Looking for a RWD gearbox for an Audi V8?

[GTWayne]

I am thinking of trying to fit an Audi 4.2 motor into a BMW e30.
Only problem at this stage is that I have so far not been able to find a compatible RWD gearbox to use for the swap.
I know about Porsche 924/944 bellhousings being an as good as fit and the Volvo 740/940 diesel box being a direct fit along with VW LT van gearboxes etc. etc. but I am thinking more along the lines of maybe modifying a Cosworth T5 Borg Warner box via a spacer between the box and bell housing?
Just wondering if any of you out there have any thoughts or useful information pertaining to the subject that you may wish to share?

[anonymous-user]

I'd try and keep it bmw by using some flavour of Getrag box with an adaptor plate to the engine

[GTWayne]

Hadn't even thought of using a BMW 'box.
I rather fancy the T5 because it is light, strong and has a lovely snicky type shift.
I have a man that can, and will, be able to do all of the fab for me and he is surounded with Audi V8 motors so I don't even need to supply an engine at this point but a gearbox and a bell housing are the minimum parts I need to get started.
I am thinking of maybe a Volvo bell housing and am hoping that once the input shaft of the T5 is inserted via a spigot bearing in the crank that the gap between motor and 'box will be enough to accomodate the chosen bell housing and will leave a minimum gap of at least 25mm to accept a custom adapter?
Many ifs' and buts' I know but you have to start somewhere right?

[stevieturbo]

Is that a different T5 to the normal ones ?

Wouldnt say they are commonly known for being that strong or slick lol
More like average in both departments.

I'm sure the likes of an M3 or M5 box would be a better and stronger option. Although perhaps more expensive.

Some Toyota Supra Turbo boxes used to be readily available and very strong. But now the drifters are aware of them and buy them all up so they can be very expensive.

Castlemaine Rodshop or Dellow in Oz do a lot of bellhousing conversions. Dont see anything listed for Audi though

[anonymous-user]

The downside of the BMW Getrag boxes is that the bellhousing is integrated into the gear case (beause they "shorten" the box by putting some of the gearspace inside the bellhousing volume.

This means you have to use the std bellhousing with a plate style adaptor to convert to your new engine bolt pattern. (i have heard of people welding new flanges on, but i personally wouldn't recommend it for several reasons)

[Chassis 33]

Right, it is possible with almost off the shelf bits. There's a company in the States now doing RWD VAG bell housings to fit the GM style of T5 box.
However...

• It's primarily designed to run the smaller engines so the 240mm clutches from the V8 manuals don't fit
• Some V8's use 10bolt cranks/flywheels so you have to use either a custom flywheel or a VR6 228mm flywheel
• VAG clutches don't have the right splines for the Ford T5 so you have to mix and match, a case of trawling catalogues to find something suitable
• The Ford T5 (which is the most popular in the UK because of the Cosworths)is not the same mounting as the GM T5
• Some of the mounting threads are in similar locations so it's not a case of simply drilling new holes as they overlap
• The Ford T5 has a longer input shaft than the GM

Regards
Iain

[cmsapms]

If the Audi engine's out of a quattro, couldn't you use the quattro box with the centre diff welded up?

[Chassis 33]

You could but the centre diffs don't last very long, and the rear diffs don't either as they weren't designed to handle all the output from the engine.
Regards
Iain

[stevieturbo]

Chassis 33 said:

You could but the centre diffs don't last very long, and the rear diffs don't either as they weren't designed to handle all the output from the engine.
Regards
Iain

But the centre diff when welded is no longer doing it's diff duties. And the rear diff is now from another vehicle.

Only issue might be in rear output shaft strength as normally drive was split between all 4, and not just two wheels.

But it is a good suggestion.

[Chassis 33]

stevieturbo said:

But the centre diff when welded is no longer doing it's diff duties. And the rear diff is now from another vehicle.

Only issue might be in rear output shaft strength as normally drive was split between all 4, and not just two wheels.

But it is a good suggestion.

If you look thru the US forums, welding the centre diff has been tried and found lacking. Never tried it personally, I've gone for the route outlined earlier.
Regards
Iain

[Transmitter Man]

I recently imported a higher than standard torque spec T5 from the US built with the US Ford/Chevy 10-spline main shaft.

As far as the US Fords are concerned T5's were fitted behind the mid 80's through 90's 302HO (5-litre) Mustang so made to handle the torque from a V8.

Stock torque handling for the World Cup T5 I think is around 300-325 lb/ft but of course it's how you drive the car. These can be supplied to handle 500+ lb/ft.

Re bell housing I've got no answer but I found Tiger in the Netherlands for you. No T5's on their site but of course maybe worth dropping them a line: http://www.tigersportscars.nl/welkom_(e).htm

There was someone in Kent that was offering to mate any gearbox to any engine but I never made a note of their name.

Maybe someone else here recollects who they are.

Good luck.

Phil

[GTWayne]

Thanks for all of the suggestions people
I have located a T5 for the right money and after doing a bit of research have found a suitable bell housing.
If all pans out then I should have a 25mm space between the bell housing and the T5 mounting face; just enough for an ali spacer!
The T5 is still the favourite for me due mainly to size and weight (75lbs!)
The gearbox will be at its limit behind the Audi motor I know but I am no spring chicken and do have a fair bit of mechanical sympathy so I am confident that nothing too dramatic is likely to befall the situation.
Clutch next.

As we all know weight is a very important factor when modifying a vehicle for speed and agility and what with the Audi motor weighing in at little over 350lbs naked + a 75lb T5 I am confident that I will be able to keep the e30 BMW that it is going into below 1200KG's.

Let the games commence

[stevieturbo]

25mm is more than enough for an adaptor. Ive seen some adaptors as thin as 10mm. Although I'd be doing steel if it was that thin.

If you need someone to waterjet/machine an adaptor, give Ralph at www.componentengineering.co.uk a shout.

He does a lot of work for me and can get all sorts cut out and machined. He made his own adaptor to fit a Rover V8 to a fwd Rover PG1 gearbox for a mid engined conversion.

[Chassis 33]

GTWayne said:

Let the games commence

Regards
Iain

[stevieturbo]

Chassis 33 said:

Regards
Iain

That's a really tiny engine

[Chassis 33]

Perfect size for one of my diecast models
Regards
Iain

[GTWayne]

Looking good Iain
What are you intending to do with regards to a clutch pack?

[Chassis 33]

Mix and match, probably annoy technical sales at AP and Alcon.

Regards
Iain

ETA let me know how you get on, I've an e30 Touring I've fallen out of love with since around Easter time but can't bare to sell it! I've got the van Swearingen's DVD for fitting an LS engine, but not the budget as yet.

Edited by Chassis 33 on Sunday 25th September 20:46

[GTWayne]

Chassis 33 said:

ETA let me know how you get on, I've an e30 Touring I've fallen out of love with since around Easter time but can't bare to sell it! I've got the van Swearingen's DVD for fitting an LS engine, but not the budget as yet

But of course
I looked at SBC/LSX options in the first instance but just fancied something a little more sophisticated and coupled with the fact that I have some very clever Audi biased co-horts on the team + my hang up on the weight issue (not me personally you understand, I AM IN GREAT SHAPE FOR A MAN OF MY AGE THANKYOU VERY MUCH! ) it would be madness to do anything else?
I already have an e36 coupe with a BMW M60 4.0ltr V8 and that is great fun

[Transmitter Man]

Wayne,

So, fully loaded how many pounds do you save with the Audi lump?

Confucius he say "make sure the clutch destroys itself before the gearbox as new clutch cheaper than new gearbox"

Phil