AFRs .....(jb4)

[Slimxy]

Hello just curious what everyones AFRs are at . Currently im using jb4 with a custom map and they're right around 14.5 roughly. I've read that this is normal since the ecu targets that stock.

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[ColonelAdama]

Hello just curious what everyones AFRs are at . Currently im using jb4 with a custom map and they're right around 14.5 roughly. I've read that this is normal since the ecu targets that stock.

normal

 

[Afterburn 549]

Great question!
We have a Gr on order and I am trying to come up to speed on all the info and mods.
Some types of cars and flashes have to have dyno and AFR set with almost every change.
If I have this right , the GR does not?
thanx

 

[Thraxbert]

On any gasoline vehicle:

Somewhere in the range of 14.5 to 14.9 (bouncing) is typical for idle and cruising.

Somewhere in the range of 12.0 to 13.0 is common for WOT, with values clustered around 12.5 being most likely.

Some cars might even go to ~15 or ~16 for low RPM highway cruising to maximize efficiency.

 

[razorlab]

On any gasoline vehicle:

Somewhere in the range of 12.0 to 13.0 is common for WOT, with values clustered around 12.5 being most likely.

Incorrect. The OEM B58 programming is around 14.X for WOT as well. 2020's stay in the 14's. 21+ are a little richer and dip into the high 13's. I have many logs of my OEM tune 2020 on track with 14.X AFR's all day long.

These are DI engines. VW also uses this fueling strategy on their DI engines as well.

 

[i3igpete]

to provide some context to what @razorlab mentioned, DI engines can generally run leaner at low and moderate boost levels due to their heterogeneous charge (locally rich, overall stoich/lean)

quick example from Heywood 2nd ed.

Also, when fuel evaporates in a CLOSED cylinder, the cooling effect of evaporation is drastically more effective.

 

[Slimxy]

normal

thanks!

 

[Slimxy]

to provide some context to what @razorlab mentioned, DI engines can generally run leaner at low and moderate boost levels due to their heterogeneous charge (locally rich, overall stoich/lean)

quick example from Heywood 2nd ed.

Also, when fuel evaporates in a CLOSED cylinder, the cooling effect of evaporation is drastically more effective.

some great stuff right here

 

[kern417]

just to add some context, the fact of the matter is that jb4 can't adjust afrs. it's not ideal, but seems to work fine. any flash tune will target lower afrs as boost increases.

 

[ColonelAdama]

Give this a read - fueling section: https://ecutek.atlassian.net/wiki/spaces/SUPPORT/pages/170557464/B58+Tuning+Guide

TLDR: The B58 will target lambda 1 (14.7 AFR) unless things start to get hot and it sees conditions that can cause knock. If you are seeing your AFR drop into the 12s, you are probably running too much boost.

 

[Extreme Power House]

just to add some context, the fact of the matter is that jb4 can't adjust afrs. it's not ideal, but seems to work fine. any flash tune will target lower afrs as boost increases.

+1

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