Conversion of Audi 4wd box to 2wd

[David W]

Has anyone taken an Audi 4wd box and converted it to 2wd.

What I am thinking of is the removal of what would normally be the output to the rear wheels in the doner car. I assume there is a front/rear diff in the box that would need to be locked up in some way so that all the drive went to the front diff.

The reason for considering this is that in the UK you can get a normal age related number plate if more than a certain amount of major components come from the same car. Also the more powerful manual box Audis are generally 4wd.

 

[wanni]

Has anyone taken an Audi 4wd box and converted it to 2wd.

What I am thinking of is the removal of what would normally be the output to the rear wheels in the doner car. I assume there is a front/rear diff in the box that would need to be locked up in some way so that all the drive went to the front diff.

The reason for considering this is that in the UK you can get a normal age related number plate if more than a certain amount of major components come from the same car. Also the more powerful manual box Audis are generally 4wd.

Correct, they are generally 4wd with a central TORSEN unit.
As you can see from the attachment ( new RS4 transmission ) there are 2 opportunities to achieve this target.
1) Is the wild way by locking the torsen unit and removing the rear wheel out put shaft.
2) Is to build an adaptive part which will be installed by removing the Torsen unit and connecting strongly the 2ary shaft with the front wheels shaft and closing with a cover the exit to the rear.
Ciao
Wanni

 

[David W]

Thanks, will these options work with the 4wd auto box used in the A8?

 

[wanni]

Thanks, will these options work with the 4wd auto box used in the A8?

They are all made in the same way.
Cheers

 

[AdrianBurton]

I have a few questions:

How much would that cost?
Who could do it?
What would that do for the strength of the trans? (how much power will it take modified?)

 

[wanni]

I have a few questions:

How much would that cost? 1)
Who could do it? 2)
What would that do for the strength of the trans? (how much power will it take modified?)

3)

1) Considere about 10-15 hours to make a reverse engineering mesurment of the parts in order to give to the designer the right inputs for the drawing which will take more or less the same time to be done with the manufacturing cycle.

2) Me, Chris, Mendeola, Hoer, Colotti, etc...etc...or if you have the possibility to have an Audi A8 2WD front wheel drive box, it shall be available out of spares, probably.

3) As I said in some other threads:
Do not consider the power but the torque. About 400-450 Nm if the car does not weight more then 1.500 Kgs and the rear tyres are reaching only agrip coefficient about 1,1. Just to give you a value which is not really understandable from everybody, it takes a maximum output torque before tyre spinning of about 4.000 Nm. This value depend from the total weight of the car, the weight on the rear axle, the position of the center of gravity, and finally from the tyre grip.
Higher the center of gravity is and higher is the weight transfer to the rear wheels in acceleration. The tyre spinning depends from the friction coefficient and from the vertical load on the tyres.
Example: total weight = 1.500 Kgs with a static distribution of 600 to the front and 900 to the rear. Due to the transfer to the rear the value of 900 might reach 1.200 which is 600 per wheel. Adding to the equation the grip coefficient, the result is the spinning torque of the vehicle.
To do this kind of calculation you need a sofisticate calculation program for dynamic vehicle performances which is not a gift, like ADAMS.
Anyway in order that there is any LSD into an Audi gearbox to the front, the fuse will be the first wheel starting the spinning.
Hope it is clear enough.
Cheers
Wanni

 

[andys]

Can you explain the reason why the AWD 01E greabox has a higher torque rating that the front drive 01E greabox?

What I extract from this is that the weakness is in the ring and pinion (or their bearings), since the AWD gearbox splits the torque between two ring and pinions (differentials) through the Torsen thus reducing the torque on each differential. Also, since the AWD gearbox has a hollow countershaft for the pinion shaft to pass through, there is no apparent weakness or weak link in this area. The front drive gearbox has a solid countershaft and pinion.

If the differential is the weak link, are there any recommended upgrades that you might suggest? Or is this asking for trouble elsewhere?

Thank you,

Andy

 

[Chris Simpson]

Hi David

You can order a new front wheel drive 01E (A8 front wheel drive) box from any UK Audi dealer - about £3000. Quaife do a LSD for that box which replaces the Audi diff and is hopefully stronger. If the conversion from 4WD to 2WD was easy and cheap I think a lot of people would have done it already. Quite a no of GT40s are using the 2WD 01E now and I have'nt heard of any problems. If you want to use the doner car registration, I think you would have to use the engine as well and probably other parts.

