Tom Wilson
January 27, 2010

Horse Sense:
In our first article on MagnaFlow's 3-inch exhaust, we mentioned the interior of Jason Cenora's '06 Mustang GT. We were just having fun, but Jason's car was torn up inside because it was in the middle of a makeover. That didn't stop him from feeling bad about it. This time, let us make a special note of saying the interior was transformed beautifully for our second test. In fact, it's so nice, you'll be seeing more of it in a feature article.

Time flies when you're having horsepower. While it seems that only last month we were trying MagnaFlow's 3-inch exhaust for S197 GTs on the dyno, it was really back in our February '07 issue when we made our initial report on these dreamy, big pipes ("Big Three," p. 122).

Or were they pipe dreams? In our first review, we lost power almost all the way across the powerband when we replaced the stock exhaust with MagnaFlow's 3-inch system. The only gain was at the power peak, where we saw an extra 19 hp-not enough to offset the string of double-digit losses on the way up the tach. Clearly, something was wrong. Sure enough, the MagnaFlow-equipped engine with the Novi 2200 was able to process so much more air, it was running lean after we bolted on the MagnaFlow exhaust system. If you read the story, you may recall how we easily spotted the lean air/fuel mixture, but didn't have any tuning capability on hand that day to do anything about it. We decided to have another dyno day and see what gains could be had with some tuning.

Today is that day, but before we verbally spin the dyno rollers again, a quick review of the test car and MagnaFlow exhaust is in order. The car is Jason Cenora's blue '06 GT, a showy number he uses to promote Hillbank Motorsports, a mail-order speed shop. While this car is dripping with neat details from the headliner to the stereo, in the powertrain department the players include only a Novi 2200 supercharger with air-to-air charge cooling. An electric water pump has been on board since day one, which was the first test since the fuel rails were upgraded. The fuel injectors, pumps, controller, and all other fuel-system components-save one-were left unchanged. They were same in both tests and therefore shouldn't influence the testing-neither should the larger fuel rails. We'll talk more about the change in the fuel system soon.

MagnaFlow's exhaust system is a 3-inch mandrel-bent assembly of two separate kits. A cat-equipped X-shape crossover makes up the first part; an after-cat with 5-inch diameter and round, flow-through mufflers make up the second half. Both halves are gorgeous, pinch-free, stainless steel parts designed for maximum airflow in high-output engines. Practically speaking, that means well-boosted, supercharged Mustangs as MagnaFlow has other, less pricey kits for stock, bolt-on, and lightly boosted blower cars. As it is, the 3-inch system can be found on the street for slightly more than $1,300, which is a solid hit to the wallet. But it's bright stainless steel, mandrel-bent, and wears two catalytic converters.

We must also note that although the system sports a pair of cats, it isn't CARB-exempted. Most importantly to us, it scrubs the exhaust so it minimizes environmental damage, even if it isn't a legally exempted part. We expect law enforcement may have other priorities.