Opinions on these methods to lower knock and IDC's...

[dpartinvr4]

The ECU cannot CANNOT directly change the Injector Duty Cycle (IDC) based off of fuel pressure changes. Simple as that. In order to do so, the ECU would need an input for fuel pressure. It does not have this (I know that you know all of this G, just stating it for others ). Thus, the ECU can only INdirectly change the IDC based on fuel pressure changes. How does this happen? The increased fuel pressure results in increased fuel delivery to the engine. The ECU sees the rich condition via the oxygen sensor. The ECU then applies long term fuel trims (LTFTs). The LTFTs result in a decrease in Injector Pulse Width (IPW). The decrease in IPW mean less IDC. This is true for closed loop operation. This can also be true for open loop operation so long as the ECU has spent enough time in the higher load areas to apply a correction there (which doesn't happen much when you remove the delays).

Long Term Fuel Trims....

[RealMcCoy]

Long Term Fuel Trims....

Only work in closed loop... They mean jack at WOT.

[dpartinvr4]

Only work in closed loop... They mean jack at WOT.

This can also be true for open loop operation so long as the ECU has spent enough time in the higher load areas to apply a correction there.

did you read it?

[RealMcCoy]

did you read it?

Yea.. And it might even be accurate for an OBDII Subaru... If I'm not mistaken, this thread is about a 1st gen 3S.

[dpartinvr4]

I still want to know his fuel trims, and his AFR.

[Chris@Rvengeperformance]

dang guys... The stock ECU pays no attention to your o2 sensors at WOT, that's why the o2 trim goes to 100. You could run 9:1 or 18:1 (please note this is just a ludicrous example, do not run these afrs, mmm'kay?) at WOT and the ecu would not step in until knock is encountered.

ANYTHING that causes the injector flow to be larger will just make the car run rich at WOT and not effect IDCs at all.. During closed loop operation if there is enough room to trim you may still be at 14.7:1 and consequentaly your IDCs WILL lower, but only because you are in closed loop.

Edit:

Additionally any air flow modifying device used to compensate for larger injectors or higher base fuel pressure can obviously affect IDCs because when adjusted the ecu sees less airflow, therefore injects less fuel.

[dpartinvr4]

dang guys... The stock ECU pays no attention to your o2 sensors at WOT, that's why the o2 trim goes to 100. You could run 9:1 or 18:1 (please note this is just a ludicrous example, do not run these afrs, mmm'kay?) at WOT and the ecu would not step in until knock is encountered.

ANYTHING that causes the injector flow to be larger will just make the car run rich at WOT and not effect IDCs at all.. During closed loop operation if there is enough room to trim you may still be at 14.7:1 and consequentaly your IDCs WILL lower, but only because you are in closed loop.

yes, but his IDC's are above 100% which is the ECU trying to reduce his knock by ritchening up the mixture, so to get back to even 100% IDC at WOT, if he turns his pressure up, it will help to reduce his knock, so his ecu won't start dumping fuel in when it does absolutely nothing IDC>100%

[Chris@Rvengeperformance]

yes, but his IDC's are above 100% which is the ECU trying to reduce his knock by ritchening up the mixture, so to get back to even 100% IDC at WOT, if he turns his pressure up, it will help to reduce his knock, so his ecu won't start dumping fuel in when it does absolutely nothing IDC>100%

loggers report IDCs WAY too high. If you are actually at 100% IDC you hit fuel cut.

[dpartinvr4]

we had him calculate "real IDC's" and they were correct. and my Hybrid HHH actually does report "real IDC's"

[Chris@Rvengeperformance]

we had him calculate "real IDC's" and they were correct. and my Hybrid HHH actually does report "real IDC's"

where's the log?