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Hmmm. Why not just design the system to work like the Panamera's? Design the transfer case to work off of the TKO or other Tremec, maybe use adapter plates for various transmission choices. This way, you have almost equal length drive shafts. The only issue would be that the rear diff would be slightly off center. This keeps it all in one nice little area, and allows you to bias the power sent to the front / rear quite easily, in the center of the whole vehicle. Something to think about.
 

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Hmmm. Why not just design the system to work like the Panamera's? Design the transfer case to work off of the TKO or other Tremec, maybe use adapter plates for various transmission choices. This way, you have almost equal length drive shafts. The only issue would be that the rear diff would be slightly off center. This keeps it all in one nice little area, and allows you to bias the power sent to the front / rear quite easily, in the center of the whole vehicle. Something to think about.
Um...yeah, that's what I was saying. The problem with the Panamera setup is the same problem with ALL of them. The engine needs to be BEHIND the transmission in the GTM, but doing that the rotation needs to be reversed. The Panamera setup would work, except that the output rotation needs to be reversed...and it's EXPENSIVE to begin with. ;) My alternative would require just a little bit more thought/work(MAYBE) in the transfer case area, but would be WAY WAY cheaper and not all computer controlled.
 

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Ok, I'll take a crack at this. Use a G50 AWD transaxle, inverted as any other GTM. This give you the awd output shaft out the rear of the trans. Build a custom transfer case that would allow a forward facing driveshaft. Transfer case would also need a set of spur gears to reverse rotation back to what the Porsche had. Snake the driveshaft past all obstacles (rear halfshafts, oil pan, front belt drives etc.) & using joints, get it through the tunnel to the front diff. The weight distribution would be similar to the 996, so use the Porsche front diff. as torque splits are already worked out. You could use the vette rear hubs in the front, but I don't know if the vette rear CVs have enough angle to allow full steering lock. May have to use the Porsche hubs, axles, with custom spindle. (I believe the 911s use struts in the front, so so they wont work). Then buy Porsche wheels for the front.
Costs are the transfer case, driveshafts, bearing supports, & used Porsche front diff & axles & custom spindles.
 

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Too much is just enough.
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You'd just have to know which way your gears are turning. It's pretty easy to change the direction of rotation using gears.
 

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Ok, I'll take a crack at this. Use a G50 AWD transaxle, inverted as any other GTM. This give you the awd output shaft out the rear of the trans. Build a custom transfer case that would allow a forward facing driveshaft. Transfer case would also need a set of spur gears to reverse rotation back to what the Porsche had. Snake the driveshaft past all obstacles (rear halfshafts, oil pan, front belt drives etc.) & using joints, get it through the tunnel to the front diff. The weight distribution would be similar to the 996, so use the Porsche front diff. as torque splits are already worked out. You could use the vette rear hubs in the front, but I don't know if the vette rear CVs have enough angle to allow full steering lock. May have to use the Porsche hubs, axles, with custom spindle. (I believe the 911s use struts in the front, so so they wont work). Then buy Porsche wheels for the front.
Costs are the transfer case, driveshafts, bearing supports, & used Porsche front diff & axles & custom spindles.
That's roughly the idea I had, except use a RWD transaxle and design a transfer case to work off of the axle. Both methods involve a long driveshaft along the bottom of the engine. Using a setup that has 2 driveshafts of almost equal length has a better power distribution.
 

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Ted, like I said, my adaptors put 930 CVs on the outers by the spindles/uprights. This makes it so that ALL the CV joints on the car will be 930 joints. The only issue on the fronts concerning steering is that the upright axis must match the CV axis. This should be easy enough to adjust for with a JCHRacer type conversion if need be. 930 CVs go better than 22 degrees in each direction before bind, so that should be plenty of steering angle.

Again, the problem with using a trans where the output sticks out the back is going to be the length of the driveshaft for the front. The other suggestion gives improved weight distribution and better drive shaft lengths. Also really nice transmissions can be had for half the cost of a G50. :)
 

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Crash, when a vehicle is driving forwards, what is the direction of rotation for the driveshaft? I want to say counter clockwise.
 

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I just drew up a sketch of the design I am talking about. I'll scan it in when I get home and post it up. :)
 

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Crash, when a vehicle is driving forwards, what is the direction of rotation for the driveshaft? I want to say counter clockwise.
I'll check a trans when I get to the shop, but I know for a fact that engine rotation, as view from the front of the engine(timing chain side) is clockwise.
 

