Paxton Novi Superchargers Comparison

So what if bandwidth is an overused buzzword—no one can deny Paxton’s Novi superchargers have it. Pulley the popular Novi 2000 conservatively and it’s a happy street blower; whip on the small pulley and it can be a nine-second terror. But the Novi family is even more than the well-known 2000 blower—it’s the more compact 1000 and the huge 3000 as well.

While there is little doubt about where the hurricane-generating Novi 3000 belongs—in Pro 5.0—thanks to all that bandwidth in the Novi family, there are valid questions about which Novi—1000 or 2000—is the way to go on the street. An open invitation to drop in on Paxton and try some blowers if we ever heard it.

We ended up doing better than expected. Instead of one car and two blowers, we tested two cars and two blowers: a ’99 GT and ’98 Cobra, each with 1000 and 2000 blowers and a few bolt-ons. We also glimpsed Paxton’s upcoming air-to-air intercooler on the GT, which did have a bearing on the results.

So what makes a Novi 1000 a 1000, and a 2000 a 2000? It’s not the housing or transmission, nor is it the mounting; all those parts are identical between the two designs. The differences are the impellers and volutes. The 1000 uses a 47/8-inch wheel and matching volute, the 2000 a 6½-inch pair. The difference then is how fast each blower spools up its boost, how much trauma it exerts on the air as heat, and how much total boost can be had given the boost and rpm ranges of the blower and engine match-up.

The testing was simple. Paxton supplied the blowers and cars, we drove the four combinations and observed the dyno tests on Paxton’s in-house Mustang dynamometer. While the dyno was informative as always, we actually found the driving experience the most instructive, probably because we weren’t really expecting the results we got.

The 2000
We began with the 2000 blowers, taking the GT and Cobra out for photos and driving impressions. On the way back to the shop and the dyno, we—and don’t tell anyone—raced Paxton owner Dave Adams on the flat, straight Camarillo farmland roads. He was driving the ’99 convertible and we were in the Cobra. The Two-Valve convertible jumped the Cobra by a good half-a-car length from a Second-gear roll. Then the Cobra would hold its own, and for a long second the two cars would hang together in a dead heat, the GT holding its lead.

Finally, as it wound into high rpm, the Cobra began to pull about the same time the GT was flattening out. The higher the rpm, the greater the Cobra advantage. It gained a full car length and pulled away by the time the speeds were becoming truly stupid for the street, and we backed off. At the dragstrip the Cobra would obviously prevail.

It takes real power to win from behind, and the Cobra has it. There simply is no denying the Four-Valve engine’s breathing and horsepower advantage once the race has settled in for the long haul. But the race has to go to the long haul—and that’s the point. Wearing the 2000 blower, the Cobra felt big and heavy until it was well up on the boost and tach, and its around-town squirt between corners was lackluster. It had no bottom-end punch, and just about the time you were ready to upshift in acceptable around-town performance driving—say, 4,000 rpm—that was right where the bigger Novi blower was starting to make itself known. In other words, the Novi 2000 Cobra was on or off, and not so much in-between.

On the other hand, the Two-Valve convertible was just the opposite. Its hit off the bottom was much sharper, and only when left to rev did it go flat at the top end. Consequently, the really not-so-light GT drop-top felt lighter and quicker than its big-brother Cobra coupe—so much so that when given our choice what to take home for the night, we chose the GT. It was a blast to hammer away from lights, from turn to turn, or just whenever to feel the right-now power. The Novi 2000 definitely provided boost earlier than in the Cobra, down in the lower mph and rpm ranges where we could use it.

We must also note the GT was wearing 3.55 gears and the Cobra 3.73s, so the difference in bottom-end response is that much more impressive for the GT. Otherwise, the two cars were basically on the same tire (diameters, traction was not a factor) and T45 transmissions.

