It’s been hit or miss for the past
year as I’ve been trying to line-up a day to take the Red Line in for an updated
dyno reading. My first (and last) dyno was in November 2010, just a few months
after I had bought it. Save for a drop-in K&N air filter, it was bone stock
and it blew 238 horsepower and 209 torque through the factory catalytic
converter. Dyno readings can be a little confusing because they measure
horsepower at the wheels. But when a manufacturer quotes their horsepower for a
certain model, they always use the power developed at the flywheel. This creates
better advertising since flywheel horsepower is before drivetrain losses and is
usually about 15% higher. For instance, the new 2015 Subaro WRX STi is
advertised as having 305 hp but
dynoed at 247 hp. Now, the 15% is a standardized formula and no two engines
behave exactly the same, but the 15% correction factor is widely recognized as
the most accurate way to calculate the difference between power made at the
flywheel and the drive wheels.
With that fuzzy math in place, my
stock Red Line produced 273 flywheel hp, some 68 more that the factory estimate
of 205. Granted, that is quite a bit more but GM’s guilty of famously
underrating engines in the past for insurance reasons, and several other stock
Red Lines have dynoed similar numbers. In fact, a dyno chart provided by GM even
shows the RL’s power curve peaking around 6000 rpm and declining thereafter. On
my last dyno, there is no peak, just a continued upward trajectory until the
6500 rpm redline when the rev-limiter cuts fuel to the engine. The Stage 2
upgrade raises the redline to 7000 rpm allowing the engine to continue making
power. Larger injectors (42 lb vs. 34 lb) and a
lighter, smaller supercharger pulley (Aluminum 2.9 in. vs. Cast Iron 3.35 in.)
supply the necessary fuel and air. Finally, a long-tube header replaces the
restrictive exhaust manifold and catalytic converter to help evacuate the spent
gases as fast as possible.
But what these mechanical
ministrations add up to have been quite a mystery until now. GM claims an
increase of 36 hp for the Stage 2 package, but a dyno test by Modified
Magazine demonstrated only a gain of 24 hp. And as for the long tube
header, Modern Performance tested it and came away with a peak reading of 8
hp.
The Friday before the dyno test was
Valentine’s Day, and I was in Wal-Mart buying seven quarts of Mobil 1 so I would
have fresh oil for the punishing dyno runs. In front of me was a whole herd of
henpecked husbands dutifully buying discounted flowers and cheap chocolates.
When it was my turn to checkout, I placed the motor oil on the counter and
quipped, “This is what I’m buying my wife for Valentine’s!” as loudly as
possible. The elderly sales clerk stopped, looked at me, and then responded,
“You can buy that for her, but I sure wouldn’t recommend it!”
With the bipolar weather the South
has recently been cursed with, Monday dawned bright and balmy. Naturally, I was
hoping for some of the chilly weather we had experienced the week before, since
cooler air is more supercharger-friendly but that was not the case. I made the
ten minute-drive to Johnson Motorsports (JMS), and in the nearly 35 years I’ve
been in Hurley, it remains the sole significant place that I can brag about
living close to. Everything else requires a minimum thirty minute drive east,
south or west.
Housed in a non-descript metal
building with a barbed-wire fence, JMS is one of the premier aftermarket tuning
facilities in the world. Yet, given the unassuming outward appearance you would
never know it. The only tip-off is a small sign out front and a steady stream of
high-performance cars that pack it’s parking lot. On the day I was there, it was
mostly Mustangs, some of which had come from as far away as Louisiana and
Tennessee. But the previous week, there was an exotic Ford GT that had been
massaged to produce 1100 hp, or roughly double what it originally came with. A
retina-searing Chrome Yellow with black racing stripes, it looked like it was
going 200 mph just sitting still. Amazingly, it still had the stock clutch and
was only now in for a stronger replacement. With an MSRP of $150,000 and just
4,000 built between 2004-2006, it remains the only modern Ford immune to
depreciation.
