Steve Baur
Former Editor, Modified Mustangs & Fords
October 12, 2006
ProCharger's D-1SC upgrade uses the same step-up or gear ratio that the P-1SC uses along with some other like-sized components. The impellers are where the significant changes occur.

Muscle Mustangs & Fast Fords currently has four supercharged vehicles in its stable, three of which are running and driving, and each one produces or will produce in excess of 500 rwhp.

These days, modern technology has allowed us to generate these truly impressive numbers with just bolt-on performance parts such as superchargers, and at these power levels, we've generally reached the limits of the factory internal engine components and driveline parts with axles, transmissions, clutches, and so on.

Once you have taken the next step of fortifying these areas, there's little doubt you'll want to take advantage of the beefy parts you just installed and turn up the wick in your ride. A pulley change is usually the easiest way to increase boost levels and subsequently power, but it isn't necessarily the best way to go about it. There's a right way and a wrong way to upgrade your supercharged stallion for more pavement-pounding power.

It's critical to consider that while your drivetrain and short-block may be up to the task, your fuel and ignition systems may not, and spinning you supercharger faster might not be the most efficient way of achieving your goals.

During a recent conversation with Dan Jones and Dorian Comeau of Accessible Technologies/ProCharger, both recommended we upgrade the P-1SC blower unit on our 331-powered '90 Mustang GT with one of their D-1SC pieces. We don't normally say no to bigger and better parts, and this time would be no different, but we wanted to know a little more about why they suggested the upgrade for our Mustang project that was running pretty well already.

While we were at it, we figured we would add an Anderson Ford Motorsport Power Pipe and see where things went. The only problem was that the air/fuel ratio during our last dyno pulls was creeping north, from 11.0:1 at 5,000 rpm to 12.5:1 at 6,200 rpm. Ask any good Mustang tuner and they'll tell you that 11.0-11.5:1 is as high as they would like to see a safe tune go.

With a 255-lph pump in the tank, ATI's pusher pump (rated at 240 lph at 43 psi), 42 lb/hr injectors, and an adjustable regulator, we were reaching the limits of the fuel system, which still employed the tiny stock fuel rails and lines.

Your new go-fast goodies just arrived at your doorstep. Does your ride have what it takes to get the most out of them?

While we had hoped to solve the situation by popping on a set of larger aftermarket fuel rails, a call to Brett Clow at Aeromotive in Lenexa, Kansas, opened our eyes a bit to the fuel-supply issue, and had us rethinking our estimation of the possible power increase.

Sure, we expected a 20- to 40-rwhp increase, but the truth of the matter is that between the Power Pipe and the supercharger upgrade we had planned, it was possible we could see nearly double that.

With the 5-liter supercharger kits still some of the biggest sellers for blower companies, this is a scenario that many 5-liter enthusiasts have or will have experienced at some point. Modular-powered Mustangs have it slightly better when it comes to certain areas, but the same information can be applied to those as well.

We have to thank both Comeau and Clow for pointing us in the right direction with our project, and for spending several hours on the phone with us so we could bring you some of their expertise within their respective fields.

Next month, we will bring you the bolt-on bonanza that started this tech article, and show you how to install the induction and fuel system upgrades, and how our ProCharged Pony faired on the chassis dyno.

Supercharger Head Unit Upgrades
Supercharger head-unit specifications differ with every company, so check with the manufacturer, but determining when you need one and which one is right for you is largely dependent on your horsepower goal and engine combination.

Our ProCharged GT has been the subject of numerous tech stories, including "Blown, Stock, and Born to Rock" (Apr. '03), where we installed ATI's 5-liter P-1SC supercharger system on the stock, 140,000-mile '90 GT, and the two-part "331 Ways to Waste an LS1" combo (Aug. and Oct, '04), which detailed the buildup of our low-compression D.S.S. strokr engine.

The 331 easily put us over the 500-rwhp mark, and the increase in cubic inches as well as the new, larger camshaft is moving a lot more air than we were with the stock short-block and cam. In discussing our project with Comeau, he recommended we move up to the D-1SC head unit. "The P-1SC is our 50-state emissions-legal base unit," he says, "and in the 500- to 600-rwhp range, we recommend the D-1SC as its aggressive boost curve works well with modified motors." The D-1SC should fatten up the low-to-midrange torque curve, which may have shifted upward in the rpm band as a result of higher-flowing engine components, while still producing the hard top-end charge we've come to appreciate.