I guess the point is....how certain are you in your calculation of 99% IDC? We can all throw around the numbers we put down in the loggers but the issue is knowing how to determine the ACTUAL IDC. I run a walbro on my car putting down upwards of 108% IDC's (which is closer to 98-99% if the scaling percentage I just tried is closer to real numbers)on some pulls at 11.2-11.0:1 though. I'll be tuning it for leaner AFR's once I get my new WB sensor.

 

what pressure are the stock injectors rated too? there must be a spec sheet to tell us how they behave above and below this pressure rating...

 

Most injectors aren't rated to a maximum pressure but rather to the industry standard of 43psi at a maximum of 80% duty cycle. Injectors can generally handle over 100psi of fuel pressure as anyone who has turbo'd a non-turbo car and has run a fuel pressure riser can attest to. I ran my stock 235cc injectors on my turbo'd 95 talon to a maximum of 120psi at 80% IDC.

 

It was the day I was getting tuned, Dynoflash told me my injectors were maxed out and running at 99% He mentioned that I should look into injectors if I planned on doing anything else. I am not sure what he uses to log. This was back in 2006.

 

The injectors I frequently run (FIC) are always rated at static flow, or 100% IDC, at 43 psi, or at least thats how they always perform and how they test independantly (now I'm waffling, and right out of the gate ). Now, this isnt the first time I've seen the 80% spec, and I feel like I was proven wrong for one brand at least, though I can't remember what forum it was on to even look it up. Someting to keep in mind though.

I'll have to search and see if there's a way to get airflow in lbs/min from EVOscan. I don't remember seeing it. On some logs from the track last night IDC dropped to 91% max when I got AFR up to about 11.4. That's somewhat disturbing, since I'm pretty sure boost is maxed out. My first thoughts are that either my boost guage went to **** or Ive misread it (no boost logging=the lose=my fault) or this turbo is going too; either would explain my embarassing 105 mph trap speeds with the same AFR and timing that got me 111 with AEM (car's all parted out, just has cams at this point).

I've got a ton of work to do on the RWD talon today, hopefully I can dig into this more tomorrow. Ideally, I need to confirm airflow in order to confirm that IDC works as it does in DSMlink.

 

I think new version of evoscan has airflow in lb/min - not yet released thou

 

I hope so, that'd be extremely useful.

 

Its based on load calc though...ooops cat of bag.

The right way is still calculating off the 2 byte load and using 2 byte airflow...least in my opinion.

 

If you can just calculate it off of 2byte load and 2byte airflow, we can simply add a definition in evoscan to calculate the formula and graph it then.

I'm actually going to go out right now and test the TRUE maximum IDC at one of the injector harnesses with my meter which reads duty cycle to see what the IDC the ECU is ACTUALLY telling the injector to do. From there I should be able to figure out the difference between whats really happening and whats being logged.

 

I gotta eat now but I wanted to point out that my testing leans more towards the injectors being 530cc than the 560cc people mentioned. More info after I fill up with some foodage.

 

Great Post, I just got off the dyno with 22lbs and logs show over 100%. It was tapped at mid 11s af. I even logged the fuel pressure to reasure there was no fuel pressure drop. Kinda dissapointed about 300 to the wheels, looks like 780 are gonna be order.

 

But this still does not confirm if injector scaling has anything to do with IDC.

 

Injector scaling has everything to do with IDC.....well, Injector Pulse Width, which formulates to IDC. Here are the 3rd gear logs driven on the exact same straightaway, one with 472 injector scaling and the next with 513 injector scaling. The percentage the IDC changed increased is the same ratio the injector scaling also changed.

IDC@7000rpm with 472 scaling: 113.8%(rounded)
IDC@7000rpm with 513 scaling: 104.7%(rounded)

actual IDC with 560cc injectors: 95.9%(rounded)
I changed the Evoscan definiton to correctly show the Pulse Width value for 560cc injectors (if they are indeed 560cc injectors from the factory) which will also show the correct IDC values.

I edited the InjPulseWidth Eval formula so no matter what injectors you are using you can edit it to show your real values.

Eval="(0.256*x)*(513/560)"

RED= scaled value in ECUFlash
BLUE=actual injector size in cc's

 

You changed the inj scaling but not the fuel map? In that case the IPW and IDC changed, but so did the AFR.

If the IPW figure we are logging is not IPW but a value that becomes IPW after it is processed with the inj size then the conventionally logged IPW will not reduce when you retune for larger injectors or higher fuel pressure, but it does.

I've been wrong before but I think in this case people are overcomplicating it based on present evidence.

My IPW logs behave exactly as I would expect them to, at the power levels I would expect them to.

 

Well, I am still waiting for my new WB sensor to come in so if someone with a wideband wants to do one pull at 472 scaling and another at 513, that'd answer that question instantly.