Theoretical intake stroke power under boost

[miniv8]

For you math guys, and there's plenty of you here, I'd like to pose a meaningless theoretical mathematical discussion.

If my engine is 632, which it is not, and I have a big ass Procharger, which I don't, how much power is put out at just the intake stroke?

Yes yes yes yes.... we hopefully will take into account all the friction losses and valve timing, that's where the guys come in that are smarter than me, but for starting the thread I thought I might use an old equation for steam engine power, namely the PLAN/33000

It goes like this:

P=Mean Effective Pressure in Cylinder (MEP)
L=Length of Stroke in FEET (times 2 for Double acting engine)
A=Area of Piston in Inches
N=Revolutions per minute
divided by 1 HP = 33,000 ft-lbf/min

so 30 pounds of boost,
4.75in stroke is 0.3958333 feet
4.6in bore is 16.62sq
there are 4000 intake strokes at 8k

I get 24 horsepower! no wonder I can't keep up with the smallblock, the boosted bigblock is basicly a two stroke!!

[ptuomov]

How’s that going to work if you have a one cylinder engine and the volume between the pro charger and the intake valve is made infinitesimally small?

The other thing to note is that if you pull a half an atmosphere vacuum in your normally aspirated small block, then can should be able to keep up with the booster big block, right?

[miniv8]

How's that going to work? I don't know, it's theoretical, but somehow they have estimated that the pressure purge from the boiler to the steam operated engine equates a specific engine output.

I am baffled everytime I put air in my tires, that it amounts to the same pressure in motion, held by an intake manifold, only being bled by intake valves!

[ptuomov]

How's that going to work? I don't know, it's theoretical, but somehow they have estimated that the pressure purge from the boiler to the steam operated engine equates a specific engine output.

I am baffled everytime I put air in my tires, that it amounts to the same pressure in motion, held by an intake manifold, only being bled by intake valves!

The first one was a trick question as the crankshaft turns the pro charger. I think that if you eliminate pressure reservoir effects and inertia effects, the pro charger would eliminate that net torque. Right?

[miniv8]

It sure would.
If it was a turbo engine, the losses from excess backpressure compared to anything else would also negate any gain, but yet, the turbos are power kings. This would be even further offset by aero drag if we ran it in a Winnebago... it doesn't mean it makes less power, it just means the total package is less efficient.

What i am getting at, is the drastically different loads in boosted engines compared to anything else.
At full load, there is is perhaps measurable power turning the crankshaft at the intake stroke.

It is small compared to the total, but calculates from this crude comparative math example, 24hp from a 30pound 632, that might equal to idk, 2800 hp? it might be only 10hp, or 15 after the valve events.

Rod pull during the naturally aspirated intake stroke is of course negligible compared to the G-force exerted during TDC, but after the valve event, it stops pulling, and starts pushing down, and pushing down is power.

[ptuomov]

The turbo engines are really easy on the rods for a related reason, one can make power without excessive engine speeds and the valve overlap period has a positive pressure in the combustion chamber helping the rod (at least until one shuts the throttle…)