Looking for advise on oil pressure sensors for an aim system. I have heard that some fail more than others. Whats good whats bad what can be repaired ?
Thanks
oil pressure sensor
Looking for advise on oil pressure sensors for an aim system. I have heard that some fail more than others. Whats good whats bad what can be repaired ?
Thanks
This sensor is made by VDO, it's a resistive type sensor. Most of us have found it to be fragile enough to mount it remotely from the engine and soft mount it on a frame rail. Failed within one season.
https://shop.veracitydata.com/collec...psi-10-bar-vdo
This sensor will work on the block or remote. Mine has not failed after more than 7 seasons.
https://shop.veracitydata.com/collec...-15psi-1-8-npt
YMMV.
David and Ellen @ Veracity are awesome for their service and advice.
“Racing makes heroin addiction look like a vague wish for something salty.” -Peter Egan
+1 for the VDO sensor, but yeah, hang it on a frame rail for durability.
The second one appears to be fuel pressure - unless you can use it for low oil pressure? :-)Originally Posted by DanW
I've only begun my dealings, but I second this!
That's exactly what I found when I inspected my RF98 Honda for the first time, but mine was the version for Pi Systems:
https://shop.veracitydata.com/collec...psi-10-bar-vdo
It's hanging on a frame rail.
I think this is the one that was intended:
https://shop.veracitydata.com/collec...pt-sealed-gage
I use the more expensive solid state ones from aim. Then for extra measure I feed them with a short AN braided line and mount them with rubber isolators.
Oops, my mistake! should have been the 0-150 version. The solid state one is much better in my experience.
https://shop.veracitydata.com/produc...pt-sealed-gage
“Racing makes heroin addiction look like a vague wish for something salty.” -Peter Egan
The AiM made sensor is much better than the VDO sensors. It's been my experience that the VDO sensors will either leak or stop working with any decent vibration in a car. I only recommend the AiM made sensors. Last summer I saw them being made, the testing and calibration they go through, and I know how few defects they have had with them. The previous version of KA sensor that AiM sold was still good, but had more trouble than the ones AiM makes. Both are miles better than the VDO.
Pressure is pressure it doesn't matter whether its fluid or gas. What does matter is if the range is what is expected. All the VDO sensors I've ever used never failed, but I don't mount them directly on motors, they're in a tee fitting that is tied to the chassis. I don't know how the aim systems work, but my CDS systems (yes, CDS) are able to calibrate any analog sensor, so I tap into the OE sensor 5V output line and calibrate. The kawi manual gives expected voltage tables based on conditions, so no experimenting is necessary. Water temp sensors can be measured with known thermometers and tables recorded for calibration purposes.
oh, and yes Dave and Ellen at Veracity are top notch
Anyone ever try Autometer? I had good luck with those on my old drag cars. Went to a sender unit when the direct mechanical adapter kept fracturing the feed line from the block.
Most of my temp and pressure sensors are the VDO style; the one exception is fuel pressure, since the VDO sensors are not rated for fuel to my knowledge. That is a solid state style, like the other oil pressure sensor linked; I have to admit, I like that style a little better, though the VDO has been indestructibly robust.
My other racecar uses an identical VDO sensor; that's actually the original factory oil pressure sender, and is in fact 40+ years old, with over 20 years of racing on it. So that's robust enough for me. While that may be only an ITB 924 - the 924 motor, without the balance shafts of the 944 design, is known to have even worse NVH characteristics than an outboard motor. The oil pressure sensor is screwed directly into the back of the head. So if it can survive that...
Additional note on the thermistors (which I use for temps). The one-wire nature of those sensors, though they are cheap and plentiful, tends not to lend itself to installation in a fluid line, which leads to additional work to ground that chunk of metal. Plus then if you use an inline AN gauge adapter, I've had to space that sensor out with an extension - if screwed directly into the fitting it can actually block like 75% of the flow!
But more critically perhaps, regarding sensor calibration, it may be worth auditing what sort of curve fit your data system uses. If the data system has the exact sensor already selectable (like the AIM setups linked), then good, odds are you can have a good match. But if you're manually entering data points, as I do too, look at the equation the system decides to use and make sure it has enough accuracy for you, in the range you care about. In my Race Technologies system - which I love, don't get me wrong - if I punch in data point it tries to do a polynomial curve fit, and the accuracy isn't all that hot.
That's because the thermal response of the sensor is actually exponential. Not so easy to match an exponential curve with a polynomial. Yes, it can be done, but at least the RT SW doesn't seem to be so awesome at it.
I've found better results for accuracy mapping all the measurements or calculations in Excel, then manually generating a curve fit there. Note that specs for some of the more common VDO thermistors can actually be found online, with resistance vs. temp lookup tables.
Mine was on this list, odds are yours will be too:
https://www.google.com/url?sa=t&rct=...95Hr3OZSLGdWc2
(hope that link works; otherwise Google for VDO TU00-0770-5104620 which is the spec sheet from VDO)
Hope that is of use to some... if you're really hankering for precision temp measurement. Though when you look at the curves, you suddenly realize that the difference between 245F and 260F oil temp is a very small number of millivolts! Then just how accurate are your measurements and devices...
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