When the 11-month development cycle started for the latest-generation Roush Mustang, the vehicle's chief engineer expected to see a mostly carryover 2009 engine. Reality skewed the expectation.
"The 2010 Roush Mustang has approximately 300 new parts and about 80% of those are in the powertrain," said Gary Jurick, Chief Engineer of the 2010 Roush Mustang. "We made a number of changes because Ford made a number of changes to some of the stock Mustang's components. For instance, Ford changed the cooling module and the air induction system, so we redesigned the Roush Mustang's electrical circuits as well as the intercooler radiator and the intercooler bottle, and we changed all of the associated hose routings and wirings."
Compared to the previous-generation Roush Mustang (2005-2009), the 2010 version presented a thorny problem to the intercooler system. "The aggressive styling of the front end challenged us to replace the double-core radiator," explained Erin Michael Dmytrow, Powertrain Engineering Manager for Roush Performance in Livonia, MI. "We came up with a full-face radiator that is placed forward of the stock Mustang's cooling module. We actually now have a larger low-temp radiator; by area, it's about 50% larger than the radiator we had in 2009. It also has a thinner core than the previous model."
The new single-core intercooler is paired with a relocated intercooler pump (from near the frame rail to behind the bumper beam and in front of the intercooler low-temp radiator), a new plastic injection molded de-gas bottle (replacing a blow-molded bottle), as well as molded-to-fit hoses (replacing cut-to-fit bulk hoses). "We thought it was going to be a quiet year from a powertrain standpoint, but it turned out to be a very large investment for us. Of the 45 new tooled parts developed for the 2010 Roush Mustang, 27 were for powertrain components and 18 for vehicle-level components," said Jurick.
Induction system revisions were done to reduce the airflow losses associated with piping that stretched across the engine compartment and to increase the cross-sectional area of the air induction system. "The air-inlet track length was shortened by more than half the size of the 2009 Roush Mustang's inlet track length," said Dmytrow.
Roush engineers opted to move the throttle body from its passenger side location to a driver's side position in 2010. "Since the routing path from the throttle body to the air cleaner was longer than necessary in the previous generation and because Ford changed the air cleaner assembly for the 2010 Mustang, this provided us with an opportunity to have a more direct routing path to the supercharger, reduce some of the induction losses, and free up some space under the hood," said Jurick.
Suspension changes include all Roush Mustangs being fitted exclusively with Cooper tires, including an optional wheel and 20-inch tire package. "All of the chassis tuning is different on the 2010 models. We retuned the dampers, specifically the front and rear compression curves have been changed. The spring rates are different, giving the car a more refined ride but with all of the handling of the previous model," said Terry Hendricks, Chassis Engineering Manager for Roush Performance.
The 2010 Roush Mustang production was scheduled to launch this month. The initial models are the Stage 1, the Stage 2, and the 427R. The most popular version, the 427R, is the first in the Roush Mustang lineup to have a supercharger to boost power up to 435 hp (324 kW) at 6300 rpm and 400 lb·ft (542 N·m) from 3500 to 5000 rpm. All versions of the Roush Mustang use the same engine as the Ford Mustang GT, which is a 4.6-L V8.