Coyote Headers and Full Exhaust - Long And Strong
Having the right headers and exhaust can increase your car's power
From the June, 2012 issue of 5.0 Mustang & Super Fords
By KJ Jones
Photography by KJ Jones
Our extensive study of '11-'12 Mustang GTs has taught us a great deal about the Coyote engine's preferences, when it comes to making performance-oriented changes. We've learned that Coyotes are heavy-breathers, and the engines thrive on intake-air improvements such as adding aftermarket induction upgrades and variable-cam-timing tweaks.
Recent 5.0-themed projects also have confirmed there are benefits in making similar adjustments on the exhaust side. Tests show that modest-to-monster power and torque increases have come from installing various exhaust bits on 'Stangs with bolt-ons or power adders.
Kurt Schutt owns an '11 Mustang GT that falls directly in line with the type of Pony we were looking for when MBRP Performance Exhaust presented us with an opportunity to test its new long-tube-header system for V-8-powered GTs. Kurt's steed is all-motor-for now-and despite having several nice appearance treatments and a cold-air-intake system, the car is otherwise stock.
The twin-post hoist, tools, Dynojet chassis dyno, and talents of GTR High Performance were called on for assistance with getting this project done. And, as a cool change from the "norm" in PCM calibrating, the all-important tuning for this effort was handled over the Internet by Chris Jones of Blow By Racing in Boca Raton, Florida.
For details on how it was done, and of course, how MBRP's 5.0 exhaust performs, read on.
Our experiments with '11-'12...
Our experiments with '11-'12 Mustang GT long-tube header exhaust systems typically are performed in conjunction with upgrades that improve intake airflow and volume for Coyote 5.0 engines. Kurt Schutt's 'Stang rolled into GTR already sporting a JLT True Cold Air system.
We decided to install MBRP's...
We decided to install MBRP's catted H-pipe on Kurt's Pony. The tube (PN S7238409; $1,206.45) is constructed with T-409 stainless and measures 3 inches in diameter (main tube) with a 2.25-inch crossover. Highlighting the H-pipe is a pair of 200-cell, high-flow, metal-matrix catalytic converters. The cats aren't nearly as restrictive as the larger, factory cans. They represent at least a small effort (on the Mustang owner's part) to be in accord with smog laws.
Despite their OEM stainless-steel...
Despite their OEM stainless-steel manifolds that closely resemble short-tube headers, exhaust flow for Coyote Mustang GTs is limited. Tubing from the factory catalytic converters actually steps downward, from 3 to 2-1/4 inches at the H-pipe. Once past the H, tube size increases to 2-3/4 inches, and remains as such throughout the exhaust system.
Finally, the MBRP Street Cat...
Finally, the MBRP Street Cat Back Kit (PN 7210409; $901.45) is the finishing touch on our exhaust project. The post-cat tubes also are T-409 stainless-steel and 3 inches in diameter. A set of polished, MBRP-embossed chambered mufflers are included with this set, along with polished 4-inch tips. One of the cool things we discovered about the MBRP pieces is that they will work with OEM H-pipes. So, if finances dictate making exhaust upgrades in stages, the MBRP after-cat can be your first purchase.
After removing items such...
After removing items such as the battery/battery tray from the engine compartment, and then raising Kurt's GT on a twin-post hoist, Ricardo pulls down the stock exhaust system, starting with the aforementioned H-pipe.
We were anxious to give MBRP's...
We were anxious to give MBRP's long-tube headers (PN S7230304; $1,080.45) a workout. The T-304 stainless-steel tubes measure 1.875 inches in diameter and include 3-inch, spiked merge collectors with bungs for oxygen sensors.
Header removal (stock) and...
Header removal (stock) and installation cannot be efficiently accomplished without raising the engine slightly, to create sufficient clearance for the tubes. Eddie breaks the engine-mount fasteners loose and uses a pole jack to raise Kurt's Coyote. The steering linkage and starter also are disconnected/removed before yanking the factory manifolds.
Eddie pulls the driver-side...
Eddie pulls the driver-side exhaust manifold down from the engine block, and then repeats the task on the passenger side.
MBRP provides all of the clamping...
MBRP provides all of the clamping hardware for the entire exhaust system. After installing the catted H, Eddie uses an air-driven impact gun to snug the clamps down first and then adjust the H-pipe for best clearance and fitment, before zapping the clamps down hard to ensure there are no leaks.
Stock exhaust manifolds are...
