Which gearbox is lightest?

[TPR]

Hi All,
I'm just starting my space frame built from drawings supplied my Mike Osborne and am after some advice.
My car is to be built as light as possible and therefore i want the lightest gearbox. I cannot find any info on this forum that has info about the weight of the various gearboxes found in gt40's.
My initial thoughts are to go with one of the audi variants or maybe renault.
Does anyone know which the lightest boxes are?
Thanks
Tom

 

[flatchat(Chris)]

Light is good ! ---we need some more info of your intentions with this vehicle --like --- intended usage? H.Power and TorQ input then tractible devices (tyres) Diameters , widths, compounds (roadies or slicks)etc
so's we don't make 10 pages of guessing:blank:

 

[SouthernGT40]

ZFQ weighs in at 65kgs.

 

[Bram Boekestein]

016 weighs 55kgs

 

[Doug Clark]

My 012 weighed 113lb (51.4kg) packed in the cardboard box for shipping.

 

[Russ Noble]

930 60kgs and this will take all the power and torque you can throw at it.

 

[TPR]

Wow, that was a quick reply! Thanks guys.
Anyone know how much the renault and porche variants weigh??
In reply to what the car will be used for, well i'm the sad sort of person who gets just as much pleasure if not more from building the thing than than using it.
That said i expect to use it for going to the odd show, occasional track day or hill climb and possibly if it goes well enough to achive my dream of driving a GT40 to Le Mans!
At the moment i think one of the audi box's is favourite for a few reasons, but in definately still open to suggestions. I'm easy wether its five or six speed, it must have a lsd or be easy to fit a lsd into and must be geared to be capable of very high top speed.
My initial thoughts are Audi 016 with lsd and lower ratio crown wheel and pinion from Roaring Forties, while i'm at it i'll probably get the whole adaptor kit from them as well, just for ease of install etc.
Does anyone know who could do this work in the UK?
Once again thanks...
Tom

 

[JimmyMac]

ZF-2 box is 141 lbs or 64 kg (excludes bellhousing)
ZF-1 box is about the same but some versions are heavier

 

[Charlie M]

According to California Motorsports, the Porsche G50 weighs 156 lb dry.

Charlie

 

[colin artus]

Porsche 915 box is light (see Ron Earps comparo pic in his lola build thread), plus quaie do an ATB diff for it.

 

[Howard Jones]

The VW 901 boxes I think thay are called are very light. The Renault R21's are lighter than the 5 speed Audi's by a few pounds. But we really can't help you with much more without complete information about the car.

 

[Cliff Beer]

Just weighed an old 016 I have sitting in my shop - 49kg (filled with new Redline). That's without throwout bearing and slave cylinder

 

[Ron Earp]

My initial thoughts are Audi 016 with lsd and lower ratio crown wheel and pinion

I don't know, I think I'd pony up the cash for a Porsche 930 or ZF.

By the time you get knee deep in the 016, with LSD, plus the new ring and pinon you'll have a lot of money tied up in a box and it'll still be an 016. The 930 won't break, and if you need five gears the ZF is the correct box to have.

 

[Howard Jones]

I think I agree with Ron. If the idea is to build a low cost car then the Audi gearboxes are a good choice. Coupled with a moderate engine (up to 375hp) and running a open diff and street tires they will produce a nice car built to a cost effective spec.

On the other hand. If you intend to go very much beyond this then I really encourage you to check into the G50XX Porsche or other purpose built mid engine gearboxes such as the ZF's and others.

As far as weight goes most of the good gearboxes in the high end class are near enough to the same weight that it won't make much difference with the exception of the Ricardos. They really are the heavyweights.

Spending 75% of the cost of a high end gearbox on a compromise upgraded Audi doesn't make sense to me. I know I did this with a Renault R21.

In the end it's up to you. Just don't think you are going to put 500hp through a $800 gearbox and have a happy ending.

 

[Jac Mac]

Dont know what your planning on for the engine dept, but if it came to the crunch I would rather have an extra 40lb of case & gear strength in the transaxle & pay the extra for alloy block & heads to save weight if I was going in your direction. The heads alone will save close to 40lb.

 

[Mike Pass]

I agree with jac mac. When I weighed the iron versus alloy heads the difference was 44 pounds. Also you lose weight from high up whereas the gearbox weight difference is low down.
Cheers
Mike

 

[TPR]

Guys, thanks again for the info, very useful.
I can see what you saying about spending that little bit more cash and getting a proper zf or 930, it does make some sense.
I have one more question for you all, approximately how much does a reconditioned zf rbt or similar cost with all the bits needed to bolt straight onto the engine and the same for the porche 930 that has been correctly modified etc etc?
Thanks again for the help!
Tom

 

[Russ Noble]

I can't tell you dollar figures, and a lot of that comes down to the spec that you choose for your flywheel, clutch, ring gear, starter position etc. You say lightness is a big consideration. At what cost?

Once you've hunted round this forum a bit you will be able to make up your own mind how you wish to proceed. I think my car will be one of the lighter ones on here, maybe some of the info in my build thread could be relevant to you. http://www.gt40s.com/forum/gt40-build-logs/16138-kiwi-scratchbuilt.html

In another query on a couple of other threads, you asked do you build your chassis/suspension and then make the body fit or take the body and make the suspension to suit. Really, that's another decision for you to make yourself. Personally I would make everything fit inside an existing body.

Both approaches will probably lead to compromises, everything does! It's a matter of YOU deciding what you are willing to compromise and why. Bearing in mind cost compromises as well!

Good luck

 

[Jack]

Tom, I chose a 930 with LSD because of the compromise for cost, reliability and strength. The long legged 4 speed is well suited for a V-8 and will do very well for a mostly "street" car. I went a bit overboard with a gearbox oil cooler, pump and filter.
I have less than 5K in the gearbox, ready to go!

Having done a few scratchbuilts in the past, I always had the body first. At the very least, all of the body dimensions should be on hand before cutting any steel!

 

[Old Roaring Forties]

For what it's worth RF no longer do any 016 trans (haven't in RF2 days) as I read that was one of your early plans in the thread.

Not to bring up the "how strong is an 01E" again, but I think saying Audi boxs are cheap and weak is a generalisation. The point of the thread is to assist Tom with info to help him choose an approriate trans.

We have not had any issues with the 01E's - behind high hp 302's on tracks, 5.4's (with 550Nm of torque standard) and 4.6's (included Bobski's turbo'd monster)

We had assistance from Prodrive do the calcs on the O1E in our application......and we do of course change them all to a Modena LSD.

I believe the gentlemen above are warning you against 016's.