AF ratio numbers, what to expect?Pls advise
05-19-2005, 10:29 AM
#1
Race Car
Thread Starter
AF ratio numbers, what to expect?Pls advise
Friends,
What would be the best AF ratio to run throughout the rev band? From idle to redline?
What number would be running rich?
What numbers would mean I'm running lean?
What numbers should I run or tune my car to get to run most efficent throught out the band? I dont mind running a bit rich at idle or even throughtout the power band just to be on the safe side
What would be the best AF ratio to run throughout the rev band? From idle to redline?
What number would be running rich?
What numbers would mean I'm running lean?
What numbers should I run or tune my car to get to run most efficent throught out the band? I dont mind running a bit rich at idle or even throughtout the power band just to be on the safe side
05-19-2005, 07:30 PM
#2
Burning Brakes
Join Date: Jun 2001
Location: Stockholm, Sweden
Posts: 1,232
Likes: 0
Received 0 Likes
on
0 Posts
I have learned that you should aim for 12.5 at full boost on these cars to be on the safe side.
14.7 is lambda 1, meaning you are burning fuel the best way possible.
I think maximum power is at 13.6/13.7 or so.
My car is 14.7 at idle.
As soon as I hit the throttle it gets richer, usually around 13.
At full boost I am more or less steady at 12.5.
Tuned it using a AFR logger ( www.zeitronix.com ) and a laptop.
Used scatter diagrams to analyse the data.
Here is a diagram from a short test run:
http://rejsa.nu/forum/viewtopic.php?...=asc&start=446
14.7 is lambda 1, meaning you are burning fuel the best way possible.
I think maximum power is at 13.6/13.7 or so.
My car is 14.7 at idle.
As soon as I hit the throttle it gets richer, usually around 13.
At full boost I am more or less steady at 12.5.
Tuned it using a AFR logger ( www.zeitronix.com ) and a laptop.
Used scatter diagrams to analyse the data.
Here is a diagram from a short test run:
http://rejsa.nu/forum/viewtopic.php?...=asc&start=446
05-20-2005, 12:56 AM
#3
Instructor
Join Date: Apr 2005
Location: Shanghai, China
Posts: 130
Likes: 0
Received 0 Likes
on
0 Posts
AF ratios
12.5 is ok for a non modded car on full throttle. In really hot conditions, I prefer to aim for about 12.0 - 12.3 to be safe. Note that what we see on a road run is instantaneous af ratio and not to be taken as the gospel truth. Always err on the side of caution. Best way is to map out the af ratio to rpm on a dyno to be absolutely positive. in any case, the lambda sensors that are installed in car are no comparison accuracy wise with the Horiba types you can use when the car is stationary. If you do a map on a dyno, then go for 12.5 on full throttle using a calibrated Horiba machine or something of equivalent accuracy.
Last edited by leonardtay; 05-20-2005 at 12:56 AM. Reason: spelling error
05-21-2005, 01:00 AM
#6
Race Car
Thread Starter
Stephen.
my ignition timing is set at 24-25 degrees. Will try not to go lower than 11.8. Have too run a little richer as it's bloody warm climate here.
my ignition timing is set at 24-25 degrees. Will try not to go lower than 11.8. Have too run a little richer as it's bloody warm climate here.
Trending Topics
05-21-2005, 08:03 PM
#8
Burning Brakes
Join Date: Jun 2001
Location: Stockholm, Sweden
Posts: 1,232
Likes: 0
Received 0 Likes
on
0 Posts
Sameer, check this one out.
279 USD, including wideband sensor.
http://www.zeitronix.com/Products/zt2/zt2.htm
279 USD, including wideband sensor.
http://www.zeitronix.com/Products/zt2/zt2.htm