A high RPM racing engine does not grunt out low end torque and isn't desired engine profile for the task.
Fuel economy suffers for racing improvements.
once an engine reaches a certain Rpm it no longer moves enough air to rev higher. even a racing engine can rev high enough to see torque begin falling off. "inherent inefficiency"!!!!!!!
Looking at extremes, lets say you have a piston in a coke bottle with a wee little valve to let air in thru the cap. Pull the piston back slow(let's say imagine slowww engine rotation on a massive diesel engine making peak power/torque) and imagine how after a complete pull, sucking thru the hole, the bottle will be comfortably full with barometric pressure 14.7PSI(depending altitude) air. Ready for its compression stroke
Now pull the piston back ridiculously hard(freaking redlining :) and the plastic bottle will want to collapse on itself as its sucking thru the little valve right!
And after a complete travel and the valve is now closed, that collapse shows you the pressure, or the "load", of air you are starting to miss out on for the best burn as the compression stroke simply has less.
Now you make a 5 liter v8 or a 5liter v12, lets say mustang 5.0 or BMW 850i. They both displace 5 liters of air in two rotations, comfortably managing the in and out thru intake and exhaust is where it gets hairy, when looking for optimal density(ford) or velocity(BMW) of air thru intake design and such.
My audi has 5 valves per cylinder, 3 intake! Imagine if I blocked them so I only had 1 intake valve, well i know my power curve would drop off faster
There are a few variables you can play with, but you can't beat physics
You can fix all that with stronger everything, still ain't beating physics
You can't just rev and rev and rev and rev! There is a limit to where the engine makes most power/fuel-used, and there is also a 'safe' limit for the engine (up in the red-line on the tachometer) where you are asking a piston to fly down the cylinder bore, stop abruptly, and then fly up (as other pistons push the crank down) and then compress the air-fuel charge, which is detonated, pushing it violently down... Those pistons are moving at MANY metres per SECOND, and there is a limit before your con-rod, gudgeon-pin, or the piston itself just cries "Enough!" and breaks.
mahjen got it right. its the nature of the beast. peak performance for an internal combustion engine happens in a fairly narrow rpm range. there is no fix for this,though variable cam to crank timing and variable cam lift go along way to flattening out the peaks. this is why a transmission is important
Look carefully at the tachometer as you operate the car. The older the car chances are the needle will not swing to the red zone. The valve springs are getting tired!
It reaches maximum efficiency at peak RPM, after that it is no longer as efficient.
because all engine has a max range where the most torque and Hp is produce. so anything before that or after that range, and the engine will lose it's efficiency and not produce.
thats physics for ya.
