AWD mid mount 6 reverse & 1 fwd gear how to fix???

[Jonesy_SA]

Hi all started this topic here (https://www.pro-touring.com/forum/showthread.php?p=410529) but felt it was better suited seperate. However in that thread i just discussed transcases to mount to a t56 that would handle 500-600hp.

Im in australlia so excuse my lack of knowlege. I chose the t56 as it seemed like a strong box relatively cheap, i still need to find a Transfer Case that can handle 500-600 hp. If anyone has a better combination please speak up!

Another issue (and main issue) i have is drive direction. This set up is for kitcar chassis with the engine mid mounted. Transaxles are to dear and dont offer the versatility i want in this AWD set up. I contemplated mounting the trans case to the end of the transmission and the diff directly to that but this would be a very long set up and place the engine to far forward (if anyone dissagrees please let me know, i dont have any measurments or seen to many trans like these as i live in Australia and our 2nd market for such parts is very low)
If i modify the chassis i could still have mid mount, but spin the engine around so the the trans runs through a trans tunnel between the seats. ie back to front of how cars are made. If i then added a transcase and associated hardware it would work fine, appart from 6reverse and 1 forward as the engine and trans are in back to front.
I seen a guy use a V-drive like off a speed boat but im not keen on this 1 bit at all, and that many transfer boxes and associated weight would ofset the point of it all.
If i somehow referse the output of the gearbox then my wheels will turn in the right direction and thus i will have 6drive and 1 reverse, BUT my transfer case would split the torque incorrectly (remeber its back to front as well) so i would end up with a torque split of say 65% front - 35 rear.
I have never pulled appart the diffs of AWD cars but how would i go swapping the front and rear diffs?
Also is there any design of transfer case that changes the direction of spin (maybe some manufacturer built a trans thats out put spins opposite to the norm or the diffs so it required a transcase that changed the direction of rotation)?
Anythoughts would be greatly appreciated.
Thanks
jonesy

[terryr]

The rotation can be fixed by mounting both diffs upside down. Now the tires spin on the ground the opposite way.

Torque split is something built in , but depending on the case maybe the inside diff can be turned around. Syclone/Typhoon sites may know.

[Restomod]

The only thing I can come up with would be to dump the T-56 and get a Porsche 911 C4 AWD trans and use it. Most replica builders use Porsche trans anyway so adapters are no problem. What are you building that has to be AWD anyway?????

[Jonesy_SA]

You know, i considered flipping the diffs but everytime i pictured it in my mind the ring and pion were spining in reverse, which as we know is noisy and not strong? I drew a little picture and roated it 180deg's and it confirms that the ring and pinion would be running in reverse.
I would like one of the Audi or Porsche AWD trans but am unaware of any that can handle the power and torque and that is cheap. By cheap in my case i need to consider the cost of rear diff, trans case and other items that would not be nessisary with AWD transaxle vs a more expensive awd transaxle. It still seems cheaper though as i was told a good trans axle that can handle this power is atleast 12-25k. A T56 is strong and aftermarket gearsets only improve it.
how much power and torque could one of those Porsche trans handle and how much for a good one on the second hand market (remebering i woulkd also need the front diff and possibly drive shafts for splines etc)?
At this stage the body is not confirmed but there is a few australian cars that would really haul in this combination. It will be on a sace frame chassis with donor vehicle body work over the top. However i just havnt selected the tin work yet. I like to be different and cause myself stress while trying to keep costs dowm. Yes i attempt the impossible :-)

[Restomod]

Sounds like you have yourself painted in a corner....nothing about the Porsche trans is cheap (about $5k)!!! The only AWD stuff I can think of that was a in a high HP car would be Lambo stuff (real big $$$$$$$$$) but the clutches are weak and even more $$$$$$$$..............

[Bruning Auto Design]

maybe I missed it, but what axles are you using?

Mid engine rock crawlers/moon buggies often use Ford 9" diffs that are mounted upside down.

Pirate4x4.com is a good source of information.

[Tiger]

What about looking for some Audi RS6 or S8 stuff, I dont know how much they will handle but they are quite strong.

