In the analysis of Dyno curves, there is always a drop off of TQ from peak to redline. Wondering why and how much it should drop off?

 

Well, since we are all here to learn, i did a little googling to get some answers...

"Torque- Defined in ft/lbs or lb/ft either eay it translates into the same amount of rotational force.
An engine's defined what work can be done. there is no alot ed ammount of time. Sure i have 500 lb/ft of torque but its at 500 RPM and im never going to get moving. (oh and torque can also be defined in Newton/meters or Kg/M. in reality it should be defined always as Newton's because a newton is a measuremnt of force, lb is a measurement of gravity pull and Kg is 1000grams, ie Mass or how much of a material is there. torque if force and there for SHOULD be defined as Newtons. but since we are living on earth with 1G Mass has weight and weight exerts force so....)

RPM- plain and simple is rotation per minute.

Horse Power: this is a hard one. THIS IS WHAT MATTERS WHEN THINKING OF ALL OUT PERFORMANCE, NOT EVERDAY DRIVEABILITY. the true formula is 33,000 lb/feet per min. but since you cant expect a horse to lift 33,000lbs 1ft or expect it to move 1lb 33,000 feet in one minute its more simply defined as Torque(RPM/5252). but that has already been said.
1HP=746w (i beleive)
1w=joule/sec.
A joule is a measurement of all out energy. what does this mean? Well alot of muscle car guys like to say its torque that gets you off the line. True, in a sence. its torque to the wheels that gets you off the line. so we have a good old american muscel V8 cranking out a flabergasting 500 ft/lbs of torque at a mere 2,000RPM. thats 190hp@2000RPM. now we have out European performance i-6 with 333hp@7,000 RPM. thats 250lb/ft@7000RPM. Which should launch faster? well lets assume in first gear the muscel car has a final drive of 16:1. 500*16=8,000 lb/ft of torque at 125 RPM. the euro sport car makes most of its power in the high high RPMS so it has a very short 1st gear. 32:1 8,000 lb/ft@218RPM this means that the euro sport car will take off faster because it has more torque at a higher RPM and therefor more HP. you se its all about gear ratio's. torque can be multiplied through gear ratio's HP is constant no matter what gear ratio you put it through.
so what does all this mean? well not only with the euro take off faster but because it has more over all energy it can go faster because in the end it takes HP (Kw) to brake through the air at high speeds, not just torque.
But let me ask you this. Which will be more comfertable for everyday driving? well the engine with 500lb/ft &2000RPM. why? well with that short of a 1st gear slow driving will waste gas and nobody wants to wind their engine up to 7000RPM everytime they need to pass somebody.
for the best all around engine an engine that makes decent torque in the lower RPM's but can hold a flat enough torque curve to make good power in the upper RPM's is perfect. if you are looking for good gas milage and a quite ride then lots of low end torque is your alley. if all you want to do is treat the road like your race trak then lots of HP is ideal.
And here is an idea to throw out at the muscle car people before they flame me for saying some euro POS will beat their cars off the line. 90% OF YOUR CARS WENT DESIGNED FOR STRAIGHTLINE PERFORMANCE. THEY ARE FULL SIZED SEDANS WITH TOO MUCH POWER FOR THEIR CHASIS MENT FOR GREAT EVERYDAY, LOW RPM DRIVING.
i love muscle cars such as the 426 Hemi, GTO, Stingray, GT500Kr, but all of these old family sedans (Bel Air's especially annoy me. they belong shoped and bagged, not raised in the rear and doing wheelies at the local 1/4 mile) built up to 400 lb/ft of torque and 350HP are stupid IMO."

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