Stuttering badly when trying to get on boost

[Rasmus]

Hi I've been having issues with my car stuttering when trying to reach boost when aproaching peak boost (1.5 bar) like 70% of the time the car just starts stuttering really badly like it keeps cutting the throttle. But sometimes it boosts just fine so I have no idea what's going on and I would apreciate if someone with more knowledge than me could take a look at my log file and see if they find something.  @2:23 - 2:29 in the log file is when the stuttering happened.

I'm using a 3 port boost solenoid for boost controll, and the engine is a 3S-GTE with a garret GT2860RS trubo on it.

 

Thanks.

mr2.pclx stutter.llgx

[ellisd1984]

You've got a target Lambda of 0.8 and your actual lambda is 0.92 at those points so you're really lean everywhere from what I can see.

[Adamw]

You are hitting the MAP limit (boost cut).  The MAP limit with the default settings starts to limit 10Kpa before the set limit.  Yours is set to 260Kpa so will start limiting at 250Kpa.

[Rasmus]

Okay thank you very much, I'll take a look at it when I get home, I don't understand how I'm now all of a sudden hitting the map limit, on the dyno I never reached the map limit, it's like the boost controller isn't working correctly anymore.

[Adamw]

You are running open loop boost control, the ecu is just sending a fixed duty cycle to the wastegate solenoid.  The boost will change with air temp, engine temp, exhaust gas temp, ignition timing, load, acceleration, etc...  All of these are usually significantly different in real life Vs on the dyno.  

[Rasmus]

36 minutes ago, Adamw said:

You are running open loop boost control, the ecu is just sending a fixed duty cycle to the wastegate solenoid.  The boost will change with air temp, engine temp, exhaust gas temp, ignition timing, load, acceleration, etc...  All of these are usually significantly different in real life Vs on the dyno.  

Okay thanks alot I'll try and adjust the boost controller later on today