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View Full Version : Bosch vs Mopar O2 sensor debate.



GLHNSLHT2
06-09-2007, 12:27 AM
I've heard for years how the Bosch O2 runs the car rich because it gives an incorrect reading to the ECU. Just curious how everyone is measuring this. After hooking up my wideband O2 I still let the 4 wire Bosch O2 control the ECU while I went through the smog test and until I could wire up the Wideband to feed the ECU. Anyway my findings are opposite of everything I've heard/read about the Bosch O2 running the car rich. It ran the car at a nice 14.7 for about 15 seconds after coming down to idle, then leaned out to 15.2. That's actually running the car lean. Anyone else seen this? Does the Mopar O2 run the car at 16.0??? Cause for me the Bosch O2 runs the car perfectly.

Thanks.

Tony Hanna
06-09-2007, 12:35 AM
I don't know that it was the Bosch sensor causing rich running so much as not being able to deliver a full 1 volt. Every one I've ever used would only light the 9 light on a narrowband gauge, but aside from that, the cars ran fine. I'd say the bias against the bosch sensors is a hold over from the days when the majority used narrowband A/F gauges for tuning.
Lifespan is another thing entirely, and I've heard the Bosch sensors don't last as long as the Mopar sensors.

GLHNSLHT2
06-09-2007, 01:33 AM
well giving a full 1v is useless anyway. I just found the instructions for my old NB gauge tonight. It specifically says the only place the gauge and sensor is accurate is at 14.7a/f Any other A/f ratio requires a wideband gauge.

As for life my old bosch lasted more than 8 years and would still be going if I hadn't gone wideband.

But what I've heard/been told/read is that the bosch O2 runs the car rich at idle and cruise because it's "innacurate". My findings were opposite. The car ran the perfect if just slightly lean a/f ratio's with it's Bosch sensor.

mo' parts
06-09-2007, 07:55 AM
i have'nt had any probs running w/ the bosch sensors. the ones i have had have lasted through headgasket failures, cracked pistons and then some.
i do not have a a/f meter at the moment as im just going straight to the WBO2 this time around. but i do have my digital voltmeter hooked up to the sensor, as i want to have some sort of idea whats going on. no matter how far i go up on my fuel press, my readings w/the mp csx stage 2 never reach above .92-.93 volts. this has somewhat worried me as now i would like to raise the boost to 16psi....... and thats the highest reading ive seen, i have even seen it read as low as .89 volts wot and 14-15psi. plugs show excellent color and no detonation. so im pretty sure there is some truth to the voltage discrepency.

MiniMopar
06-09-2007, 08:54 AM
Tony is right about the accuracy. They don't give the full range of output for you O2 gauge that TMers are accustomed to. Seems like a lot of folks are running WBs now, which is great.

Some have had longevity issues compared to the Mopar/NTK sensors as well. I swapped a 2-year old sensor for a Mopar on my CSX and picked up a few MPG. Did the same on my Shadow hoping to do the same, but nothing happened.

GLHNSLHT2
06-09-2007, 10:07 AM
i have'nt had any probs running w/ the bosch sensors. the ones i have had have lasted through headgasket failures, cracked pistons and then some.
i do not have a a/f meter at the moment as im just going straight to the WBO2 this time around. but i do have my digital voltmeter hooked up to the sensor, as i want to have some sort of idea whats going on. no matter how far i go up on my fuel press, my readings w/the mp csx stage 2 never reach above .92-.93 volts. this has somewhat worried me as now i would like to raise the boost to 16psi....... and thats the highest reading ive seen, i have even seen it read as low as .89 volts wot and 14-15psi. plugs show excellent color and no detonation. so im pretty sure there is some truth to the voltage discrepency.

I had the same experience. I threw 30% more fuel into the WOT curve trying to follow every TD'er out there saying I needed .92v+ to be safe. After hooking up the wide band the 1st time I romped on it with that cal it pegged the wideband at over 9.0:1. I think what that taught me is that no matter the voltage output the NB sensor is only accurate at 14.7:1. at 13:1 it could read any voltage, same at 17:1. And going off those voltages is retarded. I had to pull 40+% out of the WOT table to get the a/f where I want. 30% of that was what I put into it and another 10-15% off the base calibration.

GLHNSLHT2
06-09-2007, 10:11 AM
Tony is right about the accuracy. They don't give the full range of output for you O2 gauge that TMers are accustomed to. Seems like a lot of folks are running WBs now, which is great.

