Tech:Engine/K Series/Emissions System

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1971 3K with no emissions made 73hp. 1981 4K with Californian emissions system made 60hp. Testing method or emissions strangling?

Removing the emissions system from your Corolla is illegal everywhere I can think of, but results in improved performance and looks a heap better. Unfortunately, it's not as easy as just tearing all the hoses off your 4K-C, as there are at least three different types of carburettor corresponding to different emissions variations. It is reccomended you get your hands on an early 3K carburettor and use that instead.

Otherwise, sit down and study some diagrams and understand what everything in the emissions system does, you might be able to outsmart it. If you manage, write down how and tell me!

One useful emissions feature is the fast idle valve, which drops the engine speed at idle once it warms up, which is handy at traffic lights in summer. It's a box off the side of the air horn with a pipe joining top and bottom. You know your fast idle valve is working when you stop at traffic lights and your motor idles momentarily high then drops.

Another possibly useful feature is the PCV valve, and its accompanying hose and carby plate. The carb plate doubles as a heat shield from the exhaust manifold also. It has been discussed that the PCV system is good, as it removes contaminants from crankcase vapours that would otherwise pollute your oil quicker and possibly cause carbon deposits to form. Of course if your motor has excessive piston blowby, you're going to suck a lot of crud into the combustion chambers and coke up your head quicker. The PCV system may also help to prevent high-rpm crankcase pressure from building up, as the larger rings in K pistons seem to start floating around 6-7000rpm.

See also:

Article by Superjamie / Medicine_Man

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