Fuel Injector Duty Cycle Vs Rwkw?

[PSI Parts]

You guys can all laugh, but there IS a definite relationship.

Basically 6cc per minute per flywheel horsepower is a very close approximation of fuel flow at optimum air fuel ratio.

As you have six cylinders, and six injectors, that means max flywheel horsepower = Injector flow at 100 percent duty cycle.

So basically 550cc injectors would equal 550 flywheel horsepower absolutely flat out at full maximum duty cycle. But that is not real smart. You might want to limit it to 80% duty cycle maybe ? Which would be only 440 flywheel Hp.

But then there are drive train losses, typically only 85% of flywheel power makes it to the rear, so that comes to 374 Hp. Converted to Kw that is 275 RWKw.

Depending on the injectors you run, and assuming the fuel pump is up to the job you CAN figure out a reasonable RWKw versus injector size.

So absolutely balls to the wall with no margin might be injector size in cc x 0.85 x 0.746 = RWKw

Something safer and more reasonable might be injector size in cc x 0.8 x 0.85 x 0.746 = RWKw

Just curious as to what the 0.746 represents, that you have used in your calculations.

[Lunatikk]

Just curious as to what the 0.746 represents, that you have used in your calculations.

That should be the conversion multiplier from HP to Kw

[Trooper]

Just spoke to my tuner and he said there were no issues with the fuel pressure, it was 58psi when it was tuned.

Took the car on a longer trip and it does 11L/100km highway driving and 15L/100km for longish city driving.

The 270rwkw has been confirmed on two different dynos and I have reasonable knock figures (highest I have seen is 40 when really pushing it in 3rd).

Anymore comments?

[Beer Baron]

58psi is MASSIVE fuel pressure. standard is 38psi at idle (with vacuum).

[Trooper]

58psi is MASSIVE fuel pressure. standard is 38psi at idle (with vacuum).

Not at idle, 58 max so about 40 + 18psi boost.

[Adriano]

511rwhp on stock injectors.

it's all about the batch fire....

Sorry, batch fire makes no difference, when duty cycle is 100%, its still 100% if you fire it twice. There is only ways to make more power after you reach the limit of the stock fuel system, raise the pressure, which pushes more fuel through, change the injectors for bigger ones, or get additional fuel elsewhere ie water methanol or auxillery injector.

All the guys making significantly more power than the norm, i dare you to fit the fuel rail and injctors from a stock car and do a power run, the only way to be sure that you injectors are stock is to flow them agaainst known stockers.