donp@audiworld.com

I've been searching for solutions for a boost gauge for the S4. As you know there's very little space to mount a normal gauge without lots of work and hacking up the interior.

I stumbled across this document from Motorola that uses their MPX5100 series pressure sensor. Seems to me this would be a slick alternative to a round dial and if the LED bar was a loose instead of mounted on the board you could position the display nearly anywhere and just run the wiring to drive the LED bar. As shown it only does up to 15 psi but alternate versions of the sensor do up to 17 psi which would probably just enough although I have no idea what modifications would be required to the circuit. I assume this assembly cannot be purchased but is intended as a "see what you could do" kind of thing.

Anybody have some insite on this?<p>donp - '00 S4 Silver/Silver
audizone.com<ul><li><a href="http://mot-sps.com/cgi-bin/get.pl?/books/apnotes/pdf/an1304*.pdf">Motorola pressure gauge</a></li></ul>

Sander

Those sensors are pretty nice. A little difficult to get your hands on a single one maybe but it can be done I'm sure. Some time ago I built an ogygen sensor gauage that uses one of those chips that drives a 10 LED bar depending on input voltage. LM319 I think but that number could be way off. Anyway, it's pretty simple. 1 chip, some resistors and an LED bar would do it to make a boost gauge. If you wanted it to be numeric there are also chips out there that drive LED segments depending on voltage. With some trickery a true boost gauge could be constructed. Of course it would be cheaper to buy an electronic boost gauge and modify it to your own (space restrictive) needs.

Sander

rao

Check out http://www.splitsec.com They have an electronic boost gauge that operates off of a separate MAP sensor and can read either from 0-15 or 0-30 psi (depending on which MAP snesor you use). I have one siting on my workbench, along with one of their a/f ratio gauges (from my last car). It is much easire because you keep the MAP sensor in the engine compartment and you only have to run wires into the cabin, not vacuum hose.

rao

<ul><li><a href="http://www.splitsec.com">http://www.splitsec.com</a</li></ul>

Flyboy

of dash by A pillar. I searched through the archives but couldn't locate it. Anyone else see it?<p>2001 S4
(scheduled arrival Sep)
6 spd
Santorin Blue
Silver Alcantara

donp@audiworld.com

<p>donp - '00 S4 Silver/Silver
audizone.com

rao

Building one is way beyond my skills. The gauge is $140 the MAP sensor is $50-60 and is a standard part that you can get at most auto parts stores. The gauge is pretty neat, it dimms when the lights are on and has multi colored lights to make it easier to read. I don't plan on using it on my S4. If I could have built one for less that was a nice, I would have.

donp@audiworld.com

<p>donp - '00 S4 Silver/Silver
audizone.com

Tim's S4

This sounds like a pretty slick setup. I too would like an accurate boost gauge for my S4. I liked having a boost gauge in my 300ZX twin turbo. If we could design the pressure transducer onto one circuit card and the LED bar graph display on a second card, this would allow maximum mounting flexibilty. Both cards could be mounted inside the car for protection from the elements. You would only have to run the pressure line thru the firewall to the intake manifold.

Do you any contacts at semiconductor distributors where you could get pricing on the Motorola transducer IC? Also, do you have any ability or contacts to layout and fabricate the PC boards? I would be interested in purchasing one. I can check where I work on getting the PWBs designed and fabricated. Note, that I work at a large electronics firm, but they frown on us doing home projects at work. Perhaps we could have several built if there is enough interest for the other S4 owners.

Tim

donp@audiworld.com

Allied Electronics has the parts. They are the only one I could think of off the top of my head.

2.09 Bar graph display driver
0.55 voltage regulator
16.83 pressure sensor
1.75 led bar

Those are the "big cost" items. The other 8 parts are just resistors, caps and 2 trim pots. The board and other misc parts and I'm probably talking $35 in parts.<p>donp - '00 S4 Silver/Silver
audizone.com