Well,
used this equation to correct my fuel constant for slightly larger injectors ( 336cc(32lbs) vs stock sc 310cc).
310cc constant 0.32359
New constant = Old Constant x (old injector size/new injector size)
nc = 0.32359 x (310cc/336cc)
nc = 0.32359 x (.922619)
nc = 0.2985502
Plugged that number into the hpt program and reflashed car.
Results.
It worked. I didn't have problems idling before, but now at WOT all my pulls thru the gears to 200km/hr (he he) didn't go past 101% of duty cycle. The other day i was logging 130% duty cycle of the injectors (yikes). Its not a pernament fix, but does show that it works. Only pulled on MISfire code when the injector cycle was 100% from 180ish-200ish km/h. They were probably close to clipping. not good.
But ya, just thought i'd share.
Evolution of Cavyboy-->C22t--> C24na--->c24s/c
1995 Cavalier W/2k1 Engine
GM S/C 13.940@99.78pmh w/2.068 60ft
i read on a post somewhere that duty cycle should be under 80 percent at all times!!!!
tuning with your duty cycle? i hope you have a wideband!!!
|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|
yea improvement but your still way past the red line on those injectors
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
It's sad that I am pusing 370cc injectors to 93% heh...
good lukc bud!
LE61T PTE6262 Powered 
Phil - not really. 370cc injectors aren't even really good for 300 whp reliably so I can see you maxing them out pretty quickly
When I sized 550cc injectors they were barely good for 400 horses. Really puts the stock 252cc injectors into perspective.
Time for new injectrors, I'd say!
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
actually philbert your at 89% im at 93% but either way its not good
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
I'm running RC 650cc, might be moving down to some 550cc or 440cc soon, these run perfect with factory fuel pressure, just screwed with the constant...
HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED
i have 440s for sale...
i was going to use them, but new plans mean I need MUCH larger injectors
PM me
ford green tops, never ever used brand new
constant duty.......always good
Quote:
didn't go past 101% of duty cycle.
Still, anything over 100% means the PCM is trying to turn the injector on for more time than is available. What you've done is determined that you need 20% more fuel instead of 50% by making the constant match the size of the injectors.
The title of this thread should be "Changing the injector constant affects duty cycle." It's not correct until you are at about 80% max, and the AFR has to be right when that 80% shows up.
You might be able to turn your base pressure up to get slightly more flow. That would help some until the larger injectors are in.
The misfire could actually be excess spark advance or the plug failing to fire. That's the type of thing that I get concerned about. Ignoring a misfire under boost can lead to bigger problems.
-->Slow
