Engine Power Reduced?? Please Look At Tune And Give Feedback On What I'm Missing?

[Monster50iii]

Well I'm just getting going on trying to make my own tune. It seems to drive..okay, but every 5 or so miles it goes into engine power reduced mode..no codes. I keep thinking my desired boost vs target vane positioning isnt in sync enough but I'm not sure if that will cause this or not? Not sure if there are tables that need adjusting?? Any help/wisdom would be appreciated.

[LB72004]

yep, i think you bonkered your boost and vane tables and now actual boost and desired don't match and never will for long enough for the ecm to be happy.

one. some of your desired boost is below the ambient pressure at sea level (14.7) so the turbo has no way of making negative boost. this is likely the main reason. then in your medium and high altitude tables there are unrealistic boost numbers being called for. the turbo wont be able to make that much boost with less air.

think of the turbo as a pressure ratio device. with the capability of doing about 3.0-3.2 times the ambient pressure. so at "0" psi or zero boost it will be at 14.7 PSI.

if you wanted 20 psi of boost at sea level then you would have to take 14.7 psi, multiply that by 2.36 to get 34.69 then you have to subtract the 14.7 psi from it to arrive at 20 PSI.

since the turbo can only do about 3.2 pressure ratio max that would make 14.7 x 3.2 = 47 PSI. the tables in EFILive dont subtract the ambient pressure so that is what you would put in your cell. the lowest cell would be no less then 14.7. what i do is put in the desired boost that i want to run then add the 14.7 to the whole table. so 2 or 4 psi in the cruising ranges. and 32 PSI at max boost. then add the 14.7 which makes the 2 turn into 16.7 the 4 turn into 18.7 and the 32 into 46.7.

for your medium & high elevation you will need to adjust for the ambient pressures. looking at table B0202 for the altitude multiplier, you will see that 12 PSI is when the ecm is at full medium altitude and 8.5 psi.

so the max boost at medium altitude would be 12 psi x 3.2 = 38.4 PSI and high altitude is 27.2 PSI. work with these numbers to come up with new tables.

for your vane tables, you are best off logging the actual vane once you have your boost loaded up and using that to make a vane table. see here: http://www.fishtuning.com/VanePosition

I went through this same issue with mine and had a terrible time figuring out why it ran so bad. once i learned that the turbo works on pressure ratios and i started over with my tables it runs so much better now.