Re: Superchargers, EFI, & Twin Sparks

[Zamani Zambri <zzambrimail@domain.elided>]

Biba asks:

>Zamani,
>does one need to keep a laptop 'on' all the time while driving their
>car, or does one download the 'necessary' program for that given time
>onto a chip - then be able to change it, at will, by rehooking up the
>laptop and downloading another program? Did you change the program a 
>bit before having your car SMOG tested, or would you prefer not to
>talk about it?

No it's not necessary to have a laptop in the car all the time, but I
intend to have that so I can keep many maps on disk and upload it to
the ECU. I'm sure you can program it onto a chip and upload it to the
ECU but that will take a lot of development especially if you have to
figure out how to encapsulate the data on tht chip and transmit it over
the serial port.

Maybe if time permits, incorporate an LCD display which will display a
few readings like EGT, O2 sensor, temp sensor, oil pressure sensor,
intake temp outputs. This will replace the Alfa Romeo Control. 

I did reprogram the ECU to make it pass SMOG, but it's not as if you
have to reprogram it again to make the car run properly. At around
13.5:1 - 15.5:1 AF ratio your car will pass smog reasonably well for a
mildly modified normally aspirated car. I made my car run at 14.7:1
which is good enough for a steady idle, good emissions and good power.
You have to remember that the SMOG test is only done at low loads,
which in my case means around 50% absolute atmospheric pressure (the
system has a map sensor, at WOT it's 100% of atmospheric pressure or 0
psi of boost). 

At around 60% - 100% atmospheric pressure the car is run a little more
rich and ignition advance adjusted accordingly.

Of course I have access to a wideband AF meter as well to make precise
adjusments. And also my car's injectors fire sequentially so that's
also one reason why the emissions are very low. The smog test was done
with old GL HL plugs which would not allow my car to go past 5500
without misfiring and an old air filter. So I'm pretty happy that my
car is not a polluter, in fact it's way cleaner than an L-Jet system.

BTW, Autotune (for fuel only, not for ignition) is meant to be used on
the dyno, the bonus is that it also allows you to do it on the road
(though I don't recommend it). The feedback the ECU gets from the
wideband AF meter is how the ECU adjusts itself to get to within 1-3%
of the AF ratio (which the user sets for a given load vs rpm cell),
which is faster than any human can do. 

When the cell turns green it is within 1% of the preset AF ratio,
yellow means 3%. Pretty darn good way of getting a good baseline map,
and I'm not talking about a basline map enough to get your car running.
But a really good baseline map which makes good bhp. After you are get
a good baseline map, than you can call in a good tuner to get on to
more serious tuning for the extra bit of bhp.

Zamani
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