[Diy_efi] Speed-density vs. MAF/MAP...

[Perry Harrington]

On Wed, Jan 29, 2003 at 11:43:00PM -0000, Bill SHURVINTON wrote:
> Um Perry VE>100% by definition says that you have inertial supercharging so
> MAP >atmo. So you can still sense it if you are timed sampling.

But where in the intake tract would you find MAP > atmosphere?  I also assumed
we were talking about standard NA MAP sensors too.

Oh, another point (non-linear thought process), if you have > atmospheric
pressure through a MAF, reversion becomes a non-issue, because the intertia
of the air prevents reversion. This is my understanding, further discussion
would be enlightening if you think otherwise.

> 
> As for MAF on motorbikes I have yet to see a workable MAF solution that
> works with IR systems and teeny throttled volumes without screwing up the
> throttle response. Not to say it can't be done, but seems pointless. No, is
> pointless :-)

I understand "if it ain't broke don't fix it".  But how would that be fun
or challenging?

Seems to me that "MAF lag" is really the inertia of the measured volume.
This goes back to Jeff Clarke's DIY-EFI discussion on MAP lag vs TPS.
MAP just has less lag than MAF due to where it's measured.  If you made
4 tiny MAF sensors into each of the TBs, I'm sure you'd have a very low lag,
but then you have a bunch of other problems.

In the end, the food chain still exists as Alpha-N, MAP, MAF in terms of
accuracy.

I see the logic in MAF systems and have been working with one for a couple
of years.

> Bill

--Perry

-- 
Perry Harrington			Data Acquisition & Instrumentation, Inc	
perry at dainst dot com					 http://www.dainst.com/

Those who would give up essential liberty to purchase a little temporary safety
deserve neither liberty or safety. Nor, are they likely to end up with either.
                             -- Benjamin Franklin

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