View Single Post
cole930 cole930 is offline
Registered User
Join Date: Mar 2000
Location: Auburn,In. U.S.A.
Posts: 2,449

You could put a nipple fitting and attach a hose in the intake. I'm going to try
teeing into the vacuum line between the WUR and the intake or intercooler. The
intake would give you the most accurate boost reading. It's possible we may be
able, with the right gauge, to get it to read negative numbers under vacuum and
transition to positive numbers as boost builds. I'm looking into that now.

Here is what I was talking about (Off the Innovate Forum)

The GM sensors work very well with the LM-1 because they are cheap and linear. To calibrate you need 2 calibration points. A vacuum gauge would be perfect. You could do the vacuum calib at a place that services AC systems. They have good vacuum gauges.
Hook up the MAP sensor to your manifold. Put a T- connection (temporarily) in there for the vacuum gauge. Let the engine idle (warmed up). That creates your vaccum. Enter the PSI number (in absolute PSI) in the input configuration. Right click on the voltage field in the input config. That allows you to paste-in the current input voltage from the MAP sensor corresponding to the vacuum PSI.
Then switch the engine off. MAP is now atmospheric pressure at 14.7 PSI. Enter 14.7 in the second (PSI) input field and paste in the current voltage as before in the second voltage field.

This configures the input in absolute PSI. I prefer absolute because the engine does not care about outside pressure, only absolute MAP.
If you want vaccuum/boost display instead, subtract 14.7 from the vacuum PSI and enter that number there. Then enter 0 PSI in the second field. Vacuum is then displayed as negative number and boost as positive.


Last edited by cole930; 12-31-2008 at 12:26 PM..
Old 12-31-2008, 12:02 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #11 (permalink)