air fuel ratio gauge/sensor, Recommend a good set-up of a wide-band for a 914/4? Options

[Bones]

Hello out there,

Does anyone have experience running a relatively inexpensive wide-band air/fuel ratio gauge? What I want to be able to do is leave it mounted in the car long-term, so I can notice how the fuel injection is working under various driving conditions. I will be modifying my 2.0 to a larger size and still want to use the factory FI. I have read about how this is done, but I want to get the feedback on the effects my mods are having. I do not need programmable/data storing types, but I think I need a wide-band one.

I guess my main question is this:

What inexpensive gauge and O2 sensors (brand and model) will work in my car? I would prefer a sensor on each bank and a "double"-type gauge.

Thanks!
Jim

[SLITS]

I bought, but have not as yet installed, the Edelbrock set up.

There was a guy who made and sold them for $50, but I guess he ended up selling them to Edelbrock.

Just a couple of leds in a small box ... good enough for monitoring.

[Krieger]

Pelican has the plans for one on their website. I made it for $12. Welded a bung in my exhaust and bought a single wire bosch O2 sensor. I tuned my d-jet with it. I put a potentiometer in line with the head sensor to dial in resistence to trick the brain into thinking the motor was cold. I drove around and adjusted the potentiometer. This home made a/f meter was priceless and very accurate. Car was later dynoed and I did not make any adjustments whatsoever! I finally took out the potentiometer measured the resistance @ 425 ohms, then went to electronic supply and made one with these specs. Oh very early on I bumped the fuel pressure up to 36psi. This is for a mildly cammed 2270

[orange914]

Pelican has the plans for one on their website. I made it for $12. Welded a bung in my exhaust and bought a single wire bosch O2 sensor. I tuned my d-jet with it. I put a potentiometer in line with the head sensor to dial in resistence to trick the brain into thinking the motor was cold. I drove around and adjusted the potentiometer. This home made a/f meter was priceless and very accurate. Car was later dynoed and I did not make any adjustments whatsoever! I finally took out the potentiometer measured the resistance @ 425 ohms, then went to electronic supply and made one with these specs. Oh very early on I bumped the fuel pressure up to 36psi. This is for a mildly cammed 2270

you were able dial in the 2.0 d-jet?

[draganc]

Pelican has the plans for one on their website. I made it for $12. Welded a bung in my exhaust and bought a single wire bosch O2 sensor. I tuned my d-jet with it. I put a potentiometer in line with the head sensor to dial in resistence to trick the brain into thinking the motor was cold. I drove around and adjusted the potentiometer. This home made a/f meter was priceless and very accurate. Car was later dynoed and I did not make any adjustments whatsoever! I finally took out the potentiometer measured the resistance @ 425 ohms, then went to electronic supply and made one with these specs. Oh very early on I bumped the fuel pressure up to 36psi. This is for a mildly cammed 2270

Andy,
I had a look at PP and couldn't find any info.
Can you pls post a link to the $12 kit?

Thanks,
Dragan

[dlee6204]

I think this is what he is talking about.

http://www.pelicanparts.com/techarticles/m...uel_monitor.htm

I think its a bit unclear however you can find better instructions if you just google it.

[draganc]

I think this is what he is talking about.

http://www.pelicanparts.com/techarticles/m...uel_monitor.htm

I think its a bit unclear however you can find better instructions if you just google it.

Thanks a lot Doug!! (IMG:style_emoticons/default/pray.gif)

Any chance you have instructions for a EGT DYI kit?

[brant]

I've tuned a Djet before with a Wide band.
the CHT and adjusting its value is not the whole picture of a Djet.

tuning the MPS is the key item when it comes to a Djet

I don't think you will get the transitions into WOT, and different throttle settings as accurate without the wide band. I've used both on race cars for about 15 years and find the wide band much more useful.

I've used single wire-narrow band on the race track. its pretty good at the end of the straight... but not as accurate in tip in, and over-run throttle conditions.
(hard to describe, but its like the data is always a few seconds behind... essentially if you hold the throttle still and wait a second the read out seemed accurate. Seemed to work good for WOT at redline, where it really matters)

brant

[Cevan]

I bought an Innovate LC-1 for $168 on Amazon.com a couple months back. This included the controller, gauge, sensor. I've had it in the car about a month. Works great. I'm making note of the numbers under different conditions. I hope to fine tune my carbs with it.

[Krieger]

I am no electrical engineer, but I found the directions easy and I soldered it together with ease. The LEDs lit up green (rich) almost the instant you went from cruise to hitting the loud pedal, then go to the red when you took your foot off. It was fun to watch when you drive.

