spoken like a true champion....

 

Its calculated in the standard method from IPW and RPM (that Evoscan or Mitsulogger read):

%IDC = 100*(IPW*RPM)/1200

I think that the reason the IDC goes beyond 100% is because of a safety factor in the injector scaling. Stock injectors are 560 cc/min, but in the Evo ECU, they are entered as 513 cc/min.

 

I can validate this statement with assloads of DSMlink datalogs.

I saw as high as 102% IDC on the stock injectors with the turbo completely flatlined at 42 lbs/min, at 7500 rpm or so. I can post screenshots of the curves of both airflow and IDC relative to rpm if anyone is interested, per the other posts after the one quoted above. Since I tune for 11:1 both in the DSMlink calculation and on the WBO2 (they match exactly), 102% IDCs result in an AFR of about 11.2. Not even worth talking about. This all lines up exactly with the math.

The EVO8 pump is a little riskier though. On stock wiring the pump can only maintain 11:1 AFR up to 34 lbs/min at whatever boost I was running, mathematically. By logging some runs at lower boost and some runs at higher boost but pedaling it a bit, this is the exact point it ran out of capacity to hold 11:1. AFR would ride right around 12.5:1 no matter what was done with the tuning, naturally. From that point on I was no longer surprised by the number of EVOs I've seen running 12.5:1 at high boost regardless of ECU, flash, or tuning decive.

According to the math again, rewired with 13.5 volts at the pump, it will support 44 lbs/min. And sure enough, on the first pull after doing the rewire, AFR snapped right back to 11:1 at 40 lbs/min. I logged as high as 43 lbs/min at 11:1, backing up the math. I can see no good reason to not rewire the pump. If you really feel the need to keep the factory dual voltage system, I'm sure that could be accomodated in the rewire somehow, but since the stock regulator is not overrun on the stock pump rewired at full voltage, I personally could not be arsed and never looked into it further.

I have absolutely no problem running injectors at 100% IDCs all day long for years on end, based on personal experience, but I don't like running around on maxed out pumps. So I went to a 255 and AFPR to be safe. There was absolutely ZERO change in my AFR and tuning. I then went to 950s just because DSMlink makes it so easy. IDCs are never much over mid 50s.

 

Well of course if you bump up the fuel pressure the story is different. An adjustable FPR and higher flow pump are just another way to add more fuel in a given period of time.

 

Properly sized injectors are preferrable to rasing fuel pressure above design parameters.

 

Agreed. I don't like bandaid solutions with the fuel system. Higher pressure makes the injectors bigger but the pump smaller, lower pressure makes the pump bigger but the injectors smaller. I prefer to size the fuel system components properly, and give the ECU the fuel pressure it expects to see.

 

i love it classic "whats next mod" question in a tricky way so you can get smart people like war talon to help you out without flaming you.