The best location to put a wideband sensor?

[evil666]

I am going to install a zeitonix wideband soon, and I was wondering where is the best location to put the sensor to get the most precise reading for the the air fuel ratio?

Thanks for any help.
Marco.

86 Grand National t-top (59900km)
stock long block,stock suspension, red stripe convertor, te44, smc alk injection, 24lbs boost, 94 octane, hooker cat back with dyno max ultra flow muffers, tomco 30lbs injectors, dynotech stage 4 street chip, thdp, mease 24 row IC, Ron Custom max boost brake module, MT drag radials (275/50/15) 3800lbs race weight with driver. (Torque convertor not locked)
BEST E/T
60FT=1.52
1/8= 7.38
I/4= 11.74
MPH=113
BEST MPH= 114

 

[oldtimer]

In the down pipe, about 10 - 12 inches from the Turbo ... IMO

George

 

[grocerygetter]

keep it 12" away for sure...I'm overheating mine now...it's about 6" away from the hot side of the turbo.

 

[Blown&Injected]

WOW! How is it that the stock O2 is OK in the up pipe?

I was going to say down pipe just to avoid extra stuff in the pipe before the turbo but I did not expect to learn that the sensor would get over heated.

 

[grocerygetter]

well, the stock O2 is pre turbo...not a problem. The WB on my car is post turbo...the hot side makes a lot of heat and continues to collect it. Tendency of the metal used.

 

[Jbenn911]

Mine is about even with the AC drier on the DP...I ran it without a heat shield all summer with no failures. I did get a 4x4" piece of 14ga copper "just in case"

 

[ijames]

The stock sensors are unheated and depend on the exhaust heat to get them to proper temperature, so they must be pre-turbo. Heated narrowband sensors can go after the turbo if you want to but most don't. The wideband sensors also have their own heaters, and depending on brand have different limits on the exhaust gas temp at the sensor. The NTK sensor used with the FAST systems works at a pretty high temp and some guys even run it pre-turbo but most put it in the middle of the first bend in a thdp. The Bosch sensors used with the LM1 and other lower cost wideband setups need to be cooler, and the Innovate LM1 even checks the temp and gives an error if it is too hot to give an accurate reading so they need to be a ways downstream of the turbo. Like jbenn I put mine on the top of my downpipe about even with the ac accumulator and haven't had any overheating issues. Some guys put it down at the end just before the cat/test pipe, and some on the test pipe itself.

 

[oldtimer]

The stock sensors are unheated and depend on the exhaust heat to get them to proper temperature, so they must be pre-turbo. Heated narrowband sensors can go after the turbo if you want to but most don't. The wideband sensors also have their own heaters, and depending on brand have different limits on the exhaust gas temp at the sensor. The NTK sensor used with the FAST systems works at a pretty high temp and some guys even run it pre-turbo but most put it in the middle of the first bend in a thdp. The Bosch sensors used with the LM1 and other lower cost wideband setups need to be cooler, and the Innovate LM1 even checks the temp and gives an error if it is too hot to give an accurate reading so they need to be a ways downstream of the turbo. Like jbenn I put mine on the top of my downpipe about even with the ac accumulator and haven't had any overheating issues. Some guys put it down at the end just before the cat/test pipe, and some on the test pipe itself.

Excellent explanation !

George

 

[evil666]

I think the zeitronix and the inovative wideband use the same sensor. If I read everything right I could place the sensor anywhere on the downpipe as long as it is at least 12" away from the turbo. Now my question is, if I place the sensor 12" from the turbo will the reading be more presice there, then on the straight pipe or bottom of the downpipe?

Thanks
Marco.

86 Grand National t-top (59900km)
stock long block,stock suspension, red stripe convertor, te44, smc alk injection, 24lbs boost, 94 octane, hooker cat back with dyno max ultra flow muffers, tomco 30lbs injectors, dynotech stage 4 street chip, thdp, mease 24 row IC, Ron Custom max boost brake module, MT drag radials (275/50/15) 3800lbs race weight with driver. (Torque convertor not locked)
BEST E/T
60FT=1.52
1/8= 7.38
I/4= 11.74
MPH=113
BEST MPH= 114

 

[buickboy]

Make sure to install the sensor between 10 O'Clock and 2 O'Clock position in the downpipe. Moisture will kill the sensor if it is not installed in that range.

