VDO CHT "useability"

[slow.bus]

Hello all,

I have read many articles / forums etc on the 'un-reliability' of the VDO CHT - but from what I can tell / interpret - they are consistent & reliable .. just do not display the actual temperature ... is this right? Apologies if I have not searched or read enough in this forum to answer the question.

I have a VDO CHT, and am coming to grips with the fact that I probably cannot compare apples to apples to other people's reports of temps (as they have a DD, or are in other climates etc etc) ... but its what I have, and I am want to know how I am doing ... as I think I am not "adjusting" for their difference correctly ... ie over reacting when I see certain temps.

In real world driving with, properly set-up vehicles (all engine seals good), in normal summer temps ... how far off are they - and are they just off by x% - or are people seeing they display inconsistent results?

Assume outside temps are 75-90 when I do most of my driving. If am at 390, or 410 ... what would the adjusted temperature be?

[BellePlaine]

A VDO CHT gauge is quite useful. You will learn what is normal for your bus and the VDO will tell you when your engine is running too hot compared to "normal". Don't worry.

[slow.bus]

A VDO CHT gauge is quite useful. You will learn what is normal for your bus and the VDO will tell you when your engine is running too hot compared to "normal". Don't worry.

Thank you. I have been using one for a while (2 yrs) - but only slightly before original engine quit (worn cam and cat disintegrated) and since had things all rebuilt nicely with mostly NOS.

I know what was normal before, and was what I see now (more / less the same) ... but I am not convinced normal was "good" ...

All in all, I've been doing alot of changes and tuning this year and want to make sure I am not going to far (or too short) ... and previous "normal" is not a fair comparison ... so am hoping for a scale so I can compare my findings more closely to those posted here

I have a love / hate relationship with the guage

[Amskeptic]

A VDO CHT gauge is quite useful. You will learn what is normal for your bus and the VDO will tell you when your engine is running too hot compared to "normal". Don't worry.

Thank you. I have been using one for a while (2 yrs) - but only slightly before original engine quit (worn cam and cat disintegrated) and since had things all rebuilt nicely with mostly NOS.

I know what was normal before, and was what I see now (more / less the same) ... but I am not convinced normal was "good" ...

All in all, I've been doing alot of changes and tuning this year and want to make sure I am not going to far (or too short) ... and previous "normal" is not a fair comparison ... so am hoping for a scale so I can compare my findings more closely to those posted here

I have a love / hate relationship with the gauge

I don't like VDO. Reads low when it is hot outside, and reads high when it is cold outside. Plus the markings seem to require too much interpretation to get the real number.
Colin

[satchmo]

A VDO CHT gauge is quite useful. You will learn what is normal for your bus and the VDO will tell you when your engine is running too hot compared to "normal". Don't worry.

Thank you. I have been using one for a while (2 yrs) - but only slightly before original engine quit (worn cam and cat disintegrated) and since had things all rebuilt nicely with mostly NOS.

I know what was normal before, and was what I see now (more / less the same) ... but I am not convinced normal was "good" ...

All in all, I've been doing alot of changes and tuning this year and want to make sure I am not going to far (or too short) ... and previous "normal" is not a fair comparison ... so am hoping for a scale so I can compare my findings more closely to those posted here

I have a love / hate relationship with the gauge

I don't like VDO. Reads low when it is hot outside, and reads high when it is cold outside. Plus the markings seem to require too much interpretation to get the real number.
Colin

Don't let this dismay you.

I think the VDO is calibrated for an ambient temp of 70 degrees. So, when it is 90 outside, you just add 20 degrees to what the VDO is telling you. Conversely, if it is 50 degrees outside, subtract 20 degrees from the VDO reading. You get to be your own 'cold junction compensator.'

I used to have a little stick-on thermometer attached to the driver door mirror. It helped me make the necessary correction to the VDO reading.

Or you could just make it a policy to drive only when it is 70 degrees outside; the VDO gauge will then be spot on

Tim

[Amskeptic]

A VDO CHT gauge is quite useful. You will learn what is normal for your bus and the VDO will tell you when your engine is running too hot compared to "normal". Don't worry.

Thank you. I have been using one for a while (2 yrs) - but only slightly before original engine quit (worn cam and cat disintegrated) and since had things all rebuilt nicely with mostly NOS.

I know what was normal before, and was what I see now (more / less the same) ... but I am not convinced normal was "good" ...

All in all, I've been doing alot of changes and tuning this year and want to make sure I am not going to far (or too short) ... and previous "normal" is not a fair comparison ... so am hoping for a scale so I can compare my findings more closely to those posted here

I have a love / hate relationship with the gauge

I don't like VDO. Reads low when it is hot outside, and reads high when it is cold outside. Plus the markings seem to require too much interpretation to get the real number.
Colin

Don't let this dismay you.

I think the VDO is calibrated for an ambient temp of 70 degrees. So, when it is 90 outside, you just add 20 degrees to what the VDO is telling you. Conversely, if it is 50 degrees outside, subtract 20 degrees from the VDO reading. You get to be your own 'cold junction compensator.'

I used to have a little stick-on thermometer attached to the driver door mirror. It helped me make the necessary correction to the VDO reading.

Or you could just make it a policy to drive only when it is 70 degrees outside; the VDO gauge will then be spot on

Tim

Why, it is 70* outside, better hit the road.
ColinInMA
(Chloe, so far, the top CHT has been 382* Mass Pike hill climb from I-84 @ 74*)