[Blackcoog]

In the May issue of SCC there was an article to figure out the maximum output a car can handle with the fuel injectors it has on it. It was pretty neat. This way you can prove all of those people wrong that say they have 400hp when it isn't possible with their set up. Here is the equation that they give:

Max hp= [injector flow rate]x[number of injectors]x[duty cycle] all divided by Brake Specific Fuel Consumption (BSFC)

-Ok we have 6 injectors (1 per cylinder)
-duty cycle is pretty much usually 85% (it is how much the injector is open and spraying fuel; so it would be open 85% of the time)
-BSFC for naturally aspirated engines are from .45 to .55 so they say to use .5 as an average

What is our flow rate then so we can calculate this out and see how much hp our duratecs can handle before they are pushing to much for the engine to handle?


Oh and of course this is crank hp because it would be too hard to figure out all of the variables for driveline loss into an equation.

 

[Frank]

I believe we have 19lb/hour fuel injectors. (19 * 0.85 * 6) / 0.5 = 193.8hp.

 

[Frank]

Oops. You're right, the 19# figure is for the SVT Contour. According to that formula, the SVT (with its 200hp) is already passed the limit for 85% duty cycle, and our cars are on the edge of it. Does the supercharger kit include larger injectors?

 

[Blackcoog]

forced induction engines raise the BFSC to .6 and usually the percentage is higher on the injectors

 

[FastCougar]

I just found some interesting links regarding this subject.

Detailed explination of the forumal

 

[Blackcoog]

That is kind of cool now who thinks they have 400hp so we can prove them wrong!