Mitch

 

[Ormand]

The reading is not going to be precise, no matter WHERE you put the sensor, so put it where it's easy to get to, and won't be damaged. There are six cylinders feeding the turbo. Each cylinder has slightly different A/F ratio- if you're lucky, and have the flows balanced closely. If not, the A/F ratios will be MORE than slightly different. The wide-band will read the average of all six cylinders- it can't tell you which cylinder is leanest, and most likely to detonate. It can't tell you what A/F ratio will give most power, or best BSFC. It's a good reference number, and can be used as a tuning aid, but it ain't ever going to be real "precise".

 

[ijames]

So long as there are no leaks in your exhaust and the sensor is alreay far enough downstream to not overheat, the only effect of moving the sensor from downpipe to test pipe is an insignificant (for us mere mortals; it's way, way less than a second ) extra delay in the response. As Ormand said, any of these placements will give you an average of all six cylinders, which is what you want here.

 

[jeffwiz87]

does anyone have any pictures on where you put the wideband in the pipe? I am planning on getting a wideband and they say a picture is worth a thousand words.thanks guys!

 

[jeffwiz87]

???? anyone?

 

[salvageV6]

Here's mine, probably not optimum and could be 2-3 inches further down the pipe but I like the location and it's been working 3 years now.

 

[Instro84]

evil666 how do you like that zeitrinicx wideband?

 

[KevinB]

The reading is not going to be precise, no matter WHERE you put the sensor, so put it where it's easy to get to, and won't be damaged. There are six cylinders feeding the turbo. Each cylinder has slightly different A/F ratio- if you're lucky, and have the flows balanced closely. If not, the A/F ratios will be MORE than slightly different. The wide-band will read the average of all six cylinders- it can't tell you which cylinder is leanest, and most likely to detonate. It can't tell you what A/F ratio will give most power, or best BSFC. It's a good reference number, and can be used as a tuning aid, but it ain't ever going to be real "precise".

So, what would be the best way to get a good reading? An EGT or wo2 at each cylinder?


And Salvage, what the heck is that can for?

 

[evil666]

evil666 how do you like that zeitrinicx wideband?

I just bought it and I still haven't had the chance to install it yet. I can't wait to try it out and the display is really nice.

Marco.

86 Grand National t-top (59900km)
stock long block,stock suspension, red stripe convertor, te44, smc alk injection, 24lbs boost, 94 octane, hooker cat back with dyno max ultra flow muffers, tomco 30lbs injectors, dynotech stage 4 street chip, thdp, mease 24 row IC, Ron Custom max boost brake module, MT drag radials (275/50/15) 3800lbs race weight with driver. (Torque convertor not locked)
BEST E/T
60FT=1.52
1/8= 7.38
I/4= 11.74
MPH=113
BEST MPH= 114

 

[Ormand]

So, what would be the best way to get a good reading? An EGT or wo2 at each cylinder?

Because of the temp limitations, it's hard to have a wideband for each cylinder, especially on a turbo car. With long tube headers, you might be able to do it on a normally aspirated car. An EGT per cylinder would be good for tuning- that way you could make sure that each cylinder is in the right range. An interesting thing about wideband O2 sensors: they don't read A/F ratio. They read a voltage which is dependent on the exhaust gas composition, and that can be used to represent rich/lean, as a percentage of stoichiometric. For pump gas, stoichiometric is usually thought to be 14.7 to 1, but that's only true for pure octane. Ethanol, methanol, toluene, any of the things used to "blend" pump gas will affect the correct A/F ration, and it can vary from 11 to 1 up to almost 16 to 1. But since the O2 sensor really reads as a percentage of "correct", you don't miss anything by pretending that "correct" is 14.7 to 1. Since the typical O2 sensor is reading exhaust gas from all six cylinders, kind of "averaged" together, it can give misleading readings. One bad plug will give free O2 in the exhaust gas- since one cylinder isn't using any oxygen. The sensor might see this as "lean", and you might add more fuel trying to use up the oxygen. Then you could have one cylinder missing, and five cylinders too rich. Just something to think about.

 

[salvageV6]

That can is my $25 Ebay PCV catch can and checkvalve.

It actually works quite well.

I only empty it when the engine is cold, obviously.