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What does it mean? And if your percentage is over 100%, does that mean you are out of injector?
Scott
Scott
Injector PW
- Thread starter IrvJr
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Does alcohol injection have any effect? I have bluetops and have only run 12.8 @ 109. I see people all over that run high 11's with theirs. What is my problem? Is it all in the chip, or do i have any control elsewhere?
I ran my Direct scan at the track yesterday trying out a new chip. Everything looked good, except the PW %. It was 133%. I only ran 17# of boost and wasnt even pushing it hard. 769 was the lowest o2, but i got 7* of knock retard. But it only happens at the very end of my runs, all the time.
What do i do to correct this?
Scott
I ran my Direct scan at the track yesterday trying out a new chip. Everything looked good, except the PW %. It was 133%. I only ran 17# of boost and wasnt even pushing it hard. 769 was the lowest o2, but i got 7* of knock retard. But it only happens at the very end of my runs, all the time.
What do i do to correct this?
Scott
On DS pay attention to the Inj. duty cycle. If they are true blue tops (36#'s) your not running out of injector running 12.8 @ 109. As far as the 02's, there are some questions that need to be asked first. Timing in chip? Type of gas (93,100,110,118 etc..)? Static fuel pressure?
You can throw more fuel into the chip, if need be, to correct for a lean condition. However make sure, under PE, that the BLM's are not locked. HTH
Mike Banas
87GN
You can throw more fuel into the chip, if need be, to correct for a lean condition. However make sure, under PE, that the BLM's are not locked. HTH
Mike Banas
87GN
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What happens if the BLM are locked under PE? I can check that since i saved both runs.
It happens on all chips. My street chip is 20* and my race chip is 24*. The most recent runs were with 110 and the race chip and #46 of fuel pressure line off.
Scott
It happens on all chips. My street chip is 20* and my race chip is 24*. The most recent runs were with 110 and the race chip and #46 of fuel pressure line off.
Scott
There is one HUGE PROBLEM that folks just love to ignore.
As you approach 95% Duty Cycles, the injector just loses the ability to have enough time to fully shut off or go completely on, so it just starts to buzz for an instant as you go from the 95% to static. While the injector is just buzzing the metering is kafussy.
Full throttle and an injector that can't make up it's mind if it's on or off is not a good thing, commonly splet B l o w n H e a d g a s k e t. Build an ecm bench and listen to it happen or swing by here and I'll show you what it sounds like. For the lower HP engines they can live with a LITTLE. As you go faster it becomes more of an issue.
Not all engines run the same AFR for best power some need more fuel then others. Just cause so and so ran a 10.6 with Purple tops doesn't mean your engine will.
And you also need large injectors to launch a hard leaving car. Of course one way around not having enough accleration enrichment with the fuel available is going to a looser converter.
It's about the combo, and tuning
As you approach 95% Duty Cycles, the injector just loses the ability to have enough time to fully shut off or go completely on, so it just starts to buzz for an instant as you go from the 95% to static. While the injector is just buzzing the metering is kafussy.
Full throttle and an injector that can't make up it's mind if it's on or off is not a good thing, commonly splet B l o w n H e a d g a s k e t. Build an ecm bench and listen to it happen or swing by here and I'll show you what it sounds like. For the lower HP engines they can live with a LITTLE. As you go faster it becomes more of an issue.
Not all engines run the same AFR for best power some need more fuel then others. Just cause so and so ran a 10.6 with Purple tops doesn't mean your engine will.
And you also need large injectors to launch a hard leaving car. Of course one way around not having enough accleration enrichment with the fuel available is going to a looser converter.
It's about the combo, and tuning
Eric Stage I
TurboTweak Guy
- Joined
- May 25, 2001
- Messages
- 2,671
Hee hee, running static is Bruce's pet peeve
Scott,
PW is pulsewidth, usually in milliseconds (ms). The % your seeing is duty cycle, which is a percentage of max pulsewidth time available at a given rpm. Around 100% and higher means your injectors are on all the time.
Its probably gonna take more than 17psi with your combo to get into the 11's.
We can assume that since the chip is at 133% dc at full throttle, that its a race chip and that its maker may have intended for the injectors to go static and therefore run lots of boost. I suspect that you would need around 25psi to use up that fuel.
If you are truly supplying that much fuel and only 17psi, the mixture may be so rich that any O2 numbers are probably meaningless and you could be getting "rich knock".
The other option is that there is something very wrong with your fuel supply system and you're running out of fuel. You should probably see if you can monitor your fuel pressure at wot to see if it is falling off, or you could be losing fuel volume somehow.
Good luck,
Eric
Scott,
PW is pulsewidth, usually in milliseconds (ms). The % your seeing is duty cycle, which is a percentage of max pulsewidth time available at a given rpm. Around 100% and higher means your injectors are on all the time.
Its probably gonna take more than 17psi with your combo to get into the 11's.
We can assume that since the chip is at 133% dc at full throttle, that its a race chip and that its maker may have intended for the injectors to go static and therefore run lots of boost. I suspect that you would need around 25psi to use up that fuel.
If you are truly supplying that much fuel and only 17psi, the mixture may be so rich that any O2 numbers are probably meaningless and you could be getting "rich knock".
The other option is that there is something very wrong with your fuel supply system and you're running out of fuel. You should probably see if you can monitor your fuel pressure at wot to see if it is falling off, or you could be losing fuel volume somehow.
Good luck,
Eric
