Today on a revisit to [url=http://www.bob2000.com/carb.htm] bob2000[/url], the colorful how to Holley carburetor guy, I finaly decided to install an Oxygen Sensor to improve my air fuel mixture tuning. It all seams rather straight forward, keep sensor as close to vertical & as hot as possible.

Where my engine is sporting shorty Clifford headers, should the bung be located on one of the runners, at the point of collection, or just down stream of the collector and connection to the exhaust pipe?

Below is a photo of the “front threeâ€￾ header and its connection to a rust colored 2â€￾ exhaust pipe. My inkling is to install a bung just past the flared end of exhaust pipe or about 3â€￾ down stream from the three bolt flange at the black “Xâ€￾. Am I on the right track?

[img]http://i294.photobucket.com/albums/mm87/wjajr/Dart%20Engine/100_1355.jpg[/img]

Bill

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

That's where I'd do it.

I might rotate it a bit toward the fender, but still on the upper side of the pipe.


Make sure you don't have any leaks with your muffler clamp and flange clamp as the O2 sensor is downstream of these connections.......

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

I would put one there and anonher one on other pipe same placement and add a switch to read one or other ....that way you have reading front and back of engine

keep on roddin'

thinking of doing the same thing your doing, what are you going to use for a gauge? wideband?

[quote]thinking of doing the same thing your doing, what are you going to use for a gauge? wideband?[/quote]

1980Volare,

That is a very good question. Bob doesn’t indicate wide or narrow band instrumentation, only using a digital VOM and a good ground in the cockpit so one can see what is going on while under way on the great open road.

Did you look at Bob’s page, and the associated graph illustrating typical slope; mv vs. A/F mixture? He likes to run around 800 mv which is just a tad rich of 14.7:1

Several months ago I found an air/fuel gage at VIP Auto Parts, a local New England chain, priced in the mid 30 buck range. I don’t recall the brand, or if it was narrow or wide calibrated if that matters at all. That gage was rather crude in that it did not display the air/fuel mixture digitally, only a three color light scale indicating lean, good, and rich. It is just a special application volt meter. A VOM is much cheaper, and a multi tasker as well…

Summit has several gages starting around 70 bucks on up. They all have the three light display as well as a numerical A/F mixture ratio.

I think for now I’ll just install a docking port somewhere under the dash where a VOM could be easily connected, and fashion up a small wire harness to easily connect it to a VOM.

Hantayo13,

For now just one O2 sensor. I had a 93 Suburban equipped with a 350 & EFI that only had one O2 sensor on the left bank. For one old Holley on a single plenum manifold one sensor will do the job. Once the carburetor is dialed in, why would one want to look at a gage sitting in the green zone until the next jet change?

Hell, the acceleration is not great enough to “centrifugeâ€￾ fuel to cause a richer mixture at the rear of this engine… LOL

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

http://www.summitracing.com/parts/EDL-6593/?rtype=1

every time i look at this one i like it more and more, very simple yet effective.

dvom would be a good idea also.

i wouldnt see a wideband to be necessary on a carbed car. but thats my opinion

Just for info go to tuneyourengine.com (Sorry but I don't know how to make it a link). I have a Innovate Motorsports LM-1 Unit that I have never used. It was used for a magazine artical about 5-6 years ago,I ended up with it. Now I will be the first to admit that I am a tecnological caveman and will never use it. IF you think this is something you would want,any reasonable offer will be accepted. Again it is complete and I will post a picture of it within 24 Hours. (Need the wife to do it because I'm a complete dumbass as far as computers go).

Here you go as what it looks like, never even took it out of the box.

The possible error you will introduce by sampling only one cylinder is pretty much unacceptable. Especially with a carb and wet manifold flow. If you are using a narrow band, you will only be able to dial in a stoichiometric mixture because narrow bands do not give accuracy accept at lambda = 1. If you are using a wide band, then be aware that you will not have accuracy accept at relatively high loads because you have to get heat into the sensor for it to work properly. At idle and low loads, the sensor cools off too much.

Mitch

MitchB: My sample point will include first three cylinders of six because of employing a pair of 3 to 1 headers. This is not any different than what most manufactures did back when FI became the norm with one O2 sensor on one bank of a V engine.

One lingering question is; are single wire O2 sensors narrow or wide band. Bob the carburetor guy said in his tutorial that if the sensor is not hot enough to produce a current at idle it won’t mater, as it will soon. That this won’t matter because we are tuning a carburetor, not controlling a fuel injection system thousands of times a second.

The point is to tune a carburetor to just on rich side of 14.7:1 at cruse by making jet changes as needed. Hopefully the sensor will produce a current at idle as well.

Bill

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

A single wire O2 sensor is narrowband.

I'd at least use a 3-wire narrowband sensor so that it stays hot and will give a reading at idle.


narrowband sensors can be used for A/F tuning, to get you in the ballpark..... 600-700mV would be just a little rich.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Meter is sold.

Ed I took your advice, found a heated three wire O2 sensor for CHEEP at Rock auto on one of their Wholesaler closeouts.

1995 Chevrolet Astro 4.3 L ---- “Standard Motor Productsâ€￾ #SG241:P for $13.97!!!!

Additionally, Rock included their usual refrigerator magnet advertisement re-order inducement featuring a red 1967, dog dish clad, 270 Dodge Dart just like my first car I had in collage… Except my Dart was a two door hard top, not a four door. Close enough for memory lane.

Bill

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

I have a Cyberdyne LED bar-type gauge from J.C.Whitney on my narrow band O2 and it's been running fine for 5 years. Mine has red/green/yellow bars, not blue as now shown on the JCW page.

I used Sunpro gauge from parts store (Advance or similar). The two of these I have in cars have worked fine for 6+ years.

Lou

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