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 The
Sound of POWER
Adding the “Corsa Touch”
gives 5.3L ’07 Chevy Silverado a little more juice
By Bruce W. Smith
For those
truck owners who can’t leave well-enough alone, Corsa Performance Exhaust
(www.corsaperformance.com;
800-486-0999) offers a whole line of cat-back exhaust systems to enrich
the driving experience. We’re no different than a lot of listeners of
Truck Test Digest Talk Radio. We like to have a little something extra in
our vehicles when it comes to looks and performance.
That’s why we put one of Corsa’s newest exhaust systems to the test on one
of our own pickups—a 5.3L-equipped, two-wheel-drive 2007 Chevy Silverado
Crew Cab running 3.73 axle ratio and a factory limited-slip.
Corsa’s new stainless steel exhaust system is designed to replace the
factory exhaust downstream of the catalytic converter. It fits a number of
applications, including both the 5.3L and 6.0L 2007 Silverado/Sierra
pickups, both two- and four-wheel-drive.
The kit we choose was the “Touring” version (Part Number #14194) that the
folks at Corsa said was tuned more for long-distance trips and is slightly
quieter than the “Sport” version. We drive this truck a lot on trips, so
quiet at cruise is works for us.
Here’re a few more reasons we wanted to put a Corsa exhaust kit on our new
Silverad:
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Straight-through, non-restrictive design specifically tuned for the 2007
Silverado/Sierra
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Mandrel-bent, premium stainless steel construction, crafted with pride
and precision in the USA
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Patented
CORSA Reflective Sound Cancellation™ Technology for superior sound and
significantly increased flow and no drone even in 4-cylinder mode
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Lower
backpressure and Exhaust Gas Temperatures
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Dual
Under the Bumper Exit with Single Pro-Series 4.0" tips for enhanced
vehicle appearance
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No
welding required; Bolt-on installation
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50-state
emissions legal
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Limited
LIFETIME WARRANTY for as long as you own your Silverado or Sierra
ESTABLISHING A BASELINE
But before the
exhaust upgrade was installed, we took the truck to our favorite
facility—Gulfport Dragway (www.gulfportdragway.com)
to get a good performance baseline so we’d have something to compare
“before” and “after” results.
We ran the Silverado Crew Cab several times, using the tried-and-true
“power braking” method where you load the engine and trans before launch,
and the “stab-and-go” method where the throttle is floored with no engine
pre-loading. All times were recorded on our Stalker ATS radar system.
The best numbers we could achieve on the new 5.3L Chevy resulted in the
following: ¼-mile: 15.9 sec @ 86.4mph; 0-30mph: 3.2 sec; 30-50mph: 3.0
sec; and 0-60mph in 8.2 seconds.
Then a brief drive along Interstate 10 near our Long Beach, Mississippi,
office determined the sound readings inside the cab. The new Silverado is
remarkably quiet, showing a reading of just 67dB on our digital sound
meter with the truck cruising at 70mph. The engine and exhaust sound
levels jumped very briefly under full-throttle to a still quiet 76dB—most
of that sound gain from the intake and engine—nothing from the exhaust.
Base numbers established, it was off to Spears Auto Repair down the street
to get the Corsa cat-back exhaust kit installation handled. Warren Spears,
the owner, handled the upgrade.
INSTALLATION TIPS
Installation is far
easier than even we expected. The entire stock-to-Corsa exhaust upgrade
took less than 20 minutes on a lift. It is truly a simple bolt-on
performance upgrade.
The most difficult part was removing the stock exhaust because it is
welded from muffler to tailpipe. Corsa instructions say to cut the factory
exhaust just rearward of the muffler, which allows the long, unwieldy
exhaust to be removed in two pieces. But we wanted to keep the old exhaust
intact. So, we found that removing the right rear shock (or dropping the
full-size spare tire out of the way) allowed just enough room to work the
stock exhaust out from under the truck in one piece.
Putting the Corsa cat-back exhaust on was ultra simple as the photos show.
