hello all, im curious as to what you guys are finding on the high hp turbo/alcohol cars.
does somewhere such as RC engineering do the dynamic flow testing of the injectors ?mh said:to get the actual flow numbers at xxpsi you have to dynamicly flowtest the injectors (test them at all pulswidths, most injectors are not lineare in their output)
but if you assume the injector flow is linear this formula works.
squareroot(new pressure / old pressure) * old flow rate.
V(80/43,5)1680 = 2278,3cc
from what i've read alcohol FI cars usualy range from 1.1 - 1.3 bsfc
why\how are you running 14 injectors? if it's a 4 cylinder it makes more sense to run either 12 or 16?
exactly what it isSIXTYdashONE said:i think they are running 12 and then 2 injected into the upper charge pipe.. Id dig up a picture but im too lazy
I have been there before.. Chances are the injectors aren't actually flowing anywhere near what you would expect them to at the increased pressure. I have had had pretty good luck estimating (caluclating) fuel flow as above on some applications, but saw that the 160's seem to hit a wall as far as flow, in spite of additional base pressure. The only sure way to know how much fuel you're moving is to get fuel flowmeters on the car (not cheap, but a very powerful tool).i dont have an "accurate" HP reading, because of either tire spin/clutch issues on the dyno.
im using 1050 as the Hp @ the crank in my calculations.
BSFC = (lbs/hr)/ brake HP
lbs/hr = (inj cc) (#of inj)/ 10.2
another problem i have is.. how much fuel these injectors are actually flowing @ XXX psi ?
so ill make 2 calculations one using 1680 cc and one using 2100 cc
(supposedly a 160lb injector will put out 200lbs @ 80 psi ?? )
14 inj x 1680 cc / 10.2 = of total fuel lbs/hr = 2305.882
14 inj x 2100 cc / 10.2 = of total fuel lbs/hr = 2882.352
from the logs we have 10 inj @ 100% and 8 inj @ 45%
100% of 1680 = 1680 x 10 = 16800cc/min / 10.2= 1647.058
45% of 1680 = 756 x 4 = 3024cc/min / 10.2= 296.47
1647.058 + 296.47 = 1943.528 total lbs/hr being consumed by the engine
1943.528/ *possible brake # = 1.850 bsfc
with that in mind. we burnt an electrode and the plugs are showing heat in them.
any ideas ? do i need to go back to math school ?