555 EFI circuit/555 EFI again...

[TBK]

There are two versions MAP and VAC:

MAP are available in 1 BAR, 2 BAR, and 3 BAR versions. Sea level is
essentially 1 BAR. The output goes from vacuum (low voltage) to high
pressure (high voltage). On the 1 BAR version, sea level atmospheric
pressure is full scale (high voltage) and vacuum pulls the output voltage
low.

On a 2 BAR, mid scale (2.5V) is atmospheric pressure and 0V is full vacuum
and 5V is 14.7 PSI pressure.

On the 3 BAR, I believe (since I've never played with one), atmospheric
pressure is 1/3 scale, with full vacuum at 0V and 3 BAR (29.4 PSI) at full
scale.

There is also a VAC used on older carburater engines. These are MAP with
output reversed. My old carb'd X-11 used a VAC.

On a MAP pressure increases the output.

On a VAC Vacuum increases the output.

TK
-----Original Message-----
From: Ron Tyler <dcmckenna at worldnet.att.net>
To: DIY_EFI <diy_efi at efi332.eng.ohio-state.edu>
Date: Saturday, July 04, 1998 12:33 PM
Subject: Re: 555 EFI circuit/555 EFI again...


>What is the output range of the MAP (0-5v)?. Does the output increase or
>decrease for an increase in pressure?
>
> Walter,
>
>        A GM MAP increases v with increasing pressure up to 5v
>
>--
>Ron & Stephanie Tyler
>'72 LT1/T56 240Z
>http://www.whit.org/jcaudle/LT1-3.jpg
>