I am in the process of building a second 914/4 and need advice on what folks are using for cylinder head temp and wide band air/fuel gauges? I am currently using a VDO CHT gauge and an AEM air/fuel gauge on my current car. While looking for gauges for the new build, it appears that the VDO gauge is no longer available and I'm just not sure about the AEM. Any thoughts, suggestions or recommendations of reliable gauges would be greatly appreciated. Thanks in advance.

Herman

Aircraft Spruce sells CHT gauges that should be reliable and likely more accurate than the old VDO standard.

Not sure on the AFR, but wide-band is what you want unless you're trying to keep a catalytic converter happy.

--DD

I have the VDO CHT. Sorry to hear that they are NLA. I also have a PLX device A/F gauge. I really like it. Lots of features plus you can set up the controller to put out blue tooth on your phone.

https://www.plxdevices.com/v/vspfiles/suppo..._user_guide.pdf

Dave,

Thanks. The Aircraft Spruce is on the top of the list for the CHT, just have to figure how long an extension cable. I have been looking at a Dakota Digital but can't really find any information pro or con. I need the wide band AFR to keep the Webers happy.

Herman

I've been using these since I've rebuilt my engine to a 2056 about 5 years ago:

Head temp gauge:

http://thesensorconnection.com/cht-sensors...e-sensor-kit-fs

Click to view attachment

A head temp gauge is nothing more than a type K thermocouple reader. In the image below taken here (https://en.wikipedia.org/wiki/Thermocouple), we can see Tref which happens at the transition between the TC chromel/alumel wires and the copper wire.

Click to view attachment

The TC will read the temperature differential between Tref and Tsens. This is why you don't want Tref to be located in the engine compartment (Like the VDO gauge). This would not give you the proper head temp as it would be offset by the engine compartment temp. Ideally, you want the TC wire (chomel/alumel) to run all the way to the gauge, and have a compensated gauge that will have a sensor measuring the temperature at the gauge connection point (which will be cabin temp) and compensate (compared to 20-25C room temp) in order to give you the correct head temperature.

Google is your friend...


AFM gauge:

http://aemelectronics.com/products/gauges/...-uego-afr-gauge

Click to view attachment

McMark wrote about one he is using (unless he has changed since this was written)

http://www.914world.com/bbs2/index.php?sho...188&hl=CHT*


I plan on running one of these below that I purchased from someone that was upgrading to a /6 I believe.

http://www.914world.com/bbs2/index.php?sho...=174745&hl=

Thank you everyone for your help!

I was you a few months back and went with the McMark/Aircraft Spruce/CHT and the AEM UEGO, both mentioned above and couldn't be happier. I almost want 3 more CHT so I can monitor each cylinder individually, but that's a little much

For the AFR, check out the Autometer Wide-band AFR.

I have one in the teener and have been running one on the Harley for over ten years and it performs flawlessly. maybe more pricey than others but after all these years I never think of the cost.

For the CHT check out Dakota Digital. its a digital gauge with a 150-750 deg range. you will need to purchase an extended thermocouple in 14mm. for the mid engine. the included one is only 8ft. that adds to the cost.

How about a recommendation for just a sensor that does variable voltage output? Or a resistive circuit sensor with appropriate voltage divider and putput volts/temperature? I'd like to install a CHT input to my DL-1 data acq system, which can be displayed on the DASH1 and warnings set.

Alternatively, how about an existing CHT gauges that has voltage output for data acq? That's what I do for the AEM AFR gauge, it offers voltage output (and I just hide the AFR gauge behind the panel; I only want to see numbers when things go pear-shaped...)

Yes, 0-5V output, and reasonably priced too. (post #5)

Click to view attachment