Transmission/transaxle question... Mid engine AWD...

Trying to figure out how to do this setup on a budget. Can you flip the ring gear on an Eclipse or EVO transaxle like you can on a Porsche in order to make it reverse rotation?

Modded Impreza/Legacy box. FF is using this on their new 818. The STi box can handle big torque but is harder to mod into this configuration.

Edit: D'oh missed the AWD....thinking....

You're on the right track, if you can get a lateral transaxle with built-in transfer case and flip the ring gear on the front wheel output and the rear axle and install the whole thing backwards that could work. The question is which boxes can handle this.

Cut the belhousing off the trans. Turn the drive line upside down. Weld the belhousing back on.

Setup under budget!!

GVX19 wrote: Cut the belhousing off the trans. Turn the drive line upside down. Weld the belhousing back on. Setup under budget!!

Woudn't this create serious lubrication problems?

In reply to GameboyRMH:

okay you got me. you will have to move the vent ports. you would not be able to tow it flat. but I dont see any other broblems.

I believe the Kennedy Engineering folks have adapters for using the most common (915?) Porsche transaxle both right side up and upside down. Not sure whether that's a peculiarity of that trans or whether most could be run upside down. I figure like GVX19 is saying, it may need vent ports moved, and you wouldn't be able to drain and refill with it installed. Figure you may need to change the amount of oil so that things are appropriately bathed, too...

EDIT: Obviously this particular transaxle is of no use to the OP.

Ok, so I'm thinking either doing it this way, or turning the whole drivetrain sideways and using a front and rear diff. Doing this though, you're going to multiply the diff ratio. In otherwords, use a FWD only setup, turn it sideways and use the transaxle as a center diff with both front and rear diffs and associated driveshafts. Seen this done on rock crawlers, but they didn't care about a 5.13:1 final drive ratio. I do. What say you in this instance?

Bravada center diff/ transfer case, with drivetrain turned 180 degrees.

Run the former front diff in the rear, with the axle running or through oil pan.

Run the former rear diff in the front.

Flip both to get proper rotation.

I've contemplated doing the FWD-turned-sideways thing. I worry about offset weight, and about finding a diff which will behave correctly with respect to torque distribution.

I did a little googling for what uses a Quaife/Torsen type center differential but biases toward the rear, but I don't recall finding a ton of info. I'm concerned that getting this part right may break the "low-buck" aspect...

I've also thought about using an Impreza drivetrain, moved to the rear, and then using a transfer case type chain box to run a driveshaft back to the front from the original rear drive output. Kind of a bummer the driveshaft would be long, but I think it could work. The hardest part I think would be figuring out the least-bad place to send the shaft forward past the trans and engine...

Conquest351 wrote: Ok, so I'm thinking either doing it this way, or turning the whole drivetrain sideways and using a front and rear diff. Doing this though, you're going to multiply the diff ratio. In otherwords, use a FWD only setup, turn it sideways and use the transaxle as a center diff with both front and rear diffs and associated driveshafts. Seen this done on rock crawlers, but they didn't care about a 5.13:1 final drive ratio. I do. What say you in this instance?

You'll need to find a way to get 1:1 differentials or run gear reduction units (in reverse) on the axles. That doesn't sound like a cheap or lightweight solution.

turboswede wrote: Bravada center diff/ transfer case, with drivetrain turned 180 degrees. Run the former front diff in the rear, with the axle running or through oil pan. Run the former rear diff in the front. Flip both to get proper rotation.

I like your thinking. This would also help the offset weight with that thing hanging off the side. I'm sure you wouldn't have to run the driveshaft through the oil pan, just off to the other side if you clocked it the other way. Oh wait... If you have it turned so it does run through the oil pan, then you have it all in one center mass... Ok I see what you're talking about. Probably might as well just convert the engine to dry sump and get rid of most of the oil pan.

Conquest351 wrote:

turboswede wrote: Bravada center diff/ transfer case, with drivetrain turned 180 degrees. Run the former front diff in the rear, with the axle running or through oil pan. Run the former rear diff in the front. Flip both to get proper rotation.

I like your thinking. This would also help the offset weight with that thing hanging off the side. I'm sure you wouldn't have to run the driveshaft through the oil pan, just off to the other side if you clocked it the other way. Oh wait... If you have it turned so it does run through the oil pan, then you have it all in one center mass... Ok I see what you're talking about. Probably might as well just convert the engine to dry sump and get rid of most of the oil pan.

Yep. I think you could probably get away without a dry sump motor since you'll probably want the rear axle center line around the rear most cylinder, this should allow a rear sump oil pan, pretty much like a stock Bravada/4WD S-10. The only question is whether you can get a decent 5-speed to go with that transfer case.

If it wasn't for the challenge in getting the rear output routed to the front, I'd consider trying to use an 016 Audi Quattro transaxle. The rear output can be locked on or off, etc. Mounted in the rear, aka Porsche 924/944 style, you'd have to hang a transfer case off the rear output and run it ALLLLLLL the way to the front, a good place to look at leveraging a torque tube. This would require a lot of machine work and test fitting and the entire drivetrain would need to be mounted solidly or within the same range of movement to reduce the chances of it twisting itself apart.

Surprised no ones suggested it yet. Diablo trans. Should be available in junkyards.

