Notices
ECU Flash

MAF Hz formular correction

Thread Tools
 
Search this Thread
 
Old May 29, 2011, 04:41 AM
  #1  
Evolved Member
Thread Starter
 
burgers22's Avatar
 
Join Date: Jan 2006
Location: Oxfordshire
Posts: 953
Received 2 Likes on 2 Posts
MAF Hz formular correction

I have been rescaling my MAF and noticed the MAF Hz formula didn't correctly convert from display back to ROM, Not sure if this has been changed in later xmls, but here it is for your interest.

<scaling name="MAFHz" units="Hz" toexpr="6.29*x/64" frexpr="x*64/6.29" format="%.0f" min="0" max="5000" inc="1" storagetype="int16" endian="big"/>

Last edited by burgers22; Feb 21, 2012 at 12:52 PM.
Old May 29, 2011, 10:57 AM
  #2  
Former Sponsor
iTrader: (12)
 
Dynotech Tuning's Avatar
 
Join Date: Jan 2011
Location: Seekonk, MA
Posts: 1,312
Likes: 0
Received 9 Likes on 7 Posts
Originally Posted by burgers22
I have been rescaling my MAF and noticed the MAF Hz formula didn't correctly convert from display back to ROM, Not sure if this has been changed in later xmls, but here it is for your interest.

<scaling name="MAFHz" units="Hz" toexpr="6.29*x/64" frexpr="64/(6.29*x)" format="%.0f" min="0" max="5000" inc="1" storagetype="int16" endian="big"/>
Hmm, nice catch. I will have to see what my current scaling values are now.

-Jamie
(jack_of_trades)
Old May 29, 2011, 11:48 AM
  #3  
Evolved Member
Thread Starter
 
burgers22's Avatar
 
Join Date: Jan 2006
Location: Oxfordshire
Posts: 953
Received 2 Likes on 2 Posts
It will read the same, but my previous xmls didn't write back correctly. The above fixes that.
Old Feb 19, 2012, 02:25 PM
  #4  
Former Sponsor
iTrader: (12)
 
Dynotech Tuning's Avatar
 
Join Date: Jan 2011
Location: Seekonk, MA
Posts: 1,312
Likes: 0
Received 9 Likes on 7 Posts
Originally Posted by burgers22
I have been rescaling my MAF and noticed the MAF Hz formula didn't correctly convert from display back to ROM, Not sure if this has been changed in later xmls, but here it is for your interest.

<scaling name="MAFHz" units="Hz" toexpr="6.29*x/64" frexpr="64/(6.29*x)" format="%.0f" min="0" max="5000" inc="1" storagetype="int16" endian="big"/>
Just for preservation sake, I will add the correction here. The formula you posted was the original WRONG one, not the revised one. Here is the corrected one:

<scaling name="MAFHz" units="Hz" toexpr="6.29*x/64" frexpr="x*64/6.29" format="%.0f" min="0" max="5000" inc="1" storagetype="int16" endian="big"/>

-Jamie
Old Feb 21, 2012, 12:52 PM
  #5  
Evolved Member
Thread Starter
 
burgers22's Avatar
 
Join Date: Jan 2006
Location: Oxfordshire
Posts: 953
Received 2 Likes on 2 Posts
So it was Jamie, sorry about that. First post corrected with corrected formula,
Old Oct 29, 2013, 04:04 PM
  #6  
Evolved Member
iTrader: (6)
 
domyz's Avatar
 
Join Date: Jun 2010
Location: Canada
Posts: 878
Received 7 Likes on 6 Posts
This should be corrected in tephra defs. From what I know, at least 9417 SD 2.0 has the wrong formula.
without the right forumula , it's impossible to edit MAF compensation Y axis (MAFHZ)
Old Oct 31, 2013, 12:28 AM
  #7  
Evolved Member
 
merlin.oz's Avatar
 
Join Date: Jun 2008
Location: Sydney
Posts: 824
Likes: 0
Received 23 Likes on 19 Posts
Actually the correct eval is x*64/6.25

6.29 will give 1610Hz, but it should be 1600Hz, so 6.25.

A minor detail but if you want to be accurate....

Last edited by merlin.oz; Oct 31, 2013 at 12:54 AM.
Old Nov 1, 2013, 08:23 PM
  #8  
EvoM Guru
iTrader: (7)
 
CDrinkH2O's Avatar
 
Join Date: Nov 2006
Location: San Francisco
Posts: 1,142
Received 153 Likes on 116 Posts
What effect will this have on MAF Compensation if I re-flash my existing tune after changing the scaling to the correct definition?
Old Nov 3, 2013, 12:07 AM
  #9  
Evolved Member
 
merlin.oz's Avatar
 
Join Date: Jun 2008
Location: Sydney
Posts: 824
Likes: 0
Received 23 Likes on 19 Posts
nil effect, it is just to present the data accurately.
Old Nov 5, 2013, 10:13 PM
  #10  
EvoM Guru
iTrader: (7)
 
CDrinkH2O's Avatar
 
Join Date: Nov 2006
Location: San Francisco
Posts: 1,142
Received 153 Likes on 116 Posts
Originally Posted by merlin.oz
nil effect, it is just to present the data accurately.
Cheers Merlin. I was thinking it might impact Maf Comp because the Hertz values I adjusted Comp at changed once I corrected the scaling. Thanks for correcting my misunderstanding.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
mrb00st
E85 / Ethanol
186
Jul 26, 2022 12:42 PM
l2r99gst
ECU Flash
40
Aug 28, 2011 03:39 AM
JohnBradley
ECU Flash
45
Dec 9, 2007 07:55 AM
cpoevo
ECU Flash
5
May 3, 2007 08:22 AM
Iamkar33m
Private 'Evo 1 - 9' For Sale / Wanted
21
Jul 29, 2004 06:38 PM



Quick Reply: MAF Hz formular correction



All times are GMT -7. The time now is 02:52 PM.