motors in LaJolla, Ca. yesterday. It featured numerous classic Ferraris (including the '62 LM winner) and Senna's JPS Lotus Renault from about '87. On the other hand, many of you were probably having even more fun @ a track day---even if it was raining.
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Do a search on the forum for "transaxle". It has been debated before.

 

It'll depend on how heavy you are, but my uneducated guess would be that it wouldn't make a large difference. Most of the masses in a 7 are between axles with engine/gearbox slightly ahead of fleshy masses.

 

I reckon mine would be pretty evenly split without the fuss (or the packaging hassle) of a transaxle.

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Transaxle is not suited to a de-dion setup (clearance to rear) and the rear end of the tunnel would need to be widened - the car would only have the external appearance of a seven. I have looked at this, believe it or not, because the weight savings could be enormous.

 

There are also problems with the length/inertia of the propshaft. The propshaft is now geared to the input side of the gearbox, so it has to cope with spinning up/down very fast between gearchanges. Normally the only rotational inertia involved here is the inertia of the input shaft and the lay gears. A transexual would obviously be a dog design, so there is little doubt that the gear would go in, but the longer and heavier the input side of the transexual the heftier the thunk as it goes in. The shock loads would be higher (although a clutchless upchange on a sequential would see the inertia of the engine as well, so may not be so relevant), which might cause reliability problems or pass on shocks to the chassis. You would minimise this by moving the engine as far back as possible and by running as short a propshaft as possible. This would also reduce the dumbell weight distribution of the car which would have handling benefits. By the time you have done this you would have a front/mid-engined design and not much of it will still be Seven shaped.

 

I think the only way to go on the shift quality front would be sequential (properly designed remote??) rather than a cable or other operated h-gate shift.

 

*thumbup*253 bhp, up and running *thumbup*New boingy bits *thumbup*

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that said Peter it has been done and successfully.....apparently a few years back a guy up north put a transaxle in a modified (by Arch) live axle chassis and virtually cleared up on the hills.

 

The weight savings would be significant considering the following:

My complete axle and g'box weight about 75kgs. I know of a tranaxle that weighs only 32kgs incl diff.......appreciating the longer prop, strengthening/shafts etc also req'ed.

 

I've compromised and managed to get somewhere in between with a complete axle and g/box that's now down to around 55kgs.

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