My Air Fuel Gauge to replace Clock

[jbell959]

This project has been going on for more than 5 years and I'm getting close to finishing a prototype of a much less expensive solution. I really want to have one of these in all my cars because with MFI they are sure nice to have.

Some of you may have run across a thread from 2015 when I originally made the gauge in the first pictures. This is the same gauge with the exception of the face which I just replaced. This gauge was made using an Innovate analog AF gauge and a 911 clock. Problem is the cost. By the time I bought a new innovate gauge and a old 911 clock I was already into it for more than $300 and I still needed to do all the work to build the gauge and custom needle. It works really well, but I'm not using 90% of the features of the innovate gauge so it's not a great solution seeing that I want 2 or 3 more.

Fast forward 5 years after off and on research for a better solution, I've come up with a design that uses a simple magnetic movement like used in the tachs and speedos. For this one I used a fuel/oil gauge which can be had for much less than a clock. The back was modified and my son designed a back cover to mount the movement. This one is 3D printed.

Now I need to figure out a good solution for the face and needle. I really want a dish shaped metal face but since I didn't start with a clock and the screw spacing on the movement is different than the clock I will need to make the face. I've been looking for a place to stamp the metal face but so far not much luck.

My son is a wizard on CAD so I asked him to also design a simple needle that we can have made so that is also in the works. Mechanically this option is up and running but I'll keep everyone posted on the face and needle.

ORIGINAL DESIGN





NEW DESIGN

[famoroso]

Love it! Interested. Subscribed.

[MIAdragon]

I’m interested

[SkunkWorks]

Very cool. Way more elegant than my solution.

[Reiver]

Nice job there...I've had one in the clocks place for years...great way to monitor injection health/mixture and the enrichment process under load etc....a full time blood pressure device.

[ADDvanced]

Hey as someone who designs prototypes and appearance models, you might want to consider transfer/rub down decals. Super affordable. Opaque. You rub them on w a coin and they’re very thin, they look like silk screened but you won’t have setup costs and minimums. Obviously labor is up to install them correctly but could be a good fit for your goals, depending on how many you want to make / year


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[jbell959]

Update... I finished up a prototype of the new AFR gauge this morning and will put it in my car and test it for a while. I made the face out of a flat piece of metal and didn't spend a lot of time on it since it's not what I want for the final design. But this will give me something I can put in the car and test. I still need a solution for an early style needle but for now I was able to modify a later needle from an electronic speedometer.

I'm working with another Pelican on having the metal face stamped and also trying to work out a design for an early style silver button needle.

More to come..

[Chriskv]

Love it , interested

[creaturecat]

nicely done.

[PhillIB]

Absolutely brilliant. I want one.

[OSC911]

Originally Posted by PhillIB

Absolutely brilliant. I want one.

Same here - sign me up!!

[dicklague]

Wonderful work. I like the way it matches the VDO instruments on the dash.

I hope this is not high jacking your thread, but I have been working with AFR instrumentation on my 1973 2.7l 911 for some 12 years. I have found that it is the key to getting this MFI engine spot on.

I never liked instruments in real time in that how do you drive and remember the readings at the same time. I found that data logging is the only way to go.

I installed a Daytona-Sensors WEGO IV system that stores up to 2 hours of AFR, RPM, and vacuum readings that your can chart, or output in a table. The mini USB jack on the front of the unit is used to down load the data to the WEGO software for analysis.

This unit has proven very reliable and has worked well for a dozen years. The readout is digital and does not match the VDO/Porsche design however.

I installed mine in the clock hole using a platic plug from Rothsport. I also added a digital instrument for time, battery voltage, and oil cooler temperature both before and after the cooler. Here is a photo of the set up. The CL tells me the wideband sensor is cold and has not warmed up. This is replaced by the AFR when heated or running. Upper readout is 10.75 vdc [a bit low, but 911 has been sitting for a week]. Right toggle selects clock, volts, oil cooler temp. Left toggle selects before or after oil cooler temp readings.

[jbell959]

Originally Posted by dicklague

Wonderful work. I like the way it matches the VDO instruments on the dash.

I hope this is not high jacking your thread, but I have been working with AFR instrumentation on my 1973 2.7l 911 for some 12 years. I have found that it is the key to getting this MFI engine spot on.

I never liked instruments in real time in that how do you drive and remember the readings at the same time. I found that data logging is the only way to go.

I installed a Daytona-Sensors WEGO IV system that stores up to 2 hours of AFR, RPM, and vacuum readings that your can chart, or output in a table. The mini USB jack on the front of the unit is used to down load the data to the WEGO software for analysis.

This unit has proven very reliable and has worked well for a dozen years. The readout is digital and does not match the VDO/Porsche design however.

