Mafless VS Maf open loop?
Thread Starter
Joined: Nov 2001
Posts: 7,303
Likes: 4
From: Delray Beach, Fl.
Mafless VS Maf open loop? Here's my question..
If your just shutting off the 02's and 0 out the Ltrims,then tuning for WOT A/F how does the car car run at 14.7 under PT cruise.I would think what ever your WOT A/F was your idle/pt cruise A/F would mimic the open loop WOT A/F.
I know u can use the MAF/IAC/MAP for weather correction but when I looked at my tune,they had had the MAF WAY up and my target A/F at 12.5 under cruise.I for one think this isnt the best way to tune and also think its not good for rings/cyl walls/tb response or fuel ecomony.
Can someone explain this to me.
I'm not saying I'm right but if you take the time to sync Ltrims using the 02's and put 30 to 50 miles on the car they shouldnt change at all.Then tune for WOT using a WB ad your done?
Where is open (prehistoric) tunings advantage...
The FAST/Acell/BSII can be tuned in fully closed loop using a WB which corrects on the fly.I know alot of guys running them this way.I realize our cars cant do that but as the newer cars comes out they are going to this type of setup.This tells me that closed loop isnt as bad as people are making it.
I just would like some info..
Learning is fun...
If your just shutting off the 02's and 0 out the Ltrims,then tuning for WOT A/F how does the car car run at 14.7 under PT cruise.I would think what ever your WOT A/F was your idle/pt cruise A/F would mimic the open loop WOT A/F.
I know u can use the MAF/IAC/MAP for weather correction but when I looked at my tune,they had had the MAF WAY up and my target A/F at 12.5 under cruise.I for one think this isnt the best way to tune and also think its not good for rings/cyl walls/tb response or fuel ecomony.
Can someone explain this to me.
I'm not saying I'm right but if you take the time to sync Ltrims using the 02's and put 30 to 50 miles on the car they shouldnt change at all.Then tune for WOT using a WB ad your done?
Where is open (prehistoric) tunings advantage...
The FAST/Acell/BSII can be tuned in fully closed loop using a WB which corrects on the fly.I know alot of guys running them this way.I realize our cars cant do that but as the newer cars comes out they are going to this type of setup.This tells me that closed loop isnt as bad as people are making it.
I just would like some info..
Learning is fun...
You would have to adjust your open-loop fuel/air tables
to command the right AFR under cruise MAP conditions
(non-PE), and you would have to get the speed-density
part of the tune proper for representing true airflow.
Closed loop mainly makes the cats happy, needing them
to work less and not requiring full time AIR pump to let
them burn off excess products (HC/CO/NOx) in either
direction. Your best cruise is probably leaner than
stoich and your best power well fatter. But this is all
very very naughty as far as Big Mother EPA is concerned.
As far as cylinder wall washdown, as long as you are not
condensing gasoline mixture is not a factor. Stay at any
sane mixture (no need to go below 12:1 for a NA car)
and you will not go there.
MAF is self correcting for altitude etc and a direct mass
air measurement. SD tune needs the MAP to be right, and
the VE table right, then it is also relatively accurate. But
the MAF compensates better for external engine changes,
without programming, that's its only real advantage; cal
in piece-part production and then fuggedaboudit for ever
and ever amen. Yeh.
to command the right AFR under cruise MAP conditions
(non-PE), and you would have to get the speed-density
part of the tune proper for representing true airflow.
Closed loop mainly makes the cats happy, needing them
to work less and not requiring full time AIR pump to let
them burn off excess products (HC/CO/NOx) in either
direction. Your best cruise is probably leaner than
stoich and your best power well fatter. But this is all
very very naughty as far as Big Mother EPA is concerned.
As far as cylinder wall washdown, as long as you are not
condensing gasoline mixture is not a factor. Stay at any
sane mixture (no need to go below 12:1 for a NA car)
and you will not go there.
MAF is self correcting for altitude etc and a direct mass
air measurement. SD tune needs the MAP to be right, and
the VE table right, then it is also relatively accurate. But
the MAF compensates better for external engine changes,
without programming, that's its only real advantage; cal
in piece-part production and then fuggedaboudit for ever
and ever amen. Yeh.
Originally Posted by JS
Here's my question..
If your just shutting off the 02's and 0 out the Ltrims,then tuning for WOT A/F how does the car car run at 14.7 under PT cruise.I would think what ever your WOT A/F was your idle/pt cruise A/F would mimic the open loop WOT A/F.
If your just shutting off the 02's and 0 out the Ltrims,then tuning for WOT A/F how does the car car run at 14.7 under PT cruise.I would think what ever your WOT A/F was your idle/pt cruise A/F would mimic the open loop WOT A/F.
