2015 - 2021 Jeep Grand Cherokee SRT
Multi-Displacement System (MDS) valves deactivate 4 of the 8 lifters in a (V8) cylinder system when the throttle is closed or in cruise mode at low RPM. The purpose of this feature is to enhance the fuel economy available to the HEMI/SRT engines introduced by Chrysler. ALL Mopar models 2005+ are factory equipped with the MDS mode UNLESS you have a Challenger with a factory MANUAL transmission OR you have custom tuned your vehicle to eliminate the factory MDS feature. Please do not confuse MDS with Active Exhaust Valves (AEV), the purpose of AEV is to modify the decibel level (sound) of the exhaust system. If one has a goal to increase the duration of AEV this can be achieved by tuning the ECM to manually control between Default, Sport & Track mode. Borla offers the following systems to eliminate or retain the active exhaust valve feature.
The Borla "Cat Back™" name implies the exhaust system is located behind the factory catalytic converter where there factory emissions remain untouched and vehicle stays emissions compliant. This remains distinct from the Axle Back exhaust system that is located behind the rear axle. Alex Borla coined the phrase 'Cat Back' and introduced the Cat Back performance exhaust in 1978, a bolt-on replacement performance exhaust system requiring no welding, thus being secured using the factory hanger locations.
Borla Cat Back exhaust systems use engine-specific (not universal) mufflers that are designed, tested, and optimized specifically for a particular year/make/model vehicle. Borla Cat Back systems increase the overall sound level & performance.
Vehicles that don't have a factory service-point require "cutting" the factory exhaust system before installing a Borla Cat Back performance exhaust system. Borla includes instructions where to make this cut and includes the hardware to complete the installation.
Many of today's modern vehicles have a factory service-point in the exhaust system (flange or slip-fit) located in the exhaust tubing behind the catalytic converter. A Borla Cat Back performance exhaust system replaces the factory exhaust system (behind this service-point) following the same exhaust path and secured using the original vehicle hangars and rubber isolators.
Borla pioneered the automotive exhaust aftermarket in exhausts constructed in aircraft grade 304 stainless steel tubing, a material with higher content of carbon & nickel that won't rust or corrode.
BORLA® Cat-Back™ and Axle-Back exhaust systems feature patented straight-through and multi-core technology designed to unleash hidden horsepower. Increased exhaust velocity adds power, driving excitement, fuel economy, and the distinctive BORLA® Sound of Power respected by motoring enthusiasts everywhere.
Each system is built from premium T-304 stainless steel, superior to T-400 series knockoffs (such as 409), to give you the absolute best in performance and durability. Ultra-smooth mandrel bends ensure maximum flow & power, and precision computer-controlled CNC manufacturing ensures an accurate fit.
Best of all, BORLA® stands behind every system with a Million-Mile Warranty. Just what you'd expect from the world's most experienced (and most winning) exhaust brand.