Understanding AFR Values
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- เผยแพร่เมื่อ 5 ก.ย. 2024
- This is a short video about AFR values and deciding which ones to choose when tuning your engine.
The information in this video was taken from Jeff Hartman's book "How to Tune and Modify Engine Management Systems."
In this Video:
Definition of Air Fuel Ratio
Explanations of Lean, Rich & Stoich
List of AFR values and their Engine Characteristics
AFR values to avoid
AFR values to target for performance
AFR values to target for fuel economy
Side Effects of Lean & Rich conditions
Thanks for watching this video; if you have any questions, comments or concerns, contact Dobeck Performance:
Dobeck Performance
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An 'eye opener' of sorts to clear all the suspense w.r.t AFR in autmobiles! Cheers!👍👍
Thank you. Been guessing bout this for a while. Its nice to see it in writing.
not even 4 minutes and so much info, great video m8!
i definitely have rich symptoms, but it runs 14.7 up to 99% throttle, and at full it drops to 11-12. according to this it should be ideal for power, but i have a lethargic pedal, the smell of fuel, and some pretty mean pops
14.7 is too lean. Best N/A performance around 12.5 -13 and if you're boosted you need to drop it some more say 11.5 starting point.
This is great! I have been fighting my EZ EFI now trying to get it dialed in and this was amazingly helpful.
What a/f ratios do you run for you setup. And why?
@@mlin3129 my efi system kept reading low 13's and into 12's at idle and cruise and I couldn't get the EZ EFI to adjust so I swapped it with a Holley efi. I'm running a Blueprint engines 396 small block and I've been able to keep high 13's into 14's at idle and cruise. Low 13 into 12 is too rich for the motor and fouls plugs.
@@balzonyr4head thanks! I been running ez efi 1.0 for a year know.
It took me a year to get it right. The IAC screw is very sensitive. Besides that I'm looking for air fuel ratios that will really launch and smoke tires
good video I have my AEM AFR gauge right next to my vacuum gauge For those who add custom gauges to there ride consider the vacuum and AFR gauge as well
you are a god damn life saver!!
Straight to the point, great video.
Awesome information
Does those AFR numbers apply for diesel engines?
Thanks! Takes out all the guess work!
Best video on the internet
Thanks guys
Great video, but what exactly is the difference between "hesitation in throttle response" and "lethargic throttle response"?
It is related to fuel pressure and timing. For exp. I have a holley 750 cfm. Double pumper carb. First ıt was 6 psi fuel pressure and 36 degree total timing but ıt was not good. I changed fuel pressure to 3 psi and 30 degree for total timing and now ıt is a Rocket... and made afr 12.0:1.. response is related to these magic 3 items..
thanks man, needed this!
thanks
*Perfect 11 -> 12.9, high rpm = 11.5 is cool Engine*
Great video to help begin to understanding AFR's.
If i have good afr (14) at idle but drops to rich (11-12) at light cruise, what should i adjust?
Thank You
I need some one to clarify here let say i have truck or suv N/A engines where my goal aim to increase the torque over horsepower should i go with 11.5 afr at wot ?
Excellent!
OK so I have a 04 srt4 I have ran at 14.1 to 14.4 at idle and 12.4 at work with hesitation since I owned the car. Now I got a check engine light for throttle position sensor high andmas sensor now running 11.1 idle IDK if I can run at that safely and why did it change please help
Throttle postion sensor reading high explains the higher AFR reading if it read low it would make you run leaner get a digital multimeter and find out your factory closed throttle body ref voltage and its wot throttle ref voltage do some read up on how to check it if your confused fix that and your mass code and tps code will go away after a computer reset, the tps may just need to be replaced compelety , after your done pull the negative off the battery and turn the lights on for 15 mins come back turn the lights off plug the battery in you now reset your computer after this your car should run like new..
💯💜GREAT VIDEO💜💯
Good info
good info
Good info thanks
OK OK OK wait a min. WHICH fuel are you talking about? gasoline? or gasoline 10% ethanol? or E-85? or some other fuel.
14.7 is the gasoline stoich. Depending on the fuel type that number will be different. I think this applies to 87/91/93 in the US?
At my part throttle cruise i currently run 14.0 which is same as my idle. How much leaner can i go safely
15.5 to 16 is usually max
So 15.5 is safe for 91 octane? basically I want safest lean afr so I can have better mpg without causing damage to my engine another thing when you have a stock vehicle how much afr will it be running from the factory at cruise area like from 1000 to 2000 rpm (GM vehicles)
Too many variables to give an accurate answer & "better" AFR does not necessarily mean better mpg. If the engine is producing less power you'll respond by opening the throttle to maintain speed - more air will also mean more fuel, so even if the mix is leaner the MPG can still be lower.
Lean afr burn slowly and rich afr burns faster...?????
You misspelled temperature.
No chit cherlock...it must have wrecked havoc in your perfect life. Poor you...
@@DL101ca *wreaked
what about diesel guys?? anyone?
What is engine load..??
Lambda should be discussed here not AFR as stoich AFR will change with fuel composition.
for boost or N.A?
11.5 - 12.2 AFR is generally the wide open throttle for NA. usually AFR in the mid to high 10s are used for boosted applications with the idea that the richer fuel mixture is used to lower cylinder temperatures to avoid detonation. My Toyota 86 is still NA, but my AFR at wide open throttle is 11.3 because my tune runs more advanced timing for increased power.
I boosted my NA gc8 and its reading 12.2 at idle is this normal?
@@bennjiestewart3786 That's a bit too rich for idle, want to be between high 13's to high 14's at idle
Is 14.+ safe or lean? Thanks
I’m no mechanical engineer but this is incorrect atleast in its explanation of why to run those numbers. The numbers may be right but not for those reasons
But I run E85.....👍
Work with the lambda setting and aim for 1, no matter what fuel you're running in lambda, the stoich afr is always 1