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Posted by: sdoolin Jun 6 2016, 12:24 PM

I have searched - cannot find much on aftermarket CHT Gauges.

I am building a 2056 that will run dual Dells - would like to install a quality CHT gauge and wondering what others have used.

Posted by: JoeD Jun 6 2016, 12:37 PM

Researched this when I was looking to put one in my car. Most folks weren't too happy with the VDO CHT and many recommended Aircraft Spruce. I bought the following and have installed all but the sensor as I am still waiting on engine; I've included part numbers and what I paid back in November:

aircraftspruce.com

10-01425 2" CHT PYROMETER GAUGE 61.75
10-00823 CHT PROBE 14MM M-1000 23.95
10-01443 15 CHT EXTENSION LEAD 51.25

Posted by: BeatNavy Jun 6 2016, 01:18 PM

I'm running a http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=347/prd347.htm.

I think there are at least several others here as well. I think it has a good reputation, and I'm generally happy with it.

Posted by: era vulgaris Jun 6 2016, 01:25 PM

I'm running the MGL Avionics Stratomaster Velocity TC2.

Digital, 4 channels, you can see the temp of every cylinder.

User manual:
http://www.stratomaster.eu/lignes/mgl/pdf/Vel_EN_TC2.pdf

Might seem excessive to some, but it's been a massive aid in tuning and knowing that each cylinder is right on target. I also had an unexpected vac leak issue a couple months back, and looking at the gauge I knew immediately which cylinder had the problem.

Here it is in my center console...


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Posted by: Mueller Jun 6 2016, 01:28 PM

I like that one, I was just going to ask about it when I saw it on the spruce site!

Posted by: Downunderman Jun 6 2016, 02:11 PM

http://www.speedhut.com/gauges/Temperature-Gauges/Cylinder-Head-Temperature/?catid=f232|f10|f70

Posted by: Mueller Jun 6 2016, 02:41 PM

For the true DIY guy...

https://learn.adafruit.com/thermocouple/

Posted by: sdoolin Jun 6 2016, 05:52 PM

Thanks for the info - I knew y'all would be able to help. Naturally, I have follow up questions...

First - can I assume these CHT gauges utilize the OE sensor in the head (I have brand new HAM heads drilled/tapped for OE sensor at cyl. #3) and also assume they connect to the OE wiring (single lead from sensor)?

Second - era vulgaris what's the story behind that poster in your garage with the police car and the daisy dukes? I think I need one of those.

Thanks as always...

Posted by: BeatNavy Jun 6 2016, 06:20 PM

I don't think so. The Dakota Digital uses a thermocouple with a sensor (14mm?) that goes under the spark plug. No use of the OE sensor. I think others may be similar in some or most cases.

Posted by: 76-914 Jun 6 2016, 06:32 PM

Good stuff. FWIW, I found the VDO to be "somewhat" accurate if coupled to the Dakota sender. Does Dakota still offer the 12' lead, only?

Posted by: BeatNavy Jun 6 2016, 06:50 PM

No, in the 14mm spark plug size they only offer 18' lead, I believe. That fits the stock 914 plug, otherwise you're trying to make the other one fit, which is not ideal.

Posted by: Porschef Jun 6 2016, 07:26 PM

Like Rob, I've been running a Dakota unit for about 3 years. It's accurate, but I've found that under load the numbers jump around some but then settle back. I've checked grounds, but I'm thinking my alternator might be a bit weak, I'm getting 12.6-12.8 when running.

I think that's a bit low...

Posted by: ThinAir Jun 6 2016, 10:59 PM

I really like the look of this. It looks like it would work well in the stock center console holes. Does anyone have any experience with how accurate it is?

Posted by: Jake Raby Jun 7 2016, 06:52 AM

Never, under any circumstance should the stock CHT sensor boss be used with a CHT gauge.

I have proven over and over again that this position takes too long to see thermal changes, and is 50F lower in temperature, all the time, than the under spark plug location.

The stock CHT location was chosen for the EFI system for many reasons that won't apply to CHT gauge. Primarily, the fact that the location was chosen because it takes longer to warm up, and also longer to cool down than other locations in the head casting.

For a CHT gauge, the ONLY place that the sensor can be located, for any level of response time, and accuracy, is under the spark plug.

Posted by: sdoolin Jun 7 2016, 07:00 AM

Under the spark plug it is then. I assume these gauges come with the appropriate sensor(s) and wiring - I'll follow the links provided and do some more learning.

Thanks to all as always...

Posted by: Mueller Jun 7 2016, 07:16 AM

Jake, any special prep to the surface where the sensor meets the head?

Posted by: jeffdon Jun 7 2016, 09:16 AM

That is what I went with. The CHT gauge is also temp compensated, the VDO is not.

Posted by: wes Jun 8 2016, 12:57 PM

I have been reading this and was planning to put a VDO head temperature gauge in my consul as I'm installing a triple cluster gauge in the dash. Now hearing so much about the VDO head temperature gauge being so inaccurate looked into it more and have heard that if you use the sensor from the 911 it would turn better results.
Any thoughts or experience and I might add my engine is now a 2056 and will probably be doing a very minor bit of track time though nothing serious?

