A staple of the Vortech installation...
A staple of the Vortech installation is providing engine-oil lubricationto the supercharger. Pressurized oil is obtained by installing a fittingat the oil-pressure sending unit on the oil-filter housing and running ahose to the supercharger. Oil returns to the oil pan via another hoseand this fitting punched into the oil pan. A Vortech-supplied punch andfitting mean the oil pan need not be removed from the engine. At thispoint, the bracket and supercharger are installed on the front of theengine by removing several small brackets and accessories and fittingthe Vortech bracket and blower.
There has been talk inside Vortech of making a sealed box for their air filter, along with a trap door to seal the regular air inlet whenever the hoodscoop supplies the majority of air, but at this point that's just talk.
Hitting the Rollers
We began our test day by running the Mach 1 on the chassis dyno. This was done on Vortech's Mustang dyno while we observed. All went well and we soon had our dyno results.
The first official pull netted 362 hp at 6,850 rpm and 328 lb-ft at 5,050 rpm, while the second pull showed 371 at 6,700 rpm and 327 lb-ft at 5,050 rpm. That's a gain of 9 hp and a loss of 1 lb-ft of torque as the oil warmed up.
If these numbers seem low, they are. That's because the Mustang dynos--which load the car to replicate its weight going down the road--religiously read substantially lower than the more widely known inertial Dynojets--as much as 40 hp less at times.
Underneath, the mass air meter...
Underneath, the mass air meter is fitted with a conical filter andfitted vertically inside the right fender. A flex hose leads air up tothe supercharger inlet.
Lance Keck, one of Vortech's dyno operators and the guy who'd been dyno'ing the Mach 1 for days, said the car would make another 5 hp if we ran it to death warming the oil, but that was about it. So we pulled the Mach and strapped on the Cobra.
Right out of the gate, the Cobra made 319 hp at 6,400 rpm and 306 lb-ft of torque at 3,850 rpm. The second official run saw nearly identical numbers-- 319 hp at 6,400 rpm and 309 lb-ft at 3,800 rpm.
We knew the Roots-type blower on the Cobra would make excellent torque down low and would fall behind the Vortech at higher rpm, but we weren't quite ready for such a large difference. The Cobra torque curve simply sky- rockets off idle and lays down gently with advanced rpm, while the Vortech centrifugal supercharger does just the opposite. Comparing torque and power curves, the Cobra and blown Mach just about make an even trade for area under the curve. So, the Cobra is about 50 hp shy of the Mach at the top end, but the Mach trails the Cobra by 90 lb-ft of torque in the 2,400-3,100 rpm range.
The other way of looking at it is the Mach is behind the Cobra up to 4,000 rpm. But, whereas the Cobra makes relatively flat curves all the way across the tach, at 4,000 rpm the Mach's horsepower curve simply soars away from the Cobra. As for torque, the Mach has a nice little bump of extra torque compared to the Cobra between 4,300 and 5,300 rpm--that's how it outpeaks the Cobra in torque.