Tuning, o2, Air/Fuel Ratio

[Tru-Craft]

I was reading Markandsons thread about FI for our Opels.
He mentions an o2 sensor or Air/Fuel Ratio gauge.
He told me to look at the site below.

I want to use the o2 sensor as a tuning aid for my carburetor (Weber38) on my GT and Triumph TR3 and other carbed things I have.
I don't want to mount it as a permanent install.
I want to drill and weld a fitting on the header pipe.
Install o2 sensor.
Tune.
Plug hole and remove setup.
Don't need a computer output, just a gauge to show A/F ratio.

Innovate Standalone Gauge Kit w\ LC-1 & Red DB Digital Gauge DIYAutoTune.com

http://www.fordmuscle.com/archives/2...vate/index.php
Would be a great way to get an accurate carb adjustment.
Any thoughts?
Lyle

[jordan]

Of course, wide band O2 sensors are great for tuning carbs as well. Innovate also offers a temporary mount that goes into the exhaust pipe and clamps in, it would be more accurate farther forward, but if you intend on switching it around in some different vehicles it might do the trick Innovate Motor Sports On-Line Store

[2 Fast 4 U]

How about a CO sensor, wouldn't that be better for tuning your carb??
In the workshop manual it says, the CO reading should be between the 1.5 and 2.5%, then your carb is tuned nicely

[Tru-Craft]

Originally Posted by 2 Fast 4 U How about a CO sensor, wouldn't that be better for tuning your carb?? In the workshop manual it says, the CO reading should be between the 1.5 and 2.5%, then your carb is tuned nicely

I don't know what is better, trying to find a higher tech way to tune, learning something new!
I have always tuned with vacuum and plug readings.
The o2 sensor is small and portable, could be mounted and the car driven at load and different RPM ranges.
Want to keep price down also.
Don't need a computer record of all readings/rpm's, I can't adjust like FI!

Jordan, that is a simple way, no drilling/welding.
Lyle

[wrench459]

Lyle if this a street car engine. The biggest bang for the buck might be using the narrow band sensor.
It has its limitations only accurately reading from 200mv-800mv and thats after heated up.
After building my engine I checked the A/F ratio on a GA. state emissions dyno. The CO was 3 % which is roughly 13.6. I also installed a O2 bung for more tuning capabilities later on down the road. Imagine my surprise when monitoring the O2 running down the road backing off cruise very slightly...
the sensor gave me the sweetest pattern it switched just like a compter controlled carb. This is with a very modified 32/3x carb.
So a narrow band sensor could give you an indication of where 14.7 is depending on load.
Also its a great indicator of fuel lean out.

[davegt27]

I have plans to buy a wide band setup or build one

Australian DIY Wide Band Information

but for now I have 2 auto meter narrow band meters ( when my MR2 failed emissions I just went down to auto zone and bought one then another later for a second car)

I like the auto meter it works great you just have to guesstimate a little since the thing is fluctuating back and forth so you just use the center of the swing

HTH
Davegt27

[tomking]

Originally Posted by Tru-Craft I was reading Markandsons thread about FI for our Opels. He mentions an o2 sensor or Air/Fuel Ratio gauge. He told me to look at the site below. I want to use the o2 sensor as a tuning aid for my carburetor (Weber38) on my GT and Triumph TR3 and other carbed things I have. I don't want to mount it as a permanent install. I want to drill and weld a fitting on the header pipe. Install o2 sensor. Tune. Plug hole and remove setup. Don't need a computer output, just a gauge to show A/F ratio. Innovate Standalone Gauge Kit w\ LC-1 & Red DB Digital Gauge DIYAutoTune.com Tuning With Innovate - FordMuscle.com Would be a great way to get an accurate carb adjustment. Any thoughts? Lyle

If you arent going to keep the gauge installed permanently then just use a voltmeter instead to tune. IOW dont install an AFR gauge, just use your regular voltmeter set to the millivolt scale, tune and dissconnect. All the AFR is anyway is a limited range millivolt meter.

[markandson]

Originally Posted by tomking If you arent going to keep the gauge installed permanently then just use a voltmeter instead to tune. IOW dont install an AFR gauge, just use your regular voltmeter set to the millivolt scale, tune and dissconnect. All the AFR is anyway is a limited range millivolt meter.

Tom you are correct, in the case of the Innovate LC-1 controller and the Bosch O2 sensor that diyautotune supplies the range is from 0-5V so a voltmeter could be used in place of the AFR gauge. Personally I figure if you have spent the money on the Controller and the sensor you might as well complete the setup and buy the gauge, it is the least expensive part and then you don't have to do the conversion or somehow recalibrate your gauge. BTW if you are doing this for a carb setup I would not use a digital gauge as it will be flying all over the place and it will be difficult to get a reading unless the software can buffer the changes and give you a good averaging effect. In my car the gauge swings almost the entire scale when I floor it since the acceleration enrichment comes into play and then if you back off immediately it goes to full lean so the needle is getting a real workout. Maybe after I get all tuned I can make it fly around the gauge face twice and then fly off .

[markandson]

I had not been to the diyautotune site for a while so I just took a look. There are many more gauges available now compared to when I purchased mine. Mine is still the least expensive $59.00 and it is analog but still does a great job as far as I can tell. The kits are all being offered with the more expensive stepper type gauges but they are still quite reasonable at $99.00. For anyone who is messing with carbs and especially carbs cams and pistons I don't see how you could be comfortable without one of these installed for tuning, unless you are all hooked up on a dyno.

[wrench459]

Originally Posted by wrench459 The CO was 3 % which is roughly 13.1.

Sorry guys I had senior moment.. 3% CO is closer to 13.6