The bite of some Ford SVT Mustang Cobras may not be as powerful as the company claims.
Ford Motor Co. is recalling all 5,300 Cobras sold to date to fix a faulty intake manifold and muffler that rob the 4.6-liter V-8 engine of power.
Following complaints from 50 owners of 1999 Cobras, Ford suspended vehicle shipments to dealers and mailed letters to all owners offering to fix their cars for free.
The letters were mailed Aug. 7, said Tom Scarpello, marketing manager of Ford's Specialty Ve-hicle Team.
'We know exactly what happened, and we're going to make sure that it never happens again,' Scarpello said.
The recall is an embarrassment because the Cobra is a high-performance vehicle intended to burnish the Mustang's muscle-car image. Horsepower ratings are a key bragging point for automakers, particularly on limited-production, high-visibility cars like the Cobra.
The $27,995 Cobra competes with the Chevrolet Camaro SS and the Pontiac Firebird WS6, both of which claim 320 hp. Ford claims the Cobra delivers 320 hp, too.
Ford has not publicly disclosed how much horsepower was lost. But according to a company source who has taken calls from disgruntled Cobra owners, the shortfall may be as much as 50 hp. Ford has traced the power problem to the engine's cast aluminum intake manifold and its exhaust system.
Some manifolds have flash - excess aluminum buildup left over from the casting process - in their intake runner tubes. The flash disturbs airflow to the engine and can reduce power.
Ford dealers will remove the intake manifold and clean out the flash. Owners will receive a new manifold or a resurfaced manifold from another car.
Ford also will pay to replace two mufflers in the Cobra's exhaust. The mufflers are too restrictive, said Scarpello, creating more back pressure than was originally specified to the supplier, Arvin Industries Inc. of Columbus, Ind.
'There was a design that was developed for the vehicle, but the production pieces did not meet all design specs,' Scarpello said.
Ford's engineers did not catch the differences in the production muffler, he said.
Arvin spokesman John Brown confirmed that the supplier produces the Cobra muffler.
'We delivered a product that met (Ford's) specifications,' Brown said. 'We are working with Ford to help them resolve this situation.'
By industry agreement, engine horsepower is quoted to a standard set by the Society of Automotive Engineers. The standard requires that engines be tested with all engine-driven accessories required to make the engine run, including the alternator and water pump.
Scarpello said Ford did not deliberately fudge the Cobra's horsepower rating. He added that most complaints have come from owners who drag-race their cars. Some have tested their engines on dynamometers, which measure horsepower by running the vehicle on a treadmill.
Because of power losses through the driveline, the dynos measured a horsepower rating 12 to 17 percent lower than Ford's quoted figure, said Scarpello, or up to 54 hp off.
Said Scarpello: 'It is not a case of anybody being deliberately negligent. There wasn't any funny stuff going on.'