sibleyg

So here's the problem:
at the dyno yesterday, the car ran great, 260rwhp but should be able to get lots more. So we turn the boost levels up on the PFC and there is no change in boost levels. We turned it up to 1.4 bar and still no change, 10-8-10. I know I shouldn't turn it up past 14psi (0.95bar) but we were checking into why the boost wouldn't increase past 10psi.

Here's the car info and mod list:
1993 touring, body has 92k, rebuilt turbos less than 10k ago
vacuum simplification (ACS, DT, ISC, AWS, etc removed)
stock twins with ported wastegate
K&N cold air intake
M2 medium SMIC
DP
MP
Racing beat cat back
Power FC (damned hunting idle!)

Thinking about this problem, could it be the wastegate control? It keeps it at 10psi instead of letting me increase to 12 and 14psi?

The car appears to be running fine, I just can't get past stock boost levels.

Tried a search but couldn't find a keyword that didn't give me thousands of other problems.

Thanks for any advise.

saxyman990

Which settings are you changin in the PFC (There are two: boost level, and duty cycle)? The boost level doesn't do jack except tell the ECU what your goal is so it can figure out when to cut fuel. To raise the boost, you need to alter the DUTY cycles for both pre-control and wastegate.

sibleyg

changing from primary to secondary on the boost setting screen. we changed the boost level on the setting 2, increasing it slowly but did not change the base duty settings.

saxyman990

That's why your boost level hasn't changed. Changing the duty cycle is what alters your boost. I know it seems weird, but that's how the PFC controls boost: by the duty cycles of the two solenoids.

Bottom line: to change boost level: Change the duty setting.

sibleyg

So I should change the setting 2 primary and secondary base duty to what to hit 12 and 14psi? The manual is not exactly illuminating on this topic.

cavellm

Just keep increasing the % until you get to what you want.

It's much easier to use a regular boost controller. Just set the PFC for max and control everything with a profec B or something.

saxyman990

Exactly. Just be sure to do it in small increments, otherwise you could overboost.

sibleyg

You mean set the PFC to the max bar you will allow and then change the duty cycles upwards until you hit it?

I don't want to spend more time and $ on a Profec B if I don't have to. I understand it is better at doing this but I am not exactly going to drag race this car anyway.

cavellm

Set the PFC to about what you want the max kg/cm2 (not bar) that you want. Then keep adjusting the duty cycle up in like 2% increases till you get where you want.

Just be careful of overboosting when you're doing this.

And I hope that your PFC is at least initially tuned by someone. Not just straight out of the box and you're increasing boost.

Pop_Goes_The_Wankel

set the boost at something like 1.0 for primary and secondary. Then set the duty cycle for .37 for both primary and secondary. Do a run and see your boost. Then keep upping the duty cycle by .04 increments until the boost you want is acheived.

the power fc manual does state that the changing the boost will have no effect unless you change the duty cycle settings also. The boost is important because the power fc will shut the ignition/fuel off if the boost hits .25 over your target boost. To simplify things, if you set your boost to .75 and you hit 1.01 you will hit a fuel cut. So its best to set the boost higher and set the duty cycle lower.

sibleyg

cavellm, no it is not right out of the box. I downloaded the "safemap" from this site, input it into my PFC so I could at least drive it to a dyno and on the dyno adjusted the ignition and fuel maps to maintain just under 12:1 ratio, relatively safe intial calibration according to the tuner. From there we planned on redynoing the car at different boost levels. Our initial try (changing the boost setting, not adjusting the duty cycle settings) resulted in no change. I began to wonder if I missed something in the vacuum simplification, something broke during or after, or there was just something else we were missing. It looks like there was, duty cycle and understand what is not written in that damned PFC manual.

Pop_Goes_The_Wankel, thanks for the simple procedure. I'll give it a try when I get to the dyno again.

For right now, a little rich and only 10psi boost is good enough for me. At least it runs again.

All, thanks again.

sibleyg

Just to close the loop, after doing the simplification, I had the lines on the back of the turbo control backwards (top was on back and back was on top). Thought I had it right after the 3rd time checking it.

Switched them, tuned and now 12-14psi boost. Yeah!

Now if only the clutch wouldn't slip.

fd3virgin

it was easier for me to just add a manual boost controller like a profec b. kvn

Little 7

I think PFC cannot handle the boost by itself, that why Apexi makes a PFC boost controller kits beside AVC-R for PFC use.