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Well,
still can't walk with my knee yet, but took the s/c cavy out for a spin to log 1 WOT run. Now, the a/f ratios are pretty good all the way thru, using the stock 0.3xx injector constant. But when going thru the top of the each gear is show the injector duty hitting a high of 131%.
Now i have some larger 32lb(336cc) injectors in there vs the stock s/c 310 ones to help with the smaller pulley hitting 8-9psi. Now, i don't understand. If i wwere to change the injector constant to 0.2xx(the number i figured out with shifted's equation) would that make it run with learner(and even higher duty cycle)? Cause right now, the pcm things its go the 310s in there and is trying to conpensate for more air, thus leaving them open which should equal more fuel...
But on a positive note, there was almost 0 knock all the way thru the pulls. I got like .8 at 4k, and 0 the rest of the way to redline. HOWEVER, since i haven't driven my car in a week, and read the pcm, i don't know if this effect any (ie..resetting the relearned fuel trims). Cause i almost had the misfire code come up. I rarely get that even when i'm racing. Happens once in a blue moon.
Any input?
Nate
Evolution of Cavyboy-->C22t--> C24na--->c24s/c
1995 Cavalier W/2k1 Engine
GM S/C 13.940@99.78pmh w/2.068 60ft
im a fuel newb...how can u have 131% duty cycle
and on a side note....hehe.....duty
DUDE your injector duty cycle should never go above 80% you need to get some larger injectors in there now
at least some 440s if your cycle is that far off maybe even 550s
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
urs hit 93.........granted ur getting phils soon
Rodimus Prime wrote:DUDE your injector duty cycle should never go above 80% you need to get some larger injectors in there now
at least some 440s if your cycle is that far off maybe even 550s
I wonder what the stock gm sc injector duty is with the stock pulley on.
Rodimus prime,
i've got some 2.0 ion s/c injectors coming to me on friday. They are 36lb (378cc) injectors and have spacers to make them fit. What size injetors are u running? Even with HPT, is it neccessary to get a AFPR? Cause i'd like to leave the Fuel pressure alone, and just use hpt to make them idel. Is that possible? Is so, is it any more difficult then changing the injector constant?
Thanks
Nate
Evolution of Cavyboy-->C22t--> C24na--->c24s/c
1995 Cavalier W/2k1 Engine
GM S/C 13.940@99.78pmh w/2.068 60ft
crap...forgot you had an ecotec motor.
Would thin 440s would be way to big..no?
Nate
Evolution of Cavyboy-->C22t--> C24na--->c24s/c
1995 Cavalier W/2k1 Engine
GM S/C 13.940@99.78pmh w/2.068 60ft
im running stock 03FPR which is 55psi and 310cc injectors which even at 93% duty cycle are only giving me 12.6AFR in the high rpm range above 6000, im barely getting 6psi so I would say your going to need at least 440s, you should at least notice an improvement with the 370s, 131% something seems a bit off there though are you sure you have the guage set up in the vcm scanner program right?
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
Rodimus Prime wrote:im running stock 03FPR which is 55psi and 310cc injectors which even at 93% duty cycle are only giving me 12.6AFR in the high rpm range above 6000, im barely getting 6psi so I would say your going to need at least 440s, you should at least notice an improvement with the 370s, 131% something seems a bit off there though are you sure you have the guage set up in the vcm scanner program right?
Well, hopefully the new injectors will help. Really don't want to have to buy an AFPR. As for the duty cycle, i hope so, i downloaded urs from the htp forum (or was it here?). So i hope so. How would i go about setting it to make sure its right then?
Thanks!
Nate
Evolution of Cavyboy-->C22t--> C24na--->c24s/c
1995 Cavalier W/2k1 Engine
GM S/C 13.940@99.78pmh w/2.068 60ft
if it was the one i posted its ok
Im not sure how your even getting numbers that high, did you make VE table adjustments?
