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D/\rK•650

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Thank you for posting this and all the information you've provided. It crazy because I was wondering this just the other day. Im driving and thinking how accurate is this oil temp reading? Great job ❗
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MAT1955

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We had to calibrate every oil temperature sensor we purchased. For our marine racing engines that was usually autometer or gaffrig. A variance of 5 degrees from actual was common - either way 9BTW just like engine hp from mass produced engines varies 5%) anyway, even once calibrated temperature gauges relying on sensors, wiring and gauges were and I suspect still are prone to loosing their reliability. I'd be willing to bet a lot that an inferred computed modelled temperature was more accurate.
 
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krisk > how difficult was this to install the oil temp gauge and run the line ect?
If I had done the job start to finish at one time knowing exactly how it was going to end up, I probably would have spent 6 hours. That said, I don’t get in a hurry when I’m doing these kind of jobs. In other words, I’m slow. Someone who works fast could probably get it done in half the time. I have bus bars installed above my fuse box for adding electrical components, and I was doing some other wiring at the same time. The vent gauge requires removing the display on the dash, which isn’t nearly as bad as trying to put it back in. Getting the screws back in without dropping them down the dash takes some work.

The thing I would caution someone wanting to do this on a street driven car is make sure you use an appropriate oil filter. I did a fair amount of research on oil filters trying to see what the options were, and there are few that have the bypass valve pressure setting of the FL-500S, which as best as I can tell is 22psi. It’s tough because a lot of the time specs are not published and you find conflicting information online, much of which is conjecture. I’m running the Moroso race filter which is a high flow, low restriction 27 micron filter. I have no problem with this because I am changing the oil and filter every 6-10 hours. I would not run this filter on a daily driver going 5k miles or more between oil changes. Going to a shorter filter means giving up filtering surface area, so I would be careful just slapping on any filter that “fits”.
 
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krisk

krisk

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We had to calibrate every oil temperature sensor we purchased. For our marine racing engines that was usually autometer or gaffrig. A variance of 5 degrees from actual was common - either way 9BTW just like engine hp from mass produced engines varies 5%) anyway, even once calibrated temperature gauges relying on sensors, wiring and gauges were and I suspect still are prone to loosing their reliability. I'd be willing to bet a lot that an inferred computed modelled temperature was more accurate.
I’m using the AEM X-Series temperature gauge. I have no idea the accuracy of the gauge, but there was no reference to being able to calibrate it so I’m not sure that is even an option. I expect it is within a few percentage points of actual.

Correct me if I’m wrong, but wouldn’t calibration just adjust the readout up or down by X%? In comparing the gauge reading to the car inferred value, there was no linear correlation to the temperatures. So while the AEM gauge may not be 100% accurate, even once calibrated, the rate of change is going to be exactly the same plus or minus the calibration percentage change. The relation of the temperature dropping more rapidly on the gauge versus inferred when cruising and being 10 degrees lower after being higher when at 4400 RPM would not change with a calibration. Am I thinking about this correctly?
 

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Thank You for the research and the detailed write-up.

In other threads, several commented the inferred CHT (in-dash display) is higher than actual. Also by a touch.
 

MAT1955

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@krisk IMO you have expressed your point very well and are essentially on the money. What complicated matters, for us, was even respected - I'll refer to them as analogue gauges - in our opinion were erratic. That is even after calibrating them with a reliable gauge they did not seem to give consistent readings. We had all kinds of opinions as to why there was a lock of consistency. If they had given consistently low or high readings we could have allowed for that, however the erratic nature concerned us. Looking back at this makes me wonder if Ford has found this from their former racing days and has curated enough data to trust inferred data better. Whatever measurement I use I would be satisfied if I knew it was off a bit as long as it was consistently off in the same manner I could account for that and act accordingly.
 
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krisk

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@krisk IMO you have expressed your point very well and are essentially on the money. What complicated matters, for us, was even respected - I'll refer to them as analogue gauges - in our opinion were erratic. That is even after calibrating them with a reliable gauge they did not seem to give consistent readings. We had all kinds of opinions as to why there was a lock of consistency. If they had given consistently low or high readings we could have allowed for that, however the erratic nature concerned us. Looking back at this makes me wonder if Ford has found this from their former racing days and has curated enough data to trust inferred data better. Whatever measurement I use I would be satisfied if I knew it was off a bit as long as it was consistently off in the same manner I could account for that and act accordingly.
Agreed. For the "average Joe" car/boat operator it's not going to make a difference if the oil or other temps are off by say 3%. 216 degrees versus 210 degrees doesn't matter. When you get into the arena of pushing the limits of a motor and you are at peak thresholds, that 3% becomes much more important. I suspect for a full on professional or high level amateur race team having a calibrated reading would be worth the time, cost and effort, but for someone who is just playing around with a car for track days, like me, having it close is adequate. What I have found with most all gauges and readings is I learn what is normal for my machine, and those gauges become more of a warning when the numbers are outside of what I expect. That is the indicator we may have a problem and need to investigate.
 

ZXMustang

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Gee you would think Ford might have actually did some research and development on this? Crazy how that all works...
 

ZXMustang

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Also I updated a NON GTPP car to PP inferred oil temps when my guy added the FRPP oil cooler to his GT. The car no longer would go into temp limp mode on track vs before the oil cooler/higher inferred temps. Hes like you and only tracks the car.
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