UN1 Gearbox

[Robatr0n]

Wonder if you guys could help me. I have a car project in mind (and have done for some time!) but I'm actually now going to take the effort to sit down and cost the project up and see if it's a runner.

I need to find a gearbox that fits to a Subaru EJ20 Turbo engine and can handle the power/torque. Now, this in itself isn't going to be a tremendous problem but I don't want to chuck stupid amounts of money at a gearbox (Porsche G50 'box for example) so this is where it gets difficult...

I've done a fair amount of googling and the only cost effective and robust gearbox I keep finding is the Renault UN1 gearbox. I believe that there are companies that make adapter kits for fitting this type of gearbox to a 4 cylinder boxer engine which is a bonus but I wouldn't know where to start looking for the UN1 gearbox, I don't know what a fair price is for one and I certainly don't know how much they weigh.

Can anyone shed some light? Alternatively, please feel free to suggest another gearbox which I may have overlooked.

[seansverige]

Stupid question but why do you need the gearbox - and what layout, mid-rear? From your reference to the G50 can we assume it'll be used for 2WD only? If so, my first stop would be the SDR Storm website to check out the solution they used.

[Robatr0n]

The idea is to stick the EJ20T into the back of a Hillman Imp. Originally, I thought the only way of doing this would be to have a mid-engine layout driving the rear wheels but I've been reliably informed that the Subaru lump will actually fit in place of the original engine, i.e. in the back.

The Imp gearbox will be nowhere near capable of handling the power and the Subaru gearbox is quite a lump and would not make for an easy fit.

[seansverige]

Just a thought.... sounds like it'll be tight fit whichever box is used

[Davi]

any reason you can't just use the scooby box? I'm not entirely sure but I *think* you can swop the gear in the diff so it will give the correct amount of forward and reverse gears - you can get 2wd varients or adaptors to block off the 4wd which shortens it considerably too.

[thescamper]

Both the Scooby and UN1 boxes are only really suitable for a North south engine installation. The UN1 box I believe is a reno box from either the 20, 25 or 30 and Lotus Esprit so quite old now. Another north south box which can be used with a scooby lump is the beetle box.

Edited by thescamper on Thursday 27th May 15:34

[Robatr0n]

You're correct, the UN1 box was used in some variants of the 21 and 25 and apparently used for all the V6 Turbo engines (including the Esprit).

I have heard that a beetle box would fit but I wasn't sure if it could handle the power or if the gear ratios would suit.

[GTRCLIVE]

There's a Ariel Atom looking Kit car that sell a 2WD conversion for a Scooby box. Cant remember which kit it was but it was at the 2009 Kit Car Show.

[yazza54]

You can use the scooby box by blanking the drive off to the rear diff

[slomax]

GTRCLIVE said:

There's a Ariel Atom looking Kit car that sell a 2WD conversion for a Scooby box. Cant remember which kit it was but it was at the 2009 Kit Car Show.

SDR V-Storm

[singlecoil]

One thing you will need to bear in mind with your gearbox choice is the height of the engine. This is because the input shaft to the gearbox has to pass either above or below the differential. When you use a n/s gearbox the correct way round usually the input shaft will be above. It's when you turn the gearbox upside down (eg Porsche gearbox used in an Ultima) the shaft will end up below, and that can make the engine 150 or more mm lower than if it's above. Might be important.

[MKnight702]

If you want a modern cheap transaxle thats loads cheaper than the Porsche, what about all the Audi ones? Exclude any Quattro and TT but the rest should all be suitable. I know that the 6 speed one from a TDI will take the torque from an Audi V8 as there is a chap on the VEMS forum that has done a fantastic conversion on a Lotus Esprit, do a Google for Hilly Audi V8 Esprit and gasp at the craftmanship.

[yazza54]

Don't need another box! Use the Subaru one.

[singlecoil]

MKnight702 said:

If you want a modern cheap transaxle thats loads cheaper than the Porsche, what about all the Audi ones? Exclude any Quattro and TT but the rest should all be suitable. I know that the 6 speed one from a TDI will take the torque from an Audi V8 as there is a chap on the VEMS forum that has done a fantastic conversion on a Lotus Esprit, do a Google for Hilly Audi V8 Esprit and gasp at the craftmanship.

Are the Audi boxes OK to run upside down?

[Huff]

Old Beetle gearbox out of a 1303S for example?

I'm not entirely joking - does what you want, proper compact transxle that can handle 200Hp+ reliably, only 4speed though some 5-speed conversions around. Cheap. Allows direction of rotation to be swapped if needed by handing the diff side covers. Very , very simple direct rod change.

Might get you started anyway.

[MKnight702]

singlecoil said:

Are the Audi boxes OK to run upside down?

I don't know. However, if you are doing mid engine, ie engine ahead of gearbox rather than rear engine ie gearbox ahead of engine the Audi box should be fine the right way up. (An Audi gearbox was used in the Porsche 944 IIRC)

[singlecoil]

MKnight702 said:

singlecoil said:

Are the Audi boxes OK to run upside down?

I don't know. However, if you are doing mid engine, ie engine ahead of gearbox rather than rear engine ie gearbox ahead of engine the Audi box should be fine the right way up. (An Audi gearbox was used in the Porsche 944 IIRC)

Absolutely, but the OP has already said he wants to put the engine at the back.

[Toilet Duck]

Sorry for the slight derail, but why is the Impreza turbo lump not used in 7 type kit cars? I would have thought that a boxer engine would be ideal as (if I'm correct in believing) it is very compact and not tall, unlike an S2000 engine for example, so you won't have issues with the sump scrapping the road etc. They are easily tuneable and in abundance at scrap yards etc. Circa 300bhp bog standard for some of the models, and if you can modify the diff to make it RWD instead of AWD it sounds perfect.

[andygtt]

my friend has a un1 box for sale... was going to use it in his Minator but ended up with a 450+bhp monster V8 so upgraded to a porsche unit

[slomax]

Toilet Duck said:

Sorry for the slight derail, but why is the Impreza turbo lump not used in 7 type kit cars? I would have thought that a boxer engine would be ideal as (if I'm correct in believing) it is very compact and not tall, unlike an S2000 engine for example, so you won't have issues with the sump scrapping the road etc. They are easily tuneable and in abundance at scrap yards etc. Circa 300bhp bog standard for some of the models, and if you can modify the diff to make it RWD instead of AWD it sounds perfect.

The engine itself is probably too wide. My Lomax uses a citroen 2CV engine and the rocker covers stick out the sides and thats only a very small engine compared with the Subaru unit. You stuggle fitting the width of a V8 in a so the chances of fitting a boxer in is very slim.