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RichardJ · 06-18-2019, 11:12 PM

>>orangesunshine,
A belt-driven smog pump on the passenger side, sucked exhaust fumes from the exhaust manifold and pumped them back into the cylinders for a 're-burn' to cut down excess hydrocarbons<<

Come on Sunshine, you should know better than that. You are right about the tubes being part of the A.I.R (Air Injection Reactor) system.
Putting Exhaust gases back into the cylinder combustion is what an EGR does and it does that to reduce Nox. Nox output is significantly increased when combustion temperature goes above 2500 deg. EGR gasses are introduced at specific times to keep temp below 2500.

A.I.R pumps fresh air into the exhaust manifold. When you have unburned gasses (hydrocarbons), plus heat and you add fresh air, the hydrocarbons burn harmlessly in the exhaust manifold.
The AIR system has no effect on the operation of the engine and the pump uses very little power to operate.

May70 & Motorfist.
The threaded studs in the 3rd hole in, from each end of the head are correct and original. Do not remove them. Sunshine mentioned the short studs in the end holes on both ends of the head. Those are also original. but can be unscrewed and replaced with longer threaded studs if using headers.

06-18-2019, 11:12 PM	#16
RichardJ Registered User Join Date: Apr 2010 Location: So Cal Posts: 1,415	Re: 292 Intake Port Questions >>orangesunshine, A belt-driven smog pump on the passenger side, sucked exhaust fumes from the exhaust manifold and pumped them back into the cylinders for a 're-burn' to cut down excess hydrocarbons<< Come on Sunshine, you should know better than that. You are right about the tubes being part of the A.I.R (Air Injection Reactor) system. Putting Exhaust gases back into the cylinder combustion is what an EGR does and it does that to reduce Nox. Nox output is significantly increased when combustion temperature goes above 2500 deg. EGR gasses are introduced at specific times to keep temp below 2500. A.I.R pumps fresh air into the exhaust manifold. When you have unburned gasses (hydrocarbons), plus heat and you add fresh air, the hydrocarbons burn harmlessly in the exhaust manifold. The AIR system has no effect on the operation of the engine and the pump uses very little power to operate. May70 & Motorfist. The threaded studs in the 3rd hole in, from each end of the head are correct and original. Do not remove them. Sunshine mentioned the short studs in the end holes on both ends of the head. Those are also original. but can be unscrewed and replaced with longer threaded studs if using headers.