We turned to VMP Tuning's Justin Starkey to see what his thoughts were in regards to tuning the TVS blower. Starkey has a GT500 with a TVS on it, and he's one of the many shop owners who keeps pushing the envelope when it comes to the TVS. "There are no major differences in how the TVS is tuned compared to any other blower," Starkey says. "As boost goes up, so does calculated engine load, so spark tables have to be renormalized to give you more resolution at higher volumetric efficiencies. You will need to have enough mass air sensor range for the additional airflow, and the mass-air meter transfer function will need to be properly tuned to achieve a safe air/fuel ratio.
"The FRPP tune on the Pro-Cal produces between 540 and 565 rwhp. Since the tune was developed for a warrantied production vehicle (the Shelby Super Snake), it gives up a little in power so it can pass emissions in all 50 states. It's also milder in case someone gets poor-quality 91-octane fuel, and it's designed to accommodate all those limitations the OEMs have to live with. This is not to say that the FRPP tune is bad because it produces less power; it's just different, and Ford has different goals in mind than the aftermarket. I can still produce a tune that will pass emissions and make great power, but you need to make sure the car always gets good, premium fuel. I don't have to work within the same limitations as Ford, so I can make more power, though I have to do it safely."
While the blower kit itself is a perfectly matched item, when it comes to making more power, certain parts and pieces need to be upgraded to make the most power possible safely. "In most cases, the FRPP intake would peg the MAF sensor with anything more than just the addition of an upper pulley, so I installed one of our 115mm MAF housings to get more mass air range and prevent the MAF from pegging," Starkey explains. "As a side note, the TVS comes with approximately a 2.9-inch pulley. A stock blower pulley is 3 inches in diameter. The stock TVS setup is nearly equivalent in boost to the stock blower with a 2.6-inch pulley, but the TVS makes 40-50 more rear-wheel horsepower at the same boost level due to the TVS' better efficiency.
Gone is the stock airbox (left)....
Gone is the stock airbox (left). In its place is the nifty-looking FRPP open-element airbox that comes with the kit.
With the blower on and tight,...
With the blower on and tight, the fuel rails made their way back onto the engine, followed by the reconnection of the injectors.
"The TVS is rated for 19,000 rpm, and 20.58 psi per Eaton. I'm close to the blower's limit right now, making 691 rwhp and 693 rwtq on pump gas. On race gas, the car has made 705 to the tires at about 18.5 psi with the addition of headers and a bunch of other items. I have some parts that will be available by the time this goes to press, but first I will need to upgrade to a set of 60-pound injectors with the correct-style electrical connector. I am at the limit of the stock injectors right now."
Starkey also noticed how much of an impact a throttle-body change made to the car, as well as how the blower affected the overall torque curve of the vehicle. "I had installed a smaller blower pulley and made 610 rwhp, so I swapped on a 10-percent overdriven lower pulley to spin the blower even faster," he says. "This got me very little gain in terms of horsepower, but it gave me some torque. With the addition of a dual 66mm throttle body, I saw power shoot up by 25 rwhp, and boost increased by nearly 2 psi. The stock throttle body is really a restriction once you get above 550 rwhp.
"The TVS has a very flat boost curve, and this results in a very flat torque curve. My car puts out around 700 lb-ft from 3,400 to 4,600 rpm. I will say that just the right timing curve is needed to take full advantage of this blower's boost curve to produce maximum torque. This is really where the little 2.3L TVS shines over some of the big twin-screw blowers."
The MAF sensor was installed...
The MAF sensor was installed into the new air inlet tube. Keep in mind that the MAF sensor is marked with an arrow and must be installed in the correct direction.
Here you can see the MAF sensor...
Here you can see the MAF sensor protruding into the inlet tract. VMP Tuning's Justin Starkey says that with the stock pulley on the TVS, the MAF is close to pegging. If you change the pulley for more boost, a larger MAF meter must be installed to keep it from pegging.
Included with each FRPP GT500...
Included with each FRPP GT500 supercharger upgrade kit is a voucher to redeem a Pro-Cal tuner loaded with an FRPP tune. While not as aggressive as a tune from a shop, Ford has to account for varying degrees of fuel quality, as well as emissions and warranty issues. Either way, the kit and accompanying tune comes with a warranty when registered online.
The tuner plugs into the diagnostic...
The tuner plugs into the diagnostic port on the bottom of the dash. Once plugged in, the switch is flipped, and the yellow light comes on, indi-cating that the tune is being loaded into the Shelby's ECM.
Green means go! When the green...
Green means go! When the green light comes on, all systems are go, and the tune has been uploaded correctly. If the red light comes on, it means there is a problem.
Here's the finished product....
Here's the finished product. The installation was straightforward, easy to complete, and, according to LaRocca, the easiest he has ever done. The blower fits under the strut-tower brace without any modification.