Ultimate way to beat emissions tests?
 

Have an 8 cylinder engine but only have 4 cylinders fire... While I know this idea isn't new, what IS new is that you'd adjust the valve timing on the "unused" cylinders so that it sucks in air and then exhausts it instead of sucking in, compressing, igniting, exhausting.

Why would this cheat emissions? Because emissions are on a PPM basis and with more exhaust volume henceforth less "crap" per million parts.. Also I'd imagine this *might improve the efficiency of the catalytic converter though I have not confirmed this.. I am aware of some polluting vehicles being outfitted with air injection (like the California Lexus LS400) but I think this would bring it to a whole new level...

Air injection is used, not to add air and lower the PPM ratio, but to provide oxygen to continue the combustion of the unburnt fuel. In ancient cars, air was just injected into the exhaust manifold. Pre-'75 Mazdas had a "thermal reactor" that, with the injected air, acted almost like a primitive catalytic converter.

If you are pumping air through the cylinders, you are picking up particles of oil and stuff...IIRC, variable displacement cars CLOSE the valves rather than open them.

Question is...why would you want to "cheat" emissions test in the first place? If a car doesn't pass, it's probably because it needs some attention...and especially if you are doing the work yourself, it's probably cheaper than trying to reverse-engineer a variable-displacement engine.

For the sake of "cheating" the emissions test? Because you want to be able to tune your car high enough so that it has the emissions profile of a higher displacement vehicle. Small vehicles disproportionately have to adhere to stricter emissions proportionately compared to vehicles that are larger in displacement.

Air injection systems only increase the ability to burn fuel in the catalytic. They were used on carburetors which ran rich all the time and on a few fuel injected cars that run rich when cold. All extra air would reduce is HC. Air cannot be injected where an oxygen sensor would see it.

Too much oxygen makes the reducing reaction in a 3 way catalyst not work. The increase in the compound that needs reducing will make you fail your emissions. Fuel injected engines control the oxygen and lack thereof reaching the catalytic to ensure all 3 catalytic reactions have what they need to perform.

https://en.wikipedia.org/wiki/Oxygen_sensor

You're right, I forgot about how the o2 sensor would get messed up by all of that.. I guess the solution would be a modified cat and manifold that would divert the "air" and have it exhaust at the last point, past the catalytic converter. Though generally V8s have at least two catalytic converters so if the computer from a 4 cylinder can be used, then it wouldn't look for the extra catalytic converter(s) but you could still retain the stock manifold.

Google search for "o2 simulator"

On a side note, why bother w/ all this... just get the engine running right.

(Easy for me to say, they stopped requiring e-check in KY about 5 years ago. The rate at which my Saturn burns oil is alarming. If I ever have to e-check it I'm sure it would fail and the only fix is tear it all apart and rebuild w/ new rings.)

I've said this before, but...

I grew up in LA back in the '60s. At that time, you were lucky to see hills that were a couple miles away. I remember going out to play, and having trouble breathing after a couple hours. The closest I can equate that feeling to is the one time I got a good lungful of smoke when I had a carburetor catch on fire.

While far from perfect, the air in LA is a LOT cleaner than it was back then. There are more people, and more cars, so my guess is that the emission controls actually do work. So.....why cheat them?

It's not about getting the engine to "run right" but being able to tune in more fuel economy like allowing for a bit more NOX or something of the sort. Having HC or CO on the other hand, that's just wasted fuel..

It was the NOx giving JoeBob breathing trouble back in the day.

Probably why my car had something called an "ElectroNox" on it when I bought it.