(1) I know it's common lingo , but what the heck is a sleeper?
(2) If I understand correctly, hp can be measured by hp = torque * rpm / 5252... but for this to work, the hp and torque have to be at the same rpm... so how would you calculate actual hp above 5252rpms, since above 5252rpms, hp is always higher than torque?... if this question is too confusing, just tell me how hp is measured? And how is wheel hp measured?
(3) Why is fuel injection not used in racing, like NASCAR for example?

Thanks in advance for all and any help...

 

1. a sleeper is a car that doesn't look especially fast or flashy but is fast.
2. I'm too tired to explain this now. if someone else doesn't I will later. sorry
3. fuel injection is used in lot's of kinds of racing. But in the case of nascar, it's just their rules that prevent it from being used. That's how they've always done it and that's how they want to keep it.

 

1. sleeper = doesn't look like it's fast, but beware

2. hp = (tq * rpm)/5252. you're right, torque*rpm is a function of HP.. and you'll always see the 2 lines intersect at 5252 rpm on a dyno graph, unless the scales are different. when you calculate HP, you don't worry about what's on the HP side of the equation, just worry about (torque*rpm)/5252 and it'll show the HP for that given RPM.

there's 2 main kinds of HP.. the crank HP rating and the wheel HP rating. the crank HP is how much torque (rotational force) the engine produces at the crankshaft. Most car manufacturers use these #'s to advertise because they're higher numbers.

wheel HP is what matters. put the car on a dyno, redline it in a certain gear, and the dyno will record how much torque the car produces at whatever RPM and speed and gear ratio, etc.. then the dyno will plug in the torque into the formula and you get the HP readings. the HP readout will show lower than crank HP because you lose power as it transfers through the drivetrain.

3. fuel injection is good because fuel is fed electronically so you use fuel when you need it, and you save fuel when you don't. it constantly adjusts the fuel by itself according to conditions. carburated engines are usually better for racing, since you don't usually need to worry about fuel economy so much, and i believe carburators atomize the fuel charge better than f.i. cars. most (if not all) new passenger cars these days come fuel injected, they're just better for daily driving.

i know i missed some key points here but just tryin to give you the gist of it


[Modified by In7egrity, 9:11 PM 9/7/2001]

 

good stuff... thanks a lot boys!