if i was to fit a boost controller and set boost to 0 would this
a- improve mpg#

b- be safe for engine
???
thanks

 

don't think you can set boost to 0 as the lowest it wil go wil be the actuator pressure I think!! but I'm sure some one will post up with abit more know how!

harri

 

Think Harrisard is right. Setting it to 0 will mean it will run on the actuator preasure of about 0.5bar i think.

Though no sure if it will be good for your engine. u would be better off having it mapped to run at 0.5bar

 

Correct. "Closing" the boost controller just stops the boost control system from bleeding off pressure away from the wastegate actuator, thus the wastegate opens sooner and you get less boost - c0.3 - 0.4bar on a TD04 IIRC.

You can block the outlet from the boost control solenoid or just short the turbo outlet straight to the wastegate actuator to get the same results.

As for fuel economy, it can improve open loop economy a bit as you'll get less air/fuel going through the system (less air forced through at WOT and thereby less fuel injected) but it doesn't affect on closed loop fueling (e.g. when cruising) though as this tends to be off boost anyway.

The resulting lack of power does encourage you to chill out a bit which does help MPG though

 

Not to sound harsh but if you don't want to have boost and you want to get better mpg get rid of the Impreza

 

i do want boost but i do about 500miles per week

 

I do a similar weekly mileage - biggest fuel saving I found was to fit a decent stereo, turn it up and take it easy... I can get around 30mpg without too much sacrifice.

I'm debating getting a little run-a-round for the commute and saving the WRX for the weekends etc. but the saving is not as much as you'd think.