Ever since Ford introduced the modern Shelby GT500 four years ago, almost no one has complained about the prodigious power levels produced by its supercharged 5.4-liter V8. With as much as 540 horsepower and 510 pound-feet of torque in the 2010 model, there was no shortage of grunt. No, the issue was an excess of mass.
Before the contemporary GT500 was born, Ford had a blown aluminum block 5.4-liter V8 in the short lived GT supercar. However, when the engineers at Ford's Special Vehicle Team developed the GT500, they opted to mount the GT's cylinder heads on the cast iron block used in the big F-Series pickup trucks. After debuting a visual refresh for the Mustang a year ago, Ford has spent the last two months announcing fresh new powertrains for the base and GT models. That process has now come full circle with SVT rolling out a heart transplant for the Shelby GT500. The 2011 model finally has the aluminum powerplant we all wanted when it debuted, and the effect is absolutely en-lightening.
The SVT engineers actually had a reason for going with the iron block in the first place. Mustangs like the GT500 and its Cobra ancestors often end up being heavily modified for use at drag strips and race tracks, and the SVT crew wanted to make sure the standard block could stand up to the rigors of those significantly higher outputs. They chose not to use an aluminum block until they had a chance to develop one with the same strength as the iron version, and that time has now come.
We recently had a chance to sit down with GT500 chief nameplate engineer Jamal Hameedi in his office at SVT's headquarters to learn more about what's new for 2011. Switching to an aluminum block was a bit more complicated than simply digging out the casting molds that were used for the GT. The engine in that 200+ mph supercar used a dry sump lubrication system and featured iron cylinder liners. The new GT500 engine is derived from the structural design of the older block but retains the wet sump system used in other Mustangs. The real magic is something that most owners will likely never actually see.
Last June we learned about an award that several Ford researchers had received for a cylinder bore coating system they developed called the Plasma Transferred Wire Arc (PTWA) process. The Ford press release at the time framed the award in terms of fuel efficiency and gave no real hint about what was about to come. It now turns out that the first production Ford to use the PTWA process will be the 2011 GT500.
The heart of the PTWA process involves feeding a steel wire into a device that heats it up to 35,000 degrees Fahrenheit and then sprays it onto the aluminum cylinder bores. Ford is not actually the first company to use a process like this. Similar mechanisms have been used to coat the fan blades in jet engines for a number of years. One of the primary differences is that Ford is using PTWA with a conventional steel alloy rather than some super exotic aerospace material. Ford isn't even the first automaker to use this specific coating process. That honor falls to Nissan, which actually licensed the technology from Ford for use on its V6 engine in the GT-R.
http://www.autoblog.com/2010/02/08/2011-ford-shelby-gt500-finally-gets-aluminum-engine-loses-120-p/#continuedMore at the link...good to see they finally ditched the heavy-assed iron block; if they ever give it a real suspension, this longtime GM fanboy is gonna cross over...
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