|
|
Superior Automotive Holley Carburetor Dyno Testing - Fueling AroundSuperior Automotive Gets More Power From A Brand-New Holley From the November, 2007 issue of Modified Mustangs & Fords By Wayne Cook Photography by Wayne Cook
|
|
We've known for a long time that Superior Automotive in Anaheim, California, is a gold mine for Ford high-performance expertise. The folks at Superior Automotive work on all kinds of American muscle, but there's always something interesting going on from a Ford-performance perspective whenever we pay them a visit. From garden-variety Mustangs to the more esoteric visitors-such as a '48 Mercury convertible with a 460 conversion-on any given day, a visit to Superior always makes us feel like kids in a hobby shop. In issues past, we visited the in-house carb shop and came away with extra horsepower. With more than 40 years of experience, Don Spaccarotella is the apostle of horsepower at the carb shop. He's especially adroit at resurrecting basket-case Holley four-barrel carbs. This time, we thought we'd throw him a curveball and see if he could get anything out of a brand-new Holley carb.  This is our new 650-cfm Holley...  This is our new 650-cfm Holley double-pumper carb. With the car strapped onto the rollers, the idle is adjusted prior to the first pull.  Superior Automotive's Don...  Superior Automotive's Don Spaccarotella runs the '69 Mustang through the gears, settling in Fourth before the throttle is nailed, while carefully watching both the rpm and the air/fuel ratio. Several pulls were taken to ensure repeatability and to make sure there were no major problems with our project car. The new Holley four-barrel is a 650-cfm unit sitting atop a fresh 351 Windsor. The double-pumper carb has a mechanical secondary, and the only alteration is that the choke has been wired open. The carb has about 2,000 miles on it, and the engine runs like gangbusters. Holley knows what it's doing when it comes to building carburetors, and a new Holley four-barrel will usually run fine right out of the box provided it's appropriately sized to the engine. Such is the case with our carburetor. When we approached Superior with the idea of throwing Spaccarotella the new carb curveball, the company agreed to the story. Its employees have confidence in their man and know he will deliver. We wanted new baseline figures before the carburetor was modified and then a second session on the Dynojet to measure the result. To eliminate as many variables as possible, our test used the same Dynojet on the same day, with the same operator. Much of what Spaccarotella does is confidential, but if you send Superior your carb, the company can modify it, new or used. Follow us to the Dynojet at Superior to see if Spaccarotella can squeak a few more ponies out of a new carb.  Normally, for a performance...  Normally, for a performance rebuild, the carb is completely disassembled and soaked in solvent for cleaning. Because the carburetor is new, Spaccarotella says he won't remove it from the engine. The central body of the carb remains in place, while various components are removed and replaced. Here, the rear float bowl is drained into a receptacle designed specifically for this purpose.  With the float bowl empty,...  With the float bowl empty, disassembly begins. Here, the four float-bowl retaining bolts are removed.  Next, the float bowl and the...  