Posted by: tradisrad Jun 8 2016, 01:31 PM

I'm happy with my VDO gauge and sender. I'm not looking for 100% accurate numbers, but more over I'm looking for drastic changes while driving and for that I think the VDO is just fine. Plus the VDO matches the other gauges in my console (except for the wide-band o2 GAUGE)

Posted by: Mblizzard Aug 27 2016, 08:47 PM

I just added the Dakota Digtial. I was wondering what would be normal ranges?

Running around see 350 to 375. Running hard it can hit 400. Comes down quickly on normal driving but I was wondering where the sweet spot should be and where the danger zone is?

Also it seems to respond quickly increasing with throttle. Was a bit surprised by the quick changes in temp.

Posted by: eyesright Aug 27 2016, 08:57 PM

I went with a VDO CHT along with an oil pressure and temp gauge on my stock 2.0L rebuild a couple of years and 40K miles ago. Looked good under the dash. It was accurate in that my head temps were exactly what Len Hoffman and Jake said they would be with the 9550 cam kit and HAM rebuilt heads. I checked it with an IR temp gun from HF by pulling the plug wire and flashing it around the spark plug area. Hard to find an ideal spot to read from as you are shooting the gun pretty much blind and there are lots of angles to reflect off of, but all the readings were reasonable and none were higher than the VDO gauge.

Posted by: BeatNavy Aug 28 2016, 06:16 AM

Mike, I've been running the Dakota Digital for about 2 years now. Those temps you're reporting seem high - but what kind of driving are you talking about? Cruising around the parkways in my community I get over 300 only driving hard or up a hill, and then it will go back down quickly when I slow down for a light. On a long stretch of highway driving it will usually stay between 330 and 360, maybe slightly higher going up a hill.

Yes - the temps can change very quickly.

Here's the guide for reference: http://www.914world.com/specs/JakeRabyHeadTemps.php Stay away from 400+!

Posted by: McMark Aug 28 2016, 06:43 AM

This is fine for most people, and is the bare minimum.

Posted by: Mblizzard Aug 28 2016, 08:22 AM

Driving hard to me is WOT when ever possible! But based on the guidance it seems I am still too warm at the times I am not driving that hard!

In the process of refining the AF mixture as it goes a little lean at cruise (15 to 16) so I could richer that up a bit but the timing is 27 on the mark and I hane all electronic dizzy so dwell is not an issue. Verified flap over oil cooler is operating correctly. Valves recently set with head install.

So is the next step to retad the timing a bit? Any suggestions?

Posted by: Steve Pratel Aug 28 2016, 12:57 PM

I've been running the VDO gauge with the VDO sensor. It works. I'm sure there are more accurate and more expensive gauges and sensors, but I have a digital heat probe and the gauge is within 50 degrees of that. Is relatively cheap, and responds quickly to changes, but not perfectly precise I'm sure. Keeps me out of trouble.

Posted by: Steve Pratel Aug 28 2016, 01:07 PM

You can run the VDO sensor under a fine threaded bolt in the OE sensor's location, but the sensor is designed to go under the spark plug, so you will not get accurate CYL temp, only the head temp in the region of CYL 3. I tried it there, because of the location, is not as hot as on the plug, and the temp gauge is slower to report the cyl temps. So, you could spike temp in a cyl before you know it..... Important if you are racing or pushing the engine all the time.

Posted by: kgruen2 Apr 26 2017, 02:07 AM

Try Summit Racing.

Posted by: Mark Henry Apr 26 2017, 08:13 AM

While most definitely not the best gauge it is better than nothing.
My aftermarket EFI also has a head temp gauge and they seem to be in the same ballpark.

But I also agree the Aircraft Spruce Micro 1000 unit is a better choice.

Posted by: Elliot Cannon Apr 26 2017, 10:54 AM

I have used a VDO gauge with the spark plug sender. I'm not looking for dead on accuracy. I have established a normal range of 325 to 375. High way cruising it's about right on 350. It could be 350 +or- a few degrees. I can tell with a quick glance at the gauge if things are OK. I saw temps over 400 one time. A long stretch up hill for a few miles west bound from Needles to Barstow into about a 40 mph head wind. The engine wouldn't answer the throttle. I had to pull over and stop to let things cool down. Luckily no damage. Without the CHT gauge, I might have over temped and damaged something. I highly recommend a CHT for every air cooled engine.


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Posted by: kgruen2 Apr 27 2017, 02:55 AM

I put a digital CHT Gauge in mine when I had my R.A.T. 2270SR engine installed. I, too was surprised at the rapid temp changes under all driving conditions. My understanding is normal range is the low 300's, ok up to the mid to high (375) 300's. hot approaching 400 and higher. Mine runs 300-320, gets up to 350 climbing hills (drops immediately when downshifting to 4th or even 3rd). Goes as low as 220-250 downhill with foot off accelerator.

Karl