Brock's Performance

FAQ ID # 232
Last Update : 2012/11/26
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Question / Issue
Why do I need to block my PAIR and will it affect my mapping?

Answer / Solution

The factory PAIR (Pulsed Air Intake Reed) simply injects air into the exhaust track (through a hole in the cylinder head from the exhaust port to the top of the valve cover on each cylinder) to help burn any unburned fuel in the exhaust pipe.  In OEM applications, this occurs before the catalytic converter and creates additional heat to help it operate more effectively and lower emissions.  In an aftermarket application the PAIR must be removed and/or blocked to prevent excessive popping during deceleration (aka Decel pop).  There is no power gain to be had from blocking the PAIR alone as all aspects of the pair occur after the exhaust gases have left the engine. Additionally, fuel injection mapping has no affect on pair modifications. If the PAIR is allowed to operate in conjunction with any aftermarket exhaust system which does not utilize the catalytic converter, it can create excessive exhaust heat which may discolor exhaust pipes and lead to premature heat related failure (to the exhaust itself and especially to the packing in the baffle). Removing emissions components from any vehicle may render it illegal for street use, check with your state and local authorities.

Related Links
PAIR Valve Block Off Kit from Brock's Performance

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Pair, pair valve block off, pop, decel pop, remove emissions
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