Stock injectors: max capacity after tuning???

[mongraven]

How many fuel can pass stock injectors on 4g63t with walbro255, fuel pressure 5kg, S-AFC II (max 50% correction)???????
i've found a site with calculations but i can't use it, because don't understand some english words (parameters).
What is the stock injector's parameter? 285 cc/min???

thanks

 

[crankbender]

450 stands for cc/min. That means that at the rated fuel pressure (arn't the injectors rated at 43 psi even though the base fuel pressure is lower on a 1G). That said a 550 is cc/min etc etc.

The afc is ment to match the fuel to the air flow. If you are metering correctly you should not need to bump this up much. Deffinatley not 50%


AFCs are usually used once you change from the stock injectors and or mas.



Of course forgetting all this just saying 450cc is probably within the tolerance of the age of the injector...despite a change in fuel pressure. So the easy answer is 450 cubic centimeters per minute.

 

[mongraven]

thanks. but i don't understand why people change this injectors for 550 cc/min. the difference doesn't seem big.

 

[Cirus_93TSI]

your stock 450cc injectors are good for about 240-250 wheel horse power, with an afc to manage your fuel you should be able to get fairly close to 250 at the wheels if you know how to tune. but your afc settings with stock injectors will be very insignificant, maybe +5 to +10 before you max your stock injectors out at 100% duty cycle.

550s are good for ~22% more flow, which gives you fuel for nearly 50 more hp at the wheels(you would set your afc to -18 to compensate for 550s on the lowe map). so you can obviously see why people buy larger injectors, the difference between 240 and 290 hp at the wheels could mean as much a whole second difference in the quarter mile. i run 550s and mine are near 90% duty cycle with my semi-hacked 2g mas throwing the airflow reading off. and im on a low boost, so im going with 680s to leave room for some more horse power.

if you dont have a data logger already then you are in serious need of one, it makes tuning more presice instead of guess work.

 

[mongraven]

i want to stop at 6,5 sec (100km/h).
if 250 hp will be enough for it for my AWD Talon?

if no, i'll find a bigger turbo, 550cc, fmic. i think it will give me about 330 hp. isn't it?

 

[nine5raptor]

Stock injectors are easily capable of that.

Anyone know the stock 0-60 (0-62 mph = 0-100km/h) time?