MegaSquirt Re: <VV> fuel injection

[FrankCB at aol.com]

Seth et al,
    One of the advantages of MegaSquirt is that the  system is completely 
"open" so that you can use 2, 4 or 6 injectors.  This  system fires 2 "banks" of 
injectors every 2 rotations of the crankshaft, so you  can have 1, 2 or 3 
injectors firing on each "bank" of 3 Corvair  cylinders.  In fact, you can even 
have ONE of the 2  banks firing up to 3 injectors on the FIRST crank  rotation 
and the SAME bank firing up to 3 injectors on the SECOND crank  rotation.  
These 2, 4 or 6 injectors can ALL flow gasoline fuel  leaving the SECOND bank to 
flow an alternate fuel like alcohol, or H20 or  ???.  The two banks would then 
have SEPARATE control software algorithms  completely different so the 
gasoline bank could control at e.g.  stoichiometric (14.6 A/F ratio) with enrichments 
coming in at idle, acceleration  and high load.  The "other fuel" (or H20) 
could be controlled to have NO  flow at idle and at high intake manifold vacuum 
(cruising or deceleration) and  only flow under high load conditions, varying 
the flow with RPM and with  intake manifold vacuum.
    But if you go with an open system like MegaSquirt,  you'll need some sort 
of feedback mechanism to setup the software "map" to  control the A/F ratios 
under all different conditions.  You could use a  series of dyno runs coupled 
with an O2 sensor in the tailpipe.   Or, you can install your own WIDEband O2 
sensor feedback so you can setup the  MegaSquirt yourself using a series of 
trial and error highway runs.  It's  probably a lot of work that way, but 
cheaper than renting a dyno.
    The alternate to an "open" system like MegaSquirt  is using a "closed" 
system from a similar displacement engine (say a 2.8  liter Chevy V6), but then 
you have NO access to the software and you'll  still have to install the stock 
NARROWband O2 sensor that came on the car  originally.  Plus you're stuck 
with however many separate injectors or  throttle body injectors that came on 
that particular engine.
    If you do go the MegaSquirt route, you'll need to  have good experience 
installing small electronic components on small PCB boards  and being able to 
correctly solder them into position with a very small-tipped  soldering iron 
(temp controlled) using an illuminated magnifying lamp. If  you're not 
experienced and confident in doing all this you can now buy an  already built 
MegaSquirt unit at higher cost.
    You can also build your own wideband unit.  Do  a Google search on 
"oz-diy-wb" to find sources for these kits or to buy one  already constructed.
    Good luck,
    Frank Burkhard
 
In a message dated 3/25/2007 10:55:17 PM Eastern Daylight Time,  
Sethracer at aol.com writes:

In a  message dated 3/25/2007 7:27:52 PM Pacific Daylight Time,   
mahubert0811 at msn.com writes:

I am  looking to put fuel  injection on my Corvair engine.  There are a 
couple 
of kits  available, but they are more than I am looking at spending.  I am   
interested in the Megasquirt system.  Anybody have any   advice?




The electronics may be the easiest part of the  installation. The integral  
intake manifold and the"opposed" layout  of the Corvair engine make linkage  
and 
injector location a big, if  not the big, issue. It can be done and there are 
 
dozens of Corvair  motors running with FI, but there is no "bolt-on" system.  
Almost all  the installs require removing and modifying the heads, although   
perhaps a center mount 4-barrel-like set up with a throttle body (complete  
with  
TPS and IAC motor) located in the center and an injector  located over each  
(140) cylinder head inlet (the stock 4 inlets)  could work. Perhaps a  
6-cylinder 
kit (ready for 6 firing impulses)  but using a 4-barrel replacement  
controller (ready for the 4  injectors) might be adaptable. - Seth   Emerson







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