RX7Wishing

Hey guys,


Question for ya. I recently installed my PowerFC/Commander and i have a few questions. Now...before i installed it i was having issues with controlling boost on secondary transition, and into redline. This is basicly how it goes.

Boost controller (turboXS HBPC) set to 12psi. When the Primary Turbo comes online and reaches 12psi it holds.. At transition it drops to 5 to 6 psi then hits 10psi and slowly tappers to 9 to 8 psi by redline. Now that the PFC is installed it control's transition a shitload better. And also controls boost on secondary better as well.. Now im seeing this boost pattern. 11-12 (depending on outside temp) on Primary, 6psi at transition. Then 10psi till redline. Now here is my question... I have read the manual but still don't seem to grasp the concept of boost control with the squential system in place, So bare with me. What i want to do is try and smooth out transition by not letting boost drop off so sharply. And also keep my boost around 12psi till redline. I noticed in the commander there are 2 sets of boost settings.. Looking something like this


1Pr 0.80 "Dutycyclehere"
2Sec 0.80 "Dutycyclehere"

1Pri 0.80 "Dutycyclehere"
2Sec 0.80 "Dutycyclehere"

Now the pressure i listed above is just for refference and not what is actually set in the pfc (set for stock settings). Now what are the 2 different "set" of settings for? And since im using a MBC the pfc isnt actually controlling boost. But it IS controlling transition correct? So.... what do you guys reccomend? I do plan i getting it tuned in the very near future. But for right now i would like to work out my boost issue.


Things i have done...

Replaced solenoids.
checked vaccum likes and check valves
Checked for boost leaks.

Also.... Per the commander my Injector duty cycles never pass 83%..

RX7Wishing

Gah i fucked up the title... I ment to say "Controlling boost with MBC and PFC"

cewrx7r1

iTrader: (2)

With a MBC controlling boost, the only value used by the PFC is the BOOST value.
The boost value is really the value that fuel cut is based on to prevent overboosting by cutting fuel which in itself might detonate the engine. That is why you set the boost value greater than you will ever run when using an external boost control device.

What you need for your seq setup is the addition of a small adjustable water valve to control precontrol spoolup control.. Your MBC will control overall boost and the PC valve will affect the transistion boost, smaller opening will cause less spoolup while a large opening will cause more spoolup,

I use to run two valves, one for PC and one for the WG.

RX7Wishing

yea, i was going to use the PC valve before. But read that it was a mother effer to dial in right. Thanks for the feedback though.

cewrx7r1

iTrader: (2)

First you adjust your MBC for your over all boost, then go back and adjust the PCValve for transistional boost pattern. It might take a few runs but it is not hard.