Stock Exhaust Manifolds

[LannyL81]

Living in an emissions control area, putting headers on is not really an option, so....I have cut-down the AIR lines protruding into each exhaust port so that they are flush and now I question what I have done.

Was the AIR tube protrusion into port done for a reason to keep the exhaust pulse from going up into the AIR tube? Have I created a problem for myself? Has anyone done any work on the stock exhaust manifolds like this?

Thanks once again,
LannyL81
Tucson, AZ

 

[Sensei]

I'm just guessing, but I think the anti-reversion valve on the AIR line should keep you from having any problem. How is your performance and fuel economy? That is the real test. Cris

 

[LannyL81]

I should have explained my question better.

I am concerned with the exhaust pulse of one cylinder going into another cylinder (on the same head of course). The worst case of this would be if (on the same head) one cylinder is on the exhaust stroke and having another cylinder beginning the intake stroke such that both intake and exhaust valves are open (overlap). This would cause a lean condition as the exhaust gases would displace some of the fresh air/fuel charge coming from the intake manifold.

I guess if I took a look at the firing order and work out the valve timing, I would determine if this condition ever exists or not.

Of course if I were to just plug the AIR lines in the manifolds, then I could never have this condition.

Anyone done this before?

Thanks,
LannyL81
Tucson, AZ

 

[smithjw]

Last year I removed my AIR pump and bracket and also plugged the lines in the manifolds as you suggest. At each manifold, I left a one inch long piece of the original hose and on the end of the hose I put a copper end cap that you can get in a plumbing supply shop. Besides plugging the 2 manifold lines, there is one other line that I plugged on the passenger side of the engine tucked up behind the EGR.

Of course, starting this year in NY where I live, they are doing emissions checking during vehicle inspection. I was praying that I would get some young kid doing the inspection that would not notice that parts were missing. As it turns out, all the guys in the shop came over to check out the outside of the car, but nobody even opened the hood to look at the engine. I was good to go.