MAF vs MAP

[xxalexx at ix.netcom.com]

> Priority:      Normal
> To:            diy_efi at efi332.eng.ohio-state.edu
> From:          "bruce plecan" <nacelp at bright.net>
> Subject:       Re: MAF vs MAP
> Date:          Mon, 23 Feb 98 13:43:45 PST
> Reply-to:      diy_efi at efi332.eng.ohio-state.edu

> ref KV:
> GM (OEM) specific
>   IMHO it's as much about application as anything.  Both use 
> feedback from the O2 sensor for the final trimming of injector timing,
> so at less than WOT, there is about 0 difference.  Now at WOT,
> and for off-highway use racing the MAP is the winner since there
> is no MAF restriction.  As I understand things now, on the newest
> GMs some use both a MAF, and MAP.  Does anyone know if they
> do this for averaging, or backup, or what conditions they use each
> for??..
I would say atmospheric correction, most flow meters are calibrated
at STP(std temp press 29.92"Hg  68F) you need intake air and 
atmospheric pressure to get actual corrected flow.
alex