I've looked at a few of the FWD AWD type units and they all don't appear to have the rear output fliped to front. Can't reverse rotation on these easily. I've not looked at a VW haldex type or a Honda unit. They may be easier.

I've thought about using a chain to just run a driveshaft forward off of the existing rear driveshaft beneath the oilpan. I'd love to do this with a Justy drivetrain for the Subaru 360 but it just doesn't look like it will work.

the Bravada type AWD system is probably the "easiest" but also heaviest.

turboswede wrote: If it wasn't for the challenge in getting the rear output routed to the front, I'd consider trying to use an 016 Audi Quattro transaxle. The rear output can be locked on or off, etc. Mounted in the rear, aka Porsche 924/944 style, you'd have to hang a transfer case off the rear output and run it ALLLLLLL the way to the front, a good place to look at leveraging a torque tube. This would require a lot of machine work and test fitting and the entire drivetrain would need to be mounted solidly or within the same range of movement to reduce the chances of it twisting itself apart.

The current generation Nissan GT-R is set up that way. Pretty complicated stuff. Quite cool though.

turboswede wrote:

Conquest351 wrote:

turboswede wrote: Bravada center diff/ transfer case, with drivetrain turned 180 degrees. Run the former front diff in the rear, with the axle running or through oil pan. Run the former rear diff in the front. Flip both to get proper rotation.

I like your thinking. This would also help the offset weight with that thing hanging off the side. I'm sure you wouldn't have to run the driveshaft through the oil pan, just off to the other side if you clocked it the other way. Oh wait... If you have it turned so it does run through the oil pan, then you have it all in one center mass... Ok I see what you're talking about. Probably might as well just convert the engine to dry sump and get rid of most of the oil pan.

Yep. I think you could probably get away without a dry sump motor since you'll probably want the rear axle center line around the rear most cylinder, this should allow a rear sump oil pan, pretty much like a stock Bravada/4WD S-10. The only question is whether you can get a decent 5-speed to go with that transfer case. If it wasn't for the challenge in getting the rear output routed to the front, I'd consider trying to use an 016 Audi Quattro transaxle. The rear output can be locked on or off, etc. Mounted in the rear, aka Porsche 924/944 style, you'd have to hang a transfer case off the rear output and run it ALLLLLLL the way to the front, a good place to look at leveraging a torque tube. This would require a lot of machine work and test fitting and the entire drivetrain would need to be mounted solidly or within the same range of movement to reduce the chances of it twisting itself apart.

I was planning on a solid mount for the whole system. Torque tube rather than driveshaft for the front, if that's possible. Otherwise just a long driveshaft. The vehicle itself won't be too long anyway. Probably be a custom tube chassis deal. Who knows... Maybe a Ford RS200 Kit car...

The early 79/80 924 turbo has steel a torque tube with a standard spline (Shared with Chrysler, etc) shaft. The tube itself is steel and easily welded (commonly done with V8 swaps to shorten it, etc) The 79-80 non-turbo units have the same torque tube, but the shaft and bearings are different and not very useful.

The later Audi-based tubes are a bit of a PITA as they have a bell housing cast onto the end to match the Audi transaxle (same basic unit as used in early FWD Audi's, just without the extra parts for the Quattro, case is the mostly the same) They are more plentiful and if you're planning on shortening it considerably, then it wouldn't be impossible to cut the offending end off and weld on the appropriate pieces.

Are you looking for typical mid engine, rear engine, somewhere between front and rear axle engine?

[ ]-----------[ ]
{}---E D I---{}
[ ]-----------[ ]

Like dat e = engine d = driver I----- = steering wheel. LOL

Oiling concerns with a flipped trans are easily solved by building a dry sump transmission with oil squirters everywhere for all of the gears and bearings.

http://www.quaife.co.uk/shop/products/qbe87g

The good folks at Quaife make a few different types. Most are for front engine applications like this one, but they are sequential and have relocatable shifters. Cost of entry is pretty steep though.

former520 wrote: http://www.quaife.co.uk/shop/products/qbe87g The good folks at Quaife make a few different types. Most are for front engine applications like this one, but they are sequential and have relocatable shifters. Cost of entry is pretty steep though.

Yeah, that's the thing. LOL Quaife makes fantastic stuff, but it's a little rich for my blood. I was looking for something more along the lines of, "take this transmission, this transfer case, and these differentials and put them all together with custom driveshafts and you're in business!" LOL

I have no idea what I am talking about.

Could someone theoretically make "reverse" camshafts and use aftermarket programmable EFI to run and entire engine and transmission backwards?

IE, the engine spins CCW instead of CW and since the transmission is flipped 180 degrees and is running backwards it is now going forwards?

Is there more to making an engine run reverse rotation?

TreoWayne wrote: I have no idea what I am talking about. Could someone theoretically make "reverse" camshafts and use aftermarket programmable EFI to run and entire engine and transmission backwards? IE, the engine spins CCW instead of CW and since the transmission is flipped 180 degrees and is running backwards it is now going forwards? Is there more to making an engine run reverse rotation?

May be easier to get a reverse rotation gearset made. LOL

In reply to TreoWayne:

I know that they do that with boat motors. Or they used to, I assume they still do.

I think the main issues would be:

Starter

Engine-driven pumps

Helical distributor drive

Helical gears in the drivetrain