14.7 to 15.2 AFR, better gas mileage?

[foxracing4500]

hopefully a wiseman can put me in my place but the price of 93 octane in my area is $4.20 , E85 is not an option. I think I averaged out I get 16-18 mpg, I live in the country where you have to travel far to get anywhere, soo if I switched out a few cells with 15.2 afr instead of 14.7 would I even notice better mpg or not worth it? the cells I would change would probably be 3000 rpm up to 60% load.

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here I am trying to build a race car and worrying about mpg , but honestly if I can save money while cruising that would be great.

 

[Flatout_98]

I am by no means a DSM wise man. But adjusting the stoichiometric air fule ratio won't help your gas milage. 14.7 is the optimal stoich. ratio for gasoline. The optimal stoich. ratio is affected by things like heat and presure, why the graph changes with rpm. I would leave that alone. You would be better served by cleaning your air filter. And keep proper tire presure. I've found the best way for me to increase my gas milage is to keep my foot out of it. Best of luck.

 

[AK Maniak]

I wish gas was that cheap here

 

[steve]

Unless you lock your ECU in open loop changing the fuel map isn't going to help while cruising. Or if you have a wideband and are simulating the narrowband sensor, you can trick the ECU into thinking its seeing 14.7:1 when the actual AFR is leaner.

 

[habitatguy187]

Unless you lock your ECU in open loop changing the fuel map isn't going to help while cruising.

What if he gradually moved his fuel sliders until he was out of fuel trim adjustment range?