Tutorial-MAF Scaling for High Horsepower Setups
09-07-2018, 03:13 PM
#45
Moderator
iTrader: (4)
Join Date: Jul 2014
Location: My own internal universe
Posts: 10,452
Received 1,852 Likes
on
1,152 Posts
Looks like Joecar is onto it. The units in the proportional tables I posted are non-units. it's a scalar number. In the integrator side, it is seconds, and there is a multipler. The integrator is the STFT, I'm sure. Really, the long term fuel trim is a slower acting integrator. The proportional is what keeps the fuel bouncing back and forth from 100 to 800 mV so it can make sure it is near stoic. Pretty sure that's what that base correction is you posted below. I just had to reduce the proportional numbers. stock on mine in HPT were 128. I had cut them to 33 for the injectors and ended up at 11 for the tune scaling. not sure how that translates into EFILive, but I thought it was worth passing along. What it was doing was similar to when you put bigger injectors in and it swings from 14.0-15.5 instead of staying near stoic (going 14.3-15.0 or the like). Hope that explains it better or helps confirm that what you found in EFILive is matching what I found in HPT.
09-18-2018, 03:33 PM
#47
joe and Darth....it seems this last one last thing will be my final conquest when it comes to a scaled tune. Since scaling the tune I CANNOT get it to idle richer than ~15.5-16 whenever the fuel trims are turned on. I realized I hadn't tuned the car since March when it was cold out, so for fun I set it open loop to see how off the AFR would be from a cold start since its like 100* outside.....dead nuts on 14.6. Idle and cruise are perfect....until I go back closed loop. I tried the following:
-Set STFT base correction at idle to 25% of stock and 200% of stock-result stays lean
-Set the base delay to 50% of stock and 200% of stock- result stays lean
-Tried combinations of the above and still couldn't get it to idle richer.
I feel like I'm missing something or a table that I need to change to pull the AFR down in CL. Thoughts?
-Set STFT base correction at idle to 25% of stock and 200% of stock-result stays lean
-Set the base delay to 50% of stock and 200% of stock- result stays lean
-Tried combinations of the above and still couldn't get it to idle richer.
I feel like I'm missing something or a table that I need to change to pull the AFR down in CL. Thoughts?
09-19-2018, 02:01 PM
#50
Moderator
iTrader: (4)
Join Date: Jul 2014
Location: My own internal universe
Posts: 10,452
Received 1,852 Likes
on
1,152 Posts
Mine reads lean at idle also, but that's on purpose for me. What's interesting is my AFR gauge reads lean, but on the logs, it is within 2% lambda error. So I go with the logged number. AFR logs match the last dyno run I did. Kind of weird. i've learned to live with it. At higher load, the gauge and the logs match up. probably not helpful to you though, unless it is just the headers messing with the readings at low flow?
09-19-2018, 02:10 PM
#51
At WOT it does go to commanded AFR, but thats because WOT is OL I assume lol. At cruise it's not even that leave, it's mostly at idle. I assumed, perhaps falsely, that I should be able to sway the fuel trims lean or rich via SOME combination of tables.....but can't figure out which table that is. I can literally idle the car OL @ 14.6, flash the same tune with CL, and watch the fuel trims say pull 10% fuel and the wideband matches.
09-19-2018, 05:08 PM
#52
Moderator
iTrader: (4)
Join Date: Jul 2014
Location: My own internal universe
Posts: 10,452
Received 1,852 Likes
on
1,152 Posts
You're right - WOT is OL. On mine, even cruising, everything lines up nicely.Just for some reason at idle, it reads lean. i've long since assumed it was false lean, possibly incorrectly.
09-19-2018, 05:27 PM
#53
I definitely think it's truely lean as I can hear the difference in the motor when I change it to OL idle and the wideband and fuel trims both show lean/pulling fuel. Would just LOVE to understand it haha. Right now I'm using a hybrid tune, the PE table it set to 14.6 and 0% throttle up to 1200rpms and above that goes CL. OL idle, CL cruise, OL WOT haha.
01-16-2019, 10:05 AM
#58
Thank you for the detailed write up. Its exactly what i was looking for.
building a remote mount turbo lq4.
I need ac. And dont want a cramped engine bay.
car is a formula. And im not cutting or modding the front cover in any way. So its getting a a2w setup
I need silky smoove driveabilty out of boost.
stock lq4 w ls9 cam. 3k stall. I would b happy w 550-600rwhp tbh. Keeping the stock rear. I have a fabricated narrowed 9inch. But dont plan on using it anytime soon on the car.
shouldnt b tol hard to get what im asking for. With a maf setup and about 10psi
building a remote mount turbo lq4.
I need ac. And dont want a cramped engine bay.
car is a formula. And im not cutting or modding the front cover in any way. So its getting a a2w setup
I need silky smoove driveabilty out of boost.
stock lq4 w ls9 cam. 3k stall. I would b happy w 550-600rwhp tbh. Keeping the stock rear. I have a fabricated narrowed 9inch. But dont plan on using it anytime soon on the car.
shouldnt b tol hard to get what im asking for. With a maf setup and about 10psi
