Large custom Spacer between engine and transaxle.
Discussion
I have a one off special being made which uses a midmounted longitudinal engine and audi style transaxle.
However due to packaging constraints, i realistically need to space the engine forward of the transaxle by around 200mm. I cant just move the transaxle as i would end up with unacceptable drveshaft angles.
My initial simplest thoughts are, as i need to make a adaptor plate between the two anyway, i just have it made longer (subject to being able to leave sensible bolt access). Then have an extended input shaft adaptor made to ensure i can engage the clutch plate. Then have spacer made for a concentric slave cylinder.
Any other ideas?
I had thought of torque tube type set up but this is probably too short to do that.
There arent any "gears inward" transaxles short enough except some silly money motorsport stuff well out of my budget.
I was worrying if such a long input shaft would be problamatic without and additional bearing for support from any latteral movement.
Anybody got any thoughts?
However due to packaging constraints, i realistically need to space the engine forward of the transaxle by around 200mm. I cant just move the transaxle as i would end up with unacceptable drveshaft angles.
My initial simplest thoughts are, as i need to make a adaptor plate between the two anyway, i just have it made longer (subject to being able to leave sensible bolt access). Then have an extended input shaft adaptor made to ensure i can engage the clutch plate. Then have spacer made for a concentric slave cylinder.
Any other ideas?
I had thought of torque tube type set up but this is probably too short to do that.
There arent any "gears inward" transaxles short enough except some silly money motorsport stuff well out of my budget.
I was worrying if such a long input shaft would be problamatic without and additional bearing for support from any latteral movement.
Anybody got any thoughts?
gears inward ??
If the input shaft was floating on the box end and the usual spigot at the flywheel end, then I cant really see why it would be a problem.
Even if it was a solid 1 piece input....again, as long as the adaptor and box etc are all perfectly aligned, it shouldnt be a big deal really.
But by f
k, 8" is one hell of a spacer !
If the input shaft was floating on the box end and the usual spigot at the flywheel end, then I cant really see why it would be a problem.
Even if it was a solid 1 piece input....again, as long as the adaptor and box etc are all perfectly aligned, it shouldnt be a big deal really.
But by f
k, 8" is one hell of a spacer !stevieturbo said:
gears inward ??
gears forward of the diff. eg corvette transaxle, Radical RXC and some single seater transaxles. Most audi transaxles have the gears behind the diff. stevieturbo said:
But by fk, 8" is one hell of a spacer !
I know. lol. Im thinking the simplest way for the spacer to avoid machining a massive lump of metal is to use an OEM bellhousing and in effect make an adaptor plate from transaxle bellhousing to the OEM bellhousing which should be much thinner. k, 8" is one hell of a spacer !The T56/Vette version of their tansaxle is already an extremely long one, would it suit better ?
The Factory Five kit car in the US uses it like that, although the entire package is so long it's a wonder it fits in anything lol
Or would it be easier to space out the diff section from the trans, or is yours totally integrated into the gearbox casing ?
The Factory Five kit car in the US uses it like that, although the entire package is so long it's a wonder it fits in anything lol
Or would it be easier to space out the diff section from the trans, or is yours totally integrated into the gearbox casing ?
Surely on a mid engined car you try to get the mass of the engine as close to the rear axle centre line as possible? Usually the mass of the occupant(s) then puts the balance back to 50:50?
If you have a single seater then pushing the engine forwards means a massive wheelbase, and for side-by-side 2 seater you'll end up with the occupants each side of the engine, which means it'll be a tiny cabin space?
On the RS200 the engine went in facing backwards (front pulley towards back of car) and drive went forwards to the gearbox/transfer case at the front, and then back to the diff mounted to the side of the engine
I did a similar layout in the early 90's for a comp safari (off road) racer, where the engine, a 5.0 rover v8 sat facing backwards, with the diff and halfshafts just missing the front pulley (ie reawards of the engine). The occupants were say either side of a small bellhousing that took drive forwards. The backrests of the seats were basically 5mm away from the rocket covers / back of the heads!
If you have a single seater then pushing the engine forwards means a massive wheelbase, and for side-by-side 2 seater you'll end up with the occupants each side of the engine, which means it'll be a tiny cabin space?
On the RS200 the engine went in facing backwards (front pulley towards back of car) and drive went forwards to the gearbox/transfer case at the front, and then back to the diff mounted to the side of the engine
I did a similar layout in the early 90's for a comp safari (off road) racer, where the engine, a 5.0 rover v8 sat facing backwards, with the diff and halfshafts just missing the front pulley (ie reawards of the engine). The occupants were say either side of a small bellhousing that took drive forwards. The backrests of the seats were basically 5mm away from the rocket covers / back of the heads!
The AM305 V8 Vantage transmission ( a Graziano box) is gears-in-front-of-diff:
V8_Vantage_box_on_ebay
V8_Vantage_box_on_ebay
You'll need a new input shaft if you are really going to space the transaxle from the engine by 200mm. As separate adaptor shaft would be disastrous unless you can add a radial support bearing at the interface to the existing clutch shaft spline, perhaps as part of the bell housing adaptor arrangement.
