Target AFR
- Thread starter Dub-Se7en
- Start date
TO82
Member +
Its all about a healthy balance, 99% of road cars will not run a lamba of 0.9 as this is for all out power, therefore if your getting your car mapped by a company they will never map to that, as there isnt alot of room for mistakes.
It all depends what you want from your car, there is not a so called target AFR for a car, you need to look at what you want from the car, power, economy, reliability etc
It all depends what you want from your car, there is not a so called target AFR for a car, you need to look at what you want from the car, power, economy, reliability etc
munday
Member +
LOL, hope there is no sarcasm there
Obviously the figures cannot be bang on for every engine but they are the best guide.
1.1 is best for economy but also produces high levels of nitrogen oxides and other nasties so in general a lambda of 1 is used as a compromise.
Best power is at 0.9 but sometimes people map richer to help with cooling.
Obviously the figures cannot be bang on for every engine but they are the best guide.
1.1 is best for economy but also produces high levels of nitrogen oxides and other nasties so in general a lambda of 1 is used as a compromise.
Best power is at 0.9 but sometimes people map richer to help with cooling.
Phil
Super Moderator
LOL, hope there is no sarcasm there
Obviously the figures cannot be bang on for every engine but they are the best guide.
1.1 is best for economy but also produces high levels of nitrogen oxides and other nasties so in general a lambda of 1 is used as a compromise.
Best power is at 0.9 but sometimes people map richer to help with cooling.
haha no honestly...just a fan lol
so best power @ 13.23, thought 4efte started eating piston ringlands etc at those sort of figures>? or are those figures ideal so long as temperatures are kept down>? something that its hard to do on a turbocharged engine!
13.23 is roughly what an N/a motor would be running at...ya?
or is 13.23 just the ultimate figure in lab conditions for a petrol engine, all other variables(heat/pre-ignition) excluded?
Phil
Last edited:
TO82
Member +
No, no cars from factory would run a lamba 0.9 tbh mate n/a or turbo, its just that for maximum power from an engine this is the afr needed
And yes pre ignition and heat etc, all play a part in why a normal car wouldnt run this kind of afr.
munday
Member +
Yeah as long as temps don't get too high which could well be the case with the 4e engine. Best to tell with egt as well and if Temps are too high then a bit more fuel to keep it safe. Turbo or na would develop max power at the same afrs but as you say, more heat from the turbo engine sometimes limits what you can do.
So basically in an ideal world this is what you would run.
Ps thanks for the compliment
So basically in an ideal world this is what you would run.
Ps thanks for the compliment
GTti
Member +
I assume you are talking about WOT, how much boost are you going to be running?
WOT at over 1BAR plus I'd say anywhere between 10.5 - 11.5 to be nice and safe. I wouldn't run 12.5 on high boost. A richer AFR will reduce power slightly but keep the head cooler.
WOT at under 1BAR aim for a bit leaner 11.5 - 12.5.
The stock ECU seems to fuel at 10.5 on WOT, full boost.
Sustained 13+ AFR's on WOT would most likely crack your head, normal pump fuel would start to pre ignite. 13.5 - 14 should be more like the cruising AFR's at atmospheric intake pressures!
P.S Make sure EGT's aren't too hot high up on load.
WOT at over 1BAR plus I'd say anywhere between 10.5 - 11.5 to be nice and safe. I wouldn't run 12.5 on high boost. A richer AFR will reduce power slightly but keep the head cooler.
WOT at under 1BAR aim for a bit leaner 11.5 - 12.5.
The stock ECU seems to fuel at 10.5 on WOT, full boost.
Sustained 13+ AFR's on WOT would most likely crack your head, normal pump fuel would start to pre ignite. 13.5 - 14 should be more like the cruising AFR's at atmospheric intake pressures!
P.S Make sure EGT's aren't too hot high up on load.