29 The 2008 Mustang GT

The 2008 Mustang GT

Sunday, March 29, 2009

The 2008 Mustang GT

Mid June 2009 at Milan Dragway for the NMRA race, our black, automatic 2008 Mustang GT ran a best of 10.72 @ 128 mph. This was achieved in mid 70 degree temps and above all on 20in Wheels and tire’s on all four corners. The rear tire is a Nitto 305/35/20” drag radial. The gas tank had only 93 octane in it and the car sees a squirt of Alky at WOT.

It still has a totally stock torque converter, and no internal mods done to the stock 5-speed automatic trans. And recently it got a 3.55 (stock was 3.31) gear with an Eaton posi.

The suspension is totally stock. Nothing has been added, replaced or enhanced in any way on this cars chassis components other then the 20” wheels and tires.

On the 10.72 run it pulled a 1.55 sixty foot, and weighted in at a hefty 3860lbs on this day. The MPH on some earlier runs were nearly 130mph when crossing the 1320 mark, but on the 10.72 run it stayed in the 128mph area.

We’re now confident that it will comfortably go 10.50’s to 10.60’s as soon as we get it out this fall in some sub 60degree weather.

Watch our youtube video of the car on the 10.72 run. It pulls the left front tire off the ground for an instant at the launch.

In the late fall of 2007 Alternative Auto’s shop owned 2007 black Mustang GT was involved in an accident that required replacing the car with a new one in early 2008.

The replacement 2008 GT was equipped, and looked in every way identical to the 2007 GT with the exception of a different 5-spoke 20” rim & tire combo.

Basically for the 2008 season, as far as performance at the ¼ mile, and on the Chassis dyno goes… the ’08 GT picked up right where the ’07 GT left off at the end of the 2007 season. This is why no updates or articles have spawned from us on the new ’08 car during the 2008 season, it simply didn’t run much better then the ’07 GT did.

The ’08 GT has the same 16-17psi intercooled twin-screw Whipple supercharger with Alky injection. The major difference with the ’08 GT is that at the beginning of the ’08 season we opted to install a forged short block into the new car in order to eventually be able to lean on it more, and ultimately shoot for some mid 10 second ET’s in this car. The replacement forged motor that went into the ’08 GT was in no way a high dollar exotic. It simply had Stronger Forged pistons that produce slightly more then stock compression (9.8 stock vs 10.1 with new pistons).

And the forged short block also got stronger Eagle brand steel connection rods. And that’s it. We even left the stock “cast” crank in it, to prove that production “Non-Steel” 4.6L Ford cranks are very durable. The 3-valve Heads and camshafts were left the way they cam from Ford. No major head work at all, other then a light decking good clean up, and performance valve job.

The 2008 GT weighted in at a hefty 3840lbs and on 305/35/20” Nitto drag radials, and ran a best of 10.90 @ 127mph just like the ’07GT did. The ’08 GT still had totally stock exhaust except for two aftermarket FlowMaster mufflers changed at the back of the car and that’s it. The ‘08GT still had the stock torque converter and 3.31 gears in the rear and absolutely no suspension work at all to get into the high tens!! And will probably easily go deeper in the 10’s in the ¼ mile with still no suspension pieces changed at all.

The reason for this update is that in 2008 Ford Racing released an awesome sounding, and “rumpy” idling pair of camshafts for the newer 3-valve Engines. They are simply called the “HotRod” cams. We’ve used these on a couple of customer cars — combined with other parts, bolt-ons and tuning…. and found the cams to be a pretty viable upgrade in conjunction with other items as well on the new 3-valve 4.6L Mustangs. I personally couldn’t pass up how great these 3-valve cams sound idling along with the Header pinging & tinging while idling with the big cams. Plus potentially more power too.

So with that being said; in January 2009 we started doing the cam change to the black ’08 GT, and also decided to make as much of a difference at once as we could since the ’08 GT already had a forged motor in it. The decision was also made to install BBK long-tube 1-5/8’s headers and their matching 2.5” X-pipe that as two Hi-Flo cats in addition to the FRP HotRod cams. Till now the Whipple equipped ’08 GT had all stock exhaust except for the mufflers.

In a nut shell, we thought the results were pretty awesome. On average before the Cams, BBK long tubes & hi-flo cats we’re installed, the car would produce right at 500 RWHP thru the automatic transmission and heavy 20” wheels & tires, at about 16 psi of boost. Once we got the idle, and a bunch of other drivability, and tuning aspects straightened out, we began to sneak up on the Wide-Open-Throttle pulls.

The results ended up at 540rwhp with the overall boost now showing only 13psi !! Because of the better more efficient breathing of the now installed cams, headers and Hi-Flow cats, this caused the available boost to drop to about 13psi. So a 40 hp gain to the rear wheels along with the boost drop, we thought was pretty darn good for the cam and header upgrade.

But in an effort to see what more it could do, and to compare “Apples to Apples” we changed the pulley to one that was a ¼” smaller, and that brought the boost back up to only 14.5psi, (still not the original 16-17 it had before) and she picked up 22 more to the wheels. The ’08 GT is now sitting at 562 RWHP @ 14.7psi of boost with 93 octane and Alky injection.

We’re hoping that for the 2009 season this additional 60+ more hp at the wheels in cool weather should bring in some mid 10 second ETs at nearly 130+ MPH.

Watch our youtube video of the car on the 10.72 run. It pulls the left front tire off the ground for an instant at the launch.