Stock exhaust manifolds are secured using studs that are secured in the engine block. MBRP provides fasteners for its headers, which we recommend using when this system is installed.
The MBRP long-tubes really...
The MBRP long-tubes really look good on the underside of Kurt's '11 GT. Notice how well these headers clear the 'Stang's six-speed manual transmission?
Extensions for wideband O2...
Extensions for wideband O2 cables are provided with MBRP's headers and H-pipe. However, we found them unnecessary for completing the link to the front sensors. After making the appropriate connections, Eddie uses zip-ties to route the rear oxygen sensor's wiring away from any of the exhaust tubing.
Here's a comparative look...
Here's a comparative look at the ports in a Coyote Mustang's factory exhaust manifold, and those of MBRP's new long-tube headers. MBRP's headers feature larger ports and long, equal-length tubes for maximum scavenging during the exhaust stroke. Note the headers' laser-cut flange, which measures 3/8-inches thick.
Ricardo got both headers in...
Ricardo got both headers in and secured by the bottom fasteners. Then he and Eddie combined to work on finishing the header job by installing and tightening down the top row of bolts.
Header installation is relatively...
Header installation is relatively painless, provided the Mustang and its engine are raised high enough to allow adequate access into the space between the engine and frame rails.
The stock, wideband oxygen...
The stock, wideband oxygen sensors must be transferred from the factory manifolds to each collector in the MBRP header.
While fitment really is great,...
While fitment really is great, we did experience one small clearance issue (steering linkage slightly touching a tube) with the new MBRP headers. Raising the engine by installing 1/2-inch shims on each engine mount quickly eliminated the problem.
The 3-inch theme continues...
The 3-inch theme continues from the H-pipe to the back of the 'Stang. The Street Series Cat Back Kit features a pair of nicely constructed extension pipes that run perfectly to our Pony's rearend.
The after-cat's over-the-axle...
The after-cat's over-the-axle tubes requires installing two spacers between the Panhard-bar brace and driver-side framerail.
Included with the kit, the...
Included with the kit, the shims create clearance for the big mandrel-bent tube to pass over the rear without conflict with the chassis or suspension.
Ricardo positions the mufflers...
Ricardo positions the mufflers on their hangers. MBRP's cans fit in the OEM location without any extra work.
Ricardo fits the 4-inch tip...
Ricardo fits the 4-inch tip on the tail of the MBRP exhaust system we've installed on Kurt's Mustang GT. The dual-wall tips are T-304 stainless, and are super polished for a clean, high-bling look coming from the pack of a Pony.
We definitely like the look...
We definitely like the look and fit of the MBRP '11 5.0 Mustang header system, and the sound it delivers the second a Coyote is given some heavy foot, is totally awesome.
Here is the completed installation....
Here is the completed installation. Here is the completed installation.
By telephone and e-mail, Ricardo...
By telephone and e-mail, Ricardo communicates engine data to Chris after each dyno pull.
Thanks to a previously installed JLT cold-air system, Kurt Schutt's '11 Mustang GT stomped down an impressive 395 horses at the feet during the baseline-dyno portion of our exercise. That's par for the course among Coyote 'Stangs that have this mod.
With the 400-horse plateau in sight and MBRP's long-tube headers and complete exhaust system installed on the GT, the car was once again loaded on the Dynojet chassis dyno at GTR High Performance, so we could determine how much power and torque a freer exhaust will manifest.
As you see in the data from the "after" run, horsepower and torque show nice increases, as power is solidly into the 400s and the long-tubes yielded enough additional grunt to definitely get your attention. (Before you California readers get excited, none of the pieces we installed are CARB-approved/California-legal.)
A wide-open exhaust passage, using MBRP's non-catalytic H-pipe (PN S7236409; $418.95) and Race Series cat back set (PN S7226409; $901.95) should offer an estimated 20 more horsepower and 25-plus lb-ft of torque beyond the numbers we achieved with Kurt's naturally aspirated, CAI-only 'Stang.
Chris then analyzes the stats...
Chris then analyzes the stats and makes changes to the calibration based on that data (primarily air/fuel details), until maximum performance is achieved while maintaining safe air/fuel using California's 91-octane fuel.
The post-install segment of...
The post-install segment of our dyno test was highlighted by our first venture into the world of remote tuning. For assistance with its Coyote Mustang tuning (and other 4.6/5.4 custom PCM calibrating using SCT tuning software), GTR High Performance works closely with Chris Jones of Blow By Racing in Boca Raton, Florida.