Notices
Series I Engine Tuning Forum EMS (Flash Tuning, Interceptor, Piggy Back, Stand Alone)

What is an acceptable AFR Air to fuel ratio

Thread Tools
 
Rate Thread
 
Old Aug 26, 2010 | 09:26 PM
  #1  
EdwardLenczowski's Avatar
Thread Starter
Registered User
 
Joined: Oct 2009
Posts: 141
Likes: 0
From: Massapequa
What is an acceptable AFR Air to fuel ratio

I own a cobb access port and it been reading my afr as 14.5 - 15.5 at idle generally. Is this rather high or am i a little paranoid. Im running mazda maniacs base tune for my year. Help Please?
Reply
Old Aug 26, 2010 | 10:24 PM
  #2  
Charles R. Hill's Avatar
Owner of BHR
iTrader: (7)
 
Joined: Nov 2003
Posts: 4,101
Likes: 45
Yes, you are being paranoid.
Reply
Old Aug 26, 2010 | 10:36 PM
  #3  
EdwardLenczowski's Avatar
Thread Starter
Registered User
 
Joined: Oct 2009
Posts: 141
Likes: 0
From: Massapequa
Thank you charles!
Reply
Old Aug 27, 2010 | 08:24 AM
  #4  
fastlaneracing's Avatar
Rotor User
 
Joined: Nov 2007
Posts: 838
Likes: 0
From: Sweden
Whats your AFR at wot?
Reply
Old Aug 27, 2010 | 08:48 AM
  #5  
DarkBrew's Avatar
Extraordinary Engineering
 
Joined: Oct 2005
Posts: 4,733
Likes: 14
From: Burls On
Originally Posted by azathoth
Whats your AFR at wot?
+1

Log a pull to redline on your AP, upload the data, plot it in excel and post an image of the graph.
Reply
Old Aug 27, 2010 | 09:33 AM
  #6  
chonniedotcom's Avatar
Registered
 
Joined: Apr 2010
Posts: 75
Likes: 0
My log shows a AFR at WOT as 11.7.

That's alright? Still totally stock.

Thanks.
Reply
Old Aug 27, 2010 | 02:29 PM
  #7  
czar's Avatar
Almost boosted
iTrader: (3)
 
Joined: May 2008
Posts: 708
Likes: 1
From: Austin, Texas
sounds fine
Reply
Old Aug 27, 2010 | 05:21 PM
  #8  
alz0rz's Avatar
hakuna matata!
iTrader: (41)
 
Joined: Aug 2007
Posts: 6,002
Likes: 3
From: NYC
Originally Posted by chonniedotcom
My log shows a AFR at WOT as 11.7.

That's alright? Still totally stock.

Thanks.
Thats actually a nice relatively lean mixture for being stock.

I've seen stock Mazda maps produce 10's at WOT.
Reply
Old Aug 27, 2010 | 06:39 PM
  #9  
chonniedotcom's Avatar
Registered
 
Joined: Apr 2010
Posts: 75
Likes: 0
Afr 11.7

Just to be clear... that is with MM base map, on totally stock engine... no mid pipe....yet ;-)

I did not measure that with the Mazda stock ecu... not sure how to do that? as I had to load MM base tune map to get the the Access Port to log anything.

:-)
Reply
Old Aug 27, 2010 | 09:47 PM
  #10  
DarkBrew's Avatar
Extraordinary Engineering
 
Joined: Oct 2005
Posts: 4,733
Likes: 14
From: Burls On
Log it for us!

You datalog AFR and other stuff - You need to practice data logging anyway.

Plug AP into your computer

Transfer the datalog

Open in excel - if you don't have excel then download Java office suite for free

Create a chart

alt-Print screen

Paste in paint

Save as jpg

Post picture

Last edited by DarkBrew; Aug 28, 2010 at 08:21 AM.
Reply
Old Aug 28, 2010 | 02:10 AM
  #11  
chonniedotcom's Avatar
Registered
 
Joined: Apr 2010
Posts: 75
Likes: 0
Will do!!! not at the right PC at the moment.. but will fer sure... :-)


Originally Posted by DarkBrew
Log it for us!

You datalog AFR and other stuff - You need to practice data logging anyway.