I know u can use the MAF/IAC/MAP for weather correction but when I looked at my tune,they had had the MAF WAY up and my target A/F at 12.5 under cruise.I for one think this isnt the best way to tune and also think its not good for rings/cyl walls/tb response or fuel ecomony.
Can someone explain this to me.
I'm not saying I'm right but if you take the time to sync Ltrims using the 02's and put 30 to 50 miles on the car they shouldnt change at all.Then tune for WOT using a WB ad your done?
I'm not saying I'm right but if you take the time to sync Ltrims using the 02's and put 30 to 50 miles on the car they shouldnt change at all.Then tune for WOT using a WB ad your done?
Where is open (prehistoric) tunings advantage...
The FAST/Acell/BSII can be tuned in fully closed loop using a WB which corrects on the fly.I know alot of guys running them this way.I realize our cars cant do that but as the newer cars comes out they are going to this type of setup.This tells me that closed loop isnt as bad as people are making it.
I just would like some info..
Learning is fun...
I just would like some info..
Learning is fun...
I have no problems with closed loop the pcm is allready trying to acheive the desired afr and it tells you how far off you are by the trims. I would use this as a tool for closed loop and a WB for open loop... My only issue is with the maf and how it seems to want to fight other sensors
Thread Starter
Joined: Nov 2001
Posts: 7,303
Likes: 4
From: Delray Beach, Fl.
Well my MAF was jacked up sky high and my target A/F was at 12.5 for pt cruise.
This was tuned in op and it wasnt all that great,idle quality was poor,tb response was soft,it smelled horrible and got terrible mph.It did run very well at the track
I'm going back to cloed loop,ai believe if u spend enough time tuning in cl the setup will work perfectly.
This was tuned in op and it wasnt all that great,idle quality was poor,tb response was soft,it smelled horrible and got terrible mph.It did run very well at the track
I'm going back to cloed loop,ai believe if u spend enough time tuning in cl the setup will work perfectly. Trending Topics
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Ok so If I hook back up the MAF and stay in open loop it will do everything but use the narrow band o2's right, I have a WB anyways. And if you can tune for the AFR you want in all regimes why would you reenable the PE? What i'm thinking is do the tuning I need then revert to MAF, open loop and no PE. how does this sound to you guys.
Originally Posted by Pavetim
Ok so If I hook back up the MAF and stay in open loop it will do everything but use the narrow band o2's right, I have a WB anyways. And if you can tune for the AFR you want in all regimes why would you reenable the PE? What i'm thinking is do the tuning I need then revert to MAF, open loop and no PE. how does this sound to you guys.
I am pretty close and getting it just wondering if you have a WB why would you keep using the narrow band o2's and why would you use PE? Oh yeah I plugged my MAF back in and the AFR went into low 11's, how do I tune the MAF?
Originally Posted by Pavetim
I am pretty close and getting it just wondering if you have a WB why would you keep using the narrow band o2's and why would you use PE? Oh yeah I plugged my MAF back in and the AFR went into low 11's, how do I tune the MAF?
what program are you using to tune currently..i know hptuners has a writup on how to do it within their program & im sure efilive has something at least on their site...basically once you get done tuning your ve table you reactivate your maf but dont make it functional and correct the maf table for the variance. 
you dont disable PE...
you tune the car with PE enabled to the AFR that you want
you start by setting OLFA to 1.0
tune the VE(in SD by disabling the MAF).... then tune the MAF
after all is said and done you can go back and tune the OLFA...
I'm working on a write up...will be testing my methds on my car tomorrow now that my new sensor has shown up....
have a writeup already written and just need to finish up to show positive proof of my method
you tune the car with PE enabled to the AFR that you want
you start by setting OLFA to 1.0
tune the VE(in SD by disabling the MAF).... then tune the MAF
after all is said and done you can go back and tune the OLFA...
I'm working on a write up...will be testing my methds on my car tomorrow now that my new sensor has shown up....
have a writeup already written and just need to finish up to show positive proof of my method
Teching In
Joined: Sep 2005
Posts: 49
Likes: 0
From: Sydney Australia
From HP Tune help file:
Open Loop F/A vs. Coolant Temp vs. MAP: This table is used to determine the commanded AFR when in open loop mode. It divides the Stoich AFR value. AFR is determined by 14.7/table value. Example: 14.7/1.30 = 11.3 AFR
Open Loop F/A vs. Coolant Temp vs. MAP: This table is used to determine the commanded AFR when in open loop mode. It divides the Stoich AFR value. AFR is determined by 14.7/table value. Example: 14.7/1.30 = 11.3 AFR