Hope this helps.

Chris

 

[wanni]

Can you explain the reason why the AWD 01E greabox has a higher torque rating that the front drive 01E greabox?
BECAUSE, AS I SAID IN ANOTHER THREAD, YOU SHALL CONSIDERE THE TORQUE AND NOT THE POWER. IN THIS CASE THE WHEEL SPINNING TORQUE.
BY ACCELERATING WITH A FWD YOU ARE TRANSFERING WEIGHT TO THE REAR AND HARDER YOU DO IT AND EASYER THE WHEELS WILL SPIN. WITH A 4 WD THE WHEELS WILL NOT SPIN BECAUSE PART OF THE TORQUE, TROUGH THE TORSEN WHICH WILL TRANSFER ACCORDING TO THE VERTICAL LOAD ON THE TYRES.
THIS MEANS THAT MUCH MORE TORQUE IS TAKEN FROM THE GEARBOX. MORE OR LESS ALL THE ROAD TRANSMISSION ARE CALCULATED REFERING TO THE SPINNING TORQUE.
EX: ENGINE WITH 500 Nm
2WD WILL SPIN WITH ONLY 200 Nm IN 1ST GEAR
4WD WILL NOT SPIN AT ALL.
THE FIRST GEAR WIDTH WILL BE PROBABLY 18 mm IN THE 2WD AND 24 IN THE 4WD.
CAPITO?
WANNI

What I extract from this is that the weakness is in the ring and pinion (or their bearings), since the AWD gearbox splits the torque between two ring and pinions (differentials) through the Torsen thus reducing the torque on each differential.
STATICLY WITH A 50/50 TORQUE DISTRIBUTION. DYNAMICLY THIS UNIT CAN AUTO SET IT SELF TO 30/70 IN FULL ACCELARATION AND 70/30 IN AN HARD COAST DECELERATION.
Also, since the AWD gearbox has a hollow countershaft for the pinion shaft to pass through, there is no apparent weakness or weak link in this area. The front drive gearbox has a solid countershaft and pinion.THIS SHAFT IS MADE IN A SPECIAL MATERIAL IN ORDER TO HAVE A HUGE TORSION CAPABILITY.

If the differential is the weak link, are there any recommended upgrades that you might suggest? Or is this asking for trouble elsewhere?

HONESTLY......IT COSTS 3.000 €UROS. IF YOUSHALL PAY FOR ONLY ONE GEARBOX UPGRADING YOU MIGHT EASLY SPEND 20.000 €UROS.
WHERE IS THE CONVENIENCE?
WHEN ONE IS KAPPUTT....BUY ANOTHER.

Thank you,

Andy

THE ONLY THINK POSSIBLE TO BE DONE IF YOU REALLY ARE A MANIAC IS TO USE A SUPERIOR LUBRICANT AND TO ADD AN ELECTRIC PUMP FOR OIL COOLER CIRCULATION IN ORDER TO KEEP THE OIL AT 80-90°C. THIS WILL ALLOW A THICKER FILM FOR GEAR DAMPING AND PROTECTION.
CIAO
WANNI

 

[andys]

"THE ONLY THINK POSSIBLE TO BE DONE IF YOU REALLY ARE A MANIAC IS TO USE A SUPERIOR LUBRICANT AND TO ADD AN ELECTRIC PUMP FOR OIL COOLER CIRCULATION IN ORDER TO KEEP THE OIL AT 80-90°C. THIS WILL ALLOW A THICKER FILM FOR GEAR DAMPING AND PROTECTION.
CIAO
WANNI"

Wanni,

Can you recommend a "superior lubricant" for the 01E? Also, is there any value in adding a spray to direct cooler oil to the ring gear, or should I simply circulate it from the differential to the back of the gearbox (like the A8 does)?

