Alpine951

I recently realized I had the settings on a Profec b 2 all screwed up. It took a dyno day with a very erratic boost curve to figure out. The profec sets boost as a percentage not a specific psi. The limiter is a function that will lower the boost when the boost exceeds a warning setting. If boost is set at a percentage of 50% (18 psi) what effect does setting the limiter to a certain percentage have on reducing the boost?

awilson40

the limiter is an actual PSI setting.
180 on the limiter is 18 psi
I set the limit 2 psi above my max boost that I want to run.

Alpine951

I think you may be wrong Andrew. My instructions show the warning as a psi setting and the limiter as a %. The limiter is what kicks in when the warning setting is reached.

shaheed

ok after looking at my car alpine is correct, the limiter value is a % and warning is the psi value.

Alpine951

Im trying to upload the page of the directions.

awilson40

My bad...memory isnt what it use to be
I got the two mixed up.

ehall

so for my benefit, to limit boost you set the psi number that you choose as your max. The controller actually manages boost based on percentage. Is this correct? If so does that mean that 180, as used above, then translates to 18psi? Thanks guys, I'm buying one of these in the next couple of months.

Alpine951

Per the instructions:

SET

This mode is used to set the desired boost pressure. The % set is not the actual boost pressure.

You have to play with this setting to get to the max boost setting you want. In this mode 180 has noting to do with 18 psi. Mine is at a setting of 50%. WHy? Hell if I know. This is just the setting that I reach my max boost. You can go to www.greddy.com and click on one of the links, Tech I think, and you will be able to see the instructions. You need adobe to read it.

aeronautica86

so wouldn't that mean that you could set the warning at 10psi (easy to work with) and the limiter at 80% ie 8psi? In other words is the limiter a percentage of the warning psi?

shaheed

if i remember correctly % is a percentage of whatever boost you set it to run at. so if you set the boost @ 20% (and assume this worked out to 10psi), warning at 12psi and limiter at %20.

this would translate to boost set at 10psi, max spike at 12psi and if it does hit 12psi then drop it down to 8psi.