Catalyst location on lean burn Honda cars

[SVOboy]

Originally Posted by theunchosen

I vote garbage can and find a way to make the ECU run lean all the time(at least when not accelerating)

That will never work

[SVOboy]

Also, if your concern is really having the manifold crack, then that's not much of a concern. Even if it does, what does one of those cost? I used to have 3 or 4 laying around the house and I sold them to homemadeturbo guys for like 20 bucks each. They're also incredibly easy to take off and put on.

Furthermore, the o2 is where it is to help get it heated and because it needs very precise o2 measurements. It's not going to work well in the normal o2 position on a header and it won't work well bunged up on the 3rd running 6 inches from the exhaust port, either, in my experience.

[rkcarguy]

Originally Posted by SVOboy

Also, if your concern is really having the manifold crack, then that's not much of a concern. Even if it does, what does one of those cost? I used to have 3 or 4 laying around the house and I sold them to homemadeturbo guys for like 20 bucks each. They're also incredibly easy to take off and put on.

Furthermore, the o2 is where it is to help get it heated and because it needs very precise o2 measurements. It's not going to work well in the normal o2 position on a header and it won't work well bunged up on the 3rd running 6 inches from the exhaust port, either, in my experience.

-I thought the VX O2 was a five wire and therefore heated?
also this will depend if you have a VX or HX. The HX searches for the "edge" via the knock sensor not the O2 reading.

[theunchosen]

Originally Posted by SVOboy

That will never work

we'll see lol. . . As far as I can tell the ECU is deciding which mode so it doesn't have to switch back and forth frequently.

The other reason I think its possible is because pre-FI, it was pretty commonplace to switch it up so you could get high speed one day and the FE the next(The test car was a dodge charger).

The only problem that car ran into was the valves got toasted, but since then valves have gotten alot better in performance. Valves on that engine would go periodically anyway whereas I have yet to have one go belly up over 180-250K miles. So if I have to swap a whole set out from the get go and its worth it(previous owner had not replaced them from 100K-180K before that I have no data or knowledge how the car was taken care of.)

[SVOboy]

Yes, that's true, but even a heater 02 sensor is heated more quickly by being 5" from all of the exhaust ports. These engines go into closed loop operation very quickly.

[SVOboy]

Sure, the ECU is deciding, but it's incredibly complicated. Artifically forcing it is going to either not work or not work properly. You could force a chicken to fly but it wouldn't do that very well either.

Anyway, a good driver can do it with their foot.

[rkcarguy]

Number 3 is the best cylinder to have the O2 sensor on, as it gets short changed on cooling and will run the hottest, and also be the first to fail typically. I've found that it's more common for 02 sensors to fail on the VX and CX models because they get too hot, where the standard converter versions seem to last the life of the engine.
The O2 sensor needs to be at around 600* to operate properly, which can easily be attained by mounting the bung in the upper 1/2 of the header. Without the cat, however, warm up would be very slow and would effect performance.

[theunchosen]

Originally Posted by SVOboy

Sure, the ECU is deciding, but it's incredibly complicated. Artifically forcing it is going to either not work or not work properly. You could force a chicken to fly but it wouldn't do that very well either.

Anyway, a good driver can do it with their foot.

True you could do it with your foot. . .but if you eliminate the throttle body, you can very likely accelerate under leaner mixes that eliminate hydrocarbons. If you can do that you can dump the cat altogether and swap in for injection of water up front or something else(ammonia, urea, sometimes water) in back.

I can accelerate at 2000 rpm and very slight depression of the throttle. . .With the same amount of fuel, alot more air and alot less pumping I can accelerate more. So either you can have faster acceleration at the same mpg or you can get same acceleration and greater mpg.

Then a good driver can get lean burn, less emissions and less fuel all the time when otherwise a good driver can only get lean burn under very low acceleration.

[SVOboy]

Perhaps. I don't think it's practical. At a certain point of complexity a modification becomes more difficult that doing something like putting an EV fifth wheel on and making a hybrid, so I'd always prefer that.

[theunchosen]

I'm just talking about switching the throttle to WOT, and then controlling speed by a variable resistor and misting water into the intake(which would also run on a variable resistor run along the same potentiometer the fuel control is on). You of course have to bypass the O2 but thats pretty simply as you just have to make sure it outputs a steady .45-.5 volts.

Then as far as the OP is concerned he can fulfill the statement of if emissions are to be ignored in cat placement, because the cat becomes superfluous.