It’s sectioned in three parts: cat to muffler pipe; muffler; and muffler
to exhaust tips. This makes installation easy for one person to handle.
The hardest part—slipping the exhaust hangers into the factory rubber
mounts. The rest of the installation required nothing more than tightening
a couple bolts and nuts.
PERFORMANCE RESULTS
We went right back
to Gulfport Dragway and the local Interstate to record the results of the
easy performance exhaust upgrade. Here’re the results:
Corsa / GM Exhaust
Upgrade; ’07 5.3LV8 Catback System
2007 Chevy Crew Cab
2WD; 3.73:1 axle w/ factory locking diff
BY THE NUMBERS
BEFORE
AFTER CHANGE
0-30mph/sec: 3.15
3.13 -0.02 sec
0-60mph/sec: 8.13
7.97 -0.16 sec
30-50mph/sec: 2.95
2.85 -0.10 sec
55-70mph/sec: 3.10
3.02 -0.08 sec
¼-mile: 15.91@86.4mph 15.81@87.3mph
-.10 sec / +.9 mph
Top Speed: GM
throttle fuel-cut-off on this pickup was factory set at
87mp so top-speed may
be higher on 4x4 models that have a supposed fuel-cut-off in mid-90s.
Sound/dBA:
@70mph
67 68 +1 dBA
@Full
Throttle 76
80 +4 dBA
What we
found upgrading to the Corsa cat-back ’07 Silverado/Sierra exhaust system
is a slightly throatier exhaust note at idle, and a much more
performance-sounding note under heavy throttle.
As the sound readings show, that deepened sound note is mostly heard
outside the cab—not inside. What little is heard inside is not bothersome
and is almost indistinguishable during highway cruising. (If we’d used the
“sport” exhaust system, the exhaust sound is a little more prevalent
according to Corsa.)
Corsa says their in-house dyno readings show the cat-back upgrade also
adds 10 horsepower and 14 lb/ft of torque at the rear wheels. Those
numbers coincide with the performance gains we saw at the dragstrip.
We are pleased with the results. Our Silverado retains its quite highway
cruising ride while exhibiting a considerably throatier exhaust note under
full-throttle. Plus it showed an improvement in acceleration. With an
installtion as imple as this one, we like to think that’s a winning
combination.—Bruce W. Smith
How-To
Photo Story:
Corsa
provides everything needed for installation from attaching hardware to
detailed/illustrated instructions. Exhaust is made from high-quality
stainless steel.
We used
the new GearWrench (www.gearwrench.com;
800-688-8949) X-Beam
combination open-end and ratchet box-end wrenches when there wasn’t room
for our air tools. X-BEAM™lets you work with the wrench’s wider side for
more power, with less stress on your hand. The wider, super-strong
crossbeam increases contact area with your hand by 500% over traditional
wrenches, and the unique twist-handle design reduces open-end head
clearance by up to 75% to reach even the tightest spaces.
Removing the stock Chevy exhaust only requires removing the two nuts that
hold the flex joint to the catalytic converter exhaust pipe, then working
the exhaust hangers loose from their rubber isolation mounts.
The
Corsa exhaust comes with the flex exhaust so it bolts right back in place
of the stock exhaust. Put anti-seize compound on the bolts so they nuts
can be removed later if necessary.
Shooting a little WD-40 into each of the isolation mounts eases the
installation of the new exhaust. Corsa’s new exhaust had the mounts to fit
each stock hanger location perfectly.
The key
component to the Corsa exhaust is their muffler, which uses a patented
“noise-cancellation” design to provide power without an annoying drone in
the cab. All components are made from high-grade stainless steel.
The
exhaust rearward of the muffler is one-piece. Corsa offers both dual
exhaust that exits under each side of the rear bumper or this single,
twin-tip side exhaust for that custom look that we liked.
The
final installation step is to work your way from the front of the exhaust
to the rear tightening the bolts to Corsa specs.
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