![]() Switch the formula around if the GPH is known to calculate the HP that could be made,Īll of the examples here use plug numbers. How much fuel will be consumed to make 1000 HP?Ī safe BSFC number for a Turbo engine would be around 0.52. Let’s look at a turbo engine as an example. We see some DI engines running very lean but not at full power. Engines running this lean typically do not survive. The engine example of 300Hp using 20 GPH would equal a BSFC of 0.39 and a TE value of 34.4%. This is more realistic HP for the amount of fuel consumed per hour. Or if we use the 24 GPH and a BSFC of 0.44 what a horsepower figure could be. Let’s plug in another more realistic BSFC number of 0.44 and use 300HP as the power figure and see what the GPH would be. This is a little rich for peak power and shows that our plug numbers of either 300 HP or 24 GPH are not optimum. If you take the engine example discussed earlier, and plug in the values to the BSFC formula you get, On a turbo engine we may increase this upwards to 0.47- 0.52 BSFC, and that would be approx 0.82 – 0.79 lambda. This would calculate out to be around 0.85 – 0.87 lambda. Typically we see on a normally aspirated engine a BSFC value of 0.44- 0.45. This is measure fuel flow by HP observed and expressed in Lbs/ hr/ HP. So you can see that some of these internet engine performance figures defy the laws of physics.Īnother way we measure this is on an engine dyno we calculate Brake Specific Fuel Consumption BSFC. In fact I calculated one of the internet engines was making 34% TE which is above what an IC F1 engine made. Regardless of what someone may tell you, most engines make in the region of 30% TE. You can also figure out how much real HP any engine is making. You can calculate how much fuel you will need to produce a certain amount of HP with these calculations. HP = TE x Fuel flow (GPH) x 5.92 (# per gallon) x 19,000 / 2545 (BTU per HP per hour) HP = TE x Fuel flow (PPH) x 19,000 (BTU per #) / 2545 (BTU per HP per hour) So we can calculate the thermal efficiency of an engine with this. Even some of the last 1/3 is lost in the actual running of the engine, friction, alternator drag etc. There is a rule of thumb that 1/3 of the energy goes out the exhaust as heat loss, 1/3 in the cooling system, water oil etc, the last 1/3 is what we measure on the dyno. This is where you can tell if the numbers someone is telling you are real or not. We wish, but the engine is only making 300 HP. If you burn 24 gallons of fuel per hour to make 300 HP, 142lbs/1 hour, you release 2,699,520 BTU’s of energy, (19,000x 142). So 24 gallons x 5.92 lbs = 142 pounds per hour to make 300 HP. 1 Gallon of fuel weighs approx 5.92 lbs and for every 1 lb of fuel burned approx 19,000 BTU’s of energy is released. It may use approx 24 gallon per hour to make 300 HP. For reasons of simplicity let’s take an engine that makes 300 HP. 1 BTU is heat energy required to raise the temperature of 1 pound of water 1° F which is equal to 778 Foot – pounds of energy.ġ Horse power (33,000 Ft-lbs per minute) is the same as 42.4 BTU’s per minute or 2545 BTU’s per hour (33,000 /778 = 42.4165 x 60=2544.98).įor any engine you can calculate the amount of fuel used, its thermal efficiency and its horsepower potential. So, here are a few things to consider when hearing about all of these high powered internet engines.Įngines turns chemical energy (fuel) into heat energy (combustion) and some of that heat energy is turned into mechanical energy or work (torque). I thought if I put some basic proven and accepted calculations in a paper they can be used to obtain and understand what is real and what is not. The internet has created bragging rights for engines with huge horsepower figures, which never live up to the stated performance and seem to defy the laws of physics. Same can be said about cars that have real engines with real horsepower. There is a saying that money talks and BS walks. Porsche 944 and 968 Crankshaft Upgrades.Porsche 911 Type Air-Cooled Cylinder Head Rebuilding.Porsche 944-968 Engine Block Lower Member Upgrade.Replacement CDI Ignition for Porsche 911 Carrera and Turbo Engines.996 and 997 Turbo Crankshafts and Rod Bearings.Porsche 996 and 997 Turbo Cylinder Head Sealing. ![]()
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