Re: 5 Litre Windsor potential
After a quick google to explain myself a little better i found this
" Engineering-wise, Efficiency is always expressed as a percent (e.g. 85% efficient). 85% efficient means that only 85% of the input is going to be the output. By definition, the efficiency of a given machine doesn't change even though the input power is changed (up or down). The remarks about inertia and accelerating a mass are good points. However the main villians are friction and gear pressure angles (along with a few other small contributors). Most manual trans drivetrains (flywheel to pavement) lose about 15% of the power put in by the engine and most auto trans drivetrains lose about 18%. That's 85% and 82% efficient respectively. The extra loss in the auto is mostly ATF oil pumping losses.
Read no further if you don't want some details.
Gear teeth don't mesh exactly straight on, they always meet at some angle called the pressure angle. So some of the power transmitted is lost as thrust against the bearings. As you apply power, the teeth mesh, the drive gear tries to push the driven gear harder against its shaft as well as turning it. The "push" power does NOT help turn the gear, so it's lost. From triginometry, the percentage lost is related directly to the pressure angle AND NOTHING ELSE. The more power you apply, the harder the push 'cause it's a percentage of power applied. The gears have to be strong enough to take the power transmitted without failing of course.
The other element is friction (yep, you guys are right on about that). Bearing friction is directly related to the force applied to the bearing, the "push". See where I'm going? Friction (and power loss) is the coefficient of friction (always the same for a given bearing) times the "normal" force (load applied straight into the bearing). As the input power increases, the "push" power increases proportionantly. So the friction and loss increase the same amount. That loss turns up as heat. Running a trans and diff hard generates a LOT of heat, compared to gentle driving, right?"