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# How much HP will your Fuel Injectors handle?

Discussion in 'Engine Building' started by Sadistik, Jun 12, 2007.

1. ### SadistikNew Member

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-Found- Great infomation on fuel injectors!

So, how much power is this injector good for? That depends on the air/fuel ratio that is used, but a good rule of thumb is to divide this flow figure by 5 to get a hp capability. So, 322cc divided by 5 = 64hp maximum fuel flow with this injector. If you want to be pedantic, it's the mass of the fuel (not the volume) which is the critical factor. Assuming a "normal" fuel density, the mass of the fuel in pounds per hour can be worked out by Dividing the cc per minute figure by 10.5. For this injector, that gives a mass flow of 30.6 pounds/hour. To convert from pounds/hour to horsepower capability, multiply the figure by 2.04. So 30.6 pounds/hour multiplied by 2.04 gives a horsepower capability of 62.4hp - the same as we got from the cc/minute figure.

The power ratings discussed above are for each injector. This means that you need to multiply this rating by the number of injectors that are to be used. So, if you were using the Impulse RS 322cc injectors in a 4 cylinder engine (with one injector per cylinder) the max power that the injectors could deliver fuel for would be about 249.6hp. All of these figures are assuming that you are running an average fuel pressure of ~43psi and at 90% duty cycle.

Equation to figure max hp rating!

(Injector cc/10.5) x 2.04 x Number of injectos = HP rating

Example:
DSM 1/2g Fuel injectors.

450cc injectors/10.5 = 42.8

42.8(2.04) = 87.3

87.3(4) = 349 max hp rating * READ RED Sentence*

• Conversions
• 500cc per minute is approximately equal to 49lbs per hour which is equal to approximately 100hp.
• lbs/hour = cc per minute / 10.5
• lbs per hour = HP / 2.04
• cc per minute = lbs per hour x 10.5
• cc per minute = HP x 5
• HP = cc per minute / 5
• HP = lbs per hour x 2.04
*Fuel Injector information & Specifications specs

Last edited: Jun 13, 2007

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