[Diy_efi] alpha-n

[bill SHURVINTON]

OR people who are too lazy to set up SD properly and so go alpha-n

The problems with highly modified setups with IR TB setups is that the MAP
signal tends to bounce around at idle. This can be cured by a number of
techniques. The other is that you can effectively reach a WOT situation at
less than full throttle (from a MAP perspective), but it is still handy to
be able to modulate power with AFR ( up to the limits of your engine YMMV).

Then you get turbos which are alpha-N plus boost (Ferrari).

It's all about picking the trade-offs that work for you.

Bill
----- Original Message -----
From: "Joe Lutz" <joeelutz at hotmail.com>
To: <diy_efi at diy-efi.org>
Sent: Tuesday, July 01, 2003 5:38 PM
Subject: Re: [Diy_efi] alpha-n


> alpha is throttle position.  n is engine speed.  Alpha-n means the engine
is
> mapped based on engine speed and throttle position instead of load
<manifold
> pressure> and engine speed like the speed density system.  The map sensor
is
> left open to atmosphere instead of being referenced to the manifold so
that
> it only is used to measure barometric pressure.  Generally the air temp
> sensor is placed to measure ambient as well because the readings from the
> map and air temp sensor are used by the ecm to do an ideal gas calculation
> to find the density of the air so the readings need to be taken from the
> same reference.  This is usually used on motorcycles and engines with low
or
> very transient manifold pressures.
>
> Joe
>
>
> >From: "William Frye" <nova at justice.com>
> >Reply-To: List for general do-it-yourself EFI talk <diy_efi at diy-efi.org>
> >To: diy_efi at diy-efi.org
> >Subject: [Diy_efi] alpha-n
> >Date: Tue, 01 Jul 2003 09:13:54 -0700 (PDT)
> >
> >I have never heard of the alpha-n system. Could someone
> >describe how they work and how the relate to speed
> >density systems?
> >
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