Modify O2 sensors

[diamondlarry]

Originally Posted by zpiloto

Thanks. I'd need 2 and that's a little to much denero for me. Plus 4-6 week for delivery.

Eagle Research tries to say that you need 2 EFIE's but you only need 1. I found that out several years ago. Fran Giroux and I figured out that the only thing the rear sensor does is verify that the cat is working. Therfore, as long as the rear sensor sees a smaller voltage, the ECU is cool. The front sensor is the only one that controls the mixture so it's the only one you need an EFIE for. Plus, you save $50.

[ZugyNA]

http://www.lubedev.com/smartgas/ultra5.htm


Cover Oxygen Sensors with Aluminum Foil: Wrap your oxygen sensors in the exhaust pipe with 7 to 10 layers of shiny foil.

Advantage: The car computer system depends on the oxygen sensors to adjust the air-fuel mixture being fed to the engine. The cooler the exhaust gases, more fuel gets sent to the engine. The hotter the exhaust gases and the oxygen sensor, less fuel will be sent to the engine.

Directions: To seal maximum warmth inside the area near the sensor, insulation in the form of Reynolds Aluminum Foil is employed to insulate the oxygen sensor. Wrap five inches in front and five inches after the sensor to keep it warmer. We double a one-foot section of foil and wrap that around the pipe and around the sensor itself. Do not remove the sensor. Then we repeat the process several more times. Finally we use .030" copper or aluminum wire to wind around the aluminum foil to keep it from blowing away and be sealed against water. The wire comes from any welding supply. The goal is to fool the car's narrow band sensor and computer into sensing too rich a mixture so it adjusts to a slightly leaner mixture and possibly a slight advance in timing. The end result is smoother engine operation and better MPG. This trick is especially important in severe winter climates. My catalytic converter went bad after 147,000 miles. A large piece inside was blocking the exhaust flow and cost me a drop of 12 MPG. I replaced both oxygen sensors and the catcon and wrapped the sensors with aluminum foil so my MPG came back. Do not wrap with ordinary gray duct tape as it will burn off. Have your mechanic CHECK that catcon on your car. Do not take it for granted because all the good changes you make for mileage could be negated by such things as a bad catcon or bad plug wires or bad oxygen sensors some such hidden defect.

I'm pretty sure that adding resistance to the O2 output makes the mix richer. I have an EFIE the V6...helps some.

[SVOboy]

Yeah, Iono what that lubedev site is trying to say now, but the oxygen sensor is not an egt sensor. That's not how it works, making it hotter won't do jack since it doesn't measure temperature.

He says finding "good" gasoline can benefit you 35%, and I say he's full of hot air.

[zpiloto]

Maybe it heats the sensor faster to go to closed loop. My exhaust already has a OEM shield aound the pipe next to the sensor.

[SVOboy]

That may be so, but that's not what it is claiming. Then is has some BS story about how he killed his emissions system, lost FE, replaced it, gained it back, then seems to act like the foil is some great savior in the whole thing.

If this is indeed insulation, as he says, it will prevent it for warming up more quickly.

[rh77]

Originally Posted by SVOboy

Yeah, Iono what that lubedev site is trying to say now, but the oxygen sensor is not an egt sensor. That's not how it works, making it hotter won't do jack since it doesn't measure temperature.

He says finding "good" gasoline can benefit you 35%, and I say he's full of hot air.

True with the temperature reading, but many sensors have heaters for operation (many 4-wire models). I'm thinking that with an increase in temperature, the element reading changes. That's all I got...

RH77

[SVOboy]

The heater only gets it to run in closed loop faster. I moved my o2 sensor a foot closer to my enging (4" from the ports now) without seeing any dramatic difference.

[GasSavers_brick]

What does lean burn really do, anyway? I keep hearing that it doesn't help a "normal" engine but I can't figure out why. Reduces power, forces driver to open throttle more, reduced pumping losses while cruising for increased efficiency? That's all I can think of since you theoretically reduce power output in step with the leaning effect.

If you really mean business, I would source wideband O2 sensor and develop a hack box that translates between that and your stock ECU. You set the target voltage range on the wideband that correlates to your desired A/F ratio, then the box monitors the wideband and generates the right high/low outputs so that the engine thinks it's around stoich but it is actually doing what you want. To do anything with the stock o2 sensor is just a rough and only semi-controlled approximation of lean burn. The best system would allow you to switch manually between stoichiometric and your desired A/F ratio in case things get too hot, or better yet monitor the ECT itself and switch over automatically if things get out of hand.

[SVOboy]

I'm not sure why "lean burn" doesn't do much for normal people, but I can tell you that the p07 ecu for the vx has a whole other chip just for it that no one has been able to figure out how to decode,

Anyway, we tried leaning out dan's stock ecu but it just said no. I just think most engines don't have the combustion efficiency at that range of AFRs, but I'm prolly full of it.

[omgwtfbyobbq]

Lean burn improves combustion efficiency and torque, with the trade off being less hydrocarbon and more NOx pollution. Pumping losses are also reduced because more air is allowed in the combustion chamber and heat losses in the cylinder are reduced too, although I'm not sure how that works, probably has something to do with the size of a lean burn a/f charge.
Edit- Found something that says controlling swirl allows for stable combustion and better lean burn. Which makes sense, because hot spots in a cylinder could lead to pre-ignition, so controlling how the intake charge combusts (even combustion/heat distribution) is critical to being able to run lean without pre-ignition. Running an a/f ratio of 25:1 compared to 14.7:1 supposedly reduces fuel consumption by ~20% over the Japanese test cycle.