5.0 Mustang & Super FordsHow To Engine
Supercharged Mustang Tuning - Air Traffic Controlled
A Solid, Safe Tune And An Overgrown Mass Air Housing Bring Street-Ripping Performance To Our Mega-Blown New Edge
Horse Sense: Up front, we want to give a shout out to an unsung hero in this project effort. The Mustang techs who install products we test receive plenty of time in the spotlight, and to say that "bolting on various parts is something that any Mustang shop can do" is, in the grand scheme of things, pretty much a given for the type of projects we cover here in 5.0 Mustang & Super Fords. While the name James Gordon probably doesn't mean much to most of you, it's now an important name to us. James is the tuning specialist at SCT who devoted several hours of his time (on the phone and by way of the Internet) to help us develop a best-of-both-worlds tune for our radical D.S.S. Two-Valve/ProCharger F-1A combination: one that allows our '02 Mustang GT to make awesome rear-wheel horsepower without compromising its smooth-as-glass drivability on the street. The perfect mix had been elusive for a long time, but thanks to James' know-ledge and great assistance, we've finally achieved our goal-which seemed far-fetched to some people-and can now move on to higher heights with our unique street/race setup.
Go ahead and say it: "It seems like forever since you guys started working on that ProCharger F-1A/4.6-liter Two-Valve upgrade with your '02 GT." Yes, we acknowledge the fact that this project has taken quite a while to close, but we've finally come to a point where we can confidently say that success has been achieved.
To briefly recap the origin of this saga, the project came to be when your tech editor's curiosity about applying a full-race supercharger to a low-mileage, daily driven, street 'Stang finally became too great to ignore. A plan for installing the big blower (with an eight-rib serpentine-belt drive system) and all of its support hardware was concocted, and B&D Racing, ATI ProCharger, House of Boost, Aeromotive, D.S.S. Racing Engines, JBA, and SCT were selected as the primary players for getting it done.
The Two-Valve/F-1A project reached the point where it is right now, theoretically finished, almost two years after we put our diabolical scheme into effect. While the road wasn't always smooth (there were several months when we didn't work on this project because of schedule conflicts, parts availability, and so on), we're glad we made it to the end nonetheless.
One of the last details in making things right with our system is to expand our blown Two-Valve's rpm parameters. As we explained in our last report on this project, although B&D's tuning specialist Brian Schapiro was able to create a map that had the D.S.S. Super MODular 4.6 pumping 484 horses at the rear wheels, an inadequate mass air meter was severely hindering our quest for more performance. The SCT BA2800 mass air sensor is apparently unable to access and process the massive amount of air our F-1A demands and ultimately forces into the engine. This proved to be a problem during our tuning session, causing the air/fuel mixture to go lean when the blower really started pushing wind. The situation left our 'Stang with somewhat choppy drivability in the low-rpm range, and us with severe anxiety about watching the tach to prevent revs beyond 5,000 rpm (to be safe).
To remedy the problem, we're making the switch to an absolutely massive mass air: JLT's 110mm mass air housing (from JLT's Shelby GT500 True Cold Air system), which features the slot-style sensor of a Ford GT supercar. The mass air change will increase our tuning range with respect to airflow's total mass, and allow Brian to work on the tune beyond 5,800 rpm with confidence that the air/fuel mixture won't go lean in the process. The big housing and Ford GT sensor are critical to tuning for smoother low-rpm drivability as well.
Using SCT's Advantage III tuning software, Brian, with the help of SCT's James Gordon, ultimately created two programs for our project car's PCM. The Street tune is a pump-gas-compliant (91 octane) PCM calibration that Brian developed with safety in mind.
The term "safe" has a dual meaning for our setup. The first definition relates to driver safety. Remember, it's Mrs. Jones, not KJ, who occupies the GT driver seat on a daily basis. While we certainly want the supercharged GT to have the ability to scorch the pavement with little-to-no effort, we're also keeping in mind that the transition from the P-1SC's 383 rear-wheel horses (at 10 psi of boost) to the type of steam the F blower can make is pretty drastic. On the street-and on the racetrack, for that matter-horsepower is something that should be respected at all times. The missus did a fine job of handling the car with the small blower, but in the name of safety, we'll probably reserve the F-1A's full fury (more than 20 psi of boost at WOT) for use at the track only.
The other side of the Street tune's safe characteristics relates to the air/fuel mixture. As we told you in our last story on the project ("Letter-Perfect Power," Dec. '08, p. 90), for supercharged 'Stangs, Brian likes to keep the under-boost/full-throttle air/fuel ratio between 11.5 and 11.8. The air/fuel ratio (using 91-octane pump gas) is well within those parameters now, and the pre-boost/low-rpm calibration Brian developed for the street has eliminated all of the jerking, shaking, and bucking that we experienced at various points during acceleration and deceleration before adding the JLT mass air setup. It makes the 'Stang about as smooth as it was before a P-1SC was installed on its stock engine.
The Aggressive tune, which we will run with VP Racing Fuel's Street Blaze 100- high-octane unleaded fuel, has 4 degrees of timing added globally across the timing map. The timing was increased for this calibration to help improve the low-end performance of the supercharged Two-Valve 4.6. "The F-1A is a bit lazy with this combination," says Brian. "The blower doesn't really get active until mid-4,000 rpm, so we needed to add timing to help bring back some of the bottom-end grunt."
B&D Racing's Mason "Mase" Rowland has handled all of the bolt-on-and the unbolt in a few instances-tasks for our project. The engine had to be removed twice during this project, and there were bugs here and there that occasionally sent us backward shortly after making progress in some areas.
