Pulsed Air Induction Reed Valve - for all intents and purposes, it's the smog pump. Its job is to introduce fresh air into the exhaust upstream of the cat/con during deceleration and extended periods of idle to help keep the cat "lit off" (at operational temperatures). The PAIRV disappeared from the engine in '94, with Nissan citing engine improvements being responsible for no longer needing it.
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.
I don't think removing the PAIRV would cause any physical problems such as melting the cat/con, as it would actually cause converter temperatures to drop. Then again, it would offer no performance advantage, aside from maybe a small reduction in weight. In addition, it would increase tailpipe emissions, possibly to the point of failing a smog check. Personally, I left mine intact and functional.
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Check out my project progress at my 240 index page
BTW, it only weighs 3 pounds for the valve, solenoid, and bracket. I took it out because I have a SR, but you might want to keep it for emission purposes. Does Ohio regulate emissions on OBDI cars?
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Check out my project progress at my 240 index page
BTW, it only weighs 3 pounds for the valve, solenoid, and bracket. I took it out because I have a SR, but you might want to keep it for emission purposes. Does Ohio regulate emissions on OBDI cars?
I believe so...I live in Cincinnati OH and they do...thats why i am debating on whether to keep the PAIR valve...I dont know if it would make a big difference
would I be able to keep the PAIR valve..and use the PAIR hardline from the KA and route it into the SR turbo elbow just like the SR..only with KA hardline? Would that still work or not. Cuz I have not seen many swaps with the PAIR valve...and I want to try as much as possible to keep it as close to legal.
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