Emissions discussion inside.

FlightService wrote: So emissions equipment. Over the years it has gone from car killer to barely noticeable.

People who have had the VW diesel fix would argue with you.

I have to get my cars emissions tested so I try to keep it compliant. Even to the point of picking a supercharger kit for the Focus that had an EO#.

It was a point of pride with me that I had a supercharged car putting out 2 1/2 times more WHP than stock that would have still passed California emissions.

2002maniac wrote: In reply to alfadriver: Get ready for a rant guys!

No rant, just explanations on how it works.

Knurled wrote: Still doesn't smell nearly as bad as any Diesel, at least. And that is before the fuel scents I like to use.

So, after throwing $500 at the car for the fancy exhaust pipe that makes a rotary quiet-ish, after driving it around for about two gallons' worth of fuel tuning it, I may be revisiting this statement. Also glad that I grabbed the water outlet from that Duratec-engined Ranger, with a little finagling it should clear the hood and be just spiffy for RWD-izing an MZR engine.

My wagon is emissionless and thats how i drive it. Sub 3k miles a year. Truck and the wifes car both retain all the stock emissions equipment. I may be the only person in town my age who doesnt have a straight piped chevy tho.

Most of what I work on is pre-war.

We always re-install whatever emissions controls the car has.

No reason not to put that road draft tube back on the engine!

In all seriousness, I have fabricated PCV systems for some cars just to help them stop heaving oil out of the "seals" in the engine.

I'll address some specific posts after this- the basics of how I would suggest doing it.

This will get you a very good solution, one that you will probably smell something on start up, but it will be good pretty quickly, and be clean enough to probably not result in headaches (or lingering smells after the drive).

Some kind of O2 sensor upstream of a catalyst. Switch it roughly at 1-2Hz, keeping the lambda control to +- 0.04 or so as it switches.

Better if the O2 sensor is a WB one, and the system still switches.

Even better if you can include feedback from a sensor after the catalyst.

I have no idea how aftermarket cats are made, but given that the highest cost on the cats are running at market price, generally cheaper means not as good.

None the less, having something is better than nothing, and it should result in you being able to enjoy your car more.

Oh, and this assumes that you have a closed PCV system. PCV isn't as irritating as exhaust, but it's pretty nasty in of itself.

chaparral wrote: I put a cat and O2 sensors on anything that'll have electronic engine control. The O2 sensor after the cat is a true mixture sensor, with less unused post-combustion oxygen.

Yes an no. Since the sensor is basically measuring the ratio of reductants to oxidants, you still get enough of those after the catalyst so that you can get useful information.

But...

First, the signal is VERY filtered, so the lag on controlling around on it as the primary control is pretty long. Second, there are some chemicals that are made in the first brick that really biases the signal. And third- as it turns out, the catalyst actually absorbs some of the remaining O2, so that signal is normally a little richer than actuality.

If you were using that signal to add some extra feedback to the control system, it does to an amazing job at doing that. Try to get it to run about .7V is you can.

ProDarwin wrote: Related note: just how far gone does a cat need to be with OBD2 to throw a code? My DD is getting awfully stinky and at 20yrs old/170k miles I feel like its reasonable to expect the cat to be dying. But no codes yet.

It's supposed to be 150% of the certified standard... Not sure how accurate it is anymore.

Although, after 100k and 10 years, nothing is really applied anymore.

jr02518 wrote: If I convert my OBDI cars to run on E85 and keep the cats will the exhaust smell like popcorn?

Yes, you can convert it, no, it won't smell like popcorn. More like moonshine, sometimes.