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Fri Dec 16, 2005 7:53 am

VDO CHT Gauge and Berg Temperature Stick

If you have both hooked up, I would be interested to know "when and if" your “Berg” stick flickered (about 215-220 degrees), what was your CHT gauge showing?

Thanks,

Kris (Kansas)

Fri Dec 16, 2005 8:11 am

check the stream in "late beetle/super beetle"

Fri Dec 16, 2005 8:57 am

Kris,

I run Dakota Digital gauges for CHT, OT, and OP in my bus. They seem to be more accurate and more responsive than the VDO gauges I had in there before, but there is no 1:1 correlation between CHT and OT. They are related as a "second cousin" would be.

In general and in my opinion, OTs are more RPM related and are very effected by incorrect timing (especially too retarded timing). When you back off the gas, it takes a couple of minutes for the OT to drop say 20* or so. More RPMs sort of equal more OT, everything else being equal.

CHTs are more related to the total load on the engine, like pushing a heavy westy up a big ass hill, and will drop seconds after you back off the engine throttle, do a down shift, or exit the interstate. More like "vacuum related" if you have ever driven with a vacuum gauge permantetly mounted.

Just my 2 cents.

Fri Dec 16, 2005 9:06 am

Randy:

Good comments and data. Thanks !

Kris

Sat Dec 17, 2005 1:28 pm

CHT's vary too much with load, timing, fuel octane, air/fuel ratio, OAT, fan speed, fan shroud, sender placement.
But after saying that with my oil temp at 200 F on a 100 F day, my CHT under the spark plug is 325 F on the freeway.

Sun Dec 18, 2005 3:49 am

Turbo Bob:

Thanks.

So, from what the two posts I have read, it seems like a Berg Temp Stick (or other oil temperature unit) and a CHT have different purposes?

Correct?

Kris

Sun Dec 18, 2005 6:50 am

Kris,

I have never been a big fan of the "berg stick" since it just tells you if the oil "too hot" or not and is unable to give you any sort of trending information. But they are cheap and probably beat having nothing.

The VDO gauges are better than nothing, but the CHT gauge is very slow to react and the way they are designed they are only "accurate" when the outside temp is 70*, if it is 30* outside they read 40* hot, 100* out they read 30* cold. My bus is heavy and runs hot all of the time. While I intend to change that soon, right now I try not to push it too much. I drive around with bikes and kayaks and stuff.

Here is what mine used to look like

But they have all been replaced with the Dakota Digital ones (which you can also set to "flash" at certain warning points to get your attention. A lot of people put in gauges and then never look at them (or your wife never looks at them!.

Interesting reading here...

http://www.ratwell.com/technical/VDOGauges.html

The link if you are interested... http://www.dakotadigital.com/index.cfm/page/ptype=...prd347.htm

Sun Dec 18, 2005 7:14 am

Randy:

Thanks for the information and links. Read them both. Needless to say, I am REALLY confused now.

I am also not real keen on the Berg Stick. I installed one due to the fact that our son will soon be the primary driver of our 66 T1. The idea behind installing the Berg Stick was to have yet “another indicator” (flickering or solid lamp) of an impending issue.

“Like a backup parachute to the backup parachute”

I now believe all gauges; oil temperature, CHT and Berg serve a purpose. It’s the interpretation of the gauges that one needs to understand.

Thanks again for the links and post. I have always found your comments on SAMBA useful the well thought out.

Kris (Kansas)

Mon Dec 19, 2005 9:12 pm

Randy in Maine wrote:
The VDO gauges are better than nothing, but the CHT gauge is very slow to react and the way they are designed they are only "accurate" when the outside temp is 70*, if it is 30* outside they read 40* hot, 100* out they read 30* cold. My bus is heavy and runs hot all of the time.

I use the Microflight 1000 CHT & EGT gauges, there the best that I have found. These are temperature compensated, accurate within 2%, 2 year warranty. The CHT is a high quality Chrome/Constantan "E" type. E type systems produce much greater accuracy at lower temperatures (less than 600F).
My CHT does react with load but it takes a few seconds for the fan to cool the heads. The EGT reacts instantly with load and vacuum changes.