Forum » General Tuning Discussion » Target AFR (turbo)

Target AFR (turbo)

General Tuning Discussion

Discuss all things tuning in this section. News, products, problems and results. 

= Resolved threads

Page 1

Beginner here.

I just completed a the course for standalone ECU and I wanted to build a base map.

Is this a good target AFR for a turbocharged car. Specifically for EVO?

Also when do I stop adding boost?

Attached Files
  • FE727C61-B3CA-4C46-B15F-787D87408058.jpeg
  • Attachments may only be downloaded by paid Gold members. Read more about becoming a Gold member here.

That's a pretty reasonable starting point and one that should be pretty safe. The maximum boost will be dictated by the turbo and the octane of the fuel. In most instances I tend to find that about 22 psi is the point where you'll start seeing diminishing returns on pump fuel as the engine will become very knock prone, requiring the timing to be pulled which means you're adding more boost, putting stress on the engine, and making no more power.

Should I go .80 to .78 on higher RPM and load?

i remember you mentioning about there will be no more advantages once it is richer than .75 or so if I recall.

I always run 0.74 lambda at hight rpm and it gives best timing comparing to leaner mixture results. It also shows best power in virtual dyno program but Andre has already said that it might not be very accurate. Nevertheless, as i already said, 0.74 -0.75 lambda from 4500 RPM onwards makes the car faster. It also has side effect of better cooling down combustion chambers since cylinder 4 is usually hotter than other 3 cylinders and required more fuel to cool down when producing o lot of power for extended periods of time.


As they say, the engine will tell you.

As Georg said, richer will generally allow more ingition advance, but different engines will give different results.

F1, because of the fuel flow limitations, can be running as lean as 16:1 or leaner, and still be making a lot of power under high boost - but they're built for it and still get through a LOT of VERY expensive engines to get the required reliability needed for 2000+ miles of race, practice and qualifying miles... Some just don't manage it.