So How Does It Sound?
Treated with high-temp silver...
Treated with high-temp silver paint around the weld surfaces and mounted back up on the car, the fully welded Flowmaster 3-inch dual system is ready to rock. The sound with axle turndowns is simply amazing, both at cruise speed and at full throttle!
Go to www.popularhotrodding.com
and check out the video of Project Nova as we put the new Hooker/Flowmaster system through a thorough sound check!
DIY vs. A Good Shop
We opted to use the services of Automotive Excellence in Huntington Beach, California, but assembling a custom exhaust system like ours is well within the reach of the average guy, provided you’ve got the right tools. Assuming you already have a serviceable MIG welder, a compressor, jackstands, and all the normal stuff, you can expect to buy a few specialty tools for a job like this. We priced out some super affordable tools from the DIY experts at Harbor Freight that will provide similar functions to the pro tools at AE. The comparison works out like this: AE charges about $300 in labor for a job like this. You get to watch from the sidelines while the pros do it, but you won’t gain much personal experience. Buying the tools yourself, however, will give you the satisfaction of doing it yourself, while rounding out your tool collection.
Exhaust System Sizing
With the Flowmaster U-Fit...
With the Flowmaster U-Fit pieces, Super 40 mufflers, and Hooker collector adapters tack welded in place, Mayea removed the system from the Nova to make the final welds. Mayea set the Millermatic 35 to 4 amps current and the wire feed speed to between 40 and 45 inches per minute, using .035-inch wire. “You don’t want too much heat or you will blow a bunch of holes. You also need a really good ground connection,” Mayea says. Some Miller MIGs have Auto-Set, which only requires the user to set the material thickness (16 gauge in this case) and the wire thickness. Amperage and wire speed are automatically set.
It’s possible to mathematically calculate the flow requirements of an exhaust system based on the total mass flow of the system (mass of the ingested air plus the mass of the fuel), but it works out to about 2.2 cfm per engine horsepower. For a straight piece of round pipe, each square inch of cross-sectional area flows about 115 cfm, so it’s a matter of working forward from there. This handy chart takes most of the math out of sizing an exhaust system, and from this you can see that our 532hp Dart small-block breathes nicely with a dual 3-inch system.
||PIPE AREA (IN2):
||MAX HPPER PIPE:
||MAX HP(DUAL SYSTEM)
|Tools You’ll Need
|16-ton Central Hydraulics pipe bender, 3-inch capacity
|Chicago Electric heavy-duty cutoff saw, 14-inch blade
|U.S. General large tailpipe expander
Where The Money Went
|U-Fit Dual 3-inch pipe kit
|Super 40 Series Delta, 3-inch inlet/outlet
|Super Comp headers, 17/8-inch dia.
|Southern exhaust hangars