Originally Posted by 2JZfan

blowers can definitely make good power... my first project car ever was a vortech supercharged vehicle... i went "nuts" with it and turned it from a 275hp, 14.3 sec 1/4 mile car into a 900hp monster that ran 9.56 @ 143 (via $35k in mods)... so before we get into this, understand that I'm not just some biased blower hating turbo evangelist...

BUT, the centrifugals have nowhere near the HP potential of a similarly sized turbo... here are some facts:

on my 900hp car, it took about 200hp to drive the blower... that means the fuel system was using 1100hp worth of fuel, the motor was under 1100hp worth of stress, but the net horsepower making it to the flywheel was only 900hp... Imagine the strain that this puts on the snout of the crankshaft when it has to drive a 200hp accessory... a smaller blower takes less power, but it still produces far more parasitic losses than a turbo... the bottom line is, all motors are capable of withstanding a certain amount of cylinder pressure and strains before they reach their "limit"... with a turbo setup, you will get a larger percentage of this power to the flywheel and out to the wheels than you will with a supercharger, period.

the previous facts refer to peak power, which will occur near redline... when it comes to low and midrange power the turbo has even more of an advantage... the turbo's ability to make full boost from 3000 - 7000, vs. the supercharger's linearly increasing boot that only peaks at redline, is a clear win... think about it: if the turbo makes more power at 10psi than the blower does at 10psi, then obviously the turbo at 10psi will completely dominate the blower at 5psi... this would be precisely the situation at around 3500rpms when both cars are configured to run "10psi"...

Internal combustion engines follow this general thermodynamic breakdown:

1/3 of the energy from combustion is lost as heat transfers to the cooling system

1/3 of the engery from combustion is lost as hot air goes out the exhaust port

1/3 of the energy from combustion translates into useful work and pushes the piston down

The turbocharger is the closest thing in the internal combustion world to a "free lunch" because it actually reclaims some of that lost 1/3 heat energy going out the exhaust and uses it to build boost...


As far as top fuel cars only running superchargers, in reality the turbos OEM's don't make turbos that would work in this application... the largest turbo suitable for an automotive application is good for about 2400hp... so to make 7000+hp like top fuel does, you'd need 3 of them... with only 500ci, you couldn't spool 3 of these things in a reasonable time period to make the car quick reacting... bottom line, the power potential would be superior to the blower, but the drag racing elapsed time potential would suffer... This could possibly be changed with years and years of R&D and additional OEM development, but since the rules don't allow turbos, this development has never occurred...