I installed mine in the clock hole using a platic plug from Rothsport. I also added a digital instrument for time, battery voltage, and oil cooler temperature both before and after the cooler. Here is a photo of the set up. The CL tells me the wideband sensor is cold and has not warmed up. This is replaced by the AFR when heated or running. Upper readout is 10.75 vdc [a bit low, but 911 has been sitting for a week]. Right toggle selects clock, volts, oil cooler temp. Left toggle selects before or after oil cooler temp readings.

I agree with your assessment on data logging. I have another project in the works that does exactly what you're doing with your gauge. I've build a micro-controller circuit that takes input from all the engine sensors plus CHT and AFR and sends them via bluetooth to a mobile device for logging and analysis.

I'm also working on a quad gauge to replace the oil temp/pressure gauge and one of the quadrants could be a display like yours to show volts, AFR, CHT, oil temp, pressure, etc. I'll post the project in a different thread when I get a little further along.

[dicklague]

WOW! That is very interesting.

I am not that advanced in electronics design and execution so I have to rely on of the shelf developed solutions. The upper instrument is an eBay sourced unit, and the AFR unit has proven to be very reliable. I used to sell the WEGO through Pelican, but they stopped selling it.

I look forward to seeing your work. I love to keep the orignal look of these aircooled 911s, but it is great to have modern electronics helping your out to keep them in tune and monitoring their health.

[jbell959]

Originally Posted by dicklague

I love to keep the orignal look of these aircooled 911s, but it is great to have modern electronics helping your out to keep them in tune and monitoring their health.

That is exactly what is fueling all this madness. You should see my desk... covered with gauges, micro-controllers, sensors, and wires.

I think I'm going to toss out the air coil movement I was planning to use in my less expensive AFR gauge. Even though it's the same technology we have in our speedos and tachs, the VDO movements are much better than what I was trying to use. I was getting accurate readings when the movement was going clockwise, but not so good when moving the other direction. These movements need to be well balanced to work well and the less expensive ones aren't good enough for me.

I ordered a few little stepper motors like used in most, if not all, modern gauges and I'm going to build a little micro-controller stepper motor controller to drive the AFR gauge. It should be relatively easy so I'm hoping to have a working prototype next week. It will also make it easier to feed into my bluetooth setup because I'm already running the AFR through a smart device. More to come.

[PhillIB]

Originally Posted by jbell959

That is exactly what is fueling all this madness. You should see my desk... covered with gauges, micro-controllers, sensors, and wires.

I think I'm going to toss out the air coil movement I was planning to use in my less expensive AFR gauge. Even though it's the same technology we have in our speedos and tachs, the VDO movements are much better than what I was trying to use. I was getting accurate readings when the movement was going clockwise, but not so good when moving the other direction. These movements need to be well balanced to work well and the less expensive ones aren't good enough for me.

I ordered a few little stepper motors like used in most, if not all, modern gauges and I'm going to build a little micro-controller stepper motor controller to drive the AFR gauge. It should be relatively easy so I'm hoping to have a working prototype next week. It will also make it easier to feed into my bluetooth setup because I'm already running the AFR through a smart device. More to come.

Once you have a working set up are you going to be selling them or just giving details of how to build one. I would be very interested ether way. I have already sourced a clock. My Lambda controller is an LD Performance one from here in the UK https://ldperformance.co.uk/product/wideband-controller-for-bosch-lsu49/ which functions the same as an innovate.

[famoroso]

I run this wideband O2 setup on my smartphone...
https://www.plxdevices.com/PLX-Wideband-O2-Air-Fuel-Ratio-Sensor-Modules-Gauges-s/125.htm

But I love the idea of a matching in-dash gauge. Kudos to jbell959 for identifying a market need here.

[FrankM_]

Originally Posted by famoroso

I run this wideband O2 setup on my smartphone...
https://www.plxdevices.com/PLX-Wideband-O2-Air-Fuel-Ratio-Sensor-Modules-Gauges-s/125.htm

But I love the idea of a matching in-dash gauge. Kudos to jbell959 for identifying a market need here.

I was also looki g for the plx with the bluetooth iphone link and using the 0-5V to drive the ‘boost’ mini-gauge in a 930 tacho. I will build a small circuit to handle the signal and drive the gauge.

Are you happy with the plx ? Do you use the iphone/bluetooth gauge ?


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[Discseven]

Brilliant stuff JBell.

[famoroso]

Originally Posted by FrankM_

I was also looki g for the plx with the bluetooth iphone link and using the 0-5V to drive the ‘boost’ mini-gauge in a 930 tacho. I will build a small circuit to handle the signal and drive the gauge.

Are you happy with the plx ? Do you use the iphone/bluetooth gauge ?


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Overall, I am happy with it. It did the job for my Sal Carceller mandated before and after AFR readings associated with his modern MAF, Bosch four hole injectors and ECU upgrade for the 3.2.

I wish it had some data logging (or at least history) functionality.

The PLX app crashed my Android, but worked pretty well on my iPad Mini, so I was able to use that instead.