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Measuring IAT & Pre Turbine Pressure

Off Topic Discussion

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Hey all, Im building up one of my own cars for the drags and I want to keep tabs on pretty much everything as ill be doing alot of R&D and changing components and I want some solid data on whats doing what.

Id like to have Intake temp sensors pre turbo, Turbo-IC, IC to Throttle body. Would it be better to use multiple of the normal open element Intake Air temp sensors like you would in a normal install, Or is there benefits to using K-type thermocouples? (are they fast enough to react?) Or what would you suggest..

Would also like to have pressure sensors to test for any restrictions along the way, so at the same locations as above... Is multiple map sensors the way to go?

Actually I just had a thought, Is there any sensors that have a Temp and pressure sensor built into one?

Then onto the exhaust side of things, ill be having 1 open tip EGT per cylinder as well as one post turbo, But would also like Pre and Post turbo pressure readings, whats the usual way to do that... main problem being the extra heat....


So, try to answer some your question, sorry if i say somethig stupid...!

For the back pressure in the exhaust manifold, I see some guy use a copper tube from the manifold to the sensor, 1 mt long, for don't have a problem with a hot gas. Normally use 10 bar sensor. This is what I see...

For the Temp from filter to TB...normally the sensor is an open probe, 'cause you don't have a hot gas or something that can broke the probe. You can find K type sensor that have a open probe, that can be fast than the AIT.

Hi Viper,

Bosch makes a TMAP sensor that combines IAT and MAP into a single unit, we have tested these where I work (one of the companies that has a working relationship with Andre and HPA) and have found that they have the same responses as the individual sensors.

With the EMAP measurement, I use a length of thin copper tube that was re purposed from a mechanical oil pressure guage tapped into the exhaust manifold prior to the turbo, I then use a Honeywell 100psi sensor to read the value. I used the Honeywell sensor as they have a stainless steel construction, which should be more heat resistant than the other MAP type sensors that have flexible internal membranes.

This Bosch sensor is very interesting...

Thanks Black Rex and Fabry, Exactly what I was after.

That TMAP will certainly make things neater/simpler

I've just completed the turbine inlet pressure sensor install on our 86. This uses a 1/8" BSP threaded boss in the manifold collector. The AEM 4 Channel UEGO kit comes with everything you need including a 600 mm (approx) piece of stainless hard pipe and then a shorter section of teflon braid. I couldn't use it in the 86 because the install was too tight. I grabbed some 3/16" copper tube which is nice and easy to bend. I used an adaptor at each end and then connected the copper directly to the pressure sensor (which is a 100 psi sensor). The length was about 600mm which is enough to remove heat. If you want to you could always add a few loops to the copper to further reduce heat.

If you are measuring the compressor outlet temp then a standard NTC sensor probably won't read high enough. Most of these will only read accurately to around 125 degrees C and you can easily exceed this (dependent on boost and compressor efficiency). A K type thermocouple is the solution, or alternatively I managed to get a couple of high speed NTC-style IAT sensors off Shane T when I was at PRI. These measure up to 300 deg C and are super fast response. Supply seems to be a problem though as I waited for these for about 6 months.

As Andre said, most standard NTC style temp sensors will not read over 170 degrees, the image that I have attached is a standard Bosch 2500ohm IAT sensor that is mounted post turbo (about 450mm downstream of the turbo outlet) in my car, it is the light blue trace labelled Airbox Temp. As can be seen, the sensor gets up approx. 175 degrees and then reaches the Diagnostic High value set in the M1, and goes into default (the default value is set at 40degrees) until the load comes off the engine and the post turbo temps drop. This is an engine running a 36mm inlet restrictor that was being run past the optimum efficient flow rate for the restrictor, hence the rapid rise the in the turbo outlet temperature.

The temps in the dyno cell where around 38 degrees that day as well.

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