5.0 Mustang & Super FordsHow To Engine
Building a 1,627 HP 2007 Ford Shelby - 7-Second Screw
Mark Meiering is the first to take a blown GT500 into the 7s
Horse Sense: We'll admit we're terribly jaded, but when Mark fired up his Shelby in the Accufab shop the incredibly delicious sound tickled our pleasure center. Good thing, too, because if the bright bouquet of methanol fuel, the crackle and thunder of 1,700 hp doesn't do it for you, get your pulse checked. It's difficult to believe this beast occasionally prowls the streets.
Mark Meiering is a successful house painter from Albuquerque, New Mexico, with a thing for fast street cars. It's understandable. After a week of evenly applied Sandalwood Beige, any of us would look forward to a heavy-duty cruise scene on Saturday nights.
But as you all know, by the time a car makes it to these pages there's typically more to the story than boy meets blower and beats Camaro. In this case it's the familiar tale of a little was fun, so why not a whole lot more? Or, how to run 7s in three engines and two blowers.
He bought his GT500 Shelby new in 2007 and has "done a ton of street driving" with it. He says it was stock "about two weeks before I got bored with it," and he and a friend bolted on a Kenne Bell 2.8-liter screw blower in about 10 hours. This was KB's first generation Shelby blower. "It really woke up the car," Mark explained.-
The combination lasted about six months before a tuning issue rattled a rod through the side of the block. There was no warranty love coming, of course, so Mark had to paint a few extra bungalows before latching onto the then-new Ford GT-based aluminum 5.4 block to build a second engine around. The compression was set at 10:1 for a little extra punch and the 2.8 blower was put back on. Later Kenne Bell released the 3.6 blower and Mark had to have that. This proved a happy combination, or as Mark put it, "That was a fast street car! It was happening."
Of course, Mark was always fiddling with his by-then 10-second Shelby, and among other things, he tried a set of more aggressive cams. These were causing some issues when a friend of Mark's was referred to John Mihovetz at Accufab as a hot modular expert who could probably sort out the problem. This isn't bad advice, as regular readers may recall John has a twin-turbo 4.6 program he's developed to 2,800 hp and nearly 5-second timeslips in a tube-frame Cougar. The result was John built a motor for Mark in 2009 that made 1,100 flywheel horsepower, which you'd think would be enough. We documented this engine as part of a Kenne Bell 3.6-liter supercharger test in 2010 (Kenne Bell Twin Screw Supercharger - Bell Curve - 3.6-Liter Twin Screw). As this was the same engine that's still in the car the blower article gives some good nuts and bolts background if you're interested.
By that time, Mark was already circling moth-like to the drag racing flame as the only place to wring out this sort of "street car" is at the dragstrip. The Mihovetz engine with its Ford GT block, heavily prepped GT500 cylinder heads, and top-notch internals were ready to make truly serious power, and Jim Bell at Kenne Bell had become interested in the program as well. The goal was set to make it the first belt-driven GT500 street car in the 7s, a feat performed at a hot and humid test session at Fomoso dragstrip in Bakersfield, California, last September with a 7.817-/180.57- mph pass. Considering some of us on staff remember when it nearly took a Top Fuel dragster to run these numbers, lobbing a steel-bodied Mustang with a full interior down the quarter-mile in less than 8 seconds is fairly mind-blowing.
Key to making serious horsepower is fuel. It absolutely must be high-octane for detonation resistance, and like many today, Mark found alcohol just the stuff. For the most part this means E85 from local gas stations, but just as we were documenting Mark's ride, John Mihovetz switched the car to methanol, like his pure drag car runs. The two fuels are somewhat interchangeable. Yes, they do require different tunes, the methanol is horribly corrosive and requires careful attention to material compatibility throughout the fuel system, plus it requires even greater fire-hose volumes than E85. But it also has cooling and burning properties much closer to E85 than gasoline.
Supplying the necessary fuel volume is far beyond the capabilities of any bolt-on fuel pumps and lines. Today the Shelby wears a fuel cell and cable-driven Waterman Racing Components fuel pump. A belt drives the external dry-sump-system oil pump, with a cable running off the back of the oil pump to the Waterman fuel pump at the rear of the car. While capable of resetting your concept of how much a fuel pump can cost, the Waterman pump has proven bulletproof and easily capable of slaking the alcoholic 5.4's thirst. It's even silent, a plus for street operation.
