What are you guys doing for the oygen sensor setup? I'm contemplating a few things here.. I do have the AEM UEGO gauge type wideband, that does output a 0-5v signal. The only thing is that my wideband sensor is located approx right behind the testpipe. This distance from the actual outlet of the turbo concerns me, since the gauge will basically have a "delay" in it's readings, which may make for tuning concerns..or not..I never really worried about it before, since it was mostly a quick reference gague, not somethig that is actually correcting the A/F of the motor. I can move it to the stock location, but that will require me to rip the whole damn wiring harness out and I really dont want to do that.. If I decide to use my stock O2 sensor, can i leave this disconnected from the ECU when i'm still running ignition off of the stock ECU? Or will that mess up my ignitioun advance map for having a dead o2? I'm still planning on running the stock ignition until i have the fuel nicely tuned.. If I use the stock sensor, I dont want to just tap off it either while it's still connected to the stock ECU...dont want the sensor cycling all the time like it does stock.. Thoughts? Or am I just be anal about my wideband placement haha :)

Well, exhaust velocity must be high, as there is a large volume of gas being pumped through the engine. It needs to go somewhere, and reversion doesn't account for THAT much...

I would guess that you will see WAY less than a tenth of a second delay in WB readings. In a 3rd gear pull, that is not too many RPM. Not enough to really affect tuning, I don't think.

This is pure conjecture, but I started with the principle: where does the WB probe go when you go to a dyno?

Originally posted by Ducking_Fumbass
where does the WB probe go when you go to a dyno?

Bingo.

Originally posted by DarkOne

Originally posted by Ducking_Fumbass where does the WB probe go when you go to a dyno?

Bingo.

Right, but the wideband isn't actually going to control the A/F of the motor when on a dyno..I guess my only concern was at cruise and low RPM during closed loop control. I imagine maybe a one second delay from the time it exits the motor till it hits the wideband sensor..I just dont know if that will cause any issues..

Originally posted by XtremeRS
I imagine maybe a one second delay from the time it exits the motor till it hits the wideband sensor.

You vastly underestimate the velocity of the exhaust gas, even at idle, as well as probably overestimate the ability to rapidly lose fuel in the 12x12 map the MS uses.

The one thing that I've discovered with the MS and running it in closed loop with a wideband and target AFR tables is that the more accurate the VE table is the better the MS will be able to fine tune the pulsewidth. I've been tinkering with controller authority, how many ignition steps it will ignore before it corrects again, etc... and every time I tweak my VE table I take a little closed loop authority away from it and everything gets better. I found out quickly that the MS doesn't like to have a +/- 50% range for AFR correction, unless you like to have your AFR numbers look like 11.3, 12.1, 11.5, 12.9, 9.8, 11.7, when you are trying to hit 11.7 or so.

Originally posted by ner947
The one thing that I've discovered with the MS and running it in closed loop with a wideband and target AFR tables is that the more accurate the VE table is the better the MS will be able to fine tune the pulsewidth. I've been tinkering with controller authority, how many ignition steps it will ignore before it corrects again, etc... and every time I tweak my VE table I take a little closed loop authority away from it and everything gets better. I found out quickly that the MS doesn't like to have a +/- 50% range for AFR correction, unless you like to have your AFR numbers look like 11.3, 12.1, 11.5, 12.9, 9.8, 11.7, when you are trying to hit 11.7 or so.

So you are saying that you can set target A/F ratios with a wideband even at open loop WOT? That's pretty f'n sweet.. Yeah, it makes sense to have the VE table do as much of the tuning as possible, and let the o2 work a bit less at keeping a target A/F

why did you put the wideband by the testpipe?

Originally posted by turbo8u
why did you put the wideband by the testpipe?

Well, I run pretty close to the edge of tuning, and get real close to 1600 degrees EGTs, and the AEM manual clearly states that the probe shoulld not be that close to that kind of temps. I believe they recomended for a turbo setup, for a minimum of 36" after the exhaust port..Plus, it was easier for me to put it back farther, since I just ran the wiring up under the grommet under the driver seat. That and I could just easily unbolt my test pipe to weld in the o2 bung and all that..

The reason they recommend mounting the sensor 36" from the turbo outlet on TC car is to limit the amount of heat that the sensor is subjected to. 1500F or more will reduce sensor life all but if you are reading 1600F on your EGT @ your manifold then your sensor 20" down or so it will be lower. A lot of people on the EMS forum have talked about and they have mounted them closer than the 36"

The 36" is the conservative recommendation but people have mounted them closer with no ill effects. As long as the exhaust temperature is not exceedingly high at the point where you mount it, it should be OK

The main concerns that I have read/seen about are the voltage calibration issues with it, not withstanding heat.

Originally posted by Ducking_Fumbass
where does the WB probe go when you go to a dyno?

Up front in the downpipe. More and more places are going to this method because it gets a more accurate reading, than a sniffer in the rear.

Any wideband instructions I've read always say to put your sensor about 12 to 18 away from the turbo or head. A long tube header and you want it in the collector or just after.

If I were you I'd put an O2 Boss in the downpipe and relocate your wideband sensor, then use it for the MS.

Exile Racing Technologies
http://www.exileracing.com
Go that way, really fast, if something gets in your way... turn.