well as i look into the subject of drivetran and horsepower/torque...

i came accross the idea that the more power ur get outa ur engine the transmission takes the same amount of power to use...

(in my thinking) if at stock 275 horses... and a 20% drivetrain loss
im left with 220 rwhp... thats 55 horses...

saying my 460l-e takes up most of that and the axel/driveshaft/differntal take up those 55 horses

if my engine were producing 600 horsepower (flywheel)
wouldnt that same 460l-e axel driveshaft and differntail still be taking up 55 horses?

im just wondering if the drivetrain loss is a fixed loss... because i dont see how it could be relative.

 

This subject is covered often in LT1 Tech and Advanced Tech. Try searching...

Basically there are fixed and variable losses. The variable are power related. More power thru the trans and especially the rear end gears create LOTS more friction and therefore losses. That's why folks use trans and rear end coolers in things like Nextel Cup cars.

Bearing friction is usually fixed (but varies with speed of course) but in higher hp applications, with huge bearing loads in the trans and axle, even that varies with power.

Rotating inertia or the resistance to accelerate is fixed if you don't change tires, gear ratio or engine acceleration on the chassis dyno. With the typical Dynojet, if you add 100 hp (spray) to your engine, the dyno winds up faster. That is the pull lasts a second or so less time. The dyno compensates for itself, but you lose hp to the rolls accelerating the drivetrain quicker.

Bottom line is that there is no fixed % of loss if anything changes! Not what you wanted to hear, right?

 

Does the same percentage apply for torque as well as horsepower? I know that with an automatic car especially with a big stall converter you can't accurately determine flywheel torque from rear wheel torque, but if you have a manual transmission car with 365 torque at the wheels, is it still +15% at the flywheel? And does the rear gear ratio affect the torque?

 

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