Input shafts 'wind up' under torque and with an unsupported splined joint in the middle the thing will whip around and eventually fail due to bending.
What is the transaxle you are planning to use? If it is a commonly used box fro retro fitment to kit cars or race cars then there may be alternative input shafts available from the manufacturer or third party suppliers.
Chris
Input shafts 'wind up' under torque and with an unsupported splined joint in the middle the thing will whip around and eventually fail due to bending.
What is the transaxle you are planning to use? If it is a commonly used box fro retro fitment to kit cars or race cars then there may be alternative input shafts available from the manufacturer or third party suppliers.
Chris
Which Audi gearbox are you looking to use? From memory, there's a certain amount of variation in the distance from the bell housing face to the axle line on different units.
Or a rear engined gearbox flipped upside down? I've seen a few builds with people doing that for mid engine stuff with Porsche kit.
Or a rear engined gearbox flipped upside down? I've seen a few builds with people doing that for mid engine stuff with Porsche kit.
Audi 01E is the box.
So a bearing sounds like a necessity. Hacking apart a second bellhousing might be the best solution then as it has a bearing in the right place and i can use the engines OEM spec clutch, flywheel and release bearing. So in essence i would just be making a much smaller adaptor place and custom "second input shaft" to mate up between the two.
So a bearing sounds like a necessity. Hacking apart a second bellhousing might be the best solution then as it has a bearing in the right place and i can use the engines OEM spec clutch, flywheel and release bearing. So in essence i would just be making a much smaller adaptor place and custom "second input shaft" to mate up between the two.
A bearing is not a necessity.
Some sequential boxes have swappable input shafts, so what you're proposing is really not so different with an extension splined piece.
Although the cost of a custom piece like that in the first place...could well be expensive. And as a transaxle to start with, I'd imagine the OEM 01E input shaft is pretty short anyway,
Some sequential boxes have swappable input shafts, so what you're proposing is really not so different with an extension splined piece.
Although the cost of a custom piece like that in the first place...could well be expensive. And as a transaxle to start with, I'd imagine the OEM 01E input shaft is pretty short anyway,
Max_Torque said:
I'm still a bit confused tbh. You need to put in 200mm between diff and engine, but boxes with the diff behind the gears are too long, despite looking to be about, oh, 200mm longer??
Driveshaft output to BH flange between the two designs would be massively different than 200mm ?A conventional transaxle might be around 200-250mm ?
The Aston and Vette options would be more like 5-600mm ?
Exactly on the dimensions Stevie. Its a single seater replica so if the engine is mounted directly to the transaxle, it sticks out the bodywork too much to hide with minor body tweaks. Any further forward than the 200mm and it encroaches on the bulkhead.
From what i understand machining wise, its the inside spline work thats the difficult bit. My idea is get a clutch plate with correct centre spline, hack and maim then weld it to the engine side input shaft (probably seam welded then a tube sleeve welded as well??). Assuming that kind of method can be made strong enough.
From what i understand machining wise, its the inside spline work thats the difficult bit. My idea is get a clutch plate with correct centre spline, hack and maim then weld it to the engine side input shaft (probably seam welded then a tube sleeve welded as well??). Assuming that kind of method can be made strong enough.
Maybe the likes of DJM, TTV, Dave Mac etc could make you the custom input shaft spacer/extension.
I'd doubt it should be that difficult really ?
I know on some sequentials, at the front end the input shaft may have a short male spline, which then has a female splined sleeve over it and may be retained via a circlip or something. This then leaves a female socket onto which a variety of input shafts can be placed for various fitment options.
So it's definitely doable in 2 pieces, if not via one piece. But I'm sure one piece is doable too, and it will only ever have to deal with engine torque, so much less than if it was a half shaft or something.
I'd doubt it should be that difficult really ?
I know on some sequentials, at the front end the input shaft may have a short male spline, which then has a female splined sleeve over it and may be retained via a circlip or something. This then leaves a female socket onto which a variety of input shafts can be placed for various fitment options.
So it's definitely doable in 2 pieces, if not via one piece. But I'm sure one piece is doable too, and it will only ever have to deal with engine torque, so much less than if it was a half shaft or something.
Having a shaft extension made will be quite easy. As already said choose a spline to want to suit your best clutch option.
At the other end have it machined as a 'tube' with the diameter a slight interference fit to your gearbox input spline. When driven into place it should be perfectly aligned and will only need a ring of weld to provide the drive. If you make the tube deep enough you will be able to grind the weld back and remove the extension should you need to strip the 'box or replace it.
Steve
At the other end have it machined as a 'tube' with the diameter a slight interference fit to your gearbox input spline. When driven into place it should be perfectly aligned and will only need a ring of weld to provide the drive. If you make the tube deep enough you will be able to grind the weld back and remove the extension should you need to strip the 'box or replace it.
Steve
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