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Stitch's Write up Thread

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stitch write
602 views 4 replies 2 participants last post by  Stitch 
#1 · (Edited)
So I've been working on a site for users to upload & share K-Pro calibrations as well as find downloads, write ups, etc...

Since I didn't want to copy anyone elses text even though i've gotten permission from a few members, i've started writing my own.

I'm not an expert but I know enough to be able to explain to someone else the basics.


Here is my first write up on AFRs, It's just a first draft just wanted to know what you guys thought, what I should add, and what I should change.

Your input is greatly appreciated.

The Air/Fuel ratio, commonly called AFR, is a comparison between units of air and units of fuel used for combustion. This is also sometimes referred to as Lambda. The amount fuel that is added to the combustion chamber is a crucial part of tuning which directly affects performance, longevity, pollution, and cylinder head temperatures. It is said that at light load (cruising @ light throttle) 14.7:1 (14.7 units air to every 1 unit of fuel) is considered to be a perfect or "stoich" mixture which is equal to a Lambda value of 1. Anything lower than 14.7:1 is considered "richer" and anything higher is considered "leaner". The term richer means there are less units of air per unit fuel as compared to the stoichiometric mixture. More units air per unit fuel compared to stoichiometric mixture is referred to as lean. As the mixture of air/fuel leans out, the combustion temperatures get hotter and hotter. In MOST cases, a leaner mixture creates more power but the extreme temperatures it creates can be hazardous to motor longevity. As cylinder pressure increases so does the heat, so a richer mixture is needed to "cool" the motor. On most All-Motor applications, an ideal AFR under high load is between 12.8:1 - 13.5:1. On boosted applications, more pressure in the cylinders causes a drastic increase in heat which requires AFRs as low as 11.1:1 - 12.5:1 depending on boost levels. While the values given here are estimated and not exact, they are a good reference for learning purposes. A professional tuner should be considered when finding an optimal yet safe AFR for your motor. AFRs are not as crucial under light load and from the factory most if not all cars come with a stoich mixture of 14.7:1 boosted or naturally aspirated. This number is used because it creates enough power to propel the motor during light throttle with out causing as much pollution and providing a decent MPG. However, in some cases, this mixture can be leaned out during cruising loads in order to increase gas mileage but is limited by how much heat the catalytic converter can handle. Too lean under these conditions and the catalytic converter can melt shut. People who run test pipes can lean out their mixture for better gas mileage but must make sure the mixture isn't hot enough to melt valves.

Lean Pros:

Often yields more power at light to midium loads
Better MPG
Cleaner Burn

Lean Cons:
Lean detonation
Drastic heat increase

Rich Pros:
Cools the motor under heavy loads
Optimal for power under heavy loads

Rich Cons:

Sends unburnt gas into atmosphere
Fouls spark plugs
Can wash down cylinder walls.
 
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#3 ·
There are plenty of resources available on this site and the web about hondata k-pro. I'm just looking to create something different, but thank you :)
 
#5 ·
bump
 
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