Thank you,
Andy
__________________

 

[Brett James-McCall]

Can some recommend where to place the oil take off and where to spray back into the box. Thanks

Brett

 

[wanni]

"THE ONLY THINK POSSIBLE TO BE DONE IF YOU REALLY ARE A MANIAC IS TO USE A SUPERIOR LUBRICANT AND TO ADD AN ELECTRIC PUMP FOR OIL COOLER CIRCULATION IN ORDER TO KEEP THE OIL AT 80-90°C. THIS WILL ALLOW A THICKER FILM FOR GEAR DAMPING AND PROTECTION.
CIAO
WANNI"

Wanni,

Can you recommend a "superior lubricant" for the 01E? Also, is there any value in adding a spray to direct cooler oil to the ring gear, or should I simply circulate it from the differential to the back of the gearbox (like the A8 does)?

Thank you,
Andy
__________________

I can not recommend it here in this thread.
Just check my web.
Well theoreticly the spray on the pinion, but in exit and not in entry, is something that would help a lot, BUT..........:
Doing that you shall make a static test first, because you are doing 2 actions which are not naturally made originally in the box:
1) You are sucking the oil from the drain plug with a flow of about 2 US gallons per minute ( by using a TILTON pump).
2) You are spraying 2 gallons per minute in a chamber where normally it does not happen.
RISK: to fill up the differential chamber and to drain completely the gearbox chamber. RESULT: ALLES KAPPUTT
SOLUTION: increase the size of the circulation holes and/or make some new holes in order to keep the internal levels at the same high.
Be carefull when you play with those things, it seams simple like playing gameboy but sometimes MURPHY is waiting the wrong step to start his favorite game.........spraying bad luck everywhere.
Ciao
Wanni

 

[andys]

I can not recommend it here in this thread.
Just check my web.
Well theoreticly the spray on the pinion, but in exit and not in entry, is something that would help a lot, BUT..........:
Doing that you shall make a static test first, because you are doing 2 actions which are not naturally made originally in the box:
1) You are sucking the oil from the drain plug with a flow of about 2 US gallons per minute ( by using a TILTON pump).
2) You are spraying 2 gallons per minute in a chamber where normally it does not happen.
RISK: to fill up the differential chamber and to drain completely the gearbox chamber. RESULT: ALLES KAPPUTT
SOLUTION: increase the size of the circulation holes and/or make some new holes in order to keep the internal levels at the same high.
Be carefull when you play with those things, it seams simple like playing gameboy but sometimes MURPHY is waiting the wrong step to start his favorite game.........spraying bad luck everywhere.
Ciao
Wanni

Wanni,

Thank you for putting things into perspective. I see now that it would be poor engineering to not perform the appropriate tests for the reasons you mention.

Perhaps a better solution would be to get an A8 differential cover with oil pump and drive gear. All the testing has already been done.

Kind regards,
Andy

 

[AdrianBurton]

Back to this again....
Sorry if I dont seem to be getting it but why cant you just repalce the diff/ torsen unit and the shafts?

It doesnt seem like it should be THAT complicated.

 

[wanni]

If it is so easy, over there,
then no problem...just do as you are saying.
Ciao
Wanni

 

[Tobias]

Buy a 01E from the breakeryard. If it becomes kaputt, then buy a new one. Buy a lsd diff from Quaife, move it form the broken box into the new.
In Sweden there is usaly a lot of FWD 01Es on the breakeryards.
I bought a used ARX for about 400 euros. How much will it cost to build a FWD from a AWD?, it would probably bee cheaper to buy a porsche box i the firstplace, then to redesign a AWD box i think..

 

[AdrianBurton]

If it is so easy, over there,
then no problem...just do as you are saying.
Ciao
Wanni

Wanni,

Who said it was easy????
You are the trans "expert" and to me your expanation of how to do it is cryptic, at best. I am by no means an expert and have not actually seen the inside of either box. But to me it seems that you SHOULD be able to replace the diff and change the tail section.

Buy a 01E from the breakeryard. If it becomes kaputt, then buy a new one. Buy a lsd diff from Quaife, move it form the broken box into the new.
In Sweden there is usaly a lot of FWD 01Es on the breakeryards.
I bought a used ARX for about 400 euros. How much will it cost to build a FWD from a AWD?, it would probably bee cheaper to buy a porsche box i the firstplace, then to redesign a AWD box i think..

Toker,

I have not had much luck in finding any 2wd 01E's perhaps you could PM me with some places to contact.

Adrian