Allen Garrett’s Alaska Cobra Gets New Whipple Gen 4 2.9L Supercharger

Photos courtesy of Rusty Allen.

Whipple recently released its brand-new Gen 4 2.9L Crusher Supercharger for the 2003-2004 “Terminator,” and we happened upon one of the first Cobras to have it installed.

While creeping around Instagram, one clean Cobra caught our eye, and it just so happened to have the new 2.9L Whipple under the hood. Allen Garrett of Alaska (yes, you read that right!) bought the 2003 Cobra new in May of 2003 and has only put 54,000 miles on it in the past 16 years.

Garrett’s Build

The Mustang’s engine was built in Garrett’s garage in Anchorage, Alaska, and is a standard-bore 9:1 Teksid build utilizing a block sourced from a 1993 Lincoln Mark VIII. It is equipped with King SI-Series bearings, ARP 2000 hardware, Manley connecting rods, and a stock crank. Ed Schaider custom spec’d the Arias pistons. Garrett says he built the engine with the help of ModularFords.com.

“All of the well documented builds over the years enable DIY builders like me great success when building something with no prior experience.”

Garrett also explained that ABD Machine of Anchorage, Alaska, performed a crank stud installation/modification.

The picture on the right shows Alaska Raceway Park, combining drag racing and breathtaking views.

“It’s a process done on the crank for modular blower cars to install a longer 9/16 stud to strengthen the crank snout due to the forces that larger blowers exert on the crank snout. It reduces the chance of a complete crank snout failure or premature wear. Other than that, it just has the standard rotating assembly balancing. This combo is really basic, and it works well.”

Which brings us to our next point: the Whipple supercharger. We spoke with Dustin Whipple, and he gave us the lowdown on the new blower.

Whipple’s New Gen 4

“The Gen 4 rotor set is a new profile that we developed to maximize our current supercharger housings,” he explained. “In the new profile, we were able to increase both isentropic and volumetric efficiency throughout its curve, which increased its flow nearly 4%, while maintaining the same length and diameter rotor. This means that it uses the same housing, gears, hubs, and bearing plates.”

“We also moved some of the material from the male rotor to female rotor to lighten the male and lower the mass of inertia. This also stiffens the female rotor for less deflection. The end result is more airflow at the same blower speed, lower discharge temperatures, and better durability in race applications. All the Gen 3 upgrades further enhance the Gen 4, so it’s the next evolution of the 2.9L.”

The Gen 4 makes around 1-1.5 psi more boost than a Gen 3 with the same pulley size, meaning that less power and RPM are needed to make more boost. That said, you can expect 30-150 additional horsepower/torque at the same boost level than with a Gen 3 unit. Whipple also says that the blower is good for intake temperatures cooler by 10 to 80 degrees Fahrenheit. For those already running a Gen 1, 2, or 3 Whipple, a simple bolt-on upgrade can bring power levels to that of a Gen 4.

According to Garrett, his particular Cobra’s application produces 25 pounds of boost. The twin-screw supercharger upgrades also include new and advanced manufacturing methods, meaning increased efficiency as well as more accurate and tighter tolerances. Upgraded double-lip PTFE rotor seals allow for higher RPM, temperature, and pressure ratios. The new rotor housing features new angled support ribs lending to a bold appearance, and revised port shape allows for increased rotor filling and a decrease in turbulence.

While Garrett has kept the combination simple, he says that’s his favorite thing about it.

“Thanks to some of these aftermarket manufacturers, like Whipple, you can throw an aftermarket blower on and make 800+ wheel horsepower fairly easily on a stock motor with supporting mods, and run in the 9’s, which is fairly staggering considering the platform is 16 years old now. I would also say that I love the pure rawness of the car being that it is a stick shift combo which takes a bit more perseverance, patience, and a little more skill than the average combo to run successfully at 3,500 pounds well into the 9’s at 150+mph.”

On a recent visit to Alaska Raceway Park, Garrett’s Cobra ran a best quarter mile of 9.28-seconds at 153 mph. With numbers like that right out of the gate, we’re excited to see the true potential of Whipple’s newest supercharger unfold.

Article Sources

About the author

Stephanie Davies

Stephanie Davies got her start in automotive media while studying at Rutgers University and eventually landed at Roush Performance outside of Detroit, where she now resides. She writes for various automotive outlets, works with rescue dogs, enjoys driving her Roush-charged Coyote-swapped 1992 Fox body Mustang race car, and is convinced that absolutely nothing in the world beats a sunny weekend at the track.
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