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[robert dingli]

> 
> From: Jeffrey.Giberstein at Dartmouth.EDU (Jeffrey Giberstein)
> Subject: MAF
> To: diy_efi
> 
> I've  got tons and tons of questions so I hope nobody minds.  Thanks for all
> the help so far.
> 
> I'm wondering why the general practice is to place MAF sensors upstream of the
> throttle body.  I assume that this is to prevent it from being overly sensitive
> to backpressure and reversion pulses and other such mysterious business but it
> also seems like this would sacrifice a good deal of responsiveness.  Supposing
> I wanted to place my MAF sensor a ways downstream of my throttle body but at a
> point in my manifold where it still had some capacitance below it.  Do you
> think that its output would be so erratic that it would be useless?  Any
> suggestions on an algorithm that would help?
> 
> Thankkkkks,
> 

Jeff, to maximise the responiveness of the complete system, you would be better
off placing the throttle bodies as close to the inlet ports as possible.  If
possible, a separate butterfly for each runner would be best. The dynamics of 
the inlet system are significantly faster than the reponse time of the MAF 
sensor during quick throttle changes and thus there would be little gain in 
placing it further downstream.  Ideally, the plenumn would have as small
a volume as possible without restricting the gas flow, if response was all that
you were worried about.  A MAP or TPS based speed/density system would respond
as fast as you desire.

Robert
-- 
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             Robert Dingli           r.dingli at ee.mu.oz.au

Power and Control Systems                 Thermodynamics Research Lab
Electrical Engineering                    Mechanical Engineering
   (+613) 9344 7966                          (+613) 9344 6728
  University of Melbourne, Parkville, 3052, Victoria, AUSTRALIA
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