Hello,
i was wondering what are the math behind the AFR base for RX8 Series 1 and could you help me out to calculate properly.
in the ROM this value is 1/AFR
I have try all the following values (goal is to approach the E-85 ratio).
13.85 = 0.07196
9.83 = 0.090564117
8.8 = 0.094951175
Air Fuel Ratio Base
Re: Air Fuel Ratio Base
Hello I guess it’s my time to be on this forum with what I have learned with some courses I did with hp academy and me learning the parameters with the logic in the flow of controlling the engine to what I figured.
I think the afr base setting is the Stoichiometric of the fuel you intend to use.
You can look it up on the net for your intended use and cross reference the lambda 1 calibration for this setting I think it is used for. You also can check by switching from metric and imperial settings for your liking to see for yourself.
I like lambda because then it is all pretty close to a simple percentage factor from this baseline base afr setting your asking about
My factory downloaded calibration I think was e10 Stoichiometric and any feedback on others here can chime in.
I had to do my load targeting/ ve calibration for my motor setup and was prepared to it from the start because I rebuilt my motor and did a bit of port work .
I found around idle the ve was close to percentages seen in stft needed or ltft if way out .
Your desired fueling in logs is shown as cl fuel additive in relation to base afr setting and starting with an extra .zero in front of the percentage you want to change and it follows with mine but I recommend not to change much because of pollutants to the environment but gives you a bit more zip for closed loop.
I hope this helps a few people out and you might want to do the hpa understanding afr course
.
I think the afr base setting is the Stoichiometric of the fuel you intend to use.
You can look it up on the net for your intended use and cross reference the lambda 1 calibration for this setting I think it is used for. You also can check by switching from metric and imperial settings for your liking to see for yourself.
I like lambda because then it is all pretty close to a simple percentage factor from this baseline base afr setting your asking about
My factory downloaded calibration I think was e10 Stoichiometric and any feedback on others here can chime in.
I had to do my load targeting/ ve calibration for my motor setup and was prepared to it from the start because I rebuilt my motor and did a bit of port work .
I found around idle the ve was close to percentages seen in stft needed or ltft if way out .
Your desired fueling in logs is shown as cl fuel additive in relation to base afr setting and starting with an extra .zero in front of the percentage you want to change and it follows with mine but I recommend not to change much because of pollutants to the environment but gives you a bit more zip for closed loop.
I hope this helps a few people out and you might want to do the hpa understanding afr course
.Re: Air Fuel Ratio Base
ps i will be checking with a wide band aem soon just to confirm this so hang tight for a couple of weeks.-
CrazyCanadian
- Posts: 50
- Joined: July 4th, 2021, 8:32 pm
Re: Air Fuel Ratio Base
Tune in Lambda... tell the ECU what fuel you are using under fuel specific gravity.. Use the built in calculator to figure out what value you use... Your ECU is tuned from the manufacture using Lambda.
Log in Lambda... Stop living 20 years ago thinking in AFR's...
Lambda doesn't care what fuel you are running. It's always the same numbers. So long as you tell the ecu what fuel you are using it'll do all the conversion math for you..
Log in Lambda... Stop living 20 years ago thinking in AFR's...
Lambda doesn't care what fuel you are running. It's always the same numbers. So long as you tell the ecu what fuel you are using it'll do all the conversion math for you..
Re: Air Fuel Ratio Base
In these logs AFR = Lambda * 14.7. So it's more or less Lambda...CrazyCanadian wrote: ↑June 28th, 2026, 2:08 am Log in Lambda... Stop living 20 years ago thinking in AFR's...
2008 Cosmic Blue Mazda 3MPS
Built engine + WMI + GTX3071 gen2, ~550BHP @35PSI
2008 Icy Blue Mazda CX7
Built engine and stock exhaust (YES!!), JBR3" + GTX2867 gen2 + Autotech HPFP, self-tuned to 360-ish BHP
Built engine + WMI + GTX3071 gen2, ~550BHP @35PSI
2008 Icy Blue Mazda CX7
Built engine and stock exhaust (YES!!), JBR3" + GTX2867 gen2 + Autotech HPFP, self-tuned to 360-ish BHP
Re: Air Fuel Ratio Base
Okay I’m already using lambda
What I’m thinking is regardless of what fuel you use it will always be lambda 1 .
Lambda is a percentage change from stoich what the fuel burns cleanest at ?.
My factory cal in this software was set to the e10 stoich but I found I had to put 14.7 and switched metrics to imperial settings in the software to confirm . it changed to lambda 1 where I wanted it for premium gas.
I think from memory the factory cal was 14.3 so isn’t it around 2.5 percent richer being .97 lambda which would add to confusion in the closed loop fuel additives table I think some people where saying was suspect to the desire targets in your logs and then everything else would be out .
I don’t know how or if this software runs a compensation formula in the background for fuel base ratios or does it not need it ?.
What I’m thinking is regardless of what fuel you use it will always be lambda 1 .
Lambda is a percentage change from stoich what the fuel burns cleanest at ?.
My factory cal in this software was set to the e10 stoich but I found I had to put 14.7 and switched metrics to imperial settings in the software to confirm . it changed to lambda 1 where I wanted it for premium gas.
I think from memory the factory cal was 14.3 so isn’t it around 2.5 percent richer being .97 lambda which would add to confusion in the closed loop fuel additives table I think some people where saying was suspect to the desire targets in your logs and then everything else would be out .
I don’t know how or if this software runs a compensation formula in the background for fuel base ratios or does it not need it ?.