[brant]

The CHT guage (after its hot) doesn't change its signal for engine load. on carbs it would be like comparing to an idle jet... ie: it effects the entire range from idle to redline. (its a gross jet, or gross setting... not a fine tuning instrument)

so if you put a particular resistance inline you have essentially "put a big jet" into the metering that will effect the amount of fuel throughout the range. Thats not all bad necessarily, but it doesn't vary/adjust the fuel depending upon load conditions.

the MPS, measures the load conditions (vacuum) and varies the fuel load depending upon the exact state of load to the motor. Tuning the MPS will adjust the midrange (not the entire range) Again in carb language, the MPS is an "emulsion tube" in that it effects transition

the wide band gauge does a nice job of showing you those quantative measurements of your mixture during those midranges... The beauty of reading the numbers is that you get more of an idea how far above or below stoich you are.

ie: you might be slightly lean, but really close to your goal and... close enough to leave it alone vs being far far off and needing to do something about it

When we run on the track with the carbed race car... we are really really pushing the numbers. We run much too large of venturi's in order to get maximum hp and thus have a extremely small operating range between "just right" and too rich" We have to rejet depending on the ambiant temperature during the day... We have to run one set of jets in the morning, another after lunch...
Leaning it by the seat of the pants makes everything "feel" better... but usually when we tune by "seat of the pants" we find the gauge shows we are actually too lean (lean motors "feel" great right until they blow up)... The innovate shows every little detail and allows that level of accuracy.

[Rotary'14]

I just stayed at Holiday Inn,, so I might sound like know it all jack-ass.

A/F gauge and Wide Band O2 sensors are not quite the same. It depends on the type of O2 sensor used. Most old cars and "cheap" (less than $100) A/F gauge use "narrow band sensors" like the PP article. This is good for finding stoichiometric (14.7 to 1) running conditions. This air fuel ratio is good for emissions, but not the best for power. It only reads accurately in a narrow range (around 14.7) the accuracy drops off a lot if you are outside of this range. To make good power you must be a lot richer than this 14.7 value,, closer to 12~13. The narrow band O2 will always read rich. You would have just as much accuracy with your nose to the exhaust smelling for the rich smell.

A Wide Band O2 sensor needs a complex controller that usually makes this system more expensive. it will give a Linear reading from an A/F of 10 thru 20. With one of These gauges, and a tune-able FI, You can set the your air fuel ratio for various conditions,, like at WOT thru the RPM range. It's a great tool for tuning. Innovate makes some very good products I have an LC-1 installed in my car, I've also used WBO2 from Australia. Both are very good.

-Robert

[qa1142]

Will any of these wide-bank kits run from Bursch all the way to the dash?

[904svo]

Here's a low cost option for a WB02 sensor. Its what I use

http://www.14point7.com/

[brant]

This air fuel ratio is good for emissions, but not the best for power. It only reads accurately in a narrow range (around 14.7) the accuracy drops off a lot if you are outside of this range. To make good power you must be a lot richer than this 14.7 value,, closer to 12~13.
-Robert

agreed...
we like to run the race car around 13.2-13.5
I would never want to run 14.7 at redline
my builder actually likes and wants us to go to 12.5, but we fudge that closer to 13.0 in order to keep the car from stumbling below 5,000rpm.

[sean_v8_914]

Andy: got any pics of that home brewed $12 set up you mentioned?

[sean_v8_914]

one wire is narrow band. is that fast enough for tuning?

[sean_v8_914]

oops. response issue was answered

[Mark Henry]

This air fuel ratio is good for emissions, but not the best for power. It only reads accurately in a narrow range (around 14.7) the accuracy drops off a lot if you are outside of this range. To make good power you must be a lot richer than this 14.7 value,, closer to 12~13.
-Robert

agreed...
we like to run the race car around 13.2-13.5
I would never want to run 14.7 at redline
my builder actually likes and wants us to go to 12.5, but we fudge that closer to 13.0 in order to keep the car from stumbling below 5,000rpm.

(IMG:style_emoticons/default/agree.gif)

Really for our engines you should have a wide band. I had a Haltec narrow band but I sold it once I got a wide band.
Just like I sold my betamax when I bought a DVD-R....although I did get a couple more bucks for the narrow band.

[Cevan]

Will any of these wide-bank kits run from Bursch all the way to the dash?

Yes. The LC-1 does. I mounted the sensor at the collector. The controller is mounted in the back on the passenger side. The wires run through the rear engine tin into the engine bay where I mounted the momentary switch and LED. I had to run two wires back from the gauge to the engine bay.