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Old 04-21-2005, 03:40 PM   #31
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The diff height issue is not as bad as it sounds, so long as you don't allow for too large of a spur.

The Corally for example had the diff sitting about what would be the middle setting on the fk05 or about the same as the xxx-S. The real problems with the direct rear drive system are results show in the form of poor and limited gearings options along with a push that increases with grip. The high rear weight bias created by moving the motor further back along with the greater and faster power transfer to the rear resulting from the lag and power loss through the drive belt will create a situation where car's grip will increase much faster in the rear of the car than the front.

The theory of decreased throttle lag and drag through a reduction in belts without increased tension is sound but in practice the resulting weight distribution required generates handling deficiencies that more than offset the gains made in the drive train.

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Old 04-21-2005, 03:47 PM   #32
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Quote:
Originally posted by mtveten
The diff height issue is not as bad as it sounds, so long as you don't allow for too large of a spur.

The Corally for example had the diff sitting about what would be the middle setting on the fk05 or about the same as the xxx-S. The real problems with the direct rear drive system are results show in the form of poor and limited gearings options along with a push that increases with grip. The high rear weight bias created by moving the motor further back along with the greater and faster power transfer to the rear resulting from the lag and power loss through the drive belt will create a situation where car's grip will increase much faster in the rear of the car than the front.

The theory of decreased throttle lag and drag through a reduction in belts without increased tension is sound but in practice the resulting weight distribution required generates handling deficiencies that more than offset the gains made in the drive train.

Mark
You make interesting points, but aren't these problems universal?
Meaning, don't they have these problems now in 12th and 10th pan?
What would be the difference in a TC having them?
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Old 04-21-2005, 05:07 PM   #33
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"Meaning, don't they have these problems now in 12th and 10th pan?"

Pan cars, being 2wd, tend to need a bit more rear traction. 4wd allows a more balanced layout.
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Old 04-25-2005, 12:08 PM   #34
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Quote:
Originally posted by robk
"Meaning, don't they have these problems now in 12th and 10th pan?"

Pan cars, being 2wd, tend to need a bit more rear traction. 4wd allows a more balanced layout.
Actually, a better way of phrasing that is "due to the inherent push associated with an AWD design, more front weight bias is necessary to produce adequate steering."

(pan cars RULE!!!)
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Old 04-25-2005, 12:54 PM   #35
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Where is the energy loss in current designs? TC3, direct input to differential (rear) If your thinking your losing energy in some twisting, or the gears (which are around 99+% efficient), it really is miniscule.

Same goes for belts. Contrary to popular beliefe, these belts really don't stretch under power. I know you hear bla bla the belts stretch. BS. They stretch so little that any other slop in the drive train is going to have more effect then any stretch there is, which is probaly like .001 per inch of belt, if that.
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Old 04-25-2005, 03:46 PM   #36
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Quote:
Originally posted by PitCrew
Where is the energy loss in current designs? TC3, direct input to differential (rear) If your thinking your losing energy in some twisting, or the gears (which are around 99+% efficient), it really is miniscule.

99% or better? really? and especially bevel gears on a tc3. i dont agree on that figure. if you can prove anything close to that figure im selling my xray and getting a tc3. but yes i do agree that the recent touring cars are quite efficient. but until someone comes out with a 100% efficient drivetrain, i doubt the debate over what design is most efficient will die out.
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