626 Intake Manifold?

KMac

Zoomin' since 2003
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Mazda Protege5, 02
So what is the biggest benefit to changing the P5's intake to the 626 manifold?
 

tweety2300

Member
:
2001 mazda protege mp3
Nothing unless you're turbo makes none to negative impact on an na. I'm sure someone will say otherwise but I wouldn't waste the money on it
 

Ward83

Member
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2003 Protege5
No VICS system, so no screws to fall out and get sucked into the engine. However, unless you've got a turbo, it's actually a downgrade performance-wise.
 
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2002 323 Protege
No VICS system, so no screws to fall out and get sucked into the engine. However, unless you've got a turbo, it's actually a downgrade performance-wise.

Incorrect. Pending on your definition.

The stock protege manifold has two runners meaning that each runner is effectively tuned for two different rpm ranges. (Tuned prolly isnt quite the right word but *shrug*) The two runners act as means to fatten up our power curve.

The reason the difference in lengths matter is due to the premise behind and intake manifold. Effectively within the intake manifold are pressure waves that reflect back and forth off the valve and the intake plenum. Its caused by the intake of air reflecting off the now closed valve. It stands to reason that the fewer reflections off each hard surface the better the problem is that the length required to do this at times is much much longer then we have available in our engine bay.

What you want ideally is for the air reflecting back off the plenum to be at the intake valve at the exact moment it opens. The reality of course is that this is pretty impossible to achieve. Traditionally a single runner manifold sacrifices one end for another (RPM range). Dual runners allows companies to provide two tuned lengths, the alternative for us with the 626 manifold was to have decreased low end response.

The intake runner length determines where the power in the rev range will occur, how much power we generate at the rev range is down to runner volume, velocity and flow. Which is another topic for a time when I have time to post it...

NOTE: Please note that the P5 manifold isn't a true dual length manifold.
 

mazda_sp20

Member
:
Mazda 323 SP20 (Australian FS-DE Protege)
bringing up an old thread

here is a dyno comparison, back to back with factory p5 with vics and 626 plenum with no vics

sp20dyno01.jpg