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Discussion Starter · #1 ·


Edit: Photopoint sucks! I have a nice shot of the High port+low port intake runners. Their is a noticeable diffrence in the size of the runners.


[This message has been edited by Mike Gosselin (edited 07-31-2001).]

Stuck on an island
1,284 Posts
I think this why they changed the high to low desinge taken from SE-R.NET, But witch one is better I dont know ?

"The '91 thru '93 high-port engine had problems with "port wall wetting" (not to be confused with "bed wetting", though it's worse in the ARB's eyes), where the injector was far enough from the intake valve that some fuel was sprayed onto the intake port walls. When the throttle was snapped shut, the increase in port vacuum sucked this extra fuel into the combustion chamber and caused hydrocarbon emissions to skyrocket.
In addition, low intake port velocity at idle also caused an increase in port wall wetting, leading to a similar condition. The PAIRV was there to introduce enough fresh air into the exhaust for the cat/con to burn off the excessive hydrocarbons.

The '94 and newer low-port engine moved the injectors closer to the intake valve and increased intake port velocity at low engine speeds. These changes were enough to allow for the elimination of the PAIRV. They were also responsible for the improvement in the engine's low-end power."


92 NX2000, kyb agx, intrax springs, jwt pop,
3a Racing muffler with bonzi tip,
17 " mille miglia mm 112, Yokohama avid h4
ACT clutch on order

[This message has been edited by Nick (edited 07-31-2001).]
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