Hi everybody, this is my first post, i'm trying to learn all that i can before i actually purchase my z. I'm tryin to decide between a few cars and right now i'm really leaning towards the z. Anyways sorry for babblin, i've never heard of a plenum before and after bringing up a search, it looks to me that a plenum is an intake manifold, is this what it is? if not could you please explain to me what a plenum is. Thanks

 

You got it! That's exactly what it is.

Good luck and buy a Z.

Regards..

 

thanks man

 

See www.crawfordzcar.com for a pic of their modified performance plenum to get a better idea.

 

More specifically there is the upper and lower plenum on the Z that make up the intake manifold. On something like a Chevy 350 the intake manifold is one piece but, like on a V8 mustang 5.0 or 4.6, the manifold is two pieces on the Z. The upper portion of the manifold is what is available aftermarket as of right now.

 

I'm still curious why everyone calls it a plenum when right in the service manual they call it the upper intake manifold collector. It's no big deal, I'm just wondering why everyone is calling it a plenum when most are familar with the term intake manifold.

 

The dictionary says it is "an area where inside air pressure is greater than outside air pressure", like in an automobile's air intake system.

 

Because the terms are interchangeable and it is easier to type and say "plenum" than "upper intake manifold collector."

 

Yeah, but using terms like "plenum" vise well known terms like "intake manifold" starts threads like "What exactly is a plenum?" LOL, anyway I just never heard the term plenum used to describe the intake manifold before coming to this board. I just though that maybe the manufacturer refered to it that way but I see that's not the case.

 

Well, context clues go a long way.

 

ple·num Audio pronunciation of plenum ( P ) Pronunciation Key (plnm, plnm)
n. pl. ple·nums or ple·na (pln, pln)

1. An assembly or meeting with all members present.
2. A condition, space, or enclosure in which air or other gas is at a pressure greater than that of the outside atmosphere.
3. The condition of being full; fullness.
4. A space completely filled with matter.


Maybe you misread the post.

Did it go something like this? (see #3 above)

"They had a special at McDonalds. Two Big Macs for $2. Damn, my belly is plenum."

or

"I had pleny of um cheesburgers. I am upper intake manifolded."

 

Maybe you misread my last post. This is a common problem with the english language. You are smart enough to decide which definition applies in which case. Try and be a little more intelligent and a little less helpless, joe.

 

 

I agree, I have never heard the term "plenum" to describe an intake manifold until I came to this board.

Terminology changes will raise questions and threads like this like the term header and lintel. The term "lintel" is rarely used in construction anymore in favor of the term "header" but using both interchangeabley does cause confusion in the field even though they are the same thing.


Jeff

 

Has anyone done a dyno with the Crawfrod Plenum?

 

Plenum has become more of a generic term and is commonly used by many for a large single piece intake assembly. The 350Z/G35 service manuals note three major components...

1 - Intake manifold collector (upper)
2 - Intake manifold collector (lower)
3 - Intake manifold


DaveO