Propickup Digital Magazine
Issue link: http://read.dmtmag.com/i/150744
Adding an aftermarket exhaust system can help increase fuel economy and release hidden horsepower – a win/win for fleet owner and sole-proprietor alike. By Peter D. duPre O EXHAUST SYSTEMS ne of the time-honored ways to improve the power and performance of pickup is to open up the breathing of the engine. Cold-air intakes and other modifications help on the front end. But their effectiveness is determined by how freely the flow of exhaust gasses is between the exhaust valves and the tip of the tailpipe. After all, the engine is just a fancy air pump – and the more efficient it is moving air from the intake to the exhaust, the better it will run. In the construction business world, however, hot-rod modifications are generally frowned upon because they are expensive ABOUT STAINLESS Vehicle manufacturers switched to stainless steel exhaust systems starting in the early 1990s because the EPA demanded that all exhaust/emissions systems be warranted for a five-year/100,000-mile minimum. The majority of automakers chose 409-grade stainless steel because of its superior resistance to corrosion and degradation to the acidic exhaust gases and external environmental factors. Aftermarket stainless exhaust systems generally use a 300-Series stainless, which will not turn brown from exposure over time to atmosphere and will only slightly discolor from high heat. The downside to this is 300-Series stainless doesn't handle heat cycling quite as well as 400-Series, becoming brittle over time from cycling from hot (operation) to cold (shutdown). For heavy-duty applications where prolonged operation means higher exhaust temperatures, such as with turbo-diesels, and deliver a diminishing return of gains for number of dollars spent. Such upgrades just don't pencil out. Sometimes all it takes to make a truck's engine more efficient is a simple upgrade to the exhaust. GOING CATBACK 400-Series is usually the better choice since it can stand operating temperatures up to 2,000 degrees without degradation. For contracting and landscape use, where the undercarriage may see scraping and the truck sees a lot of heavy use, we'd recommend going with 400-Series stainless exhaust systems instead of either aluminized steel or 300-Series stainless, especially if you are in an area where road salts are used during winter. Simply swapping out the exhaust system behind a gas pickup's catalytic converter with a performance aftermarket "cat-back" unit can add an additional 7 to 15 percent in horsepower and increase fuel economy up to 5 percent depending upon the vehicle and the exhaust system. Although the swap-out is 44 PROPICKUP Big Book 2013 ProPickup_2013BB_Exhaust Systems.indd 44 8/6/13 10:04 AM