cfm to hp conversion

[Gamesy]

i was wondering if anyone knows what the the ratio was for CFM to horsepower conversion was for the eg33

[svxfiles]

Originally Posted by Gamesy

i was wondering if anyone knows what the the ratio was for CFM to horsepower conversion was for the eg33

Not really sure what you are looking for, but;
If we have a 202.5 CID FOUR STROKE engine,
turning at 5400 RPM,
assuming 100% volumetric efficiency,
the engine pumps 546,750 CID/M.
Or 316.40625 CFM.
Sooo our 230 HP takes 316.4CFM,
or .7269135 HP per CFM.
Or 1 HP per 1.3756793 CFM.
Why do you ask?

[Gamesy]

gauging turbos which are too big or too small

[svxfiles]

Originally Posted by Gamesy

gauging turbos which are too big or too small

I am not the guy to ask.
I have a 1750 CFM belt driver supercharger on my Claret.
But with the right pulley combination I can make the SC smaller.

[Gamesy]

i tried PMing Tom but his box is full

[svxfiles]

Originally Posted by Gamesy

i tried PMing Tom but his box is full

YT has not done a turbo 3.3...
yet

[Crazy_pilot]

Originally Posted by svxfiles

yet

Gamesy, check out Garrett's site (Link), they have a lot of good info regarding turbo selections. Around here somewhere I have the calculations showing that for ~600 HP you'd need either a single GT3788 or 4088 pushing about 23-25 PSI, or a pair of GT2860RS in the 76 trim, 0.86 A/R running the same pressure. A TT setup for that sort of power would be difficult though, those turbos would be running right to their upper limits. For those power levels the engine would be consuming 44-63 lb/min of air. Not sure what that works to in CFM.

[Gamesy]

thx crazy, but i dont plan on running that much power lol just to put the car a little over 300

[radarwhiz]

Originally Posted by Crazy_pilot

check out Garrett's site Link

Great info here. According to their formulas, assuming eg33 VE is ~92%, for a target HP of 300 we'd only need 2.75 lbs of boost. That sound right to anyone else? seems a bit low to me.

[svxfiles]

If you did not alter the stock VE,
with the appropriate A/F ratio,
you would only need 7.5 PSI,
OF COLD AIR,
to make 345 crankshaft HP,
in theory, of course.

[Gamesy]

Originally Posted by svxfiles

If you did not alter the stock VE,
with the appropriate A/F ratio,
you would only need 7.5 PSI,
OF COLD AIR,
to make 345 crankshaft HP,
in theory, of course.

not sure what VE is short for.
so the assumption is that stock 230 crank hp is roughly 180 whp
7.5psi would be roughly 270.
roughly what an sti puts to the wheels.

[dragoontwo]

Volumetric Efficiency

[radarwhiz]

VE=Volumetric Efficiency

Originally Posted by Gamesy

not sure what VE is short for.
so the assumption is that stock 230 crank hp is roughly 180 whp
7.5psi would be roughly 270.
roughly what an sti puts to the wheels.

In theory.

[radarwhiz]

Originally Posted by svxfiles

If you did not alter the stock VE,
with the appropriate A/F ratio,
you would only need 7.5 PSI,
OF COLD AIR,
to make 345 crankshaft HP,
in theory, of course.

I'm doing a bunch of equations for different displacement, HP target, VE, RPM, and intercooled or not just to understand the theory.

With your example of 345 HP at 92% VE, ~12:1 A/F, 130 deg. manifold temp, at 6500 RPM it would need 7.9 lbs.

Does VE change with forced induction or is that changed with engine mods, ie: intake or exhaust mods, ported heads, ect?

[svxfiles]

Originally Posted by radarwhiz

I'm doing a bunch of equations for different displacement, HP target, VE, RPM, and intercooled or not just to understand the theory.

With your example of 345 HP at 92% VE,
~12:1 A/F,
130 deg. manifold temp, at
6500 RPM it would need 7.9 lbs.

Does VE change with forced induction or is that changed with engine mods, ie: intake or exhaust mods, ported heads, ect?

Some musings;

Volumetric efficiency changes with engine design, and is different at almost all RPMs.

With our IRIS we can achieve over 100% VE!

12:1 A/F is a safeish, but not ideal ratio.

Our average intake manifold temperature is 200°f!

Sean, "musings", nice choise!