Supercharged Lincoln Continentals

[Daniel Ciobota]

Frederic,

I read your post and I'm a little worried about your setup.  Yes, you
friend was right about about the computer being able to change the fuel
tables to accomodate for the airflow diferences and the larger
injectors.  However, from my experience with some fords (not yours,
though) I haven't seen any engine a map sensor capable of detecting
boost, except possibly for turbos and supercharged t-birds.  If your 3.8
is the same as the one used in Tauruses (Tauri?) then _definitely_ not.

Why is that important? Timing control.  Running full timing advance
under boost can cause detonation, so most "pressurized" engines employ
some sort of boost sensor to retard the timing under boost.  A trick
used by late model mustangs nowadays is to buy a custom burned chip
which replaces the ecu's internal tables, like timing advance and
injector pulse width with ones which take into account measured boost.

Your other problem, the maf voltage peaking out too early, can also
cause detonation due to the ecu's fuel table limitations; it's designed
to look up voltages up to 5.0 volts only.  The fix would be to buy an
aftermarket mustang maf calibrated for the injector size you currently
use.  See an earlier post I made.  You'll need to reset the computer
again, and let it relearn the new voltage/airflow settings.  However,
since the fuel table for a supercharged engine diverge _very_ quickly
from the default tables under boost conditions, you will initially
experience detonation until the computer adapts.  Your alternative is to
either use an boost sensitive fuel pressure regulator (fmu) or find out
if you can get a chip burned for your ecu.  I know several sources to
ask if you're interested.  In the mean time I urge you to be very
careful with your current setup.

Good luck,

Daniel



Frederic Breitwieser wrote:

> >Say Fred.
>
> Say Garfield :)
>
> >Uh, is the MAF unit you refer to above, the STOCK OEM MAF unit that
> >comes on all 93 Continentals?
>
> Yes, its the MAF that came with the car.  The only thing I did to the
> engine support system was to replace the injectors with one size
> larger
> than OEM, bolt on a paxton supercharger from a Mustang 5.0L, and move
> the
> air conditioning compressor from the back of the engine to the front
> of the
> engine (its a transverse engine, looking at it with your knees against
> the
> bumper).
>
> The engine is the factory 3.8L engine, balanced, blueprinted, intake,
> heads
> and exhaust ported, with forged pistons and shot-peened rods,
> maintaining
> the original compression ratio, at least thats what the shop said when
> I
> got the car back.  I drove the car around for about a month, then had
> time
> to put in the new injectors (one size larger), and the paxton.
> Brackets
> had to be fabricated, and the air conditioning compressor relocated,
> because the Paxton unit wouldn't fit in the front of the engine
> between the
> engine and the radiator support bracket - its fatter than the A/C.
>
> When I first got the supercharger attached to the new, longer belts,
> the
> car ran like crap.  I replaced the MAF with a 5.0L MAF (from the same
> car I
> got the paxton from), and it ran the same way.  Idle was okay after
> the car
> ran for about 10 minutes, but hard acceleration was pretty bad, so I
> put
> the original MAF back in.  I decided just not to push the car for a
> week,
> and worry about taking it out the following weekend (I installed this
> on a
> Sunday night, which was pretty stupid).  Anyway, over the week, from
> driving from upstate NY to NYC, the problem went away.  I'm assuming
> the
> ECM learned a new trick.
>
> Anyway, you weren't interested in the brackets, so onto the MAF
> issues.  I
> just looked at the MAF for ya, and it says this:
>
>         FORD
>         F12F-12B579-AA
>         AFH55-03B
>         2F0
>
> I know this is the MAF that came with the car... when I first did
> this, the
> car ran like complete crap at idle, and after a few minutes, seemed to
> be
> more "stable".  Under boost conditions, the car ran like crap,
> sputtering,
> and obviously being confused.  I put the original injectors in
> thinking
> something was wrong with them, and it got worse under boost.  So, I
> put the
> new ones back in, called a friend, who told me to drive nicely for a
> week,
> and the ECM should learn about the new injectors, as it will be using
> the
> O2 sensor.  So, I did that, and he was right, it did get much better,
> and
> started to purr like a kitten, in about, oh maybe 30-40 miles worth of
>
> highway driving?   SOmething like that.  Under boost, it still ran
> like
> crap, though the point where it would cough seemingly getting higher.
> So,
> I tapped the intake and put on a 0-10PSI pressure gauge, and watched
> what
> was happening.  7PSI is about all the ECM will take before the thing
> chokes
> to death.  Below that, it runs fine with more power/torque I can
> actually
> feel.
>
> That was then, this is now.
>
> After learning a lot more about MAFs, MAPs, EEC-IV, Fuel Injection,
> etc,
> I've done some tests over the last few months.  The MAF reaches full
> voltage (5.2 or 5.3V) somewhere between 1-2PSI.  Its a cheap analog
> gauge,
> so it could be off.  Anyway, the MAF is maxed out right away, and
> somehow,
> the car is either ignoring it, adapted to it, or something else
> happened
> because of the larger injectors, I really couldn't tell ya to be
> honest.
> But this MAF does max out at about 1-2PSI.
>
> I don't have a scan too, but the engine light and the service light
> stay
> off.  Originally, the service light would blink on and off when I
> first
> installed everything, and eventually it stopped, at about the same
> time the
> car seemed to "adapt".
>
> There are only two situations where these modifications don't peform
> well.
> The first is when the car sits overnight in 0 degree weather, the
> engine
> turns right over, but runs a bit rough for abut 35-40 seconds, then it
>
> settles down, but no engine/service lights.  The second is if the
> car's
> been run on the highway for about an hour or so, then is shut down,
> the
> service light comes on if I start the car within a few minutes, but
> goes
> out after about a minute.  This happens when I drive home from work
> (65
> mile ride), and stop at the smoke shop on the way home to get a
> nicotine
> refill.
>
> Other than that, it seems okay.  I hope I told you something useful,
> or
> answered your question.  To be entirely honest, I "slapped" this
> together,
> without any real research or understanding of fuel injection systems,
> and
> lucked out.  I know 10 times what I knew then, and still haven't a
> clue (10
> times zero is still zero, right?)
>
> Frederic Breitwieser
> Bridgeport, CT 06606
>
> Homebrew Automotive Website:
> http://www.xephic.dynip.com/
>
> 1993 Supercharged Lincoln Continental
> 1989 HMMWV
> 2000 Buick-Powered Mid-Engined Sports Car
>
> -