Contour Enthusiasts Group Archives Forums Modifications Duratec Performance SECONDAIRES - Some interesting findings

I run Alex Pepper's OBD-II Very excellent software and hardwire setup...

In order to track the Manufacturers enhanced data... You must first download the data files off the OBD-II site. Then while you are connected just open the "Enhanced" folder at the top of the program screen. Scroll through the 275+ different things it can track (a lot we can't use on our car - like 4x4 activation and such - it's very indepth!) and find secondary control (I forget what it's called off hand) Just poll it. That simple.

Antiramie - They only way to find if the secondaries pinned are not to your liking on your car is to try it. I had no problems with it. Some have...

For details check out a couple current threads for some good details plus of course the Search will net you a plethora of great threads. I started 2 of them - that will help you find some quicker... Also Brad Noon & Blorton

And then it appears on the drop down menu on the graph page when replaying the run? Nothing like something simpe staring you right in the face. :rolleyes:

hmmm... there's a group buy going on for that scanner but i already have the autotap and don't want to shell out for another one.... lemme see what i can do, maybe someone i know has it (anyone in the SE-Michigan chapter have it)... cause i would really like to plot this and get this all down on paper

OK, I have problems with your instrumentation and testing methods.

First off, the intake manifold pressure is highly dynamic, especially the closer you get to the ports. A pressure switch can read peak wave pressures which will give false "high" signals. A better choice of pressure instrumentation for the manifold would be an absolute pressure transducer (or a vacuum gauge). This will tend to average out the peaks and valleys.

Secondly, intake manifold pressure is controlled by throttle position, not engine speed. It is proportional to engine load, so gearing obviously has an affect too. So when you were tipping in and tipping out and noticing that the pressure switch was changing, well, you were measuring your own foot.

Also, I wonder what the limit of your switch is. It sounds like it's about .45 to .5 bar absolute (about 6.6 to 7.4 psiA). At light load (small pedal angle) that sounds about right for 3100 rpm. That would also explain why your light went on when you tip-in quickly as there is a quick change in load.

So, pressure wouldnot be the best way to determine when the secondaries open. I would suggest reading the signal from the ECU to the IMRC controller. I know your'e not reading actual valve position, but you'll at least know when the computer wants the valve to open. It's fully opened / fully closed anyway. Or if you want to measure actual secondary valve movement, try rigging a rotary or linear potentiometer to the assembly. Or have DemonSVT use his scan tool.

The priciple that the secondaries operate under is fundamentally engine speed based. There can really be only one good switching point between these two runner lengths, and that indeed IS the lag inthe power curve (trust me, if there was another reason, the calibration would never have been released).

If you'd like a more detailed explanation of how this works, I can surely provide one here. But I'm already too wordy to begin with!

So, I would say that your intentions are good, but you need to change how you're getting your data. Then I would suggest testing at constant vehicle speed points (like every 10 mph) in 3rd, 4th, and 5th. And even 2nd if you want to.

Good luck!

Okay maybe you MISUNDERSTOOD how i'm reading the data. It's a pressure switch as in Physical pressure not vaccum pressure. Take a look at the lower manifold, then move the butterflies to the open position. In one spot on the lower manifold is a little lever. We JB Weleded a pressure switch right here, so when the butterflies open the piece attached to the butterflies would apply presure on the switch and closing the circuit. AGAIN THERE ARE NO VACUUM SWITCHES IN THIS DESIGN.

Just wanted to clear that up.

Bllliiiiiiiip, "Yes, can I have to much information for one thousand Alex?"

You've let your engineering training get in the way of seeing the one little problem with your response... The pressure switch isn't an atmosheric pressure type, it's a physical button attached to the secondary actuator to turn on a small lamp when the secondaries open. No PSI, no bar, nothing but phsical connection purely dependant on the TPS vs RPM tables within the Ford ECU. Good bye engineering and hello common sense. :p

Yes you're right, I misunderstood. But since your statement was "we put a pressure switch on the lower manifold," I don't know how I was supposed to know it was a physical switch on the secondary actuator rail.

Now I have no clue how you got what you got, because the results make no sense to me without more information.

As far as too much information Brad, a critical part of the test description was left out, and I tried to scientifically explain what he saw as best I could. Sorry. You know as well as anybody here that if there is even one "what if" left out of your statement here, everybody grills you on it.

The engine speed dependance still holds true, though. The switchpoint may change at part load to some extent for driveability, but it can only change so far until it's useless. Unless when Puck revved the engine to 5000 at very low throttle, it was indeed an incredibly small throttle angle.

May I suggest reading the actuation signal from the ECU to see what the lag is between when the signal is sent to when the valves are actuated? Perhaps the ECU activates the valves at 2500 at WOT but it takes until 3000 for them to open?

Test away, Puck!

I know, just razzin ya autoeng...

I know.

Honestly, it helps... I do write waaaayy to much!

I've watched them open. They are fairly quick. (not as fast as mashing a gas pedal though)

The PCM does not get an open signal until they are actually open. There is a switch in the IMRC box that is tripped at full travel. When they open is PCM dependant.