Horse Power Loss ?

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Small Block

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This issue or question came up on another post and some of us felt this should be a stand alone topic so here goes.
We hear of HP projections at the crank on a motor and then there are projections of rear wheel HP which is considerably less than that at the crank. What in your opinion or fact would be the contributing factors for this loss of HP at the rear wheels. We know there are many. Some losses can be eliminated or lessened cheaper than others. What are the remedies on a street car. Just to name a few that comes to my small mind:
Frame connectors........
torque boxes.........
sure grip rear........

What else
 
Drivetrain loss, IE Torque Convertor, Transmission, Driveshaft, Rear Differential, normally accounts for 15-25% of your engines power.

Reducing Weight and easing Intake and Exhaust Restrictions are usually the most beneficial Modifications, Seat of the Pants wise....:read2:
 
Hey Prine: You aren't John by chance are you? Any idea of the fix on any you named off. Is there anything one can do on the drive shaft HP loss? Been to the strip many times and some cars sound tougher hat all get out but they aint goin no where very fast.
 
Small Block said:
Hey Prine: You aren't John by chance are you? Any idea of the fix on any you named off. Is there anything one can do on the drive shaft HP loss? Been to the strip many times and some cars sound tougher hat all get out but they aint goin no where very fast.
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lol..thats funny and true,amazing how many guys claim their cars run 10's but for some strange reason only run 14's..lol...some suggestion's would be change to manual steering if your running power thats a weight loss of 32 lbs right there,take out the back seat,lighter wheels,deffinately install frame connectors,sure-grip unit,drag shocks,and sticky tires to get all your power to the ground,of coarse you can take whatever you want out of the car if your not using it,heater core,passenger seat,spare tire,bumper jack ect..anything you eliminate makes the car lighter..hense faster...
 
Small Block said:
Hey Prine: You aren't John by chance are you? Any idea of the fix on any you named off. Is there anything one can do on the drive shaft HP loss? Been to the strip many times and some cars sound tougher hat all get out but they aint goin no where very fast.
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John Prine visits Dear Abbey....not FABO!
 
The big factor in drivetrain loss is friction. You have to reduce friction to get any gains. There are some tricks but to do most of them, you better know what you are doing. You can run lighter fluids in the rear. Changing from ball type bearings to needle type bearings will help. As was mentioned, anything that is being run buy the engine, (power steering, fan, alternator, a/c) all drain off horse power. Just swithing from a 727 to a 904 tranny will save about 30 HP. Even the U-joints can drain off some HP if they are installed wrong. The tires you use can have more rolling resistance than others. And on and on it goes. There is HP inside the engine that is waiting to be freed up as well. By swithing to a roller cam and rockers from a flat tappet of the same size you will free up HP just because of less fricton. It's just a matter of where you want to start.

Jack
 
Rotational Mass is a big one....Wheels, tires, axles, drive shaft, tranny, tq converter/flywheel when spinning combined have a huge amount of inertial kinetic energy all of which resists a change in speed either accelerating or decelerating. To increase the rotational speed of all of these items takes a significant amount of energy which never gets to the ground. This energy is seen as a loss when comparing Flywheel HP to Wheel HP.
 
Good mentions here.

I was wondering about torque converters. How much power some loose over others. Efficent or not? How well they transmit the power. Etc. I guess.

Manual trannys do not have that problem, but the way the gears are cut, size gears, as in thickness and diameter all have to have a play.
Has anyone ever seen a list of the power loose's through certain manual trannys?
Some have to be better than others.
 
I've seen ads in different magazines for a company/shop that does 904's for BB's and what not. Can't remember the name i can picture the add in my head and it seems like there's a dodge dakota launching for the pic.:dontknow:
 
SMR trans?????????

Big blocks never came with a 904, but you can install the guts into a 727 case.
 
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