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Reading more and more about the IMRC, I just have to ask... When I read how the IMRC controls the opening and closing of the "secondaries", what do secondaries mean?

What I understand, or what I think I understand, is the DOHC part of the engine. Meaning, we have 2 intake and 2 exhaust ports for every cylinder. So, when your sceondaries open, you run on double intake and exhaust ports as oppose to just 1 intake and 1 exhaust port?

Thanks for helping me.

Darrell.
 

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When people refer to the "secondaries" on their Duratec engines - what they are referring to is a butterfly placed in the secondary intake port. This butterfly is computer controlled to open about 3000+ rpms. This is to help intake velocity at low RPMs and give the engine a little more power.

Hope this helps...

-Nick
 

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A little more power? How does 30hp sound?

hehe. (yes, a Neco member dynoed his couger when his secondaries failed to open.. he zipped tied them open and gained back 30hp....115hp w/secondaries closed...145 with secondaries stuck open.)

You can basically see on the Upper Intake Manifold how the 2 sets of runners per cylender are setup. There is 1 long runner and 1 short runner per cylender. The runners run oppositly. At 3800 RPMS the second runner is opened by a butterfly located in the Lower Intake Manifold.


Like Slockin said, the secondaries help maintain proper airvelocity for the given engine speed. So this is why they open up..when the engines reaches high rpms and needs to breath more. So keeping them open all the time is Not a good thing.. and will cause a loss in TQ due to TOO much air flow at low engine speeds.
 

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Originally posted by: atlas
Stupid/Simple Question
"...there are no stupid questions, just stupid people" :rofl:

but it wasn't a stupid thing for your to ask... I always like it when people take action to learn about the car that they trust their life with... its good that you are trying to understand how things work, and WHY they work the way they do.

Also Kenny - that was a good explanation i must say... heh, i even understood it :tongue: (mostly cause you didn't use a ton of abbreviations like some tech. people around here.) :)
 

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Yes I love my secondaires. They are quite fun.
 

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DOHC means Dual Over Head Cam...

Meaning there is one cam for the exhaust valves and one for the intake valves per bank of cylinders. In our V6 there are 4 cams total, and in a DOHC I4, there are 2 cams...

It does not mean there are 2 exhaust ports and 2 intake ports. It doesn;t even tell you the number of valves. Just the number of cams utilized in the valve train.

The Secondaries are part fo the induction system, and completely separate from the cams...as all ready explained.
 

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beat out a kitted/loud old boxy Prelude last night with my secondaries stuck closed.

heh heh heh.
 
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