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Drivetrain loss?

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Old 09-15-2003, 11:41 AM
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Default Drivetrain loss?

Anyone know what % a typical bonneville loses before it puts the power to the ground? The % difference typical between crank hp and torque and wheel hp and torque?

I've heard as high as 25%, but don't see much out there on it.
Old 09-15-2003, 10:12 PM
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Between 18 & 20%.
Old 09-15-2003, 10:17 PM
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so were losing like 46 ft lbs of torque?! so its only putting like well in my case like 184 lbs of torque to the ground? or am i confused beyond measure.
Old 09-15-2003, 10:20 PM
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The power at the crank and the power to the ground are totally different, now imagine lesser cars with WAY less torque...only getting double digits to the ground
Old 09-15-2003, 10:24 PM
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so were losing like 46 ft lbs of torque?! so its only putting like well in my case like 184 lbs of torque to the ground? or am i confused beyond measure.
Thats exactly right. For instance if you make 200hp on the dyno it sounds a little low, when really the engine is putting out 250. If you make 320hp to the wheels the engine is putting out 400hp! That is why I have always said Series II L67'* have way underrated torque, because GM rates them at 280lb.ft, but I have seen stock L67'* pull 270lb.ft to the wheels which is over 330lb.ft at the crank. Once you get up into high horsepower numbers it gets really really crazy.
Old 09-15-2003, 10:33 PM
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Very interesting. On my Aurora when I dynoed it I figured and many others that a Northstar weither 4.0 Aurora or 4.6 caddy will lose 24% through a 4t80-e tranny. My baseline dyno was 190HP at wheels =250 crank. I'm sure Jim liked this little fact.
Old 09-15-2003, 10:36 PM
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Da na na na na HEY da na na na na na HEY



190 HP at the ground is nice...still 35HP more then my 89 ( and it was 165 at the crank)

Thanks for that little tid bit Taylor...
Old 09-15-2003, 10:45 PM
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so im guessing the numbers that GM advertises are at the crank? to make it sound more impressive.
Old 09-16-2003, 12:40 AM
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me too, 85 Buick Somerset, 92hp. My first car.


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