[s-cars] Replace those Delphi/Lucas injectors

[Brian Powell]

A number of us have been experimenting off-list with finding a
solution to the extremely poor emissions (under all ranges) and
O2-loop controlled performance (not power, but overall engine
performance) with the Delphi/Lucas injectors and MRC software. With
differing software revisions not clearing it up, and talks with
others, I did a number of limited tests (with what I have available to
me) and have found that simply replacing the Delphi injectors with RS2
equivalents solves the issues.

Chris Myers and others have found that the tip and nozzle design of
the Delphi/Lucas injectors do not provide adequate atomization in our
intake manifolds. Chris stated, "The main difference between the
injectors is the design of the tip.  The Lucas part does not protrude
as deeply into the injector holder and inside the tip there is a
plastic divertor that splits the spray pattern into two "jets"
shooting off left & right of center-in this case right onto the sides
of the bottom of the injector holder causing fuel to drool & drip into
the intake ports creating a rich condition during cruise -not such a
problem when boost is occurring, but during normal vacuum conditons
very poor fuel atomization occurs.  The Bosch injector's tip protrudes
down to the bottom of the holder and sprays directly out from the
center of the tip."

So, I ordered a set of RS2 replica flow matched injectors from 034 for $265:

<http://www.034motorsport.com/product_info.php?cPath=24&products_id=369>

These are a newly designed injector from Bosch (in the last 5 years,
much newer than the early 80s technology of the Delphi) that are all
flow matched as a set to RS2 specs. These units have a very fine tip
design for atomization, especially compared to the poorly designed
firehouse nozzle of the Delphis.

Without a wide-band O2 sensor, I couldn't make a full suite of tests;
however, using VAG-COM, I was able to show that there is no loss in
power or timing (indicative of being too lean; although, the Delphi's
are rated at 37lb/hr--388.5cc/min, and the RS2 are 405cc/min @ 3.8bar
which means the RS2 can flow more) during WOT.

Several of us around the country have failed emissions with the Delphi
injectors, and so I found a friendly testing station to let me do some
tests at 2.5k RPM (the standard test here in CA) and got these
results:

                %CO2   HC      CO
Delphi          >20    132     0.8
Javad RS2       14.7   12      0.0
Improvement     >33%   91%     100%

Keep in mind, I kept the software the same, the only change between
the two are the injectors. So, for HC and CO (the two measures of
emissions in CA), I had over 90% reduction by simply swapping
injectors without changing the WOT performance of the car. After two
weeks of driving, I have no soot on my tailpipe or bumper (previously
very sooty with Delphi), the car idles perfectly (with the Delphi's
dumping inconsistent fuel, the idle would vary), my fuel consumption
has gone down (I was getting about 17-21mpg with the Delphi--very
inconsistent), no more CEL light with O2 control limit reached, and
the car just feels much smoother with general driving (yes, that is
subjective). Basically, I keep the performance, but gain a wonderfully
smooth and clean car under loop control.

My moral: Keep your software, it wasn't the problem at all, and it
runs beautifully with the RS2 injectors, BUT ditch the Delphi's ASAP
and pick up some RS2 injectors (either true or 034 replicas).


Cheers,
Brian