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Old 11-03-2008, 10:40 AM   #85
Scooby Specialist
Member#: 110304
Join Date: Mar 2006
Location: Crestline, CA
2004 Volvo S60R
No more Subie


Originally Posted by BAC5.2 View Post
Fair enough. I didn't doubt you knew the shortcomings, and I think it's a pretty cool thing to actually build a rig to test. Have you considered adding bracing to simulate the trans being bolted to an engine block? That might bring to light different locations of problems.

Do you think the bracing will help with the issue of wheel-hop-induced-case-breakage (where the front diff actually jumps and cracks the case around the output stubs/sockets)?

Now THAT would be a cool test to perform to actually find out. Do you have anything that would allow you to do that?
If you look back through the thread, there are 2 seperate braces I'm developing. The bigger one goes on the passenger side and resists torsional flex that spreads back from the area around the pinion bearing. The other brace is on the driver's side and supports the the diff housing area behind the ring gear. The diff housing brace reduced measured flex on the driver's side of the diff housing significantly both at 230 and 300 ft./lbs. (on the order of 50% IIRC with measurements taken exactly where xdrain's transmission cracked from wheel hop). So short answer. My data suggests that these braces will help. You can look back through the thread where I've posted exact figures.

Yeah, I'd love to put together a rig that's less limited. Bolting the thing to an engine block and using much more beefy material for the rig itself would probably yield results that are closer to real world driving. I'd also have to find some way to provide resistance to the shafts that equals what I'd find in a 3,000lb. Impreza and actually run the engine with a functioning clutch assembly to see just how much the case reacts to torque as metered through the clutch. At this point I'd start getting into the realm of testing at the same level as an auto manufacturer with a fortune 500 R&D budget. Basically, I knew I had a shoestring budget as far as the big picture was concerned so I focused on getting a before and after data set where all other variables would be the same.
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Last edited by jhargis; 11-03-2008 at 10:55 AM.
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