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+--- Thread: Headflow formula? (/showthread.php?tid=33004)
Headflow formula? - lolsteve - 11-01-2016
Does anyone know a formula for converting headflow into hp
Obviously it's going to be rough but I'm just interested when people say "this head can mame xx hp based on flow"
RE: Headflow formula? - toseland - 11-01-2016
Dont forget the head gasket modifier that you have to include for headflow leakage on the rover engine.. somewhere between 60 and 100%
RE: Headflow formula? - cully - 11-01-2016
also the calculation for the fuel magnets and electric turbo you've fitted
RE: Headflow formula? - Mattcheese31 - 11-01-2016
If you have to ask you'll never know
RE: Headflow formula? - lolsteve - 11-01-2016
Well now im not on my phone at work was able to do some proper googlin
http://ls1tech.com/forums/advanced-engineering-tech/1024133-head-flow-direct-relation-hp-tq-also-peak-rpm.html
Here is a 4-year old quote from a great head porter and engine guy, Larry Meaux:
"Peak_HP = Flow_CFM * .257 * Number_of_Cylinders
This is the estimated potential Peak HP to expect.
You multiply 87 percent (.87) times cam's theoretical max lift , round off to nearest .050" in Flow Test, then see what CFM is at 28 inches of H2O.
example=> .700" Lift cam:
.700 Lift times .87 = .609" Lift
Flow head at .600" Lift , then take CFM at 28 inches and calculate HP potential with above formula.
.257 Factor = for beginning engine builders and engines near 10.0:1 Comp Ratio
.285 Factor = would be for Professional engine builders with wet sump pans, lightweight rotating assemblies, low tension great sealing rings, deep oil pans, etc. and excellent use of inertia/wave tuning with 9.5 to 11.5:1 Comp Ratios or 11.5 to 13.0:1 CR ranges without fully utilizing inertia/wave tuning effects
.300 to .310 Factor = Current ProStock Technology with dry sump, unlimited carburetion, High Comp Ratio, ultra lightweight rotating assembly, etc, and maximum use of inertia/wave tuning, etc, 14:1 to 17:1 Comp Ratios.
RE: Headflow formula? - welshpug - 11-01-2016
flow is but a tiny part of the puzzle, I know of a few engine builders that dont use flow benches at all.
just engine dynos and trial and error, after a bit of maths and what looks right and what worked last time!