The mass air swap proved somewhat challenging due to the enormous size of JLT's 110mm housing and the 9-inch, conical air filter element used to keep debris out. Fitting it all into the passenger-side front fender (remember, there's also intercooler tubing in that area) requires a bit of additional clearancing, and it absolutely cannot be done without the 45-degree, step-down rubber coupler that's required for installing the large mass air housing onto the supercharger's 4-inch air-inlet tube (available through www.racepartsolutions.com).
With everything now buttoned up, we have to admit that applying ProCharger's F-1A race supercharger to our 4.6-liter, Two-Valve street car has probably been one of the most challenging projects we've done thus far. It feels good to have successfully pulled it off, as our '02 Mustang GT is every bit the same street 'Stang it was before the project started, but a D-1SC will easily bring the same amount of pump-gas horsepower and torque that we dialed-in for Mrs. Jones (see On the Dyno for the all-important numbers), and doesn't bring with it the same airflow and tuning challenges.
From a comparative perspective, however, the total performance capabilities (maximum horsepower/torque, boost) between the first-level race ProCharger we installed and the company's aggressive street unit (D-1SC) are like night and day. An F-1A's 25-plus pounds of boost (achieved with only a small blower pulley and high-octane race fuel) is beyond unnecessary and probably unmanageable for a New Edge street car. But when it's all said and done, there's no disputing the high wow factor of a super-sized, sinister-sounding F-1A ProCharger blowing into a Two-Valve engine-and the even-higher cool factor brought by the fact that a girl jockeys the combination's 500-some-odd rear-wheel-horses each and every day.
Here's a closer look at our new mass air, installed in the passenger-side fenderwell of our test 'Stang. Converting to this setup requires a wiring upgrade to make the stock Two-Valve mass air plug compatible with the '05-up slot-style mass air plug.
To accomplish the union, DiabloSport's MAFia (PN 7324) can be used as a simple electronic link. It also allows us to notch up the voltage mass air voltage range accordingly if necessary. The tube and sensor combination allowed Brian to make a tune that keeps mass air ad counts (the product of mass-air-sensor voltage times 205) around 980 at 6,700 rpm with the new MAFia set on 0. The maximum number of ad counts is 1,023; with our previous setup, we were reaching that limit at barely 6,000 rpm. The mass air and the MAFia are both available through JLT for $429.
Our final (for now) dyno session proved to be much more successful than all of our previous test efforts with the 'Stang's new powerplant and supercharger. With the rpm increase we gained thanks to the addition of a JLT 110mm mass air housing and Ford GT slot-style mass air sensor, B&D Racing's Brian Schapiro was able to tune the GT to more than 500 rwhp with 91-octane gas, 15 pounds of boost, and perfect air/fuel ratios throughout the power band.
We realize that with an F-1A blowing into the D.S.S. SuperMOD 4.6, our test car's horsepower, torque, rpm, and boost can all be considerably greater than the number we settled on. While our stopping point of 6,700 rpm was brought about by what might be limitations of our engine's valvesprings (it was our oversight not to add high-rev springs when the cams were installed), we also feel that 535 horses are plenty enough for Mrs. Jones to have at her disposal for the ride to-and-from work, the mall, or wherever she goes.
Projects such as our Two-Valve/F-1A deal are prone to experiencing bugs of various sorts. Shortly after our dyno test, we discovered that a tight clearance between the water pump and an idler pulley from the supercharger system was causing two sides of the eight-rib serpentine belt to make contact intermittently, which led to complete and total destruction of the belt.
After investigating a bit further, we also discovered the idler pulley was slightly misaligned. With a serpentine-belt drive system, proper belt alignment is important, as there are many pulleys that the belt must pass over (including the blower's pulley), and belt misalignment can cause accessories to function improperly or become damaged. Add to that the fact that eight-rib belts aren't cheap, and you can understand why it's critical that alignment is true, especially at high rpm.
To remedy the situation, our friend Marc Rubin removed 1/8 inch from the idler pulley's surface and turned "gates" into its front and back sides to help prevent the belt from falling out of alignment. Marc also made a 0.128-inch spacer for the idler pulley. The spacer sits between the timing cover and the idler's standoff, and pushes the idler outward enough to make up the slight alignment difference we saw between the alternator pulley and the idler.
We didn't measure the distance, but we believe this space between the water-pump pulley and idler wheel is an intermittent contact area between two sides of our serpentine belt.
We always appreciate the fine machine work of our buddy Marc Rubin. Marc took the blower kit's idler pulley and "turned it down" (removed 1/8 inch of its surface) using a lathe to help create greater clearance between the two conflictive pulleys in our setup. Shown with the modified idler is a 0.127-inch washer Marc created to establish better alignment between the idler and alternator pulley.
Changing the serpentine belt is a bit of a pain and requires removing the supercharger head unit. A belt swap can be knocked out in the driveway, as it only requires a 3/8-inch-drive breaker bar (used to turn the belt tensioner); a 3/8-inch-drive ratchet; 10mm, 13mm and 1/2-inch sockets; and a screwdriver. If the belt hasn't completely broken, use a digital camera and take a reference photo similar to this one once the head unit is removed. A road map detailing the way a belt is routed can be a big help when installing one for the first time.
We also surmised that the belt may have been hitting a timing-cover stud that protrudes outward into the serpentine belt's path. Although cutting the stud down is part of the eight-rib conversion's procedures, we took it a step further and ground the stud down to a nub, ensuring it won't come into contact with the belt.