

| Subject: | Re: VDO Gauge Guru - temp vs voltage??? |
| From: | Bill Kasper |
| Date: | Wed, 5 Sep 2001 08:22:16 -0700 |
on 9/4/2001 10:40 PM, David Marshall at vanagon@VOLKSWAGEN.ORG wrote: > In my former 1984 Westfalia I would be hard pressed to get the oil above > 105C and usually it would be about 95C - this is with a 1.8L engine. My > Syncro goes up to 120C and this is with a 2.0L engine. Originally I thought > it was displacement differences, but now I know this is not the case. My 84 > Westfalia would be +- 0.1V 14.4V while driving down the highway and the > voltage would not change more than 0.2V with the lights on. My 1988 Syncro, > along with a friend's 88 Syncro both drive at around 13V and the voltage > fluctuates with the electrical accessories that are turned on. With high > beams on I am close to 11.5V. Now, we both notice that the lower the > voltage goes in the system the higher the oil temps got - instantly - if you > turned on the lights would add about 5 degrees the instant you turn on the > lights. Now today for the experiment, I took a 1.5V dry cell and installed > in in series with the positive lead of my gauge and the reading went no > higher than 105C when I pushed the engine really hard. So... after all of > this I have some questions: > > - What voltage are these gauges supposed to run at? > - Does anyone have a resistance to temp graph? The one in the Bentley > manuals for the water temp is wrong when it comes to oil temps. > - What is wrong with our Syncro electrical systems that it can't hold 14.4V? > I even tried the same alternator in both vans and the problem stayed with > the Syncro... david, that's very interesting. my alternator went bad on our trip, and i had a good used one installed with new brushes...the adjustable voltage type. the mechanic set the voltage at the battery to 14.7-14.8 so the drop with items on wouldn't drop it below about 14 (so he says; we tried the lights and powering a window and it went to about 14.4-14.5; putting the fridge on later while driving wasn't a problem, but i don't know the numbers). let us all know what you find out? bill '87 syncro westfalia http://www.scruznet.com/~kasper/pics/westy/
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