Brad Kowitz from TrailRecon (Ig: @trailrecon) recently brought his 1974 Jeep Cherokee (dubbed “Prickly Pear”) to the MagnaFlow Tech Center in Oceanside, California for a custom exhaust upgrade in order to let its vintage V8 finally breathe free.
Camping Like It’s 1974
The vehicle is a rolling callback to the world of 70s off-roading, complete with a collection of period correct camping gear: from an old school Coleman cooler, lantern and mint-condition camp kitchen kit (complete with checkers and backgammon boards) to a set of military mess kits, an unused camping stove from 1958 and a Little Brown Jug for water. These adornments and creature comforts perfectly suit the classic off-roading experience that Brad is trying to evoke with this project.
Before bringing the Jeep to us for its exhaust revamp, Brad replaced much of the interior, including removing the old seats for more modern perches, as well as replacing the carpet, disintegrating cardboard headliner and the vinyl cargo liner. Removing the surface rust found beneath the headliner proved quite a chore, but the end results were certainly worth it.
After upgrading the interior, it was time for Brad to get Prickly Pear geared up for its first proper outing, which meant packing a spare tire, TrailRecon tool bag, recovery kit (including tow strap, a couple shackles, a tree strap and a snatch block), bottle jack, tire repair kit, voltage meter, battery pack, some spare parts, ARB tire deflator kit and a good knife. Brad also replaced the alternator, which was barely pushing out 13V.
He also took Prickly Pear to Shift Autowerx in Escondido, California, where they rebuilt the transmission and transfer case. They also installed brand-new 1310 driveshafts in the front and rear.
Let The V8 Breathe!
With all those pieces of gear and mechanical concerns squared away, the Cherokee was finally ready for its first major voyage: to the MagnaFlow Tech Center for a new custom exhaust system.
In Brad’s own words, Prickly Pear’s existing exhaust was an utter “hack job.” MagnaFlow Spokesman Richard Waitas deemed it a “necessity build,” as it was originally constructed to make room for the auxiliary fuel tank that the previous owner had installed (and Brad has since removed—saving over 80 lbs. of curb weight!).
The system was a true dual exhaust with no crossover pipe, which may sound cool, but is hardly optimal for exhaust flow and engine performance. This is because dual banked exhaust systems that include a crossover can take advantage of exhaust scavenging effects, which make the most out of the vacuum left behind by each cylinder bank’s exhaust pulses to help pull the corresponding exhaust pulse through from the opposite bank of cylinders. It’s basically the same principle that makes drafting the car in front of you so effective in motorsports such as NASCAR.
Muffler Surgery & An xMOD Upgrade
Things got even more interesting when Rich and the Tech Center team started taking apart the old exhaust, including the fact that the system featured a heat riser valve that was as busted as it was obsolete. To Brad’s delight, Rich took one of the old mufflers over to a bandsaw to cut it open and have a look at its internal construction.
The surgery revealed an archaic multi-chambered three-pass muffler design which sent exhaust gases swirling around inside the muffler body before finally exiting through the outlet. While effective for sound deadening, this old design was horrible maximizing efficient exhaust flow and performance, let alone creating an enjoyable engine note.
In contrast, Prickly Pear’s new MagnaFlow exhaust features some cutting edge technology in the form of one of our xMOD Universal Mufflers, which feature a straight-through design and an accessory port that can be fitted with several modules in various configurations in order to allow Brad to tune the exhaust sound to his liking on a whim.
And A Catalytic Converter!?
At Rich’s suggestion, a MagnaFlow metallic catalytic converter was also integrated into the system. While this may seem like an odd choice considering that Prickly Pear is old enough to not legally require a converter at all, the purpose in installing it wasn’t to improve emissions, but to reduce the amount of smelly, unburnt hydrocarbon’s that the Jeep’s old school, less-than-efficient V8 kicks out.
Unlike more modern catalytic converter designs that feature a ceramic matrix and utilize computer sensors together with the fuel injection system to monitor and modulate converter performance and keep the ceramic matrix from melting down, this converter uses a metallic substrate that can withstand higher temperatures and greater variability without coming apart internally. Perfect for a vehicle that lacks any sort of fuel injection or computer systems.
As Rich points out, this entire custom exhaust system can be built by customers at home with a bit of welding skill and our catalog of Custom Builder Parts. He also designed the layout of the new system to be easily serviceable in the future. Most importantly, Brad loves the way his new Prickly Pear exhaust sounds!