After Power Trip's scorching 10.45/128 run, there's not much more to prove with this project. Sure, a brake-booster swap from my vacuum setup would undoubtedly raise launch boost numbers from the current six-and may very well push the e.t. into single digits. But I really like the feel of the vacuum setup so I have no plans to change it now. And of course, there's the issue of a roll cage...I won't install one and cut up my ride, I've gone way too fast without one already, and this is a street car first.
However, there is one thing I'd like to upgrade: the GNX-style exhaust system. I removed the GNX suspension years ago but kept the stainless GNX exhaust on as it is a quality piece. It is a 2.5-inch system that sounds and performs fine, but there are two problems: one, the design, created to clear the GNX's panhard/stiffhard bars, runs the tailpipes fairly close to the upper control arms and the rear wheels. As this car has notched frame rails for bigger rims and tires, and I plan on getting wider meats soon-it would certainly cause interference.
And two, this turbo V-6 is flowing so much air through the 3.5-inch downpipe, the 2.5-inch system might be corking up the flow-even at pump-gas boost levels.
So in the interest of bigger rims and bigger power, I contacted Buick specialist Jack Cotton of Cotton's Performance Center and requested his 3-inch dual exhaust system. It arrived the next day, so I arranged with contributor Chris Werner to do the install at his place, and local shop TTP for before and after dyno testing. Keep reading to see how this system did.
For video of Power Trip's dyno runs, visit the 3-inch Turbo Buick Exhaust Dyno Test Video Link.
 Here's the current exhaust:...  Here's the current exhaust: a stainless 2.5-inch GNX system. Note how the mufflers are split wide to clear the GNX suspension's front torque arm mount brace, and the tailpipes are of a straighter design to go over the GNX's panhard/stiffhard bars. Also note the copious amounts of oil coating the underside of this Regal: you might laugh, but it keeps the rust away! |  Jack and Brian Cotton of Cotton's...  Jack and Brian Cotton of Cotton's Performance Center were instrumental in building this 10-second Buick. As Cotton's fabricated my beautiful 3.5-inch downpipe, I wanted to utilize their expertise on the exhaust system as well. This dual 3-inch exhaust (PN EX102AL) features aluminized steel construction and mandrel bends. Stainless, straight-through Magnaflow mufflers are utilized for big flow, and this system comes with installation hardware as well. And the best part: at only $579, big flow doesn't have a big price. |  Up at Chris Werner's place,...  Up at Chris Werner's place, we lift the Buick up and get to work. To remove the GNX exhaust system, we start by loosening the four front flange bolts with a 14mm socket/ratchet combo. |
 Then the four muffler clamps...  Then the four muffler clamps in the rear, as well as the two hangars, are loosened. |  The front of the system is...  The front of the system is dropped down. This GNX-style exhaust has been on for years now and apparently the mufflers and over-axle pipes have gotten pretty attached to each other, so Werner uses a screwdriver, then an air chisel, to remove the pipes from the mufflers. |  The chisel is able to separate...  The chisel is able to separate the passenger-side front pipe from the front of the muffler, and Chris tries to remove the pipes over the front of the axle by twisting them out. No go-the mufflers have to be chiseled off before there is enough room to finally twist them out the rear. |