Little did Ron DiDonato know when he started Superior Metal Fabricators back in 1979 that, more than 30 years later, his business would involve making performance-minded exhaust systems for all sorts of cars and trucks. At the time, Superior was based in Anaheim, California, and was a go-to for folks who needed specialized equipment fabricated, such as stainless steel items used in the hospital supply business.
But having a side interest in racing sprint cars opened up other opportunities in manufacturing and, when the racing world changed its rules concerning decibel ratings of the race cars, DiDonato worked at building compliant muffler systems for the racers, and soon began working with and shipping directly to a lot of the race teams involved in the sport.
To keep up with the demand, DiDonato started SpinTech Performance Mufflers in 1995 and moved into a new shop located in Riverside, California. SpinTech was beginning to make a name for itself and, after DiDonato saw what was being done with mufflers in the race world, he began thinking about building performance mufflers for the street.
Through the ’90s, the SpinTech side of the business was outpacing his other business, and the company gained a reputation as a problem solver: If you had an odd application, you went to SpinTech because they’d develop a complete exhaust system for you, from the end of the header to the tip of the tailpipe.
By 1997, when SpinTech developed the use of oval tubing in their exhaust systems, things really started to get interesting. By using oval-shaped tubing, they were able to effectively run the same amount of volume through a 1-3/4x3-inch pipe as they could a 2-1/2-inch round pipe. They can easily accommodate the need for 3-1/2x6-inch applications (equivalent to a 5-inch round), and have custom built even larger setups for customers when needed.
The space saved by using the oval tubing allowed SpinTech to tuck an exhaust pipe up closer to the floor of the car, usually eliminating any chance of it hanging down below the frame or rocker panel. And for lovers of lowered cars, this simple change was a godsend.
A portion of SpinTech’s business has come about because no one offered solutions for newer cars, either (Pontiac GTOs from 2004-06 and Dodge Dakota trucks are just two popular examples SpinTech can supply exhaust systems for). DiDonato admits he does like the challenges associated with unique applications because it allows him to find creative ways to solve routing problems.
Such is the case with the X-frame cars found under ’58-64 Chevys. On earlier cars of the ’30s and ’40s, it was a simple fix by running the exhaust inside of a framerail and parallel to the driveshaft but, with this type of X-frame, it is exceedingly difficult to run any performance-sized exhaust, unless you do it with SpinTech’s oval tube (they offer it in 2-1/2- to 6-inch sizes).
SpinTech also offers complete exhaust/muffler kits as well as individual parts and pieces to complete any job, but to figure out what was specifically needed for a ’61 Impala (no “kits” exist), we followed SpinTech as they designed and built a system using their 1-3/4x3-inch oval tubing (similar in volume to 2-1/2-inch round) and a pair of their mufflers. The end result provided a nice rumble at idle and just enough “noise” to indicate there was something under the hood without it being overwhelming to the ears. Like DiDonato says, if it sounds too good to be true, it’s SpinTech!
With the fabrication of the exhaust completed, all that was left was to add some heat insulation to the floorboards above the mufflers and wrap the exhaust with some composite fiberglass material from Design Engineering Inc. (DEI). Wrapping the exhaust is easy (DEI’s website gives you the formula to figure out how much you’ll need) and it comes in 15-, 50-, and 100-foot rolls in both 1- and 2-inch widths.
DEI claims a 50 percent drop in underhood temperatures when using their wrap and it certainly helps when you have to run an exhaust system up close to the floor (as in just about every hot rod). They also sell stainless steel locking ties to finish off the ends of the wrap job. As for DEI’s Floor & Shield II material, it has a 10-mil aluminum face bonded to 1/8-inch composite glass-fiber core and is backed with a pressure-sensitive backing. It’s similar in concept to what rodders use for sound deadening inside their cars (and it can be used for that, too) but this material can withstand up to 1,750 degrees of direct continuous heat. The material is 3/16-inch thick and comes in three sizes: 21x24-, 21x48-, and 42x48-inch sheets and, after making some templates, an installer can easily cover whatever they need.
And, after investing in a custom exhaust system for your ride, a little bit of insurance to help keep it (and you) running cool would seem to make sense. The following photos show how the exhaust was custom-made by SpinTech and then wrapped with DEI products.