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I am looking for recommendations for a 0-5V pressure transducer for monitoring the exhaust backpressure/turbine inlet pressure of my 1986 Porsche 944 Turbo. I currently have a Snap-On fuel pressure gauge connected to the factory oxygen sensor bung in the exhaust crossover pipe (pre-turbine), but I would prefer to datalog this information for later review using my VEMS engine management system.
A quick internet search revealed a number of pressure transducers that thread into an O2 sensor bung, but most are only rated to 200 degrees C. Are there any high-temperature sensors that would stand up to EGTs in the 800+ degree C range? The 944 Turbo has another port in the exhaust crossover pipe for a CO test pipe, but on my car this is occupied by an EGT sensor probe.
This need not be a permanent installation, just something that would stand up to high EGTs for testing purposes.
If you do find one, please post about it.
In the meantime, would it be possible to fabricate a tube* - steel brake tubing (AKA Bundy), for example - with ends for the transducer/sender and pipe fitment, that would remove the sender from the higher heat around the pipe? You would be giving up some response, especially for transients, but failing a proper solution?
*Like these - https://www.google.com/imgres?imgurl=http%3A%2F%2Fwww.dieselmanor.com%2Fdm_products%2Fimages%2FEGT-25125-lg500.jpg&imgrefurl=http%3A%2F%2Fwww.dieselmanor.com%2Fdm_products%2FDM-EGT25125.htm&docid=0idd_Pzjqp3YpM&tbnid=BfDaNITCCspQzM%3A&vet=10ahUKEwju8_eVopjdAhXbdN4KHcRlA18QMwiYAShRMFE..i&w=500&h=426&client=firefox-b-ab&bih=1019&biw=1908&q=high%20temperature%20exhaust%20pressure%20transducers%3F&ved=0ahUKEwju8_eVopjdAhXbdN4KHcRlA18QMwiYAShRMFE&iact=mrc&uact=8
 - These are the highest temp' ones I can find, though still short of what you are looking for @1200f continuous and not sure about accuracy at such low pressures, though, so it would pay to carefully read their spec' sheets or perhaps contact their support people? - http://www.pcb.com/testmeasurement/Pressure/Extreme-Environment-112A-116B-Series
You shouldn't need a pressure sensor rated anywhere near that high, even OEM diesel DPF pressure sensors just use a fairly long metal pipe, then a section of flexible hose. Remember there's no flow going through the sensor, so the temperature won't be anywhere near EGT. But that's just my $0.02.
Thanks for the responses, guys. The more I think about it, the more I realize that there is no need for the sensor to be mounted directly in the exhaust stream. The factory 944 Turbo uses a long metal pipe that sticks up into the engine compartment and is used for emissions testing (it is capped off by rubber and a hose clamp). This tube was broken on my car, so removed it and drilled and tapped the ID of the port in the exhaust pipe and installed an EGT sensor there.
I think I'll try something like the copper tube on the diesel site that Gordo linked to, and attach it to the factory O2 sensor bung, which is in the same crossover pipe (pre-turbine).
I'll do some more research about a suitable pressure transducer and post my finds here.
T1 have also added a dampener on their EMAP installations, it give a more concise pressure reading and less shock to the sensor
Honeywell has a series of sensors that go for 40-50 USD that I recommend for EMAP/TIP usage
how do those sensors fair for engine oil pressure?
Remote mounted as recommended, seems like a very cheap way of measuring oil pressure.
I really appreciate the info and ideas.
The T1 Performance site that Chris250 offers an overwhelming array of goodies for high-performance cars, and I found the damper that Chris mentioned. The product description basically sums up everything we have discussed thus far:
I can see these same pressure fluctuations (caused by the cycling of the the exhaust valves, wastegate, etc) on the analog Snap-On fuel pressure gauge needle at higher RPM; in the meantime I might try one of those liquid-filled gauges for fun to see if it dampens the needle oscillations somewhat . . . .
I'm sure that is the same pressure sensor that AEM use in their oil/fuel pressure gauge that I use near daily going car to car, very robust and concise. If it's not the same its pretty close