Tom Wilson
August 18, 2011

Horse Sense: With everything new, working on this Fox was déjà zoom all over again. Even the undercar view was near-showroom, with just-out-of-the-crate major components everywhere surrounded by fresh hardware. Nice.

The lazy timing-which explains the big reduc-tion in NOx-was the result of too much blower boost for the 91-octane gasoline on hand

Of all the centrifugal superchargers available, the Paxton Novi 2000 is easily one of the most versatile. Its incredible performance envelope spans the gulf from slow street cruising to 1,000hp blasts at the dragstrip, and it's supported by an absolute dreadnought of a mount.

Those were reasons enough for Mark O'Neil at Probe Industries/Coast High Performance to select the big Novi for his project Fox Mustang. A totally rejuvenated 5.0, Mark's car is actually being built for his son-enough to make us wish for adoption-with the multiplexed goals of providing a way-cool street ride, looking good at car shows, and turning a mean tire at the strip. Just the job for a Novi.

Furthermore, as a street car, Mark's finished project has to keep within the guidelines of California's every-other-year emissions testing. A trip to an inspection station for a thorough eyeballing by a guy with a clipboard, along with a load test on a chassis dyno with a sniffer up the tailpipe, will give you emissions religion, too.

Luckily, Coast High Performance, the engine-building division of Probe Industries, has long offered an emissions-legal 347 short-block. The Novi 2000 has likewise earned a California Air Resources Board exemption order, so the two can be paired under a 5.0's hood and remain legal. That's a neat trick, and with the combination of 347 displacement and no-excuses blower power, this combination will be able to make 400-plus horsepower on lazy days and easily north of 600 hp when feeling more energetic.

In one regard, getting a Novi onto a small-block Ford is little different than hanging any other centrifugal on a pushrod Mustang engine. The alter-nator and air-conditioning compressor are remounted to the supercharger bracket, the blower is added atop the bracket, some plumbing gets done, and a drivebelt is threaded into position. Yet in detail, the Novi does things its own way, especially when it comes to that massive bracket, and because these superchargers are typically fitted to already modified engines, each installation takes on a custom flavor. That was certainly the case with this install, which you can see from the photos and captions.

So you know what you're looking at, the Coast High Performance project car is a '91 hatchback with the company's Street Fighter 347E emissions-legal short-block. This gives a 9.0:1 compression ratio from its Probe SRS series forged pistons, which reciprocate inside a standard factory block. The crank is a 4340 Scat unit, while the rods are RPM by CHP lightweights. Clevite bearings are used throughout.

Camming is via Probe's e-legal hydraulic roller. It measures 0.542/ 0.563 inch valve lift and 225/232 degrees duration at 0.050-inch valve lift. The lobe centers are a fuel-injection friendly 112 degrees. Speaking of fuel, a 255-lph in-tank pump does the heavy lifting, and 42-lb/hr Ford Racing Performance Parts injectors do the spraying.

The cylinder heads are Windsor Jr. aluminum units, while the intake manifold is the new Edelbrock Performer RPM II. The headers are Edelbrock units as well, with the remainder of the exhaust essentially an '03 Cobra unit. Why the Cobra exhaust? Because, with many of the other modifications on this car, Joe Gosinski at Chicane Autosport got the call to slide a Cobra IRS in place. It works with a Tremec T56 six-speed manual gearbox, aluminum flywheel, and Centerforce Dual Friction clutch.

As we said, it's enough to make us wish for adoption.

From an emissions standpoint, the supercharger installation didn't make much difference (see chart on next page). The numbers that matter are HC (hydrocarbons), CO (carbon monoxide) and NOx (oxides of nitrogen). Besides the test results, we've listed the maximum allowable and statewide average emissions in each category. The CO2 and O2 measurements are measured but not regulated by the state. Because we had the numbers, we passed them on to you for reference.

These numbers were obtained at a steady 25-mph cruise on the dyno rollers. That was only 2,100 rpm in this car-clearly well below the threshold where the supercharger comes into play, hence the lack of change in emissions.

The hardware and tune between naturally aspirated and supercharged tests were close, with a few notable exceptions. The hardware differences included the addition of the supercharger and the change from 30- to 42-lb/hr fuel injectors. Fuel pressure remained at the stock 38 psi, and the air/fuel ratio was the same with each test. The ignition timing, however, was 32 degrees for the naturally aspirated test and only 13 degrees for the blown examination. The lazy timing-which explains the big reduction in NOx-was the result of too much blower boost for the 91-octane gasoline on hand. As such, we're still waiting for final dyno numbers, as these timing numbers were not ideal for making power. As we went to press, the plan was to change blower pulleys to limit boost to 8 pounds through 6,000 rpm, and therefore allow more aggressive timing. Certainly the increase in rpm and timing should return extra horsepower.

All told, it's amazing a large-displacement, supercharged 5.0 Mustang with all the usual breathing improvements can legally head down the road. But the photos will show you-at least to a large extent-how it was done on this rejuvenated 5.0 classic. Do you love this country or what?

Naturally Aspirated CO2 O2 HC CO NOx
14.5% 0.5% 29 ppm 0 391 ppm
With Novi 2000 14.6% 0.2% 9 ppm 0 176 ppm
Allowable Maximum 96 ppm 65 746 ppm
Fleet Average (statewide) 20 ppm 9 199 ppm

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M5lp 0408 29 O Paxton Novi 2000 Supercharger Signage
Here's a nifty sticker to have on your hot rod, especially one as fast as this one. Just to the left of this signage is an 80mm Pro-M mass air meter and conical air filter. They are suspended in the passenger front fender, as there is insufficient room between the big Novi and the inner frame rail/fender to work.