|
|
|
|
Thread Tools | Display Modes |
05-08-2017, 10:46 AM | #1 |
Scooby Newbie
Member#: 356242
Join Date: May 2013
Location: Jacksonville, FL
|
When do you rescale your MAF?
When would you want to rescale your MAF?
The common response I get is when you change your intake system. Does this include changing the intercooler? On my 2011 wrx I recently put on 38mm ewg, 1000cc injectors, pump, PW verticooler, colder spark plugs on top of full 3" dp. I got my injectors latency and scalar dialed in, my A-D learning values are all within +-5%. On WOT runs, my 1/3 corrections and learning values are zero. Thus, do I have to rescale my MAF?
* Registered users of the site do not see these ads.
|
05-08-2017, 10:47 AM | #2 |
Scooby Newbie
Member#: 356242
Join Date: May 2013
Location: Jacksonville, FL
|
If I don't see much change between the commanded AFR and the actual AFR can I also ignore rescaling my MAF?
|
05-09-2017, 07:53 PM | #3 |
Scooby Specialist
Member#: 385256
Join Date: Mar 2014
Chapter/Region:
NESIC
Vehicle:'18 Giulia QV '21 Giulia Q4 |
No you should not have to rescale your MAF. If you change anything in the intake tract before the compressor then you will need to rescale.
Last edited by 86Dreams; 05-10-2017 at 03:04 PM. Reason: poorly worded |
05-10-2017, 01:46 PM | #4 |
Scooby Specialist
Member#: 353788
Join Date: Apr 2013
Chapter/Region:
South East
Location: S Florida
Vehicle:1997 Cherokee Tuned by AlanSnackbar |
I had to scale mine when I put the K&N drop in. Anything intake wise needs it scaled
|
05-10-2017, 08:58 PM | #5 |
Scooby Newbie
Member#: 356242
Join Date: May 2013
Location: Jacksonville, FL
|
|
05-11-2017, 04:13 PM | #6 |
Scooby Specialist
Member#: 353788
Join Date: Apr 2013
Chapter/Region:
South East
Location: S Florida
Vehicle:1997 Cherokee Tuned by AlanSnackbar |
Yes. Showed the car running lean. EJ's are super sensitive to any air changes.
|
05-15-2017, 09:40 PM | #7 |
Scooby Newbie
Member#: 356242
Join Date: May 2013
Location: Jacksonville, FL
|
Thanks Josh,
My next question would be how do you differentiate between having to change the injector values vs. maf calibration? If all of my learning values are within +- 5% then when do I decide my maf needs to be rescaled granted I changed nothing before the compressor? I understand that the voltage-airflow relation needs to change if the correspondence is wrong, but conceptually because I put a different intercooler will this change the actual airflow going through the sensor itself to warrant a change? Random questions 1. If there is an air leak after the compressor, does it make the engine run rich on WOT and lean at idle? 2. And if there is an air leak before the compressor, does it make the engine run lean? |
05-15-2017, 10:12 PM | #8 |
Scooby Specialist
Member#: 453872
Join Date: Sep 2016
Vehicle:2005 wrx wagon 48w |
here is a LV of my car. (2005 wrx) stock inlet up to the turbo, vf48 with a big intercooler. injectors are from a 06-07 wrx using stock scaling and latency from a 2006-2007 wrx. the front O2 and MAF sensor are only a few months old.
as you can see if you leave the intake stock you should not have to scale the MAF, at least not the low end. if your pushing way more air than stock the top end might need some work. now if you have leaks it will throw your readings way off and will be pointless to use as a tool to scale the injectors. the reason you have no corrections at WOT is because you are in "open loop" which ignores the o2 sensor. you need a wideband to tune the higher flow ranges of the MAF. Last edited by CarmelValleyWRX; 05-15-2017 at 10:17 PM. |
05-16-2017, 06:40 AM | #9 |
Scooby Newbie
Member#: 356242
Join Date: May 2013
Location: Jacksonville, FL
|
Thanks CarmelValleyWRX:
So do people rescale their MAF for closed loop only? I have a wideband and based off my logs it looks like the commanded fuel final and actual O2 readings are exactly spot on. My AFR's are a bit wacky apart from WOT (I just blame that on how sensitive the AEM UEGO seems to act) |
05-17-2017, 10:31 PM | #10 |
Scooby Specialist
Member#: 453872
Join Date: Sep 2016
Vehicle:2005 wrx wagon 48w |
you can adjust the whole maf scale if you want. if your wideband matches the ECU commanded fuel through the entire range of MAF voltage thats good and you dont need to rescale it.
|
05-18-2017, 03:41 AM | #11 |
Scooby Newbie
Member#: 428541
Join Date: Aug 2015
Chapter/Region:
MWSOC
Location: Tinley Park, IL
Vehicle:2016 STi Base Lapis Blue Pearl |
If you change your intake you'll need to rescale / calibrate the MAF. You want your total corrections (AF Correction 1 + AF Learning 1 = Total Correction) to be +/- 5 % for closed loop (Generally up to ~2.77v depending on your year and settings).
You want your open loop to be +/- 1-2% of commanded fuel final. You'll want to change load compensations after you get your MAF scaling and this includes changing things such as Intake Turbo Inlet Turbo TVG Deletes Intake Manifold After market TMIC FMIC BOV Cams Porting and polishing of anything in the intake path including heads Things that would allow for a larger pressure differential such as FMIC, throttle body, etc would almost certainly require a change with Tip-In Enrichment. |
09-29-2019, 02:09 PM | #12 | |
Scooby Newbie
Member#: 146760
Join Date: Apr 2007
Chapter/Region:
RMIC
Location: Colorado
Vehicle:2004 WRX Wagon WRB |
Quote:
|
|
09-23-2020, 08:44 PM | #13 |
Scooby Newbie
Member#: 510671
Join Date: Jan 2020
Chapter/Region:
SCIC
Location: California
Vehicle:2006 WRX Gray |
So I bought a base MAP from XPT tuning. My car more or less completely matches the build list for the XPT tune EXCEPT the intake. I am thinking of borrowing the MAF scaling from another tune I have that was setup for my specific intake. I am copying and pasting the whole MAF section in ECU flash. How does this idea sound ?
|
Thread Tools | |
Display Modes | |
|
|