Horsepower Calculation
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From: Berkeley Springs, WV
Horsepower Calculation I know air flow grams/cylinder does relate to the amount of horsepower the engine is making. Is there a formula to calculate roughly how much horsepower an engine is making by knowing the air flow in grams/cylinder?
Found this:
Horsepower is not easily calculated, but online calculators can get you close.
Instructions
STEP 1: Horsepower is a measure of output: one horsepower is the amount of power required to lift 33 thousand pounds, one foot off the ground, in one minute. It is defined by a formula: load times feet per minute, divided by 33,000.
STEP 2: If you know these numbers, you can plug these into the formula and calculate your horsepower.
STEP 3: If you do not, it is probably easiest to calculate your horsepower using a horsepower calculator. Find one by typing in the phrase "horsepower calculator" into a search engine like Google or Yahoo!.
Like that helps. sheez
Here's a couple calculators but none of them are cyl mass
http://www.speedworldmotorplex.com/calc.htm
http://wahiduddin.net/calc/calc_hp_dp.htm
Horsepower is not easily calculated, but online calculators can get you close.
Instructions
STEP 1: Horsepower is a measure of output: one horsepower is the amount of power required to lift 33 thousand pounds, one foot off the ground, in one minute. It is defined by a formula: load times feet per minute, divided by 33,000.
STEP 2: If you know these numbers, you can plug these into the formula and calculate your horsepower.
STEP 3: If you do not, it is probably easiest to calculate your horsepower using a horsepower calculator. Find one by typing in the phrase "horsepower calculator" into a search engine like Google or Yahoo!.
Like that helps. sheez
Here's a couple calculators but none of them are cyl mass
http://www.speedworldmotorplex.com/calc.htm
http://wahiduddin.net/calc/calc_hp_dp.htm
From fluid/thermodynamics, the power a motor generates is pretty much based only on the air mass flow into the motor, heat added through fuel and combustion, and work produced as a result. Now, basic laws of thermodynamics of systems will allow you to solve for power, however, the number of variables is incredible and they are difficult to account for. The power calculators online are extremely inaccurate because they don't take into consideration several variables of engine design and theory and they make several gross assumptions. It would be nice to have an accurate power calculator, but frankly you're better off comparing your build to others' to guess your power. As of now, this is the most accurate method to guess your engine's power.
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Most of you all are reading way too much into my question. I know there are specific formulas to calculate horsepower. To understand my question, I guess you need to be into turning our engines and looking at the logs. If you watch the air flow in grams/cylinder it will give you a rough idea of how much power you are making. If you are only doing .90 grams/cylinder then there is no way you are making close to 500 rwhp. I was just wondering if someone has done alot of dyno tuning and watched the air flow and had a good idea of how much power was being made to different air flows.
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From: Berkeley Springs, WV
No I am just logging the air flow pid out of the main spark table. The higher you go in that table the more power the engine is making. If everyone that dynoed their car reported what the highest air flow/cylinder was it does relate to the amount of power the engine is making.
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No it doesnt work like that John. You would be closer if you used the lb/min reading off a stock car with stock cal From 300-550 or so its in the ballpark of 10*lb/min from what Ive seen.
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Teching In
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If you can convert it to grams/minute, head down to "FUEL FLOW" here and you can input your grams per minute.
Might not help at all, but a good resource; (authored for 3/S engine, but standard rules apply)
http://www.stealth316.com/2-air-fuel-flow.htm
Might not help at all, but a good resource; (authored for 3/S engine, but standard rules apply)
http://www.stealth316.com/2-air-fuel-flow.htm
I am not sure what program you are using, but I have already done this. The trick here is that you need to have the airflow model correct, meaning the tune needs to be done the proper way. No tuning by IFR, or PE only ... the VE table needs to be spot on, and the MAF table needs to be spot on and enabled (this may not work with SD modes). Quite a few people have reported (to me) great results. Read below for info. 
http://www.hptuners.com/FORUM/showthread.php?t=10358
http://www.hptuners.com/FORUM/showthread.php?t=10358
