Build me a Small block
Tom - Fair enough - I thought you were arguing it was - and fwiw I agree its not the most accurate of guides.
You'll note I used the word "guide" instead of "calculator" ?
I guess the main problem i see is that some folks think the slide rules perform some "Physics" type calculation where losses are "magically" assessed etc.
So back on the soap box :read2:- Truth be told they are far simpler tools than that - and in reality rely on pre-assigned data and use a common constant simply to arrive at an arithmetical sum......
Quote from the link -
"MPH" is the terminal speed (trap speed),
"ET" is the elapsed time,
"224" is the empirically determined coefficient that includes the necessary unit conversion factors,
"hp" is the peak engine horsepower output at the clutch (net power), and
"weight" is the the total weight of the vehicle (with driver) in pounds.
Its as simple as "Raw Data > Constant > Result" -
Where the Raw data and the result are measured in the same units.
.......so it stands to reason that when MPH and weight is used to determine HP, it arrives at FLY HP as a result of the equation.
FWIW - The the bottom of the linked page, there are three different calculators using a slightly different Constant in each - the LRT calculator seems to be the most accurate for street type cars - but the "Hale formula" one supports the 400HP=12sec=3600lbs FLY benchmark ive always gone by.......
MichformulaS- Im no Physicist , and I agree with this part -
so I agree that if you spin them up faster they will take more hp but it is not proportional
. - because rotational and inertial friction increases as more energy gets put in, and each drivetrain combination has different losses, its not 1:1....another reason why they couldn't use RWHP to calculate a reliable "Constant" for a reference tool.
Re the SWAG thing - most of the gun builders I know assume a 120 HP loss for a 727 and a 8.75/ford 9" diff.
JUst an observation - That would mean that the factory Hemi is producing appx 300 Rear wheel HP - the Moroso gives them way more than that - more proof if anyone needs it. LOL!! :-D