Hummers, 500 cid, and Fuel Injection

Mon Mar 30 16:40:10 GMT 1998

Hello Bernie, Paul, and others.

>Are you a "rock crawler"?   I am VERY interested in low RPM performance.   I
>am considering a low stall speed converter. What sources have you found?

Yes, most definately am.  There are rocks in the Delaware river, right?
<Grin>.

>Reply off list since this is pretty far off topic,

Actually, I don't think replying here is not that far off topic, because
the vehicle is fuel injected (now), and running turbos to boot as well.  A
friend of mine who is much more verse in engines than I basically set me up
as a project (I assisted), in exchange for my putting some computers
together for his body shop - point of sale/quoting/accounting/Novell type
of thing.

1st Build:
Anyway, I agree using the Caddy 500cid was not the best way to go - a
Diesel would have been, however I couldn't find one reasonably priced at
the time, and I happened to fall into the Caddy engine almost by chance.
So, the engine was rebuilt, mostly with aftermarket "marine" parts due to
my friend's connection with a marine place.  A custom aluminum manifold was
built by said friend, providing for dual Holley 650 carbs.  What was neat
was the way he drilled out the top plate above the runners, the carbs could
face either way.  Maybe not the most flow-efficient design, but it allowed
me to rotate the front carb 180 degrees, so the float bowls were facing
each other.  This idea, combined with a very steep incline (almost 60
degrees!), means one carb will be lean as can be, and the other almost
flooding.  The engine won't stall.  Add the complexity of making everything
incredibly air-water time, it certainly was a fun project.  We kept the HEI
distributor, and ran everything off a standard Holley inline fuel pump.

2nd Build:
Now the fun began... I had a lot of problems with the carbuerators for a
variety of reasons, though nothing terribly major.  Then, my distributor
worked loose (bouncing off rocks I'm sure doesn't help) and the engine
backfired through the carbs.  Not good.  So, my friend offered once again
to pitch in, and use my truck as an experiment, and we opted to play with
Fuel injection.  We are 1/4 partners each (total of 1/2) of a drag car we
were racing at the time, which is fuel injected, based on Ford products, so
we more or less copied that setup, and started tweeking.  I said here in
the past we had installed Haltech, but I was incorrect.  I looked at it
this weekend and it is in fact a Tec II Electromotive unit.  Fuel was
handled by summit racing pumps of some sort (they sit inside the frame
rails actually, for protection, so seeing what they are is rather
difficult, I hope they don't break), running fuel through two pumps to the
engine, on either side of the fuel rail, with inlets on the back, and the
return line off the front, on a Y adaptor returning to the fuel tank.

Injectors were adapted to the homemade manifold, using bosses ordered from
somewhere.. might even have been summit.  The injectors were ordered as
replacements for a Corvette engine, 45lb I believe.  Maybe 40.  its been a
long time.  I spent some of this weekend looking for the build/dyno sheets
I have... but no luck yet.  I'll keep looking.  I figured you guys would
want the details rather than "I think" or "it probably has".  The camshaft
I know is OEM, coming from the engine originally.  The throttle body
problem was solved by replacing the burnt throttle plates in the carbs, and
gutting the fuel stuff off, though the jets are still there, and at some
point I debated running another fuel through the carb hoping to keep it
from leaning out so much.  But, I haven't gotten to it yet (2 years now).
I was thinking Alky.

The turbo's are very small, aquired junkyard style off two Dodge Daytona's.
 They are small because they are connected to once side each - from a turbo
point of view, they spin off a large 4 cyl engine (1/2 of the engine).  We
had a lot of issues getting this to work, until we put in a crossover pipe
on the headers.  Added nice droning noises I have to admit.  There are no
wastegates nor blow-off valves, as the boost doesn't really get any higher
than about 7-8PSI, which is tolerable on this setup.  I've never measured
it, though the computer never complained. All this flows through a pair of
chery bomb mufflers - the worse for turbos I know.  originally, I had no
mufflers - which is the best for turbos :)

Now, here is the clencher - the engine is not run in the low RPMs at all.
While rock crawling, and short sprints in the mud, I'm generally sitting in
the 3000-3500 range... the reason for this is the transmission I have,
combined with the axle gearing, is ridiculously low.  So, I didn't build up
a 1800 RPM grunter at all...  To do 65 I have to sit about 4500 RPM in 4th
gear.

If you guys were smart, you'd buy stock in gasoline companies that deliver
to Newburgh NY <smile>

Hope that helps everyone out :)

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