Mark Houlahan
Tech Editor, Mustang Monthly
June 1, 2000

Step By Step

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138_03z 1999_ford_mustang_cobra Right_front_view
This is where the ’99 Cobra’s shortcomings have shown up—on the dyno. Though our Cobra put out a best of 265 hp, this number came about after letting the engine cool down significantly. We repeated the cool-down process for our after numbers as well.
The new parts are shipped to the dealer using a large pallet. The parts list includes a new Extrude Honed intake and a revised muffler configuration. The EEC-V also receives a new program as part of the procedure.
138_05z 1999_ford_mustang_cobra Engine_view
The technician removed the air-intake system, coolant hoses, and alternator before the intake itself could be taken off. The air-intake system, throttle body, and plenum cover will be reused.
138_06z 1999_ford_mustang_cobra Engine_view
Before the intake can be removed, the main engine wiring harness attached to the intake must be dislodged. This is the last step before taking the intake off the engine.
138_07z 1999_ford_mustang_cobra Engine_view
Now the intake can be removed. Published reports indicated the stock intake penalizes output by between 5 and 7 hp and the mufflers add a restriction of roughly 7 hp. As a side note, the indicated compression ratio has also been found to be suspect and restrict another 1 to 2 hp. These numbers correspond closely to the before-and-after numbers we recorded.
138_08z 1999_ford_mustang_cobra Intake_manifold
The original injectors are transferred to the new intake, along with the original fuel rails.
This is one of the intake ports on the original intake. Notice the roughness of the port and the amount of material found around the injector boss.
Now take a look at the intake port on the new Extrude Honed intake. Notice the smoother contour of the port and the reduced material surrounding the injector boss. Think of the new intake as a GT-40 intake with a ported lower.
138_11z 1999_ford_mustang_cobra Engine_view
With the intake ready to be installed, new gaskets are set in place and the intake is lowered onto the engine.
138_12z 1999_ford_mustang_cobra Engine_view
A new tensioner is also included in the kit. Ford heard of ’96-’99 Mustangs having problems with throwing belts when launching out of the hole at the dragstrip, and a new tensioner provided the fix. For 2000 V-8 Mustangs, Ford introduced a new, front-accessory drive system to fix the problem once and for all.
138_13z 1999_ford_mustang_cobra Exhaust_view
With the engine back together the focus turned to the exhaust. On the ’99 and 2000 Cobras, each side of the after-cat is one piece and can be removed as such.
138_14z 1999_ford_mustang_cobra Exhaust
From the outside, the two differ-ent exhaust systems look the same. However, the improvements were made within the muffler for increased flow and more power. The new mufflers also rewarded us with a more assertive, throatier sound.
When the mechanical work is done, the EEC-V is reprogrammed with a more aggressive tune-up.
138_16z 1999_ford_mustang_cobra Left_front_view
“Yeah, the car picked up 17 hp and 15 lb-ft of torque. I shouldn’t be late for dinner anymore,” Richard says.

All we wanted was a Mustang that could whip the pants off of an F-body. What we got was a Cobra with the same advertised horsepower as the Z28 and Trans Am, but quarter-mile times fell way short of what a 320-horse musclecar should run.

In our Oct. '99 issue, we were able to wring out a 13.79 at 100 mph with a brand-new '99 Cobra, but to run that number the entire air-filter assembly was removed and the valve covers, intake, and mass air meter were treated with bags of ice. Meanwhile, bone-stock F-bodies have been known to rip off low-13s without breaking a sweat, much to the chagrin of all Mustang owners and enthusiasts.

For the same article, our Cobra test car was strapped down for a few dyno pulls to verify the amount of horsepower making it to the rear wheels. With little break-in time and only 13 miles on the odometer, a first pull of 238.9 hp and 252.3 lb-ft of torque didn't translate into visions of seeing F-bodies in the rearview mirror. In the Cobra's defense, those numbers did increase to 266.6 and 285 respectively after thorough icing of the engine and removal of the air-filter assembly.

Once more people realized the Cobra was down on power they got on the phone to Ford SVT to request an answer to their power predicament. Their requests were heard and an Owner Notification Program, or an optional recall, was ordered. The answer to the problem came in the form of a new after-cat exhaust including revised mufflers, an Extrude Honed intake, and a reprogrammed EEC-V computer.

However, what kind of increase would the new components provide? To find out, we sat in on the rejuvenation of Richard Ringled's Cobra convertible. Before the installation of the new parts, Richard's Cobra belted out peaks of 265 hp at 6,000 rpm and 266 lb-ft of torque at 4,400 rpm on Dynamo Motorsports' Dynojet. Once the new components were installed, a return to Dynamo rewarded us with an increase of 17.2 hp and 15.7 lb-ft of torque. Factoring in a 15-percent horsepower loss figure, our before numbers (265 rwhp translates into 312 hp at the flywheel) were not far off the factory's 320hp rating. With the Ford-improved 282 hp at the rear wheels, that translates into roughly 330 hp at the flywheel, more than the factory rating. However, to truly put these numbers in perspective, we've heard of bone-stock F-bodies layin' down 280-290 hp at the rear wheels with the same factory 320hp rating.

It looks like Ford's improvements level the horsepower playing field, but for Cobra owners visiting the dragstrip there's still the predicament of finding a way to get it to the ground. Oh well, one thing at a time.

Horse Sense:
Not only did the new components boost horsepower on Richard Ringled's Cobra, fuel economy also improved from an average of 22 mpg up to 24 mpg--an improvement Richard is most happy about, since his daily-driven Cobra sees a round trip of 95 miles a day.