Power FC lag times???? way to negative?
03-18-10, 11:32 PM
#1
lag times???? way to negative?
have 500 on the car now and been fiddling with the data logging. i am running stock 850's as primary injectors and i have them set to 65% at a -58 lag on front and -48 lag rear and i get a 11.7 to 12 AFR with idle timing it like 17 with a 2 split. i have all settings set up for manual idle since i am not running any emissions equipment. i also have tried to lean out some lean afrs and id dont seem to help. and shouldnt the INJECTION MAP be disabled and do nothing as i dont have any o2 feed back set up?
03-19-10, 04:27 PM
#3
Eye In The Sky
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O2 FB only works on the upper left hand corner of the correction map and also requires the air pump to be working. Turn O2 FB off. The PFC still takes the correction map and applies it to the base map even without O2 FB working.
Run a recalc to move the correction values to the base map. Then start tuning the AFR.
Run a recalc to move the correction values to the base map. Then start tuning the AFR.
03-19-10, 11:25 PM
#5
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No matter which of the possible tables you use to lean out the idle area,
the PFC will not let you lean out the primary injectors beyond a set small value.
The only way to do this is by using negative lag.
the PFC will not let you lean out the primary injectors beyond a set small value.
The only way to do this is by using negative lag.
03-20-10, 09:17 AM
#7
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Base fuel pressure (fuel pressure at 0 psi) also has an affect on idle AFRs.
A stock FD had a base fuel pressure of around 38 PSI.
I am currently working on a FC which has a base fuel pressure of 44 psi and requires -.40 primary lag.
Experiment and learn.
A stock FD had a base fuel pressure of around 38 PSI.
I am currently working on a FC which has a base fuel pressure of 44 psi and requires -.40 primary lag.
Experiment and learn.
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03-20-10, 07:19 PM
#9
You can never get 850 primaries to idle properly lean on the PowerFC. Negative lag is a hack to make it a little better so its not horribly rich but it affects some throttle transitions and drivability smoothness. You can also never get it to idle at 13 afr no matter how much negative lag you put, I'm assuming its another PowerFC unknown limit.
If you want your car to run nice, ditch the 850 primaries and get 1600cc secondaries. That way you have all the fuel you'll ever need and if you go single or whatever (assuming you are still twins), you don't have to spend more to upgrade your fuel system.
Also, you can probably lower your idle area more to get it leaner. I usually just set idle area on 850's to 1.5 ms since that just makes it hit the limiter. Make sure you have your INJ MAP recalculated before touching the base map so you know what the real numbers are.
thewird
If you want your car to run nice, ditch the 850 primaries and get 1600cc secondaries. That way you have all the fuel you'll ever need and if you go single or whatever (assuming you are still twins), you don't have to spend more to upgrade your fuel system.
Also, you can probably lower your idle area more to get it leaner. I usually just set idle area on 850's to 1.5 ms since that just makes it hit the limiter. Make sure you have your INJ MAP recalculated before touching the base map so you know what the real numbers are.
thewird
03-21-10, 12:20 PM
#10
ok got ya.i am looking for 500 hp in the future so i already have 1600's on my car. now dont i want to tune the correction map to get it as close as i need then run recalc to make the base map the foundation and then do the final tuning on the corrections map right?
03-21-10, 05:17 PM
#11
I use the correction map to do live tuning but then recalc the base map when I'm done so I can export it to excel and look at the fuel curves. When I'm trying to perfect drivability I just use the base map only with excel spreadsheets to make sure all the lines are nice and smooth and transition nice. When I'm tuning idle, I do it directly off the base map manually.
If you think you might need more fuel, just put the 2000cc secondaries and lower your primaries. I have tried 850, 550, and then 750 in my primary rail. I still have the 750's in there and they are better then the 850's but they still aren't close to how smooth I could make the car drive with the 550's as well as the nice lean idle. When I pull my motor out soon, I'm going to try 650's. If I can get mid 12's without negative lag I'll be happy.
thewird
If you think you might need more fuel, just put the 2000cc secondaries and lower your primaries. I have tried 850, 550, and then 750 in my primary rail. I still have the 750's in there and they are better then the 850's but they still aren't close to how smooth I could make the car drive with the 550's as well as the nice lean idle. When I pull my motor out soon, I'm going to try 650's. If I can get mid 12's without negative lag I'll be happy.
thewird
03-28-10, 11:39 AM
#12
Ive got my 850's to idle in the mid 12's at 0 lag with the injector atomization port hooked up, I had it capped off before and couldnt get it to lean out past high 11's/low 12's. I tried adding a bit of negative lag and had a nice steady idle in the mid 13's but I never drove it like that because I wasnt sure how it would affect the rest of my map and didnt want to risk anything but I know its possible.
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