MAP

[Mark Pitts]

I was thinking of using one of the Motorola pressure sensors.. but they =
dont like reverse pressure, and I'm shure at some point in development =
I'm going to end up with fire out of the inlet trumpets (always have =
done in the past with carbs!) so the reverse pressure pulse will kill =
it. The Honneywell things are mini MAFs, and so will read either way. =
The comment I've also received indicates..'yes but you end up with a =
leak' I'm only talking about a pin hole in the manifold (and you need a =
little bypass to keep the ticking over anyway.. and that is going to be =
a lot of air compared to this!)=20

What I'm trying to say is.. the sensors measure in the range of 1 cubic =
centimeter per second, or more depending on sensor , and I dont think =
that these type values are going to be a problem.

The MPX sensors wouldn't enjoy boost too much either.

As for calibration.. yet another lookup table.. or just offset =
everything in the tables to account for non linearity.

I guess pressure in a plenum chamber is fairly constant.. and there must =
be places where air is NOT rushing past the surface (i.e. where my 'pin =
hole' is) to make a suitable sight for a sensor. (far corner from the =
throttle body?)

I started a thread on.. lets turn a peice of 6" drain pipe into a MAF, =
with a bridge and some nichrome, I'm still going to try it, but at the =
moment I'm interested in converting a normal 'carbs and distributor' =
system to mapped timing, no MAF.

Sorry if the above mail doesnt read too coherently, but this idea is =
chasing several paths round my brain at the same time.

Mark

A copy of that tread would be most welcome! Win95 ate my mails last =
week!

----------
If you'll look only a week or so back, you'll find a thread (I think
started by me-self) that resulted in several suggestions.  If you
can't find it, I'll look (I printed it and put it 'somewhere' for
future reference).  The sensor is off-the-shelf, is available from
Newark for about $25.

Tom

Tom Cloud <cloud at peaches.ph.utexas>