Simple trick to pass smog check?

[McLovin]

I was thinking this morning - wouldn't this be a very easy mod that would pretty much ensure that any car would pass a smog check?

(I'm not suggesting doing this, it may or may not be legal, just curious if it would work)

1) Weld in a bung (like an oxygen sensor bung) in the exhaust system somewhere. Maybe right before the muffler.

2) In normal use, just have it plugged with a bolt. But for a smog test, hook up a hose to it, hooked up to a high volume electric fresh air pump.

It would seem that any fresh air pumped into the exhaust flow would pretty much reduce NOX and CO2 on a 1:1 basis, i.e., if the exhaust flows at 350 CFM and you "inject" fresh air at 350 CFM you'd cut down measured emissions in half.

Would it work?

[stomachmonkey]

Easier.

Drive car till near empty.

Do a tune up, fresh plugs and filters.

Dump a few bottles of gas line antifreeze in.

The stuff is pretty much pure alcohol.

Get smogged.

Fill with gas.

I used to do that with my Starion.

Worked every time.

Saved me from the yearly cat bypass swap out.

[McLovin]

Interesting. I wonder if the reduction could be calculated. I.e., if you dilute the gas by 10%, you get a 10% reduction in NOX and CO2.

[Hugh R]

Don't think so, the machine looks for a certain amount of oxygen so it knows the tester is not cheating by not inserting the probe entirely.

[87maniac]

stomachmonkey has the answer.

Instead of gas line antifreeze, you can use pure methanol
I also add a couple of oz. of acetone. To a tank w only 3-4 gallons of gas.

Be sure to fill tank ASAP after doing this.

No law against putting your own 'additive mix' (a.k.a. homebrewed Techron) in your car.
. . . or is there?

[KNS]

Careful with putting methanol in your gas tank. From another site:

Methanol is very corrosive to the fuel system components when compared to gasoline. Steel, aluminum, pot metal, and soft materials in the fuel systems can be attacked by Methanol.

Also, someone made a comment on a Rennlist about water /methanol spray to cool intake temperatures. While a different scenario than in the fuel Steve Weiner responded this way:

"Methanol attacks the Nikasil plating in the bores of the cylinders so I would caution anyone from doing that".

[Hads930]

Isn't this essentially what Porsche did with the 930? I removed mine when I had my engine out, as have most owners I would assume. It had an fresh air pump and injectors that were in the exhaust port of the cylinder head, remove the pump and injectors and plug the open port in the head. They did not make a cleaner engine, they just diluted the exhaust.

Air pump removal????

[island911]

eh-ehm.. with EFI, if one of the injector leads accidently pops off that cylinder becomes an air pump.

So you want to make sure nothing like that happens or it will false the sniffers.

[John Rogers]

With my 2007 Chevy, the smog shop just plugs in the ODB2 reader that looks deeeeep inside the car's computer to see what is happening. No rolling test at all, not sensor up the butt, ETC.

[fastfredracing]

Originally Posted by john rogers

With my 2007 Chevy, the smog shop just plugs in the ODB2 reader that looks deeeeep inside the car's computer to see what is happening. No rolling test at all, not sensor up the butt, ETC.

Same here in Pa, only pre OBD2 cars get the sniffer. Anything newer just gets plugged into the diagnostic port, no codes, and all monitors ran= instant pass. We also check the gas cap .
Emissions testing is such a joke .

[Porsche-O-Phile]

It isn't about emissions anyway. It's all about money.

[Noah930]

Originally Posted by Porsche-O-Phile

It isn't about emissions anyway. It's all about money.

I wonder how much greenhouse gas is expelled by emissions testing. Not just from the cars running on the rollers, but also by the pre-test warming up that gets done (whether by the owner or the tech).

[J-Mac]

In Ca any 2000 and newer car now just get plugged into the ODB port for Smog tests. Visual check and gas cap check still apply.

Originally Posted by john rogers

With my 2007 Chevy, the smog shop just plugs in the ODB2 reader that looks deeeeep inside the car's computer to see what is happening. No rolling test at all, not sensor up the butt, ETC.

[id10t]

So what you are saying is that there is a market for a fake OBD port with a mini-computer behind it that can receive signals and spit out the correct responses....

[Rawknees'Turbo]

Originally Posted by Hads930

Isn't this essentially what Porsche did with the 930? I removed mine when I had my engine out, as have most owners I would assume. It had an fresh air pump and injectors that were in the exhaust port of the cylinder head, remove the pump and injectors and plug the open port in the head. They did not make a cleaner engine, they just diluted the exhaust.

Air pump removal????

Nope, that is not how the 930 air pump worked (did not dilute the exhaust gasses). Injecting air into each exhaust manifold port raised the exhaust system temperature and helped to burn off unburnt, wasted fuel in the exhaust (something that the 930, K-Jetronic fuel system is notorious for), and with models that had catalytic converters, an air pipe was hooked to those, and the additional air supply from the pump increased the temperature of the catalyst and helped its operation.

[Hads930]

Originally Posted by Rawknees'Turbo

Nope, that is not how the 930 air pump worked (did not dilute the exhaust gasses). Injecting air into each exhaust manifold port raised the exhaust system temperature and helped to burn of unburnt, wasted fuel in the exhaust (something that the 930, K-Jetronic fuel system is notorious for), and with models that had catalytic converters, an air pipe was hooked to those, and the additional air supply from the pump increased the temperature of the catalyst and helped its operation.

Thanks, learned something today.

[FLYGEEZER]

Moth balls in the air cleaner usta work years ago on a 1976 Buick I owned in New Jersey. No testing of any kind here in Kentucky for several years now. No safety inspections either. That part of it sucks. Lotsa unsafe junk on the roads along with bad drivers.

[widebody911]

Originally Posted by Rawknees'Turbo

Nope, that is not how the 930 air pump worked (did not dilute the exhaust gasses). Injecting air into each exhaust manifold port raised the exhaust system temperature and helped to burn off unburnt, wasted fuel in the exhaust (something that the 930, K-Jetronic fuel system is notorious for), and with models that had catalytic converters, an air pipe was hooked to those, and the additional air supply from the pump increased the temperature of the catalyst and helped its operation.

Close. The exhaust manifolds were actually thermal reactors, which were basically huge heat sinks; the air was pumped into those, and the unburned fuel burned inside the thermal reactor.

[beepbeep]

Originally Posted by McLovin

Would it work?

Not here. At least not on catalyst-equipped car. Here in EU, sniff test is usually done by four-gas machine. Just piping in fresh air might help burn some CO, but lambda (and probably NOx) would be through the roof.

Basically they insert the probe into exhaust pipe, which measures CO, CO2, HC and O2 in real time. If mixture is stochiometric and catalyst works, HC, O2 and CO will be low.

Why would you want to do such thing (remove lambda sensor) in the first place? Car are programmed to run rich at WOT anyway, so you wouldn't gain any power.

[Rawknees'Turbo]

Originally Posted by widebody911

Close. The exhaust manifolds were actually thermal reactors, which were basically huge heat sinks; the air was pumped into those, and the unburned fuel burned inside the thermal reactor.

Only on the very early, USA models that had thermal reactors - the rest, including 1986-1989 USA models, and ROW, were as I described. And the air injectors are placed in the cylinder head exhaust ports on all of them.