More Power and Torque for Corvette C5s

The new Bassani 421-series header and Aft-Cat system net 30 more HP and35 lb-ft more torque than a stock C5 system

Cam Benty Sep 16, 2004 0 Comment(s)

First Impressions

When it comes to Corvette and late-model Chevrolet performance, RogerVinci of Vinci Hi-Performance always has an opinion with credible merit.After conducting the baseline and Bassani Xhaust testing, Roger said, "Iwas very impressed with the entire system Bassani sent us. We havetested exhaust systems for most major C5 system manufacturers and, whileI always find things I like and things I do not, most manufacturersappreciate the critique and attempt to correct issues that we find."

In the case of the Bassani system, Vinci not only conducted chassis-dynobaseline to Bassani tests, but also drag testing. At Orlando Speedworldon July 30, 2003, the stock automatic-trans Corvette made a 13.83/101.45pass. With the exhaust system installed, on September 10, 2003, roundtwo testing was on. The results: 13.33/104.5. That's an impressive 0.5second quicker in the quarter-mile and nearly 3 mph faster through thetraps!

And while the performance was pleasing, Roger Vinci had even more praisefor the Bassani system. "A few items that stood out on the Bassanisystem were first the header-to-cylinder head gaskets they furnished.They are a work of art. They consist of a pair of machined plates fittedwith soft packings at each port. This system presents a positive sealthat will probably never need replacing.

"Second, the tri-Y header is a 4-2-1-style header. The headerincorporates a technique whereby two cylinders per side are connectedtogether into two separate collectors, then the two collectors areconnected into a third collector--thus '4 into 2 into 1.' This technique,coupled with the unique optimum-length tubing, provides the huge torqueincreases the header demonstrated on the chassis dyno. Obviously, thismuch plumbing requires more pieces for the installer to deal with.Bassani separates these pieces for easier installation, then provides aneat system to fasten them together. A pair of short tubes are weldedalongside a slot on each of the primary pipes of the slip-fitted tri-Ycollectors. Allen-head bolts are provided to complete a leak-freepackage.

"The rest of the system utilizes fitted flanges and ball-end fittingsfor a perfect, adjustable, rattle-free fit. The third item I foundimpressive is the Ferrari-like exhaust note that's so different from anyof the other systems we've tested. Upon testing the car on the road, Iwas equally impressed with the very noticeable increase in brute powerat low-end and midrange rpm. The power is right where you want it. Youknow, we spend very little time at 6,000 rpm and a whole lot of timebetween 1,500 and 5,000, and that's where this system really performs."Roger concluded by saying, "I highly recommend this system to any andall street and strip or autocross enthusiasts."


6 The first piece of header tubing is installed from below on thedriver side.

7 The second piece of the header system is installed from above,and make sure not to damage the spark plugs.

8 With a slight amount of manipulation, the headers line up andfall into place with little effort. They are left untightened while thebottom collector flange system is installed.

9 With the collectors in place, the headers will look like this.The collector system bolts in place with pinch clamps to avoid exhaustleaks.

10 With the catalytic converters bolted to the collectors, theoxygen sensors are screwed back in their original locations. These twooxygen sensors are at the back of the catalytic converters. The LS1 andLS6 engines utilize four oxygen sensors. The Bassani X-pipe systemincorporates all of them.

11 The pre-catalytic converter oxygen sensor is mounted in thehole located in the header flange of the Bassani system.

12 The after-cat portion of the Bassani X-pipe system is made ofstainless steel. The secret of the system lies in the X-pipe located inthe muffler-shaped portion of the exhaust. Good stuff happens in there!

13 (above & right) The X-pipe is slipped in place and held with clamps andhangers similar to the OEM system. Overall ground clearance with thesystem is 1 inch higher than the OEM system.


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