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Old 03-15-2006, 01:29 PM   #1
thomasj
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Default Fuel Injector Duty over 100% ?

I wasn't hitting peak boost using a Cobb AP Stage 2 map (I was hitting about 15.0) so I shortened the length of my wastegate actuator by one full turn. I'm peaking at nearly at 15.7 now and have seen 15.8 once on a cooler night. I'm in Florida so we're not blessed with the best combustion-happy weather.

With that said, I figured I'd do logging with ECU Explorer to see how things were holding up.

Fuel Injector #1's duty cycle hit over 100% on several occasions. I'm not sure why that is. See this link for my data log. It's from a 5 mph to 131 mph run. I pretty much redlined 1st through 4th gear to demonstrate full load on the car so I could pinpoint potential issues.

Can somebody review this spreadsheet and offer insight? I didn't see any negative knock correction while in boost so I'm happy with that. However, if someone sees ANY other issues or can advise on the FI duty, let me know.

It only contains about 30 seconds worth of data so it's not that painful to look through. I put together some charts together in the spreadsheet too for giggles.

http://thomasj.org/subie/2006-03-14-ecu-logging.xls


Thanks in advance.


Tom
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Old 03-15-2006, 01:52 PM   #2
rjrutzky
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Stage 2 on stock injectors = 100% duty. Simple as that.
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Old 03-15-2006, 03:34 PM   #3
thomasj
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Thanks for the fast response. I was thinking about shortening the wastegate actuator arm another 1/2 - 1 turn in hopes of hitting 16 psi regularly. Based on the numbers in this spreadsheet do you have any idea of how much more boost I could safely run before a) running too lean and/or b) putting too much pre-load on the wastegate?

I'm at about 11.25:1 AFR right now on full throttle.
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Old 03-15-2006, 04:02 PM   #4
rjrutzky
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Quote:
Originally Posted by thomasj
Thanks for the fast response. I was thinking about shortening the wastegate actuator arm another 1/2 - 1 turn in hopes of hitting 16 psi regularly. Based on the numbers in this spreadsheet do you have any idea of how much more boost I could safely run before a) running too lean and/or b) putting too much pre-load on the wastegate?

I'm at about 11.25:1 AFR right now on full throttle.
Is that a wideband reading? You are already too lean IMO. I would turn the boost down instead of up. 11.5 afr and 30 deg timing at redline in 4th is scary to me unless your running 100+ octane.
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Old 03-15-2006, 04:31 PM   #5
thomasj
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Thank you for the fast response and the tips.

It's a narrow band sensor (Air Fuel Sensor #1 according to the ECU) that's already in the car. With that said, hopefully, the reading is slightly inaccurate in my favor. That's just wishful thinking, though.

Also, I was running roughly 94 - 94.5 octane gas at the time of this test. Maybe I should try again with just 93 to see if it richens at all.

Do you have any tips in getting closer to target boost without running the HWG map or further preloading the wastegate actuator? Thanks again.
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Old 03-15-2006, 04:31 PM   #6
TravisSTi
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There are a few things you can do to lower the Injector duty. Lower your boost in that range, get larger injectors, or a water injection system.
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Old 03-15-2006, 06:19 PM   #7
boundy3
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11.25 is the lowest the stock AF sensor will read.

I too have seen over 100% IDC and I'm only stage 1.

I remembering reading a while back about others also seeing greater than 100% IDC and there being talk about how IDC is calculated and is not completely accurate (obviously since were seeing over 100%).

The only real way to see if your not getting enough fuel is to do some logs with a wideband.

Did you do any logs before you turned the wastegate, and were you seeing the same IDC%'s?

good luck, and I wouldn't worry about it too much.
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