Erratic VE idle/cruise vs Large Injectors 1700cc

[Nastruck]

So I've tuned roughly around 80-90 vehicles of my local area from stock to built boosted vehicle. Seems like the larger the injector the more erratic the VE table gets below 60-70kpa. My buddies car camed 5.3, s485, fic1700cc, 06pcm is very erratic between 30-60kpa. 50kpa it gets so lean it asks for almost as much fuel as it does tipping into boost. I understand that this section of the VE with Large injectors the PCM is expecting a linear injector flow, but down low its hard to control this area and is no longer linear as stated on my ERM tuning tutorial and in this page here.
http://www.enginelabs.com/engine-tec...tion-with-fic/

Injectors we have are Fuel injector Clinic but still same situation. Now is there a way to go about smoothing this lower section of the VE out. lowest I seen the Injector pulse is 2.1. This is with all proper data emailed with the injectors being used. Does the pulse width need to be lower in this area to help smooth this out its just very strange looking at 50kpa.

[mowton]

Without a log its tough to answer, but if you are street tuning the VE, are you filtering out Decel error data and throttle changes greater than 5% over a 200ms period. That and engine temp and if tuning in closed loop (LT/STFT) are the basic filetrs I start with. Will quiet alot of the erroneous error values created by driving on the street.

Assume also the boost referenced regulator was set to 58 psi without the line attached.

Also, not related but the PE enable looks a bit late for my liking. The MAP is 90 kPa and the throttle is 90% which basically says you have to be really hard into the pedal to trigger the PE. Again without a log its tough to see how it is responding,

Ed M

[Nastruck]

I'll try and get a current log soon its pouring rain today here. Tuning is open loop on PLX wideband. I'll check out the PE. This is a fresh restart file cause didn't realize before had the wrong map sensor data and the kpa was higher than it should have been for a Zr1 map sensor. I know older file the throttle % was way lower in case of part throttle boost load while cruising

[Nastruck]

Also this was all just sitting in the driveway trying to get idle/P/N/Gear load part of the VE decent enough before going driving again. How do I go about filtering out decel error and throttle changes to 5%. Is there a section in the tutorial with the filter setup? I'm not home with my laptop to look through it

[mowton]

I'll try and get a current log soon its pouring rain today here. Tuning is open loop on PLX wideband. I'll check out the PE. This is a fresh restart file cause didn't realize before had the wrong map sensor data and the kpa was higher than it should have been for a Zr1 map sensor. I know older file the throttle % was way lower in case of part throttle boost load while cruising

Forget the PE throttle, my bad, only the Hot Throttle is 90's but I would change that just incase as well. The Cold is fine....sorry

Ed M

[mowton]

Also this was all just sitting in the driveway trying to get idle/P/N/Gear load part of the VE decent enough before going driving again. How do I go about filtering out decel error and throttle changes to 5%. Is there a section in the tutorial with the filter setup? I'm not home with my laptop to look through it

Yes, Module 11M Filter Addendum pg 80 has a section were you can actual select the filter elements and copy/paste to the Graph filter section and connect with AND/OR as required. Includes a section defining the 3 FTC conventions for the decel filtering.

Let me know if you need anything else

[Nastruck]

Only 2 more things. I have logs cruising around and running down the track on the wrong map settings from previous tune. Only thing you can't see a mph cause its a Th400 if you wanted to see any other logs.

Other thing I'm curious about. I've read many many different ways to build boost faster at the line. Car has Lingenfelter LNC-003 2step without timing retard option. Would you suggest adding timing or pulling timing in this spark area to build boost faster at the line. Car had a stuck waste gate partly open so it wouldn't build boost much at the line then boost creep high by end of the track 1/8mile, but I been looking into many different suggestions on how people try to build boost faster on the 2step and trans brake. With pro tree we need it to build as quick as we can cause I think theres a 7 second time frame before you get a red bulb before bumping into double bulb at our track.