Air/Fuel ratio tuning

[ZRrrr]

Curious if anyone has ever used a just a wideband air/fuel ratio gauge for engine tuning?

I came across an E-bay ad for a company in Florida selling this "chip" you placed in line that tuned your engine to exaclty 14.7. Cool, but sounded hokey. I see Koso sells a gauge.

 

[Garryese]

I have used a gauge as a tuning aide, but would not depend on it for much more than confirming what you already suspect. Quite useful if used with a dyno.

Keep in mind that 14.7 is the mathematical correct ratio based on 100% effeciency in mixing the fuel/air charge which is not going to happen in the real world.

 

[TABSTER]

I agree with Garryese. The A/F gauge is more of a conformation tool. I would use plug color and piston wash as the gospil.

 

[TABSTER]

A little Tuning 411

 

[ZRrrr]

That's pretty much the answer I thought I would get, but figured I would ask.

 

[Ancient Sledder]

I might be wrong but I think a sled needs 12 or 12.5 to 1 air fuel ratio. I believe 14.7 is for a car.

 

[snotterite]

I might be wrong but I think a sled needs 12 or 12.5 to 1 air fuel ratio. I believe 14.7 is for a car.

14.7 p.s.i. is Normal Atmospheric Pressure at Sea Level.

 

[Summiteer]

14.7 p.s.i. is Normal Atmospheric Pressure at Sea Level.

101.3KPA, 761.7 mmHg

 

[Modman]

Curious if anyone has ever used a just a wideband air/fuel ratio gauge for engine tuning?

I came across an E-bay ad for a company in Florida selling this "chip" you placed in line that tuned your engine to exaclty 14.7. Cool, but sounded hokey. I see Koso sells a gauge.

Koso gauge is pricey and I have had trouble for two seasons with my Koso EGTs. You're better off to get an Autometer or some other automotive type of A/F gauge and rectifier (if you need one). Koso's displays are some of the best for "readability" (compared to some others like Westach's) but they are quite a bit more expensive.

I think you meant 14.7:1 ratio. Yes, they are good for tuning, better for tuning than an EGT IMO, A/F ratio is a more scientific approach than EGT's since it is less likely to be influenced by engine factors and probe placement (EGT's are more prone to this than A/F), less "false positives".

As stated, always confirm with plug and wash reading. Once you have determined the baseline settings for your sled, your EGT and A/F readings are relative to the baseline setting and are your reference point for knowing where the max values are.

Here is a good read on baseline setting
DigatronTech

Some good plug reading tips and photos

Piston Reading
Plug Reading Spark Plugs
SparkPlugs
[media]http://tsrsoftware.com/images/read_plugs-tsr_software.jpg[/media]

 

[ZRrrr]

Great answer.

Plug reading and piston wash are not a problem. A few life lessons taught me those. I thought the A/F gauge might be an interesting adder to the mix. When tuning last year I found a couple situations where the sled was good, however when I tried to lean it up a little the sled felt underpowered. Wash and plugs looked even better but again, power was down. It's that fine line or "edge" that was mentioned earlier. I know EGT's can play with your head like that.

 

[Ancient Sledder]

14.7 p.s.i. is Normal Atmospheric Pressure at Sea Level.

You are correct on the pressure,but for engine tuning it is 1 pound of fuel for every 14.7 pounds of air.