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PostPosted: October 13, 2007, 11:13 am 
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Joined: September 2, 2007, 11:08 pm
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Location: Irving, TX
I'm still collecting info on the W196 that I want to build. So far, I've clobbered the problems of engine, transmission, brakes, wheels, tires, cooling, and basic chassis design.
At this point I've got one hang-up. It could be a biggie.
Have a look-see:

Image

I've decided to build the bottom variant using the longer wheelbase of the upper car.

I've concluded that the driveshaft will have to pass under the driver's seat and to the differential.
The original cars had a driveshaft that attached to a power take off half way down the side of the block, ran under the driver's right leg, and to a rear mounted transaxle. The input shaft on the tranny was below the right side axle and the gear box was behind the differential.

Look back at the drawing. Notice that the axle centerline is about even with the driver's waist.
Lowering the differential so the pinion is below the driver's seat would mean raising the back of the car about 6 inches. Not an option.
Raising the driver would mean sitting on top of the car instead of in the car. Not an option.

How do you magically connect the driveshaft to the rear end?

Here's the first solution I've come up with:
1) use an independant front suspension out of a small 4x4 truck. That would point the differential backwards and keep the drive force on the front face of the ring gear teeth.
2) stuff the front half of a 4x4 transfer case behind the differential.
3) run the drive shaft to the front driveshaft output of the t-case.
4) connect the transmission input shaft from the t-case to the yoke on the differential.

This would transmit same-direction rotation to the rear end and allow correct positioning of the rear axle.
Since I've got my own machine shop, adapting half a transfer case would not be overly difficult. I could make the block off plates and modify the shafts as necessary.

It's a bit of a complicated solution but the extra weight would help offset the nose-heavy V8 front engine design.


Whaddya think? Am I totally insane?


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PostPosted: October 13, 2007, 11:40 am 
Use an Olds Toronodo setup and make FWD?


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PostPosted: October 13, 2007, 11:45 am 
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Joined: August 15, 2005, 10:13 pm
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Location: Charleston, WV
How wide is this car and what rear end are you using?

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PostPosted: October 13, 2007, 12:42 pm 
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To me it looks like the driver is sitting on the driveshaft anyway. The pics make it look as if the driver is sitting pretty tall in the saddle.


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PostPosted: October 13, 2007, 1:04 pm 
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Joined: September 17, 2007, 10:36 pm
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Location: Montreal, Canada
I would agree... the driver's sat pretty high up in those days. Wouldn't surprise me at all if they sat on the diff.

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PostPosted: October 13, 2007, 1:21 pm 
Why not shorten one axle way up and have an offset rear diff? Del Long has a similar arrangement in his locost, his engine sits in the passenger footwell & the trans/driveshaft run through the passenger compartment to an offset rear end.

--JOsh


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PostPosted: October 14, 2007, 12:10 am 
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Joined: September 2, 2007, 11:08 pm
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Location: Irving, TX
Maybe this pic will clarify things.

You can see that the driver sits with open legs. The car isn't wide enough to have the driveshaft run beside the driver unless you have a driveshaft coming out the side of the engine block like the original.
Unfortunately, the original transmissions are made from Unobtanuim and I'm not even going to kid myself into thinking that I can build a manual transmission from scratch.

FWD is not an option. I plan on using a V8 engine with a dry sump oil system to buy precious hood clearance. It will be pushed forward where the inboard brakes were mounted so I can have room for the transmission.
I planned on a small diameter drive shaft passing under the driver. I can angle it slightly to either side to provide a better fit for the rear drive system.

The car pictured is a short wheelbase version with outboard brakes. You can add about eight inches to the wheelbase.


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PostPosted: October 14, 2007, 3:24 am 
FWIW the early Toronodo trans was a variant of the TH400 I believe a TH425 sized to handle a 455 in a 2 ton + car sitting alongside the engine with a seperate diff assy which is near the front of the engine.


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PostPosted: October 14, 2007, 9:08 am 
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Joined: October 14, 2007, 9:02 am
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Location: Salem, New Hampshire
feets wrote:
...I'm not even going to kid myself into thinking that I can build a manual transmission from scratch.

...


Not so fast!

With most FWD transmissions, the axels run behind the engine. So take a FWD engine/transmission, turn it sideways and use one axle to go back to an offset differential. Leave the other (now front) axel out and make a block off plate to keep the transmission oil in.

I know what your thinking: the diff in the transaxle won't allow this to work. So you'll need to lock the diff, either by fabricating a spool or just welding the spider gears.


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PostPosted: October 14, 2007, 9:44 am 
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Location: Irving, TX
god thinking. However, there's no room for a transaxle. I barely have room for the engine. I really need to run a laid down Offy or other small engine but I'm determined to run a V8.
After all, this is a race car.
A transaxle would require more room than what I've got.
If I did manage to run one to offset the driveshaft, were would it go? That would leave no room for a axle on that side. The side of the differential would be inches away from the hub. That doesn't leave any room for suspension movement.


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PostPosted: October 14, 2007, 10:23 am 
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I had some time to kill this morning so I drew this onto your pic. It probably wouldn't work. I'll let you tell me why.


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PostPosted: October 14, 2007, 1:22 pm 
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Joined: April 23, 2006, 8:26 pm
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There are quick-change differentials that have the input shaft surprising low, much lower than the output shafts. Being dry-sump, you can lower the engine for a straight shot to the diff.

I think you can get what you want with off-the-shelf parts.

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PostPosted: October 14, 2007, 1:48 pm 
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Two sets of Chain drive to the drive shaft, so you can lower the shaft to floor height?
Dale


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PostPosted: October 14, 2007, 7:39 pm 
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I know about the quick change diffs but I haven't seen an IRS version.
One reason for the dry sump was to lower the drive shaft. The other was to gain the much needed hood clearance.
As for the chain drive, that's what I was doing with the transfer case. However, the chain is always the weakest link in any chain drive system.

As for the u-joints, I've thought about that route. However, you've got to extend the pinion at least 6 inches forward of the axle to clear the ring gear. I'm willing to slip the differential back that far. Nosing teh differential down a little will help but I don't want the fluid to start pushing out the pinion seal.
The next hurdle is that the best double cardan joint I've found will operate at 32 degrees. Going steeper than that will be tough. I don't know that a FWD type axle with a CV joint will live very long at that angle under power.

I've got some feelers out to people in the race world to see what they have to say.


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PostPosted: October 15, 2007, 12:26 am 
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Location: Visalia, Ca
I've seen quick change IRS units, I'll post if I can find it again.

Rod

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