It also takes a blower. Kenne Bell has kept the program sourced with 3.6-liter, liquid-cooled units, the better for KB to develop its largest blower currently (there's always a larger one coming…). We won't re-plow the 3.6 story here, but will point you toward the photos showing the low-restriction inlet developed on Meiering's car. It's key to getting 1,700 hp worth of air into the engine. We'll also note Kenne Bell's 3.6 Shelby blower kit is pretty much a bolt-on on Mark's car. Liquid-cooling was used, along with boost in the mid 20-psi range.
As for the core engine, it's a 5.4 using the Ford GT block—3.555-inch bore x 4.165-inch stroke—and heavily prepped GT500 cylinder heads. It's mainly the work of Fred Grouchulski at Mihovetiz's engine shop Accufab Racing Engines. While it does rev, this is no flyweight small-block, but rather a bulletproof, built-to-take-it drag motor jammed with the knowledge and hand-detailing it takes to prevail at these power levels.
To get an idea of the mechanical robustness, the engine specs include a billet Bryant crank and John's special Manley Pro Series connecting rods. Fred calls these "spark diesel rods" because they're about three times beefier than gasoline rods, hefting in at 1,900 grams worth of bobweight. Equally stout are the custom JE pistons with their 0.250-inch-thick skirts and ditto on the piston pins. It's all good to 3,000 horsepower says Fred.
He considers this a low-compression engine at 12:1—alcohol is forgiving of high cylinder pressures—and everything is coated for reducing friction or as heat barriers. The rings are file-fit Total Seals with a tough-as-nails stainless steel upper ring. The engine was broken in on Pennzoil 5W30 mineral oil, then run on frequently changed synthetic Lucas 5W30 due to oil dilution by the rich alcohol mixtures.
John notes he's seen 50hp gains from increased header size at this power level, and Mark's engine benefits from enlarged headers. He also notes the Mustang/Shelby body accommodates only a small rear tire and thus can't handle excessive torque. So John has tried to shift the torque peak higher by widening the overlap and extending the exhaust duration in the custom camshaft grinds.
For another look at this family of engines, check out our inside look at John Mihovetz's 4.6 program (Mercury Cougar Cobra Hybrid - Mad Motor-World's Quickest Modular). A few details have changed since that '09 article. John's switched to methanol and a different chassis; it makes an additional 500 hp since our chronicle—but the general idea applies to Mark's larger 5.4-liter engine.
Speaking of articles, comparing this story to our earlier article on the Kenne Bell 3.6 supercharger as run on Mark's engine, some notable configuration changes have occurred leading to the 7-second run. Most importantly, the giant Kenne Bell Mammoth inlet was discarded in favor of a pair of even larger rear facing throttle bodies. They aspirate unimpeded from the high-pressure area at the base of the windshield, an arrangement we've long thought superior to sneaking air through holes in the radiator support or fenders.
In preparation for the 7-second attempt, the engine was dyno-tested and the car hit the chassis dyno several times. Even though most of the dyno work was quick tuning checks at reduced ignition timing and other brief, not full-rpm runs, we did get a good clue of what the engine produces: a documented 1,627 hp at the flywheel and 1,225 hp at the tires. As we just hinted, the combination makes north of 1700 hp at the track, as that's the only place the engine has been run with something approaching a hot tune. There should be a little more in it given a cool day, and Mark suspects there's a 7.60 timeslip under ideal conditions. When it does, Mark will follow his usual drill of leaving on the transbrake at 3,500 rpm and running it out the back door at 8,400 rpm.
The engine is perfectly happy; overall it's a smooth ride with the new torque converter. Things to work on are weepy head gaskets, something of a constant at this power level, and something Accufab can cure with its dry-deck trick which separates the water path between block and heads, with no water passing through the head gasket interface.
That done, we think Mark might be content to rest a bit. The road to the 7s has been longer, and more labor and fiscally intensive than he really enjoys. A man of the street, Mark finds the racer's reality tiresome. The constant upgrading, compounded by whatever custom work required because you've upgraded everything it bolts to … it's not the street with its cruising and quick blasts. But he's got a solid 7 in his pocket and it would be nice to shave a tenth off that…
On the Dyno
It's rare that we get both chassis and engine dyno data on the same combination. Unfortunately, the rpm range crossover is minimal, but that brief meeting of data does show that there is a bit of drivetrain loss when you install an engine in a Mustang. In either case, Mark's Shelby is putting down huge power.
In either case, Mark's Shelby is putting down huge power.
|Chassis Dyno||Engine Dyno||Difference|
Mark's ticket from his test session at Famoso dragstrip in Bakersfield, California, is more impressive when you realize it was run in 90-degree weather.