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
maybe cause he has slightly bigger injectors than the stock sc ones (310 vs. 336) and if he was using the stock 310's then he would hit 100% but since hes using the 336's he is getting more than 100%???? ionno just a thought....
2000 Camaro V6.
| SLP Loudmouth | CAI Intake | HID's |
Quote:
im a fuel newb...how can u have 131% duty cycle
You can't. That value is what the ECM is calculating as the required duty cycle to achieve the desired AFR. It's a cry for help from the pcm. The reason the AFR's are reasonable is because increasing fuel pressure is forcing more fule out the injectors, which BTW are on all the time. But if pressure drops, or even if the air humidity / temperature change, that will change the actual AFR and the pcm won't be able to compensate for it.
Quote:
If i wwere to change the injector constant to 0.2xx(the number i figured out with shifted's equation) would that make it run with learner(and even higher duty cycle)?
No. That number represents the amount of time the injector is on. It indirectly tells the pcm the injector is larger. It says "you don't need to turn the injector on as much since it flows more." The computer will respond with "Ok, so I'll reduce the duty cycle to keep the AFR where it should be."
How do you like that?
-->Slow
rod,
haven't changed anything yet. Just wanted to do some logging with the car the way it is.
Slow,
I know it seems 'impossible' to be open more then 100% but from what i've read in the ion s/c forum, a lot of those gus with 2.6" pulleys are doing just that with their 42# injectors (stage 2 kit). They are ove 100% as well,but maybe not has high as 13x. yikes..that is high.
So you think it if change the injector constant it will not only low the duty cycle, but still keep enough fuel in there?
Nate
Evolution of Cavyboy-->C22t--> C24na--->c24s/c
1995 Cavalier W/2k1 Engine
GM S/C 13.940@99.78pmh w/2.068 60ft
What slow is saying is: at or above 100% duty cycle, your injectors are not closing, they are constantly open, anything higher than 100% means you are farther from an appropriate sized injector, not that any more fuel is getting in the engine. By raising fuel pressure you can change the amount of fuel that flows through them, but you cannot raise it enough to enable the injectors to close, and still maintain an appropriate AFR. Your injectors are too small. You ideally want injectors that never exceed 80% duty cycle, as that leaves room to grow, and also time for them to close between pulses, so they don't overheat by being open constantly. Running the way you are, you are asking for an injector to fail, and your motor to blow.
By changing the injector constant, you do not affect the amount of fuel that flows, just lets the engine know what sized injectors it has, so that it can idle and drive at part throttle easier. At this point the ONLY way to get more fuel in, is to raise fuel pressure (wrong way), or get bigger injectors (right way). Hope that clears it up.
15.3 @ 89.97mph, 14's on the way?
Quote:
By changing the injector constant, you do not affect the amount of fuel that flows, just lets the engine know what sized injectors it has,
Or, to put it another way, you cannot make the injectors bigger by changing the constant. When the PCM is calculating that it needs 50% more fuel than what your injectors can safely deliver, you need bigger injectors.
I've seen people do what you're doing before... use the fuel pressure increase from boost alone and leave the injectors at or over 100%DC. There's been some heated arguments on other forums about whether or not this is safe. To me it's a crap shoot. If an injector fails, a filter starts to plug, you run on a fiarly cool day, or if a pump starts to fail, you may lose the engine. To each their own, but most people choose to install correctly sized injectors (or turn up the base pressure appropriately).
Oh, and maybe someone can correct me, but aren't the Ion guys locked into using a stock tune? That would explain why they can't make the adjustments to bring the injector constant into line. I remember reading that their pcm's don't tolerate any funny business with airflow or pressure sensors.
-->Slow
Clipping injectors = bad....mmmmmmmmmmmmmK
I used to race cars, now I race myself.
5K PB: 24:50
10K PB: 54:26
hey pm me if ur interested in buying some 441 ford lightning green top injectors. i have a set of 8 coming in the mail and of course i only need 4 lol.
u can also im me on aim at driveover55
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