Plug AP into your computer

Transfer the datalog

Open in excel

Create a chart

alt-Print screen

Paste in paint

Save as jpg

Post picture
Reply
Old Aug 28, 2010 | 10:17 AM
  #12  
chonniedotcom's Avatar
Registered
 
Joined: Apr 2010
Posts: 75
Likes: 0
Picture of log

I could not figure out how to chart it properly... I would get a nice line showing the RMP, but other values would be burried at the bottom and would not show any usable data.

Last edited by chonniedotcom; Apr 27, 2013 at 12:11 AM.
Reply
Old Aug 28, 2010 | 10:56 PM
  #13  
ronx8's Avatar
zoom zoom!
 
Joined: Sep 2007
Posts: 360
Likes: 0
From: SoCal
i usually get low 12's at WOT
Reply
Old Aug 28, 2010 | 11:01 PM
  #14  
alz0rz's Avatar
hakuna matata!
iTrader: (41)
 
Joined: Aug 2007
Posts: 6,002
Likes: 3
From: NYC
that's 11.1 not 11.7
Reply
Old Aug 28, 2010 | 11:34 PM
  #15  
Flashwing's Avatar
3-wheeler
 
Joined: Dec 2005
Posts: 2,734
Likes: 1
From: Phoenix
This is a pretty big topic and not one that has a definitive answer. There is not really an "ideal" air/fuel ratio because a proper ratio will vary based on RPM and calculated load. What is considered proper is going to depend on your fuel octane, ignition timing and current operating conditions of the motor.

The MazdaManiac base calibration does not make any changes to the stock fuel tables so what you are seeing is the stock fuel settings for the RX8. MazdaManiac is well aware of what air/fuel rations are optimal for the performance of the vehicle based on your modifications so you have nothing to worry about.
Reply
Old Aug 29, 2010 | 01:02 AM
  #16  
chonniedotcom's Avatar
Registered
 
Joined: Apr 2010
Posts: 75
Likes: 0
Loaded first map...

I took the base settings and increased the RPM limiter and adjusted the idle up about 30 rpm to see if it makes any differance.

RMP's are now hitting 8500 vs the 8000 limit as stock. Idle did not seem to change. At least I could not notice.

Gonna play a bit more tomorrow after I get my midpipe on... I got the stock pipe out this evening without any issues. Bolts looked like new....no rust!!! Crazy for an 04.

Cat also appeared to be in good shape, maybe it was recently replaced? Car is new to me only 3 months ago... so who knows. The screen in the cat had very little deposits on it... Will take a picture later.

Will log more tomorrow... see where I land. Go for a good cruise, hit different RPM's and loads.

:-)

Last edited by chonniedotcom; Aug 29, 2010 at 01:04 AM.
Reply
Old Aug 30, 2010 | 04:04 PM
  #17  
chonniedotcom's Avatar
Registered
 
Joined: Apr 2010
Posts: 75
Likes: 0
Did another drive and logged...

Hey gang...

Did another drive on the highway yesterday....

Attached are some screen shots:

Fisrt pick is a 2nd gear pull WOT

Second is a 3rd gear pull at WOT

Mods done:

Agency Power twin res midpipe, K&N airfilter. 2004, 4 speed AT tranny.

This is the first run of a stock map just loaded with max RPM's increased to 9000, Thats it.

I am thinking that I should see a higher mass airflow? maybe not? Stock airbox used.
Also... is 11.17 a good AFR for that type of engin operation? Should I not want that a bit leaner?

I will keep this map on for a few more drive cycles see if anything changes...

Any coments???

Last edited by chonniedotcom; Apr 27, 2013 at 12:10 AM.
Reply
Old Sep 4, 2010 | 05:37 PM
  #18  
8upbad's Avatar
Jared
iTrader: (3)
 
Joined: Jul 2009
Posts: 777
Likes: 1
From: South Florida
Awesome thread, thanks for sharing!
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
RevMeHarder
New Member Forum
7
Jul 12, 2025 07:22 PM
JimmyBlack
Series I Major Horsepower Upgrades
273
Feb 10, 2020 10:23 PM
RXFEVER
RX-8 Parts For Sale/Wanted
38
Aug 29, 2018 10:14 AM
RXFEVER
West For Sale/Wanted
17
Sep 11, 2016 02:51 PM



You have already rated this thread Rating: Thread Rating: 0 votes,  average.


All times are GMT -5. The time now is 07:10 PM.