Re: EFI vs CIS, the need for speed

["Graydon D. Stuckey" <graydon@apollo.kettering.edu>]

On Tue, 10 Mar 1998, QSHIPQ wrote:

> benefits are probably due to less intake air restriction.  So the question is,

That is true also.  Although it isn't the whole benefit of EFI, the side 
benefits are some of the best.  Eliminating that CIS airflow meter was a 
major improvement.

I have noticed that even the OEMs are reverting back to systems that do 
not use airflow meters.   They do it for cost as much as anything else, but 
also for less restriction.

> can you take that 2 grand and spend it more wisely elsewhere?  I argue so,
> btdt.

Yep, agreed.   However, we hope to get that figure down to much less than 
one thousand soon.  Then the argument starts to slide over to the other 
side. :-)

> to CIS.  Better economy?  Not sure I go there with you.  Port FI is Port FI.
> Lamda is lambda. Lower emissions?  Not sure I go there either.  A CIS -lambda

Definitely.  EFI has much finer control over fuel than CIS, and it is
easier to calibrate, so it is easier to get really low emisions.  I'm
not talking the garage sniffer test either.  I mean a real FTP test. 
Actually, though, _I_ don't really care much about emissions.  Its good to
reduce them, but I think "emissions" gets far more attention than it
deserves. 

> So, EFI is a good thing.  Graydon, yours works well, and I applaud all your
> efforts in making it work on a 5cyl.

Thank you, thank you :-)  (blush.)

> When you get the sequential EFI setup, 
> do call me directly.  :)

Don't count on it.  FMS already has sequential ECUs developed for other
customers who are concerned with emissions, but in all their dyno testing,
they have not found more than a couple percent improvement in overall
power due to sequential alone over simultaneous.  Seq does nice things for
idle quality and emissions, but very little for power above idle.  With
that in mind, I won't bother even wiring up a seq box when I can have a
sim box done in 2/3 the time.  The seq box requires more sophisticated
sensors, and you then have to wire the injectors correctly, or it will
squirt in the wrong sequence.  I'll bet you wouldn't be able to tell if
the sequence was wrong, but if it wasn't right, you wouldn't realise any
of the anticipated benefit (real or imaginary) of seq anyway, so why
bother? 

> My .02
> Scott Justusson

My 2000 bux worth...   :-)

Later,--------------------------- -   -   -   -
Graydon D. Stuckey		 / \ / \ / \ / \
graydon@apollo.kettering.edu	|Mr. Muffler... |
810 733 0255			 \ / \ / \ / \ /
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