The Autonerdz Community Forums - pressure transducers

Brad H Super Nerd Offline Elevation 367 metres Posts: 1,115 Kalgoorlie Western Australia Australia Gender:	pressure transducers Jul 28^th, 2009 at 6:22am what is the recommended pressure transducer to connect to the pico for cylinder pressures?
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Re: pressure transducers
Reply #1 - Jul 28^th, 2009 at 7:48am

Brad,

At this time the Fluke PV350. It has its issues but has been proven in the field. Most notably problems with noise.

We are now evaluating a dual transducer unit as seen in the movie The Wrangler From Hell.

We just got our production units here yesterday. There have been some hardware changes since we looked at the prototype so we have to go through the testing process again to be sure these meet Autonerdz performance standards.

This kit comes with two pressure transducers and a vacuum one. You can use two of them at the same time. This opens up a whole new list of possibilities with transducer diagnostics. The unit also has independent filtering.

We will not put these units on the website or offer them for sale until they have earned the Autonerdz seal of approval.

We have run into a hitch in our initial testing. Not sure how this will be resolved or how soon, but we are working with the manufacturer toward a hopefully quick solution.

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James Senior Member Picogroup Offline Posts: 115 Savannah, GA Georgia USA	Re: pressure transducers Reply #2 - Jul 30^th, 2009 at 4:59am Tom, are these "PICO" brand units or someone else?
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Re: pressure transducers
Reply #3 - Jul 30^th, 2009 at 8:10am

James,

These are not the Pico units. The Pico unit is a single transducer. This one is a dual unit.

I have yet to see a production Pico transducer. We have a prototype here that we have played with and it also shows promise. Same thing applies to that one. We will not offer it until it has earned the Autonerdz seal of approval.

You can find both of these offered by some vendors already, but you won't find them on our site until we feel they are ready for prime time. Wink

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Re: pressure transducers
Reply #4 - Aug 24^th, 2009 at 1:18pm

The Saga Continues....

In our DCTI pressure transducer evaluation and testing saga, we are learning way more about pressure transducers than we ever wanted to know Shocked

We have hit a snag regarding an odd behavior of certain types of transducers we had never really explored. We are not sure yet, but it seems the type of transducer design as well as the materials impact this behavior. Many we have looked at, as candidates for this new package, have tested perfectly on the bench but under dynamic conditions, found during a running compression tests, the negative pressures skew. They show negative pressures that are impossible.

Many of this type are in use today and marketed by Snap-On, ATS and others. These sensors are just not suitable and do not meet our standards for accuracy. As you know, our group is a discerning bunch. But, we are not being too picky here, these are all wildly inaccurate. Some have software compensations that are designed to cover up the problem but they do not solve it.

We do think we are heading in the right direction with this and will soon be looking at an entirely different design transducer that I hope will not exhibit these issues. Once we do, we will have something quite unique and superior. We want to actually solve the problem, not cover it up.

The goal here is to get a transducer setup that is versatile, accurate, and produces a clean detailed pattern. More on this, as it develops.

We will eventually produce a presentation detailing the issues and comparing behavior of different units. Hopefully along with one that is the way it should be....

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Jim_Wilson Super Nerd Picogroup Offline nothing to say Posts: 929	Re: pressure transducers Reply #5 - Aug 25^th, 2009 at 9:09am Quote: This opens up a whole new list of possibilities with transducer diagnostics. I have to ask... can you elaborate on that teaser? I just don't have the imagination the rest of you have
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Re: pressure transducers
Reply #6 - Aug 25^th, 2009 at 10:10am

Jim,

I should have said world of possibilities instead of list because I can never anticipate the creative imagination of this group either. I am continually amazed at what they come up with.

Having a unit able to use two transducers simultaneously is new. There are some examples of how this can be useful in the Wrangler From Hell movie. Looking at two cylinders running compression simultaneously takes a lot of variables out of the picture. I also think that observing intake and compression pressures together will be useful. I'm sure the 'list' will expand once we get this in the hands of the experts. Wink

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Re: pressure transducers
Reply #7 - Sep 4^th, 2009 at 9:04pm

Tom,

I've heard the manufacture of this startling new dual transducer device is pretty bright, working hard with multiple engineers on a custom transducer assembly. I've also heard that he too strives for perfection and quality. This might be also why he wanted your organization to "bless" it and be involved in it's final phases of development. Wink

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Dan Spatig Freshman Member Offline Posts: 28 Broadstairs,Kent,UK United Kingdom Gender:	Re: pressure transducers Reply #8 - Sep 22^nd, 2009 at 3:32pm Hi Tom, I have just looked at the Fluke transducer, are adapter plugs needed to connect it? From what I can tell it would be 4mm to 4mm banana plugs if used with the normal leads. Was this also the transducer used on the fuel rail in the Wrangler video? Thanks Dan
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Re: pressure transducers
Reply #9 - Sep 22^nd, 2009 at 3:52pm

Hi Dan,

To attach the Fluke PV350 to the Pico, we suggest using the Pico MI078 BNC to 4mm adapter. This eliminates any lead between the PV350 box and the scope, which can be a major source of interference. We include one of these in each Autonerdz kit along with all the other added goodies..

We used a prototype Pico transducer on the Wrangler From Hell fuel rail. This prototype was not accurate. However, we have since got our hands on a production unit, which works much better. Still not available for distribution yet.

The PV350 is not suitable for fuel rail testing in this manner. In our opinion, too noisy and poor resolution on the injector pulses.

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Dan Spatig Freshman Member Offline Posts: 28 Broadstairs,Kent,UK United Kingdom Gender:	Re: pressure transducers Reply #10 - Sep 22^nd, 2009 at 3:55pm Thank you for the quick response Tom.
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