Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Ah HA! Why pinned secondaries suck down low.

It hit me like a "two-ton heavy thing" when I was getting out of the shower this morning.

It's very simple when you think about it, and doesn't have as much to do with flow velocity for you doubting thomases as simple placement.

The truth is, the injector is located in the primary runner. With the secondary pinned open, and since the incoming air stream will follow the path of least resistance and is mostly filling the cylinder through the secondary runner, the fuel is not being carried into the cylinder properly.

So if we try a different upper like from the 3.0, I bet it would work better.

Comments?

Dan Beggs
99 Cougar V6, tweaked

ok - so who's the man?!

who asked about another intake ???

who had no idea about the injector, but knew that there had to be something better???

hehehe

I haven't been following the posts too closely with those that have recently pinned them open, but...

The system was designed for emissions. The primary, longer path was designed to swirl the air and get a more even mixure of air/fuel. Therefore, a more complete combustion. It happen to work well for torque too and was able to be tuned with timing for two peaks. Obviously, at higher engine speeds, the government doesn't care about emmisions so Ford satisfied both the gov't and the public.

So, I assume that you're going to have a really dirty system (cylinder, O2, exhaust) in a short period of time.

Aaron

Good point Aaron, that is very much a possibility.

However, since my commute is high speed highway where the secondaries are already open anyway, I'm hoping not to accumulate any buildups. But if I did more city driving, I'd be less inclined to pursue this type of mod.

Frankly, I'm more concerned about options towards filtering out or externally dumping the crankcase vents. Our intake manifolds get awfully nasty in a hurry anyway.

Dan

There is a guy over on the NECO boards selling a "PCV Mod" for 30 bucks.. I have it but havent installed it yet. His handle is WDOMKR or something to that affect and the website he uses to sell the stuff is STPerformance . I bought it so when I replaced my upper and lower manifolds with the SVT stuff, they wouldnt get fouled to hell like the stock stuff does.

I just emailed them, hopefully they will reply about what is in it.

-Lance

I pinned open my secondaries and it bogged through the whole RPM band! Wasted 30 mins trying to get to it (diff. operation on 95s) and then just yanked it back out! It's not worth it. It's there for a reason -- low-RPM torque, something our cars need unfortunately.

What you should do is shave down the secondary rod and plates like the throttle body.

Still leaves the long runners that produce low end torque and opens up some high rpm horsepower.

I don't agree with your assumptions at all. If what you suggest were true, why even have the short runners at all? Wouldn't they hurt performance when they open.

They are there to provide different flow velocities during different rpm/load situations.

Fair enough, but the engine clearly needs more air than either runner alone can provide. By the time the secondaries do open, the engine is consuming enough air that the injector pulses can be delivered properly.

Btw, did you know that the intake tracts are kept seperate all the way to the valves? So if the IMRC fails, it essentially becomes a 3 valve motor. Small wonder people really notice it when something happens to disable the IMRC's.

Don't get me wrong, I very much agree that proper runner lengths are important at different rpms, I'm just saying perhaps the low rpm problems would be not as major if, for example, the injector could magically be moved to the secondary tract.

Speaking of magic, I'd sure like a star trek type simulator where one could play with this kind of stuff through a voice activated interface. "Computer, analyze pcm and remove throttle hang."

But I digress...

dan