[kyle_blake]

Hi,

Just wondering if anyone has any pics of where you installed your wideband 02 sensor on your hooker headers?

Assume right before the collector however I was thinking of half way between the pipe that joins the two banks? I dunno probably not a good idea as the pipes join way to far back.



Manual says :A weld-in M18 X 1.5 boss is supplied for sensor installation. Mount the O2 sensor in the
exhaust system at least 18 inches downstream from the exhaust port. If you anticipate
high EGT's (over 800C), run a turbocharger, run at high RPM for extended periods of
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time or plan on running leaded race fuel then you must mount the sensor at least 36
inches or more downstream of the exhaust port as all of these can cause the sensor to
overheat. On turbocharged engines the UEGO sensor must be installed after the turbo
charger, if not, the pressure differential will greatly effect the accuracy of the unit. For
accurate readings, the sensor must be mounted before catalytic converters and/or
auxiliary air pumps. To prevent collection of liquids between the sensor housing and
sensor element during the cold start phase, the installation angle should be inclined at
least 10° towards horizontal with the electrical connection upwards, see below.

[Scott65]

Mine is mounted about 6" aft of the collector flange. Has worked for 10 plus years. I don't know if it's the perfect location, but it works.

[chiphead]

Mine is installed in the H-pipe, I get an average of both sides of the motor. It does take a few seconds to warm up, and the reading flicks around due to the averaging effect. However, my H pipe is closer to the collectors based on your picture.

In your case, I would put 2 sensors, one on each side right after the collectors. The bungs are cheap, you can move the sensor. You could watch one and then the other with the wideband and see if they are similar or not. If similar, you could watch the slightly leaner side. If massively different, you need to figure out why and maybe run 2 gauges. Your H pipe is so far back that I'm not sure how accurate it would be, depending on gas flow across the H-pipe and any air leaks. Warmup time would be longer, and response would be much slower with a single sensor in that H pipe.

[72projectbird]

Mine is mounted driver side pipe, about 8" after the collector.

Made a custom pillar mount for the gauge too.

[kyle_blake]

Thanks everyone, there was some show on tv where a manufacture was showing all wrong ways to mount a sensor and i swore he said you want it right after all the 4 header pipes converge and maybe 2" after that. Probably doesn't matter so much. I'll try 6" after the collector on the exhaust piping driver's side then. If the shop is doing a good job and good on time i'll have him install a bung with a plug on the other side. i remember to keep over 10 degrees tilted up.

thanks for your help

[amcmike]

You want it as close to the collector merge as possible for two reasons.

First, it has to reach a minimum temperature to operate accurately.

The second reason has to do with response-delay. If you're datalogging, you want the sensor to pick up the signal as close to the combustion event timing as possible. That way the reading point is showing true to the speed/load point being compared. In other words, by the time the exhaust pulses reach the sensor, you could be one combustion cycle set behind if it's too far downstream. At high rpm, there's only milliseconds between engine rotations. And long tube headers are already... well... very long.

The written instructions you listed in your first post are referring to the cylinder head exhaust port. They just want to make sure you don't run them so close that they get too hot and become damaged. Reason being, some race teams may use sensors in several (or all) of the primary tubes, so they can calibrate individual cylinders. And when they do they'll put them as close to the head itself as they can, for best time-accuracy reading. If they put them too close, it's possible the sensor may become overheated. So their instructions are really about CYA, not about best readings. But unless your turbocharged, putting it at the collector (whether short or long tubes) is not an issue for too much temperature. As a matter of fact, a lot of OEMs run shorty headers with the narrow band right at the collector.

For best results, use the criteria in the video (within 2" of the merge).

[kyle_blake]

Hi, thanks for the information , when you said the criteria in the video, what video? Oh you men the tv series horsepower tv or what have you. ok ah i think i found it : https://www.youtube.com/watch?v=zzzLHYNPW4E

just re-watching it now.

[HWYSTR455]

I use these type of collectors, with the O2 bung already in them:

https://www.summitracing.com/parts/hed-21142/overview/

.

[kyle_blake]

Wow those are cool, i always thought headers went into their own collector from factory, do you just attach that part backwards to it then build out your pipe going to mufflers?

so the shop ended up removing the mufflers which were there from 1988. he couldn't just use the same pipe that was in place on the outlet, had to use 2" of new pipe. All the work looked good as far as I can tell. The o2 bung looks fine and angled up as the manual wants. It was 2.5 hours charge but i was happy as the guy who did the work was the guy who owns the shop as the guy who quoted me work as the guy who said you can bring your car up on hoist and you can drive it right off hoist. Your car is my only business during this time.

so all in $390. Was a good experience and the car sounds good, I wonder if mufflers actually affect performance. seemed a bit more responsive.

thanks again everyone.

[HWYSTR455]

Originally Posted by kyle_blake

Wow those are cool, i always thought headers went into their own collector from factory, do you just attach that part backwards to it then build out your pipe going to mufflers?
.

Yes. As long as you use one that is the same size as the headers/pipe you're golden. There are also clamp on types, but I prefer to use the collector type.

.