strange injector duty cycles?
Thread Starter
Eats, Sleeps, Dreams Rotary
Joined: Aug 2002
Posts: 3,118
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From: Dallas, TX
strange injector duty cycles?
Hey guys and gals,
About a month ago I went on a couple of high boost runs after I got my PFC tuned.
PFC was set to .90, and spiked at .99 (don't let your PFC control boost...). On one of those runs, my injector duty cycle hit 98.6% on a stock fuel system.
After the 5th highway run that night, I burned out my clutch. Still works good, just not if I drop it. Anyways!
I've set my boost to .70 on low setting as to preserve my clutch until I can get it replaced. Tonight I was running another car for sport (ZX2 focus..) haha, laugh, I know.
Point being, my max boost was .72 on a run, and my injectors hit 92.4%!! Why is it that on such lower boost levels, my injectors were >90%? It doesn't make sense to me.
Both times my intake temps were appx 45-55c. I can't see why my injectors were working almost as hard with around 3lbs less boost as before.
I plan on getting a supra fuel pump tomorrow and finding some 850cc primaries (anybody have 'em??). That should be enough for now, until I get my ported motor and bnr 2 or 3's..
It just boggles my mind that my injectors were hitting that hard on almost stock boost levels!
Ideas?
About a month ago I went on a couple of high boost runs after I got my PFC tuned.
PFC was set to .90, and spiked at .99 (don't let your PFC control boost...). On one of those runs, my injector duty cycle hit 98.6% on a stock fuel system.
After the 5th highway run that night, I burned out my clutch. Still works good, just not if I drop it. Anyways!
I've set my boost to .70 on low setting as to preserve my clutch until I can get it replaced. Tonight I was running another car for sport (ZX2 focus..) haha, laugh, I know.
Point being, my max boost was .72 on a run, and my injectors hit 92.4%!! Why is it that on such lower boost levels, my injectors were >90%? It doesn't make sense to me.
Both times my intake temps were appx 45-55c. I can't see why my injectors were working almost as hard with around 3lbs less boost as before.
I plan on getting a supra fuel pump tomorrow and finding some 850cc primaries (anybody have 'em??). That should be enough for now, until I get my ported motor and bnr 2 or 3's..
It just boggles my mind that my injectors were hitting that hard on almost stock boost levels!
Ideas?
Banned. I got OWNED!!!
Joined: Jun 2002
Posts: 3,323
Likes: 1
From: Buckhead
I think I have the answer, with my car, I will spike pretty bad and my power FC does not register the spike. For example..on my dyno we had my cars boost pressure hooked up to the dyno machine and it clearly showed a 15 PSI spike, even though I was set for 12 psi. My max boost was only .85. In otherwords, the power fc does not register the spike, but the injector duty cycle will register.
Thats my guess, the injector duty cylcle #'s were from the spike at transition. Set your power FC to be have the INJector duty cycle as the only thing you are viewing and run it hard from a stop, run till 6K or so in 3rd gear. I bet around 4500-5000 rpm you see the duty cycle spike and then it drops down.
Thats my guess, the injector duty cylcle #'s were from the spike at transition. Set your power FC to be have the INJector duty cycle as the only thing you are viewing and run it hard from a stop, run till 6K or so in 3rd gear. I bet around 4500-5000 rpm you see the duty cycle spike and then it drops down.
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