Next, the float bowl and the metering block sandwiched between the float bowl and main body are removed. The float levels are fine; Spaccarotella is interested in the metering blocks. P Here are the results of the... Here are the results of the best baseline pull. Our Windsor uses the stock crank and displacement. So with 274.83 hp at 5,100 rpm and a torque reading of 311.99 lb-ft at 3,700 rpm, these numbers are pretty respectable for a street-driven daily driver. The graph contains the same information as the numerical tables, however, certain parts (such as the substantial dip in both horsepower and torque at 4,350 rpm) become more evident on a graph. | RPM | HP | TQ | | 2,800 | 144.91 | 271.80 | | 2,900 | 155.99 | 284.30 | | 3,000 | 166.82 | 292.05 | | 3,100 | 175.73 | 299.41 | | 3,200 | 185.15 | 305.52 | | 3,300 | 193.20 | 307.48 | | 3,400 | 200.70 | 310.03 | | 3,500 | 206.77 | 310.28 | | 3,600 | 218.60 | 311.63 | | 3,700 | 219.79 | 311.99 | | 3,800 | 226.26 | 311.34 | | 3,900 | 229.64 | 309.26 | | 4,000 | 234.82 | 308.33 | | 4,100 | 233.51 | 305.53 | | 4,200 | 243.28 | 304.23 | | 4,300 | 247.18 | 301.92 | | 4,400 | 250.03 | 298.44 | | 4,500 | 254.66 | 297.22 | | 4,600 | 254.66 | 290.76 | | 4,700 | 257.52 | 287.77 | | 4,800 | 260.79 | 285.36 | | 4,900 | 263.35 | 287.53 | | 5,000 | 272.18 | 285.90 | | 5,100 | 274.83 | 283.03 |  Work begins on the metering...  Work begins on the metering block, which has been placed in a spotless aluminum tray. The other Holley carb shown here (foreground) was also scheduled for rebuilding and tuning that day.  New jet sizes are part of...  New jet sizes are part of the carburetor hop-up. Passageways going to the power valve are also enlarged. The size of the replacement power valve is part of the secret recipe.  All the care in the world...  All the care in the world doesn't mean anything if the reassembled carburetor leaks. Even on a relatively new carb like this one, the gasket material needs a little gentle persuasion with a fine-wire brush to create a clean surface for the new gaskets. Similar modifications were performed on the forward metering block; the carb was then reassembled on the engine. The numbers tell the tale.... The numbers tell the tale. The Dynojet recorded a peak horsepower figure of 289.48, an increase of 14.65 hp. The 322.69 lb-ft reading is also a substantial improvement, amounting to 10.70 lb-ft. Here's the chart for the final pull. Although the dip at 4,350 rpm has smoothed out, another smaller bump has emerged right above 4,600 rpm, necessitating a few additional tweaks from Spaccarotella to eliminate it. With a gain of more than 14 hp, accompanied by a 10.7 lb-ft improvement in torque, the Superior carburetor hop-up is a resounding success that you'll notice right away and feel through the seat of your pants. | RPM | HP | TQ | | 2,800 | 152.30 | 285.69 | | 2,900 | 163.15 | 295.48 | | 3,000 | 170.56 | 298.60 | | 3,100 | 181.43 | 307.38 | | 3,200 | 189.66 | 311.28 | | 3,300 | 193.06 | 317.81 | | 3,400 | 205.74 | 317.81 | | 3,500 | 212.66 | 319.12 | | 3,600 | 220.02 | 320.99 | | 3,700 | 227.33 | 322.69 | | 3,800 | 232.87 | 321.86 | | 3,900 | 237.50 | 319.85 | | 4,000 | 243.43 | 319.62 | | 4,100 | 245.84 | 315.57 | | 4,200 | 250.25 | 312.93 | | 4,300 | 255.85 | 312.50 | | 4,400 | 259.06 | 309.23 | | 4,500 | 259.18 | 302.50 | | 4,600 | 264.33 | 301.81 | | 4,700 | 263.62 | 300.18 | | 4,800 | 275.27 | 301.20 | | 4,900 | 277.63 | 297.58 | | 5,000 | 283.13 | 297.41 | | 5,100 | 287.16 | 295.72 | | 5,200 | 289.48 | 292.38 |  Spaccarotella does a final...  Spaccarotella does a final walkaround and safety check before firing up the Mustang. Not shown in the photo is an even larger fan to ensure adequate engine cooling.  After two pulls, it is clear...  After two pulls, it is clear that a few more small adjustments are needed. The engine stumbled when the throttle was nailed, so Spaccarotella increased the volume of the primary accelerator pump shot as well as the volume for the rear pump.  As a final step before testing,...  As a final step before testing, Spaccarotella enlarges the air-bleed passageways by an unknown amount. The exact balance of the modifications he does is the secret to success. When Superior Automotive rebuilds your Holley carb, you get every trick in its proven book. Once the Mustang was run on the rollers, it didn't take long to notice a worthwhile gain.
|
|
|