Standard my00 injectors are good for x KW ATW? - Page 2 - Perth-WRX.com

Kato · #11 05-12-2006, 12:53 PM

Quote:

Originally Posted by EVL WRX

CC of injector divided by 5 x how many cylinders = Max BHP at 100% duty.

So 440cc injectors in a 99 will equate to a max BHP at 100% duty cyle of 352 (263kw).

At 85% IDC to be safe it is 300hp (224kw)

Assuming around a 15% drivetrain loss, that would mean at 85% ICD the injectors can support 190kw's at the wheels..

At 90% ICD (still pretty safe) they'll hold 201kws atw...

Use an FPR to up the pressure and they'll hold more kw's at the same %'s...

Hope this helps

Cheers

Wow that is some quality info. Many thanks!

Question though... why divide by 5 ?

EVL WRX · #12 05-12-2006, 12:59 PM

No idea John, that's the formula that I've used for my last few cars... It's all over the net and seems to be the accepted method to work out power levels with injectors...

BOMB3R · #13 05-12-2006, 01:01 PM

Which means my injectors could handle 250+kw, cheers mate.

tuna · #14 05-12-2006, 01:25 PM

very subjective, assuming fuel qualities and assumption on a static 15% drivetrain loss...

EVL WRX · #15 05-12-2006, 01:33 PM

Definately Stace, That formula works on the assumption the injectors are flowing the stated CC and the drivetrain loss is close to 15%, for extra safety you could calculate on a 20% loss and go from there.

Also, I read soemwhere the higher HP you go, the lower the drivetrain loss. For example, a 200hp car may lose 30hp throught the drivetrain which is 15%. But the same car with same drivetrain running 500hp shouldn't lose 15%, there is only so much heat that be taken out of the drivetrain.

Or it read something similar to that anyway..

Kato · #16 05-12-2006, 02:41 PM

Yeah I would be applying a big safety factor to any numbers from that formula. However, a very handy tool for quickly working out a rough injector size.

Now to find out why divide by 5

Some days I hate my brain