Injectors...
09-28-2006, 02:08 PM
#1
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Injectors... So, some of the resident geniuses have made some helpful spreadsheets when it comes to tuning for larger injectors...and for that, I think I speak for most of us when I say, "We're greatful!" However, there are several other injector tables in our tuning packages outside of flow rates and I'm confused (I hope I'm not the only one) on when to get my hands dirty with these. From what I can tell, there is:
IPW Voltage Adjustment: changes IPW as the battery voltage changes. I figure this one is pretty much what it is and should be left alone.?.?.
Injection Timing (or offset maybe?): changes the actual opening of the injector in accordance with coolant temp. As the motor warms up, this number gets bigger. Why?
Injection Timing Trim: values shouldn't exceed the previous table...used to limit maximum offset?
Injector Flow Rate: Populated by spreadsheet mentioned above. If this table pretty much determines how long the injectors stay open (based on flow) and the timing/offset table determines how early the injectors open, how do we optimize these for better power? Or am I totally off track?
Injector Voltage Correction: can adjust for voltage swings in the fuel pump...innactive from factory.
Minimum IPW: smallest possible commanded pulse width for a given RPM.
Default Min. IPW: table used in place of the Min. IPW table if commanded pulse width is smaller than the values in that table.
Small Pulse Adjust: values added to short injector on times (less than 4ms). If the computer is commanding a short injector duration, why would you want to make it stay open longer? Factory, these are set to increase as commanded injector duration is decreased.
Granted, these tables might be called something different in HPTuners vs. my copy of EFI Live. But, I'm pretty sure we both have these tables. Any ideas on when to use them or what to use them as a fix for (i.e.- lean tip-in, lazy NBO2's, injector swap side effects, etc.?)
IPW Voltage Adjustment: changes IPW as the battery voltage changes. I figure this one is pretty much what it is and should be left alone.?.?.
Injection Timing (or offset maybe?): changes the actual opening of the injector in accordance with coolant temp. As the motor warms up, this number gets bigger. Why?
Injection Timing Trim: values shouldn't exceed the previous table...used to limit maximum offset?
Injector Flow Rate: Populated by spreadsheet mentioned above. If this table pretty much determines how long the injectors stay open (based on flow) and the timing/offset table determines how early the injectors open, how do we optimize these for better power? Or am I totally off track?
Injector Voltage Correction: can adjust for voltage swings in the fuel pump...innactive from factory.
Minimum IPW: smallest possible commanded pulse width for a given RPM.
Default Min. IPW: table used in place of the Min. IPW table if commanded pulse width is smaller than the values in that table.
Small Pulse Adjust: values added to short injector on times (less than 4ms). If the computer is commanding a short injector duration, why would you want to make it stay open longer? Factory, these are set to increase as commanded injector duration is decreased.
Granted, these tables might be called something different in HPTuners vs. my copy of EFI Live. But, I'm pretty sure we both have these tables. Any ideas on when to use them or what to use them as a fix for (i.e.- lean tip-in, lazy NBO2's, injector swap side effects, etc.?)
03-24-2007, 04:07 AM
#7
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The main reason to even look at these let alone touch them is if you are having trouble controlling fueling. Normally this is at low rpm/map area's when using large injectors which when they fire dump loads of fuel.
You can look at dropping min pulse etc to get closer to commanded values at idle etc.
(ie) Think 60lb injectors on stock engine with forced induction. Fine for high rpm/map operation but at idle the stock min pulse width is going to mean more than 2x the fuel is dumped in at min pulse with the 60's
You can look at dropping min pulse etc to get closer to commanded values at idle etc.
(ie) Think 60lb injectors on stock engine with forced induction. Fine for high rpm/map operation but at idle the stock min pulse width is going to mean more than 2x the fuel is dumped in at min pulse with the 60's
