MoTeC Global Forum

Interested in what can be done to improve cam targets on avcs ej20/25 engines, larger cams, and or more crank oil clearance seems to make it harder for cams to start on targets, talking 5degs out at some points.

running more proportional gain going to help?


cheers
Michael

Are you referring to the lag its got when idling to track from 0deg to lets say 10deg when you rev it up?

or is it just not tracking all the time?


For the first instance, i never run 0deg on a cam advance table. since if 0 is just over 0 deg itll shut down oil supply through the actuator completely. When you ask for a sudden change then it lags. If you let it idle on 1deg it will track to 10 degs instantly

More P gain will add more DC for the same error at an instant. Have you got a "actuator normal position" set?

No, it's lag and lack of holding at any change in the map at any rpm.

Log on this shows it can get -6degs on one cam and -1.6 on the other if asked -5degs on both as well.

cheers
Michael

Hve you got the offsets set correctly?


I do the offsets with the cam control solenoids unplugged to get both cams to 0. If you make a "normal position" table, both cams will use this table, and if there is a difference between the 2 in how they react it might cause some headaches.

Have you logged the DC of the 2 cam actuators? are they not maybe on the limit you have specified in the cam control setup?

Is reaction slow? Add P gain

If they are reacting okay but just not reaching the target, maybe add some I gain.


Ive found that same is you on non-stock BMW N52s, but luckily there is only one inlet and one exhaust so the normal position table helped.

Yes added some P and will see how it goes.

The issue is it's a built engine and have no idea if both cobe center lines are the same on each In cam, the offsets are both the same, wouldn't assume both cams are the same on the stops either.

Both cams use one table.

logged actuators and are within limts of the min and max targets.

I have another car which uses std cam setups which is perfect, and uses 2 in the P where the other std map come with 1.2, so done some work and see how it goes.

cheers.

I dont think it abnormal that the map you get is not 100%,it might need a bit of tweaking to get it the way you like it.


I usually add Pgain on the 4g63 Mivec installations from what the startup map suggests.