We spent the better part of a day at Custom Dyno Tuning in
order to test every possible combination of the C&L TrueFlow
system. To keep the playing field level we used the Predator's
data-logging function to ensure our intake air temperature
(IAT) and engine coolant temperature (ECT) were consistent
run to run. We aimed for starting IAT of 72-76°F and ECT
between 180 and 190°F. When ECT's climb above 190°
the 05's computer retards timing to avoid engine damage. Therefore,
as an added measure of consistency we also monitored spark
advance at 4000, 5000, and 6000 rpm. If we observed any pull
back in timing we'd repeat that pull.
We made over 16 dyno pulls, with the first and last pulls
made with the C&L kit installed and computer upgraded
with the Diablo tune. This way we also covered any potential
of the '05 needing to "learn" the new modification.
Below we have detailed the three most interesting comparisons
from our testing.
How much better than stock?
The first test, and the one of most interest, is the straight
forward comparison against the stock setup. We knew from our
impressive track gains that there was going to be no false
sense of the butt-meter with this product. The dyno confirmed
that with no uncertainty. With the stock air box and factory
tune the '05 Mustang made 255 peak horsepower at 5100 rpm.
Peak torque measured 277 lb-ft. at 4300 rpm. With the C&L
air inlet system and matching Diablo tune the power improved
in single digits up to the same 5100 rpm peak. However it
is what occurs after that point that is noteworthy. Whereas
our '05 drops off after 5100 rpm, the effects of the C&L/Diablo
kit allows power to climb another 1000 rpm, with the new peak
horsepower being 270. From 5700 to 6100 rpm the C&L/Diablo
is up over 30 horsepower and nearly the same on torque versus
the stock curve.
|Graph 1: Stock
Air Box and Tune vs. C&L/Diablo System
While this test clearly shows the worthiness of the C&L
system, the gains may be a bit inflated. This is because we
know from our original
dyno testing of this particular '05 that we may have a Ford
PR "dud" on our hands. Other than this '05 we have
not seen another produce a horsepower peak as low as 5100 rpm.
Most five-speed manuals are making peak power around 5700, and
the factory rating is at 5750 rpm. We believe this particular
car from the media fleet to be one of the first off the production
line, and therefore it may have an early PCM flash or a deliberately
fat air-fuel curve to avoid media mishaps. Take note of the
A/F ratio before and after the C&L tune. In stock form our
test vehicle dips into the low 10:1 range - drowning in fuel
even by forced induction standards. The Predator tune brings
the ratio into a more acceptable mid 12 range.
Can we improve with a leaner A/F ratio?
The next step in the dyno testing process was to use the
Predator's built-in capabilities to fine tune the fuel and timing
parameters. With the canned tune putting A/F ratios at 12.4:1
after 5500 rpm, we suspected there may be a bit more by approaching
13:1 across the board. The Predator offers two possibilities
to alter the A/F ratio. One way is to decrease the fuel by going
a certain percent in the lean direction. This yielded no gains
in our testing and we actually observed very little change,
if any, to the air fuel ratio. The other method to lean up the
A/F ratio is to add timing or spark advance. Using the Predator's
"Global Spark Adjust" parameter we played with varying
degrees of advance over the base Predator setting until we found
peak power. While the gains were not massive, with the maximum
4° additional advance allowed by the Predator we picked
up some single digits here and there.
|Graph 2: C&L/Diablo
Tune vs. C&L/Diablo
Tune 4° Spark Adv.
How does the competition stack up?
Manufacturers may hate when we do this, but readers love it
and that's what counts. Since Custom Dyno Tuning has a Super
Chips Tuning system in house we figured it'd be worthwhile
to see what sort of numbers we could generate with SCT's X-calibrator
product (see side bar.) We cleared the Diablo Predator tune
from the computer and then loaded on SCT's base "cold-air"
tune. This is a canned tune from SCT aimed at '05 Mustang's
with any type of aftermarket CAI (cold air induction) kit.
This tune actually lost power across the board compared to
the Predator tune. In fact, the SCT cold-air tune put A/F
ratios in the mid 13's above 4k, something the '05 clearly
does not like.
CDT's owner Arlee Taylor then went into the SCT X-Calibrator
tuning software and modified the tune to add 3% more fuel
than specificed in the SCT cold-air tune. The tune was then
uploaded to the '05. This time the engine responded with an
average gain of 4 HP and 4 lb-ft across the
board over the best Predator tune. The gains are minor but
clearly due to even finer finessing of the air-fuel ratios
across the power curve.
Without a doubt the 2005 Mustang GT is gasping for air. Open
up its' airway, make the appropriate fuel and timing adjustments,
and you've unleashed some significant horsepower.
|Graph 3: C&L/Diablo
Tune vs. C&L/Diablo
Tune +10% Spark Adv.