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.
Nissan actually licensed PTWA from Ford for use on its V6 engine in the GT-R.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.
Hameedi believes that Ford has an important advantage over Nissan. Anyone that has ever used a teflon-coated pan is familiar with the problem of the non-stick coating peeling off over time. In the past BMW has also had issues with the nickasil coatings prematurely separating on some of its aluminum blocks. Getting any dissimilar materials to adhere to each other is always a problem, so the initial surface has to be specially prepared in order for the coating to have something to hang on to. Nissan licensed Ford's coating technology but used its own surface preparation process. According to Hameedi, Ford's surface preparation works so well that even after engines have gone through a full durability cycle the bores still look like new.
Using the PTWA process allows the block to have a thinner surface coating - only 150 microns deep - that is just as tough as one with cast or pressed-in iron or steel liners. However, using less material results in lower weight. According to Hameedi, the GT500 block is 8.5 pounds lighter than the sleeved GT version. Overall, the complete engine is 102 pounds lighter than the 2010 cast iron engine. The steel coating has also helped Ford reduce the internal friction of the engine, aiding both efficiency and power production.
