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Steady State ignition - knock limited

Road Tuning

Discussion and questions related to the course Road Tuning


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Hello Andre,

i'm new to tuning from scratch [=

searched the forum but did not came across a straight answer to my questions..

for reference, the engine is a turbo B18c.

Q: i guess that i cannot get to knock level at low load\rpm, how do i need to approach that ?

-follow the trend from the base map until i get to the point of knock?

and then apply and adjust the changes to the lower load\rpm levels ?

lets say i start to get knock at 3500rpm at -40kpa (0 is atmospheric pressure) i continue to tune all the 3500-4500rpm level and then apply and adjust that changes to the lower levels?

Q: is it safe to get to knock every cell that we tune on steady state? do we need to give the engine time at idle somewhere ? (except from cooling temp)

sorry for my bad english, thx!

Anyone ?

Hi Chen, you're right that you are unlikely to get the engine to knock under light load and low rpm. You also don't need to make every cell knock when you're road tuning - this would be impossible in some cells and very time consuming. Instead what we're doing is optimising our timing under WOT ramp conditions and then extrapolating the results into the low load area of the map. This is likely to mean your light load timing may not quite be optimal but there isn't an easy way to sort this without a dyno.

Thanks for the replay. (:

ok so for my better understanding..

i need to know if my approach is good or bad.

i'm starting with the calibration file i have with my ecu software (if i dont have i will copy from another software)

i will take precaution and decrease all of my cells by 5-7deg until 0kpa.

from 0 kpa into positive boost i want to start with 5 deg and start upping the deg until knock.

Example: let just say my minimum boost pressure is 15psi. i tuned all of the cells from 0 to 15psi (4000-9500rpm) at 24deg, no kncok.

the logic says that i will hear knock at lower rpm, then i will decrease 3deg and do another pull to ensure that there is no knock.

am i keep on going like that? is that a good method ?

also a question from before, is it safe to get to knock every time and then move on to do another pull ?

thanks