Wargasm

Hi, I have been running my DIY wideband setup over the last few weeks and had a question..

I have mounted it in the stock sensor location right up by the turbo, but some people don't seem to like this location.

So... let's get to the bottom of this

Where do YOU think the sensor should be and why and what is your __evidence__ that you are right?


I'll go first :

Sensor is acceptable up near the turbo because it seems to give valid values and has not broken yet. Also, the Motec user manual (which uses the same sensor) says:

"It is recommended that where possible the sensor be placed at least 1m from the exhaust ports to avoid excessive heat and at least 1m from the open end of the exhaust system to avoid incorrect readings due to outside oxygen. This is however not mandatory, and where necessary for shorter exhaust systems the sensor should be placed closer to the engine."

So I take that to mean that 1 meter away is better, but closer up near the turbo is OK too.



Anyone else got any input?

jeff48

The conventional wisdom in the OZ camp is that the NTK L1H1 sensor should not be placed in any position where it is likely to see temps in excess of 800C. The reason for this is that the sensor's heating element brings the unit up to peak operational temp (around 750 C). Temps over the operational temps may have a negative effect on the accuracy of the sensor. It is also suggested that ultra high temps (over 900C) are likely to permanently damage the internal cell.

It is also generally agreed that "post cat" ( either pre cat or main) is inappropriate because the effect of the cat on the hydrocarbons may affect the AFRs.

The most approved placement is in the midpipe, just after the joint with the DP.

All that said, my L1H1 has been in the stock 02 sensor location on the DP (about 6 inches from the turbo) for over 2 months without any noticeable damage. Since it has been there I have had the car do 4 runs on the dyno and 2 1/2 hours on a road course.

I would move it, if I could get a welder who isn't afraid of my car.

phlanigan

I decided to locate my sensor on the downpipe just after the final bend to horizontal, and it too apparently provides solid readings.

I can't say my decision to locate the bung was driven entirely by concerns for either heat or oxygen leaks. The location was convenient (didn't have to remove the DP) and the cable is shielded from heat by the plate against the passenger side of the tranny tunnel on the run to the shifter opening and into the passenger area.

As for accuracy, I have dyno time scheduled in two weeks and I plan to check the DIY against their tailpipe sensor.

Can't comment on the longevity, as I've only got about 200 miles on the sensor now.

I got a guy at my local Midas to do the welding for $50 while I "supervised."

Jodeny

iTrader: (3)

Has anyone compared their readings with an FJO wideband or something similar??
John

jeff48

Yes- I compared my DP mounted OZ WB outputting through a datalogit with the dyno's Motec. Motec showed consistently between .1 and .2 AFR numbers richer than the DIY v 1.0 kit from Tech Edge. With a DIY showing slightly leaner than actual I would say it is close enough for my car.

Jodeny

iTrader: (3)

Thanks Jeff.
John

Wargasm

Jeff, when you tested your DIY vs the Motec, was this a concurrent test? I am assuming the Motec was rammed up the tailpipe and the DIY was in the stock location... is that correct?

Thanks very much!

Brian

jeff48

Brian

Yup the test was concurrent. The NTK was mounted in the OEM position and the MOTEC being an exhaust mount.

My exhaust is a 3 inch catback with the midpipe cut and a flowmaster high flow muffler welded into place. The wastegate is plumbed back into the system. In other words NO CATS.

In addition to keeping an eye on the 5301 display and the dyno's computer display----I datalogged each dyno run through the datalogit and compared the AFs from the datalogit to the graph from the dyno. I am fairly confident my posted results are accurate and I have a high degree of confidence in the OZ WB.


Disclaimer:

"Your results may vary"
or as the Russians say----->"Trust-----but Verify"

(damn lawyers )

Badog

My favorite location is within 4 inchs of the DP to MP flange, either side.

In this location and run concurrent with a WB O2 off of a DynoJet (same sensor but hooked up to a O2 pump) it read very, very close. I liked the response better on mine. I also like about a 5 degree tip-angle down, instead of parallel to the ground. I like to pretend this gets rid of any condensation when off.

Tony

mpetersrx7

Are you guys facing the sensor toward the tranny tunnel or toward the outside of the car?

Thanks,
Mark

Badog

Facing the tunnel would not allow enough clearence to fit the sensor tail in there. Think of almost parallel to the ground, tail facing either driver or passenger sides.

The best place I have seen the bung is on the DP, on the curve out of the engine bay and before the stretch parallel to the ground. The bung was angled towards the passenger tire a little bit. Nocab72's old DP from his twin days.

mpetersrx7

Sorry I was not more clear...I meant parallel to the ground but facing the tranny tunnel (or driver's side) or parallel to ground facing the passenger side. I was planning on using the hole under the passenger seat to route the wiring this weekend.

I like you idea of locating the sensor on the curve before the portion goes parallel. I will look at any clearance issues with this spot.

Thanks Badog.

-Mark

Badog

You bet!

I ran my wiring in through the same hole, using the 4 meter wiring. If you use the DP where I mentioned, you can run it through the firewall/kickpanel and to/behind the glove box. And you only need the shorter length of wiring. I ended up ordering another 4m for the unit when I do other peoples cars.

I don't like my current setup, too many wire runs. Rmagic has the cleanest install with everything behind the box area.

Tony

rxrotary2_7

mine is facing up twords the trans tunnel... i was under the impression that the sensor should be mounted between 10 and 2 (on a clok) 6 being the road... the reason behind it was so the sensor doesnt collect anything like condensation.

Badog

Right, Keith. I have about a 5 degree tip in angle with mine. In the DP location I have seen, it's even prettier.

Off to go practice tipping some 16s...

Rotarded

Thanks Tony! Couldn't just say it was my DP, huh??

Badog

Haha. It's ROTARDED'S CURRENT DP!

Sorry.

weaklink

Mine is on the DP, just before the bend towards the cat. There is a pre-existing thin flexible piece of metal there that acts as a nice shield for the cable all the way to a preexisting hole under the passenger seat where my controller sits. Easy run with jackstands and no cutting involved. The wire to the display runs under the sill, behind the kick panel up into the glovebox, where it sits nicely next to my AVC-R.