legacycentral bbs

I'm finally ordered up a wideband (LC-1 + XD-16) and should arrive next week. Have a few questions...

1. Should I install the wideband in the original O2 sensor location or the secondary location in my DP? From what I've read, the 2nd. Is mine too far back to get good readings?
   
2. Should I use the 0-1V analog output from the LC-1 and feed it back into the ECU for the O2 sensor or just leave it as is? In theory, the LC1 should provide a lot more accurate readings than the stock O2, right? If one goes with this route, are there any issues / gotchas with it?
3. If I used the LC-1 output for my ECU O2, can I just wire up a harness for the 2 wires, or does our ECU get cranky that not all wires are disconnected and throw an error code? I should also install the LC-1 O2 senor into the first (original) O2 location in the DP, right?
4. The typical location for the AFR gauge is in the area under the radio? Anyone have various pics of their gauges handy?

Your wideband should be installed as close as possible after the turbo. Use the first downpipe bung for sure.

I have a fair amount of experience with the LC-1 both installing & tuning with them, and I would recommend against wiring it to run as a narrowband O2 if at all possible. I found that if it isn't grounded just right, it will give the ECU incorrect readings, and even when grounded properly it doesn't respond the same as a factory-style unit. On vehicles with dual exhaust, and 2 primary O2 sensors, it's really obvious how different an LC-1 (wired as a narrowband) reacts compared to the factory sensor in the other pipe. The OEM sensor is actually very accurate near 14.7:1, the Innovate won't do any better in that respect.

If you don't have a bung in your exhaust manifold, put another bung next to the first one in the downpipe. Hotter is better concerning O2 sensors, although Innovate recommends to install theirs right after the turbo.

Gauge placement? Put it wherever you can actually SEE the thing...that's all that matters there!

My PLX wideband suggested mouting it downstream a bit from the turbo (IIRC, 12"+ away). PLX seemed to suggest that it can overheat if too close. WBO2s have internal heaters if the exhaust cannot heat it sufficiently. If there are no leaks in your exhaust it will make no difference in it's readings how far downstream it is located. As long as it is before any catalyst, that is. Mine has been mounted in both locations and I saw no difference in it's performance either way. Upstream was a tad easier on the install side of the picture.

The LC1s secondary output can be programmed to any voltage shape you like. If you program it to a very fast slope, such as 14.6a/f = .5 volt and 14.8a/f = .95 volt it will simulate a narrowband O2 sufficiently well for the factory ECU. In reality, the factory ECU is not looking at a specific voltage, it's looking for the switch from Hi to Low and back again. As long as that takes place at the appropriate A/F ratio the ECU will be happy. If you wished, you can even fool the ECU into running leaner or richer at idle and cruise (closed loop) by programming the LC1 for a switchpoint richer or leaner than 14.7.

You can check out my build thread in the Picture Forum for pics, but I was able to install my wideband completely through the factory O2 sensor plug ( I did sacrifice on old O2 for the connector). It has power and ground (for the O2 heater circuit) and has the signal return to the ECU (for narrowband). The only wires you would need to run to the cabin are for the gauge itself (and the serial port if you wish).

http://bbs.legacycentral.org/viewtopic. ... c&start=30 In the first pic you can sort-of see how the WBO2 is wired through the factory O2 connector.

I had my zeitronix Wideband mounted down lower on my Down pipe and it seemed to work just fine. But if I put it in the SS, I'll probably add a bung just after the turbo.

On a side note, what model/year DP did you buy? On my friends SS the 95-01 JDM WRX one fit perfectly, but I just had to cut up and reweld my 02-07 one to get it to work. Just a heads up

SLODRIVE wrote:Your wideband should be installed as close as possible after the turbo. Use the first downpipe bung for sure.

WRONG!


I have never heard/read of that recommendation.


Mount the sensor in the second bung.

Also, I wouldn't run the 0-1v output into your ecu...I did it in my SS and it totally freaked out the ECU.

I'd use the bung further back. Mine is in the 2ed location and I've had it overheat on long pulls even back there. I added a heat sink (per the instructions) and haven't had the problem since.

I left the stock O2 for the ECU, but I've often thought that it would be cool if I could use the secondary output for the ECU and shift the scale to control the closed loop AFR. I haven't tried it yet though.

Gary

PhyrraM wrote:The LC1s secondary output can be programmed to any voltage shape you like. If you program it to a very fast slope, such as 14.6a/f = .5 volt and 14.8a/f = .95 volt it will simulate a narrowband O2 sufficiently well for the factory ECU. In reality, the factory ECU is not looking at a specific voltage, it's looking for the switch from Hi to Low and back again. As long as that takes place at the appropriate A/F ratio the ECU will be happy. If you wished, you can even fool the ECU into running leaner or richer at idle and cruise (closed loop) by programming the LC1 for a switchpoint richer or leaner than 14.7.

