Fuel Requirements Based On Horsepower
Enter the number of injectors: 
Enter the flow rate of each injector in cc/min: 
Enter the hp you wish to achieve: 
A minus figure indicates you have enough fuel.
A plus figure indicates the amount of extra fuel needed.

The basic formula for calculating fuel requirements is (no. of cylinders x injector flow rate) / 6.75, this equals to about a 90% duty cycle. For example a car with 4 cylinders and 430 cc/min injectors, would have enough fuel for (4 x 430) / 6.75 =  255 hp.

Another useful formula is for calculating the percentage increase of fuel flow through the injectors if the fuel pressure is raised. The formula for this is the square root of (new pressure / stock pressure). So for example let's say you increase your fuel pressure from 38 psi to 48 psi, you percentage increase of fuel would be (48 / 38 = 1.26315). The square root of 1.26315 =  1.12, so you have now increased fuel flow by 12%. So if your injectors are 430 cc/min, you would now have (430 x 12% = 51.6) + 430 =  481.6 cc/min injectors.

This page was created by Dennis Heath.
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Please note that I am not a mechanic by trade, and that any information offered on this web page is free and without guarantee. Should you choose to perform any of the procedures listed on this site, you will be doing so of your own free will, and I will not be held responsible or liable for any damages that might occur from using information obtained here.