AlsCobra

Finally you're getting to your point. The rotors are over a foot long and still have a solid steel core and are heavy enough to make it substantial to spin. Next time just get to the damm point already. This is not poker. Just show your hand instead of compiling evidence. Geez.

slostang

Whats the difference? I have seen F1's make 1000 wheel and have seen big singles make 1000 wheel? Pick one....

Blower you hit the gas and you have power

Turbo will be there in a second

Pick your poison..

AlsCobra

Right. They're both a blast. And this is argued on almost every car site out there. When Pete was posing we had the same argument once a week. Either way damm it's fun.

Blackbird.

I'll agree to that. My KB gives me a fat grin everytime I put the hammer down!

airoscar

The power requirement can be estimated without going in detail looking at the structure of the compressor unit, just the efficiency is needed for that particular unit.

What you need is the air flow rate and pressure (which I don't know), but I'm sure someone with a 5.0 knows roughly how much air flow goes through the engine at various engine RPMs. [it can be calculated since you know the displacement and how fast the engine spins to displace the volume in the cylinders]

Power is work divided by time. The work done on a gas is the pressure times the the volume displaced. Hence work divided by time turns out to be the pressure times the volumetric flow:

p = P * (V/t)

Where, in your case, the pressure differential is the boost pressure and the volumetric flow is your cfm.

The previous equation is for SI units. Plug the correct conversion factors for hp, psi and cfm and you you get:

p = 0.00436 * P * (V/t)

This is the power you actually need to compress the gas. Then you have to factor in the efficiency of your compressor.

Here are some typical efficiencies for compressor used on car engine (in reality the effiencies vary with different spin speed):

centrifugal or turbo: 69%
centrifugal (reversible): 55%
roots (2 lobes): 50%
roots (3 lobes): 55%
screw: 72%
vane: 62%
spiral G: 68%
comprex: 84%

So hope this helps. Depends on how fast your engine is spinning, I'd imagine at WOT you could end up using more than 100HP on the compressor, but at idle there is probably barely.

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PS. I think it's important to note that the difference in power comsumption between SC and Turbo is not the way they are driven - being shaft driven or exhaust driven both require energy input; Turbos use exhaust gas pressure that in turn poses back pressure on the engine which is essentially still driven by the engine. The main difference is their efficiency. If you have a more efficient compressor, regardless turbocharged or supercharged, you use less power to drive the compressor.

Bigjohns97

Just go with a whipple FRPP kit and forget this thread

Blackbird.

Honestly. Once you get a supercharger/turbo you're not gonna care about this parasitic loss BS. It's negligible considering the overall hp you've gained.

Five Oh Brian

Just my two cents to add. The Vortech V2 S-trim I had on my '07 GT was 72% efficient per Vortech, while their updated V2 & V3 Si-trim (featuring an improved vane design) is 78% efficient. That's actually a very efficient centrifual blower.

The more efficiency, the more power you get for a specific amount of boost. I believe that's what the OP needed to know.

2012BLKV6

Last part is wrong. The higher efficiency, the more BOOST you get. Boost is power when talking FI.

Energy in, compressed air out. Gotta look at it ignoring the motor.

airoscar

Just to give you an idea:

The supercharger on a 5.0L engine, assuming it produces 9psi boost at 6000 RPM with 65% efficiency, uses about 60 HP.

Brian's supercharger with 72% efficiency will use a bit less horsepower. The power used to drive the compressors is really not that much, and not that different either whether it being SC or turbo. the reason they are so keen on the efficiency has to do with heat i think, because any inefficiency is basically heat generation.