Prior to the dyno runs, the
mechanics had some problems getting my car properly lined up. Monty Johnson, the
owner, admitted that front wheel-drive cars tend to move around on the dyno and
as such, he’s much more comfortable with an 800 hp rear wheel-drive car than a
300 hp front wheel-drive car. Before the first pull, I asked him to observe a
6500 rpm limit so we could see where the air/fuel mixture was. Like all Saturns,
the Red Line runs rich from the factory as a safety feature. The stock dyno runs
illustrated this when the air/fuel ratio dipped into the 10s during the
test. Ideally, you want a stoichiometric air-fuel ratio
(14.7:1) off idle and cruising, and a leaner (11.8:1) under wide-open throttle.
However, by running an unorthodox 2.9 supercharger pulley, I’m taking a risk
that the fuel injectors might not be able to keep up with the demand as the
engine reaches it’s 7000 rpm redline. And a lack of adequate fuel at such a
stratospheric limit could potentially end with a catastrophic failure (i.e.
blown engine).
When my Saturn was finally ready
for the first tentative run, it looked like an open-heart patient. With the hood
popped, there were no fewer than three thick cables running from the engine bay:
The first was the cable intercepting the tachometer signal, the second was to
read the air/fuel mixture and the third one was new, a cable they had to
splice-in which could display the supercharger’s boost (PSI).
Monty started my car, commenced
giving it gas, and the front wheels began slowly turning the huge drums. He
methodically shifted through the first three gears before he flattened the
accelerator in fourth. The engine began rising to a crescendo, and it was here
that I fully understood how much louder it was without the sound-deadening
properties of the cast-iron exhaust manifold and the catalytic converter. It was
roaring like Hurricane Isaac and in the small enclosed shed, it sounded akin to
a giant circular saw slicing through sheet metal. After a seeming eternity,
Monty lifted at 6500 rpm and I stole a glance at the monitor which read 269 hp
and 242 tq, increases of 31 hp and 33 tq over stock. He also pointed out that
the supercharger had made a maximum boost of 18.5 PSI, quite an improvement over
the factory 12 PSI.
After studying the air/fuel ratio
and determining it was safe to press on, Monty was convinced there was more left
in the final 500 rpm. Unfortunately, he didn’t allow it any time to cool down
and these cars are notorious for heat soak. The second run, Monty took it to an
ear-drum shattering 7000 rpm but maximum power dropped to 266 indicating that
the extreme temperatures were causing the engine to pull timing on the
top-side.
He immediately moved a mobile air
conditioner in front of the radiator to pump cooling air into it, and directed a
huge fan to blow on the engine. He came back in ten minutes for the final run,
even though after four years of driving it, I knew it was no where near cool
enough.
Regardless, he pushed the engine
until it bounced off the rev-limiter at 7100 rpm, but it paid off as it spun the
rollers to 270 hp (or 310 flywheel) from 20.3 PSI of boost. Personally, I was
hoping for 275 at the wheels, and I think that was attainable had the weather
been more conducive and it was given enough time to cool down. For instance, the
conditions during my first dyno in November 2010 were much drier and cooler.
That notwithstanding, Monty
and the mechanics present agreed that it was still a heroic output for a stock
2.0-liter engine originally designed twelve years ago. Current engines such as
the 2.0-liter turbocharged four-cylinder in the Focus ST benefit from new
technologies such as direct-injection and variable valve-timing that help boost
horsepower. But even tested the same week at JMS, a friend’s tuned 2013 Focus ST
only made 241 to the wheels. Monty also mused how
far four-cylinders had come with mine as it makes the same horsepower as a 2010
Mustang GT V8, but weighs 1000 lbs less. I also told him not to forget that it
gets 30 mpg, a feat no supercar can replicate at any price. In fact, following
the three wide-open throttle runs from idle to redline, it still turned in 28
mpg at the next fill up. Click
the picture below for the full, record-setting dyno run.
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