Some have had longevity issues compared to the Mopar/NTK sensors as well. I swapped a 2-year old sensor for a Mopar on my CSX and picked up a few MPG. Did the same on my Shadow hoping to do the same, but nothing happened.


It would of been real interesting to put a wideband on Gus' old minivan and see where his a/f was. I wouldn't be half suprised to find he was way rich and with some fuel adjustments could of been the 1st minivan in the 12's like he was hoping for so badly.

Tony Hanna
06-09-2007, 10:34 AM
I had the same experience. I threw 30% more fuel into the WOT curve trying to follow every TD'er out there saying I needed .92v+ to be safe. After hooking up the wide band the 1st time I romped on it with that cal it pegged the wideband at over 9.0:1. I think what that taught me is that no matter the voltage output the NB sensor is only accurate at 14.7:1. at 13:1 it could read any voltage, same at 17:1. And going off those voltages is retarded. I had to pull 40+% out of the WOT table to get the a/f where I want. 30% of that was what I put into it and another 10-15% off the base calibration.

And I'm assuming that was with a Bosch sensor?:eyebrows:
A new Mopar sensor most likely would have been showing a full 1 volt, letting you know that you were too rich.
Yes there are better ways to tune now, but believe it or not, there was a time when wideband sensors were priced well above what the average person could afford. Did everybody just drive around in stock cars? No. There were quite a few "retarded" people using narrowband sensor outputs and EGT's to successfully tune cars running in the 10's, 11's and 12's.:)

GLHNSLHT2
06-09-2007, 11:16 AM
Yes it was with a Bosch sensor. Kind of the point of this thread. What would the NTK sensor be saying with a wideband hooked up to verify.

Tony Hanna
06-09-2007, 11:27 AM
With a fresh NTK (Mopar) sensor you should have been getting a full 1 volt being that rich.
That's the major problem with the Bosch sensors. For some reason they just won't output much over .90 volts regardless of how rich the engine is running.

MiniMopar
06-09-2007, 11:31 AM
It would of been real interesting to put a wideband on Gus' old minivan and see where his a/f was. I wouldn't be half suprised to find he was way rich and with some fuel adjustments could of been the 1st minivan in the 12's like he was hoping for so badly.

You are probably right...those were different times. I'm sure his was way rich, but he was also running a bone stock 2.5L bottom end. That is probably why it lived for so long. I remember when he finally toasted a piston on the Slugmobile after a long highway pull. An EGT gauge probably would have prevented that too.

His methods were great at the time. I had no money, so a $30 Cyberdyne some pressure switches and a bunch of junkyard solenoids/injectors were within the budget,

mo' parts
06-09-2007, 11:47 AM
With a fresh NTK (Mopar) sensor you should have been getting a full 1 volt being that rich.
That's the major problem with the Bosch sensors. For some reason they just won't output much over .90 volts regardless of how rich the engine is running.

thats the case im finding out now w/ my 3 wire bosch. i just fixed a major boost leak, no other changes, and i just ripped it down the street. the stock shelby gauge was into the "turbo" writing well past 15 psi, im guessing 18+psi. 58 psi fuel press and ffv injectors and it still never got above .90 volts, nor below. plugs show no signs of detonation and no pinging. i just changed to some 9yc's before the blast.
looking at the cost for a new mopar o2, i think i'll keep w/the bosch and put the money toward the WBO2 for now, assuming you can have the computer use the signal from it as well as the gauge.

Tony Hanna
06-09-2007, 11:52 AM
...assuming you can have the computer use the signal from it as well as the gauge.

That sould be no problem, just make sure the WB controller you buy has a narrowband output.:thumb:

Tony Hanna
06-09-2007, 12:06 PM
You are probably right...those were different times. I'm sure his was way rich, but he was also running a bone stock 2.5L bottom end. That is probably why it lived for so long. I remember when he finally toasted a piston on the Slugmobile after a long highway pull. An EGT gauge probably would have prevented that too.

His methods were great at the time. I had no money, so a $30 Cyberdyne some pressure switches and a bunch of junkyard solenoids/injectors were within the budget,

That's the thing that gets to me when somebody starts bashing the "old school" tricks. Sure there are better and easier ways of doing things now, but for somebody on a tight budget, they work just as well now as they did then.