Finland

Well, sometimes working as a test engineer has its perks. I recently decided to enter the realm of electronic boost control. I've been putting this off for a long time, because I just didn't want to leave the relative safety of mechanical boost control. I decided to bench-calibrate my boost controller to create what I believe to be an ideal boost curve and stepper motor duty cycle .

See the pictures for the setup. I used a manual regulator and analog gauge to pressurize a manifold to approximately 10Psig (my target boost level). I would set the boost controller to a given setting, then log data from two different pressure transducers. I placed one transducer on the test manifold, which would simulate engine intake pressure, and another at the stepper motor output port to record the pressure output to the wastegate.

The idea is to control the stepper motor duty cycle and at the last possible moment, allow the wastegate output vent to atmosphere...all the while trying to not create a pressure spike.

With my car, I just don't have any room for error (overboost), so it's best to try to come up with a theoretical best fit calibration before starting to play with it on the car. Anyways, here's the data..

http://ffdet.com/members/jan/bc/profecdata.doc




I think I found a close to ideal starting point with the low boost set to the 4th dot, and the balance set to approximately 37% of full scale.[/img][/url]

BoostR41

awesome info Jan. I am goin to mess with my response for mine since the internal gate on the 18g is known to creep

99blusi

Now that's an interesting approach. I've been working on my spec II for the past few days setting low boost and today setting up the high boost. Did you get that from old Billy boy?

Finland

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 99blusi &raquo;</TD></TR><TR><TD CLASS="quote">Now that's an interesting approach. I've been working on my spec II for the past few days setting low boost and today setting up the high boost. Did you get that from old Billy boy?</TD></TR></TABLE>

Sure did...let's just say the price was right That's exactly why I conducted this experiment today, I spent about 1 hour on the bench finding a good starting point, so hopefully I'll spend less time fiddling with it in the car.

99blusi

It was alot of fun messing with it actually...but after a few 15psi pulls I figured I better get it back in the garage before "THEY" figure out where I live and just start sending the tickets in the mail.