I agree with all this...except that the problem with using an LC-1 as a narrowband sensor has nothing to do with the voltage...the switching time itself is a little different. I saw this myself on my GTO; I ran the LC-1 in the LH exhaust pipe and it was easy to see how the sensor reacted in my tuning software versus the stock sensor in the RH pipe. Comparing it to previous logs confirmed it.

That said, I didn't really notice a difference in driving, but the ECM had to work a bit harder in closed-loop operation. I don't know how the Legacy's ECU will react...but either way, why not run both sensors?

My buddy's STi has an Innovate WB near the top of the downpipe. It's been there for months and it's never had any trouble. >shrug<

I have a newsflash for you...it gets to WAY hotter than 900 degrees right after the turbo on these cars...

I never ran a pyro on my SS...but the one on my Audi goes to 1450 on hard pulls...and it is located right behind the turbo (because some idiot put it there instead of in #3 exhaust runner )

I've had mine mounted in the second bung for a couple years, and and self tuned the car quite successfully. Back in the second bung, the off-boost response of the wideband is a bit laggy. It is noticeable when logging all relevant parameters.

However, when tuning under high load, there was very little lag to the wideband, most likely from the massive increase in flow. I had no trouble tuning the car for power with the wideband mounted that far back. But yes, off-boost the sensor was noticeably slow in its response to rapid changes in throttle position. It doesn't matter to me since I know my fuel map is tight, and I still get a reading of what my acceleration enrichment is doing.

555BCTurbo wrote:I have a newsflash for you...it gets to WAY hotter than 900 degrees right after the turbo on these cars...

I never ran a pyro on my SS...but the one on my Audi goes to 1450 on hard pulls...and it is located right behind the turbo (because some idiot put it there instead of in #3 exhaust runner )

I believe you about the temp...Like I said, so far the one on the STi has been fine. At the dyno shop I worked at, we always put them as close to the manifolds as possible because they responded better, making tuning a bit safer. We never used EGTs, so I honestly have no clue what they were on any of the cars. We never had any problems, but I gotta admit it wasn't an AWD dyno, thus we never had Subarus. I'll let you know if my buddy's ever craps out.

Subarus probably have a *bit* of a safety factor in this regard. The turbo itself is mounted ~14" from an exhaust port. Most cars are much closer.

That being said, most exhausts (including the factory one) are designed to retain heat all the way to the catalytic convertors.

As far ar using the secondary output for the ECU narrowband? I can't comment on slow response as my PLX has always been fed to a Power FC, which is slow to switch into closed loop mode anyways.

Its usually best to keep the a/f sensor approx 6-12 inches from the turbo outlet. Ive ran both my zeitronix and aem that way with good results.

Alright, got my LC-1 and XD16 installed this weekend. Driving around town/highway noticed some things and have another round of questions

1. Driving around town the ARF is ~14.5. That's a normal range right?
2. During WOT, the ARF quickly drops and holds around 11.5-11.2. Boost is ~9.5 psi. This is still a little bit on the rich side right? I don't have a select monitor (yet), so not sure if the MAF or injector duty cycle are maxed out. Would it be safe to increase the boost some more, making sure it doesn't get too lean -- say 12.5 AFR?
3. After WOT and then coasting, the XD16 gauge often displays 'o2 sensor' for several seconds, which I believe is from it being super rich/lean. This is a normal behavior?

1. Yeah that's normal.

2. You could probably bump it up to 10-11 psi without any issues.

3. If you're just coasting, AFR's should be really lean, and depending on how the sensor is setup, it may just do what you're describing.

On coast, in a manual car, the ECU shuts the fuel off, so the wideband will not be seeing any fuel, which causes them to read some sort of default reading (my PLX reads "lean")

Just got a Used/New PLX R-500. SCORE!!!!!!

Says to mount 24" from engine block/Turbo... Sensor will fail if EGT hits 1550F or higher....

well, I have mine mounted 4" from the turbo in the downpipe. We will see.....

hmm blast from the past thread

After reading all the complaints about people's LC-1 probes dying due to heat, can't say I've had any problems with mine (yet). Been mounted in that 2nd bung, shown in the first post picture.

Conversely, with granular data logging, there IS a lag between the time the stock O2 sensor senses a rich condition compared to when the wideband does (under WOT conditions).

My LC-1's sensor is just a few inches behind the turbo, and after beating on the car for almost a thousand miles...no overheating problems whatsoever. Same with Rob's STi, it's been running in a similar spot all year with no wideband issues.

Yeah I've had my Zeitronix behind the turbo in the stock O2 sensor location without any issues yet.