THE SHOP

July '16

Issue link: https://read.uberflip.com/i/688875

Contents of this Issue

Navigation

Page 75 of 119

70 THE SHOP JULY 2016 PERFORMANCE With regard to stainless steel, two spe- cific grades are used most commonly by performance aftermarket exhaust system manufacturers. This includes Grades 304 and 321. Grade 304 stainless steel is high- quality stainless, highly resistant to cor- rosion (both from exhaust deposits and from ambient/road conditions), and is non-magnetic. While Grade 304 stainless steel is used as an industry standard for high-quality exhaust components, Grade 321 stainless steel (often referred to as "aircraft" grade) offers even higher resistance to heat, fatigue and cracking at extreme heat levels. This grade is a good choice for extreme heat levels as are encountered in turbo exhaust systems. In essence, a high-quality stainless steel exhaust component (headers, pipe, muf- fler, etc.) should feature either Grade 304 or 321 stainless steel. Inconel (available in Grades 625 and 718) is a high-strength nickel-chromium- iron-molybdenum alloy (often referred to as a "super-stainless steel" material). The high level of nickel lends this material's use to extreme applications such as For- mula 1, NASCAR, submarine propulsion motors, naval military exhaust systems, etc. Inconel's benefits primarily include its high rupture strength and ability to with- stand extreme temperatures for prolonged periods. Titanium offers a higher strength-to- weight ratio as compared to steel, and its melting point is higher than other mate- MATERIAL MELTING POINT COMPARISONS (DEGREES F) Low-carbon mild steel .................... 2500 High-carbon steel ............................. 2600 Stainless steel ..................................... 2750 Aluminum ........................................... 1220 Titanium ............................................... 3040 Inconel .................................................. 2600 Running an engine on a dyno requires the use of the dyno shop's headers in order to monitor air/fuel ratio. When running a fresh engine on a dyno, avoid using the headers that will be installed in the vehicle. Dyno sessions, especially on a new engine, will result in high exhaust temperatures, which can easily discolor new headers. A good dyno shop will have headers on hand specifically for dyno runs. Don't sacrifice your new headers for a dyno session. If the dyno shop doesn't have headers on hand for your engine, buy or borrow a used set just for the dynamometer runs. Getting Ahead on Getting Ahead on Getting Ahead on HEADERS

Articles in this issue

view archives of THE SHOP - July '16