A question of accuracy

[WesRagle]

Hi Guys,

Maybe this is a strange question but here goes.

Below is a ""Characteristic Curve" for a typical "VDO-Style" transducer many of us use for measuring oil pressure. If you notice, down around the 2 bar point (~30 psi) and lower, where I would start to be concerned about the oil pressure indication, there is a potential +/- 5 psi indicating error with what would be considered an in tolerance transducer.



Question: Does anybody care? Is it worth the approximately $40, two extra wire runs, and *not* mounting transducer directly to the engine in order to provide an accurate indication?

Just curious what others think.

Thanks,

Wes

[mike.smith]

My oil pressure registers around 50 psi on average. The VW will run fine with OP down in the 20's psi. Mine used to max out at 35 psi for 3 years before I cleaned up the oil relief plunger and ports in the case. No abnormal wear and no issues for those 3 years. So I don't see any issues at all with the accuracy of the VDO.

[lgsievila]

Hi Wes,
In my Dynon Skyview Installation Manual they specifically said, "Do not mount the transducer directly to the engine". Didn't really know why but I followed their directions. When I was running an AeroVee I had an oil line with orifice going to the transducer that was mounted to the engine mount with an adel clamp. When I repowered with a CAMit I did the same thing and checked with a steam gauge to verify my Dynon was indicating correctly. Also did some reading about VDOs failing sooner when mounted directly to the engine. I am still using the same original VDO.

Not sure how all this Corona stuff is going to come out but we are still planning on coming down for Grandson's graduation on June 1st. Maybe see you then.

[achesos]

Despite becoming admittedly more anal retentive as I've gotten older, the precision and accuracy of the indicated oil pressure would not be worth it for me - I"m more interested in the trend information here...
If it indicates stable at 25 (+/-5), things are good right? The opposite condition would of course be of much more interest.
As long as the alarm is set to help alert you if it is in fact trending to worst case, does it really matter that it was 'right' on the way down?

[WesRagle]

Hi Guys,

Thanks for the replies. That's pretty much what I thought. Just not a whole lot of need for extreme accuracy. The trend is more important.

And Loren, be sure to come by when you are in this neck of the woods. Also, be sure you are current ;-)

Wes