TwinTriangles

Quick poll for those using PFC to control boost, I seem to have a low sec. boost issue but I was just looking to see what duty cycles you guys are set at and what boost is at that duty cycle setting.
And if anyone knows the preset duty cycles that come set in the PFC brand new that would help too thanks .
JDub

Brentis

same here.. I've been unable to get to 13psi and keep messing with my boost duty and can't seem to get it. I've had it up to 84% to no avail.

TwinTriangles

Oh geez 84%, I run a stedy 10psi pri. with it set to 40% & with the stock ecu it ran a steady 13psi...

Badog

The 7-07 base map has:

Primary .90 56
Second .70 64

Primary .90 62
Second .80 70

I run:
Primary 1.00 65
Second 1.05 75

ZeroBanger

I run 1.0 50 pct
1.0 50 pct

that gets me about .80. when I want to get to .90 I set the WG DC to 58

94rxrob

iTrader: (1)

I have my pfc primary boost at .65, 38%
secondary at .60, 44%

With this I am still getting steady boost of .73 - .75

I haven't lowered the waste gate duty cycles more to see what changes it makes to see if I can get the boost closer to where I have it set, but it seems like I may need to drop quite a bit more to have .75 boost if I actually have the primary set to .75

So my main question is, is there any problem with having very low wastegate duty cycles in order to control boost?

Badog

And I get exactly what I am set to.

Badog

The lower the duty cycle, the more chance you can go OVER target, the higher probablity of boost spike. The WG cycles less. I would start raising the duty cycle until you start hitting the target boost level.

Badog

You guys with sigs longer than your posts annoy me.

Same to you.

SleepR1

Something wierd is going on with Power FC during hard acceleration on boost. I notice that the twins have a tough time getting past the boost dip during switchover (4500 rpm). The target of 0.85 kg/cm^2 (~12 psi) is reached on the primaries, but once the revs climb past 4500 rpm the boost drops to 5 psi, and doesn't climb back to 12 psi like it's supposed to with my foot on the floor. The revs to climb to 8000 rpm eventually albeit at a slower rate with only 5 psi. I've found that if I lift and SQUEEZE the accelerator to the floor that the switchover is more seamless, and the boost DOES climb back to 12 psi from 5000 rpm to redline (8000 rpm). What the heck is going on?

My boost settings are:

Setting 1. Primary, 0.85 kg/cm^2, 78% duty cycle, Secondary, 0.85 kg/cm^2, 78% duty cycle

Setting 2. Primary, 0.95 kg/cm^2, 86% duty cycle, Secondary, 0.95 kg/cm^2, 86% duty cycle.

I currently run Setting 1 on the street. For track, I back the boost down to 0.80 kg/cm^2, 74% duty cycle for both primary and secondary turbos (J-spec twins).

94rxrob

iTrader: (1)

Baddog, thanks for the response.

The reason I kept lowering the wg duty cycle is due to me going way over my settings. Even with me lowering the primary boost to .65 with the wg duty cycle at 56%, I was getting steady boost in the .83-.85 range so I kept lowering the wg duty cycle to attempt to bring the boost down to closer to where I want it to be. Spiking so far doesn't appear to be a problem.

SleepR1

It sounds like you have to raise the wastegate duty cycle to keep the boost spikes down?

radkins

The big wastegate dutycycles debate reminds me of how much I love my Profec B

TwinTriangles

Speaking of.... Why do so many people use the profec B instead of the AVC-R ?
Just Curious...

radkins

It's very simple and works very well.

CCarlisi

Sleeper it sounds like you have a leaky check valve. I haven't looked at this stuff in awhile but I believe if you have to lift to get a normal boost pattern your vacuum check valve is leaking. By lifiting it creates vac in the manifold which repressurizes the tank.

Brentis

Good thread.

I run .90 82% on pri .90 84% on sec. It seems I may have a crack in my housing or my primary is going bad as I cannot achieve .90 on my primary regardless of what I set the base duty.

SleepR1

Used this site as a reference:

http://www.autosportracetech.com/RX-7/rx7stuff.htm

Replaced vacuum chamber check valve, double throttle control check valve, pressure chamber check valve, and one other vacuum line check valve. Replaced wastegate/precontrol solenoid pair (two nipples each solenoid), and turbo control solenoid (two nipples, sits on top of the air control valve). Will follow up once I get a decent road test @ this evening's Putnam Park open track event!

xph

OK, well not to disagree, but I think this note from the datalogit manual, pretty clearly states that you lower then number to keep boost spikes down...... you raise it to get quicker spool times....

"Duty setting determines the Waste Gate Control Solenoid’s initial position (% opening) before the Boost Control system starts to control boost
Click in the box and type in the desired Value
• If the number is too LOW, boost will lag and take more time to reach the desired Boost level. This will cause no damage but may make the car feel sluggish
• If the number is too HIGH, boost may spike and over shoot the desired boost level before settling back down"

X

damian

iTrader: (2)

baddog, do you also run the stock pills in the lines?

Badog

Stock pills! Was the stock WG with the sotck twins.

damian

iTrader: (2)

>>Stock pills! Was the stock WG with the sotck twins.

huh?

you know, the restriction pills in the lines from the primary turbo to the WG/PC actuators....unless it was the newer turbos with the restriction built into the housing....that is what I ment.