[Jonesy_SA]

I found a Lamborghini trans and front diff which was around 30k however there is a ton of engineering to get the engine to mate up as i believe the V12 sits on top of the trans and not quite sure how its all connected and these parts were separate again. (i would say the clutch is made weak so owners blow up the clutch before the trans, AWD and that much power, something has to give if you do enough stationary starts).
I found an Audi S8 and box for sale although a trip tronic box, it looked ideal, however from memory it had separate diffs (not sold with package) and thus i would need to modify the trans to get the torque split correct and somehow change rotation again so i figured i was back in the same boat.
I haven’t chosen my diffs but something strong and mates well with the trans. i haven’t done any research but any independent suspension diff that meets these requirements would be fine.
For argument sake lets say Corvette C4 or C5 to keep with the other mechanical donor vehicle. If i flip this diff, what issues will i have??? I’ve pulled open a few diffs and noticed the ring and pinion gears are cuts on angles, i assumed the angles provided greater strength, or surface area or something and thus designed to have most speed/rpm/torque (i add speed here as plenty of vehicles have put tremendous loads through the diff in reverse where as i have never seen it done at 100mph) put through in drive i.e. spinning in the direction that equates to forward motion. I have not looked at any of the other gears such as planetary gears/spider gears etc to see what spinning under load at high speeds in reverse would equate to.
Let me clarify this was my own belief, please disprove me for the sake of this project. Also as stated there is always a loud whine in reverse which i assumed was produced from the diff (I’ve noticed this in many cars).
I’m not familiar with Rock crawlers or what’s done with their diffs. I must admit i never did hear of them flipping the diffs over, i have only seen them use front and rear diffs in their normal locations the right way up. Do they modify the crown and pinion of diff centre at all, why do they flip them over to start with? If they do flip them and don’t replace the centres to suite then I wonder how noisy they are and how they would cope at high speed (rock crawlers are slow but yes lots of torque!)


HOWEVER, what about current AWD and 4X4 vehicles that uses separate front and rear diffs (not a transaxle with diff built in). I have created a image to help with this thread and further explanations from forum members and explain myself offcourse ;-p


From my image you can see that 4x4 and AWD vehicles either:
A – share a common differential (diff centre, gearing drown and pinion etc)
B- use two different sets of gears from front and rear due to the spinning of drive shafts in forward.

The good news is, as far as I can see it means I could possibly flip my chosen diffs over and achieve my 6 forward gears, or find a AWD vehicle with strong diffs and hope to god the gearing is around what I need…..
A easy answer to this question is if anyone has a 4x4 Workshop manual or front and rear diffs centres, either compare diffs or open the manual to both diffs and compare the centres, crown, pinion, spider gears etc and see what the answer is, can anyone do this?
Now, no doubt I have missed something so please tell me all the problems with my drawing and conclusions?????

[dannyho]

I'm pretty sure they they make reverse rotation ring and pinions so that you can flip them over without a problem, or better yet it's likely that your front diff spins opposite the rear diff and maybe you can switch them? I'm not sure about this, it's just a thought

[4OfaKind]

Give the guys at Quaife America a call. They already built a pure race version of what you are trying to do.

https://static1.pt-content.com/images/noimg.gifhttps://static1.pt-content.com/images/noimg.gif


Here are the Specs:

Quaife R4 GTS

Engine Ford Aluminum V8 6.0 litres
600bhp at 7500rpm
550 ft lbs. torque
Chassis Tig welded, multi tubular space frame
Gearbox QUAIFE 6 speed 4 wheel drive sequential, magnesium casing
Suspension
(front & rear) QUAIFE twin wishbone, push rod, in-board suspension with double adjustment Koni, vented magnesium alloy housing, incorporating a one-piece drive hub running on Timken taper roller bearings with internally mounted drive/steer joint
Steering Rack QUAIFE high ratio rack and pinion (2:1)
Wheels
(front & rear) Techno Magnesium 11" x 18" centre lock
Brakes
(front & rear) 6 - pot AP racing calipers
360mm diameter carbon discs
Dimensions Length 180" (15ft)
Width 74"
Height 44"
Wheelbase 103"
Weight 1150kg (total)




They may be able to point you in the right direction,

Mal

[Restomod]

Well there is is.......good luck getin that on the cheap though.......
I think you can save yourself a lot of $$ and a lot of headaches if you go just rwd. It gets simple and cheaper then.......

[calforniacuda]

What do you think about how the Skyline/GTR accomplished the stated goal? By the way, it requires an irs.

[EPYON]

That car sounds hot . Is it really for sale ?