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WOW!!

Trying to not sound concieted, but I just had another stroke of genious hit me!

We don't even need a special transfer case! Just flip over the front and rear diff housings!!

Alright! Now the cost and complexity has come down EVEN MORE!!

Off the shelf diffs, transfer case, uprights, CVs, axles. The only thing really needed is going to be custom length drive shafts!! And maybe a mixed set in the rear shafts for the offset rear diff.

Really, I think this could be achieved for just a few thousand $$$! :)
 

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Crash, off the shelf parts from what platform? Subi? Porsche? Toyota? I think the platform here makes the world of a difference.
 

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You know, I'm actually mildly excited about this. If anyone is serious about this thing I think I might enjoy helping put something together. The car may end up a single seater since the driveshaft/transfer case may end up leaving virtually no room for the passanger seat, but it would still be way cool to have an AWD GTM. :)
 

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ANY OF THEM!!

As funny as this may sound, an automatic driveline out of an SUV may be just the thing. The Jeep Quadra Trac drivelines are already set up for AWD on the street with a clutch system to bias against front diff usage. They are relatively light, and handle being bolted up to a V8 already. Combine that with Toyota diff housing because they have been around FOREVER and can be had cheap in the yards, and you should be pretty good to go. Yeah it would be an automatic, but that solves another issue, which is the shift linkage part. These automatics are all switch and cable shifted. Could also do it with the Toyota engine/trans too. There are plenty of those packages in the yards, and 300+ is EASILY achieved out of those V8s.
 

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Why not just specify a WRX platform from the get go? They do manual AWD systems, already designed for car uses, and those cars often see 300+ hp in a rally car. Not to mention that your gears aren't built around a truck. How many wrecked AWD Subis are out there? Tens of thousands I'd say. The only question I'd have is, can you put a LS and Subi trans together?

Look what I found! But the guy yanked the AWD and put in a T-56.
http://www.lsxtv.com/forum/ls-powered-subaru-wrx-1592.html
 

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The one issue I see with the Subie is that it is wide and low, as far as the engine. If you stuck with the Subie engine, this would make the rear diff somewhat of a challange as it would have to be WAY to one side. Possible to overcome this with an opposite side extension tube, but for suspensions sake, it would be better to have the diff mounted as close to the center as possible. V8 would work well in this regard. I haven't gotten into the Subie diff housing situation before so I don't even know what they look like. I know the Toyota's are a little hefty, but STRONG. Either way, so long as the diff housings can be inverted, it will work.

Just because it comes from a "truck" these days doesn't mean it's not sofisticated, and the benefits are that it is readily available and relatively cheap.

I see you modified your post, so you weren't thinking about keeping the Subie engine, but rather using the LS. That's good. That's the main issue I can see off the top of my head.
 

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Crash, my issue with it coming from a truck is that the gears and engine is set up for a truck. Trucks are more for hauling, so more torque than horsepower. In this case, you'd have to rebuild the engine and probably try to swap out the gears in a truck. You don't need the tall gears that are usually used in a truck. The only truck I'd see passing for a suitable donor would be a TRD Tundra.
 

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Crash, my issue with it coming from a truck is that the gears and engine is set up for a truck. Trucks are more for hauling, so more torque than horsepower. In this case, you'd have to rebuild the engine and probably try to swap out the gears in a truck. You don't need the tall gears that are usually used in a truck. The only truck I'd see passing for a suitable donor would be a TRD Tundra.
Tall gears+light car+lots of torque+All Wheel Drive=TO MUCH FUN!!!

I want to say that the stock tires on my Jeep are 31s? and a 27 inch tire can easily be fit to the GTM with slight mods. I really don't think that the gearing would be that far off, and if you don't know, pretty much any gear ratio you could want is available for the Toyota truck center diffs because of the rock crawling stuff. You MAY have to do a gear change, but I guarantee you that there are more gear sets available for Toyota truck diffs than for Subie diffs. :)
 

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I wonder what Dave would think? :001_smile:

You shoehorned what into a GTM? A truck?

So, now that you have this awesome and cheap idea about how to go off roading in a GTM, when will we see it happen? It would be a fun build thread. :D
 
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