The 1000
After our first drive and dyno session, Paxton replaced the 2000 blowers with 1000 blowers and retuned the cars to work their best with the new combinations while retaining the same peak boost (around 8 pounds for the GT and maybe 12 pounds for the Cobra). Thus, with the Novi 1000 the Cobra blower pulley was 3½ inches, for about 11 pounds of boost. Paxton was thinking the standard pulley for an upcoming kit to be 3¼ inches and a bit more boost, maybe 12-14 pounds. A 3-inch, race-only pulley is also available. The GT was set up using the standard Novi 1000 kit.

Strapped to the dyno, the 1000 made a hair less peak power on both cars. If you were going by dyno charts alone, the 1000 would not look compelling.

On the road, the Cobra was the one making big gains. The Novi 1000 blower proved a great fit between the Cobra’s 7,000-rpm redline and its air needs in the midrange. By giving up a little boost—and yes, power, on the top-end—Paxton was able to pulley the Novi 1000 to actually make boost 400 rpm earlier on the Cobra. Again, this means the 1000 is running out of breath as it comes up to 7,000 engine rpm, but you don’t really feel it. If you drive Novi 2000 and Novi 1000 assisted Cobras back-to-back, you’ll notice the 1000 doesn’t have the sparkling top end of the 2000, but the difference is surprisingly inconsequential.

So, the benefit is the Novi 1000 Cobra comes on faster, and it doesn’t feel like it has a flat bottom end followed by a killer top end. Instead, it pulls more authoritatively starting in the 3,500-rpm range and builds up to the nearly 7,000-rpm redline. In fun street driving we definitely preferred it to the Novi 2000 combination. At the dragstrip the 2000 would still post better times as the engine spends more time at high rpm, but around town, the Cobra had lost its low-end lethargy with the 1000.

Not so happy was the Novi 1000–assisted GT. The smaller blower gave about the same low-to-midrange torque, but the top end power was definitely flat and uninspired. So while the Novi 2000 GT felt chest-beating muscular from the get-go to where the engine simply couldn’t go anymore, the Novi 1000 gave a good heave, but then petered out. Unexciting and definitely slower than the Novi 2000 combination, the 1000-blown GT gained nothing and lost top end.

Why did the Cobra like the 1000 and the GT didn’t? The intercooler. The blower has to compress that much more volume of air when an intercooler is fitted, and that takes a larger blower. This means the 1000 had to be working fairly hard to make the same boost as the 2000, which translates into less efficiency (more charge air heating). Later, taking its experimental intercooler off gained over a pound of boost, says Paxton. Then the results should have followed the Cobra results, but the car went straight into prep for the SEMA show, so no one can say definitively at this point.

What’ll Ya Have?
For once, from the confines of our writer’s harness, the recommendations of what to do are easy. For street driving, the intercooled Novi 2000 on the GT is wonderful. A rowdy, romp ’em, stomp ’em bronco of a Mustang, the Two-Valve and big blower combo delivers big grins and best-available acceleration in the low- to mid-speed street regime. If you have a GT and wish you had a Cobra, forget it. Your GT with this big blower is faster for the first third of the race and arguably more fun day in and out. Bolt on and enjoy.

If you own a Four-Valve Cobra, our street recommendation is the Novi 1000 to fill the midrange hole and gain meaningful top-end to boot. However, there are some of you who may not mind the off-boost milquetoast power of what is essentially a stock Cobra, and are willing to live through that for the ultimate top-end booster ride. Then the Novi 2000 is indicated. It should also help tame wheelspin at the drags as the power comes on a tad later.

If you’re racing either car, then bigger is better and the Novi 2000 is bigger. And don’t worry about not buying enough blower—the Novi 2000 is plenty for either car until you find yourself in the Pro pits.

Now, just to confuse the issue, Paxton’s tech-types say the non-intercooled 1000 option works quite well as a street blower in either GT or Cobra application, given no intercooler. We have to agree given this test. And to really drop a wrench in the works, Paxton is upping the 1000’s impeller diameter to more than 5 inches shortly. Combined with some volute tuning, the company is hoping to capitalize on the 1000’s early boost characteristics without getting into overspeed or heat issues. Combine that with the production intercooler and it’s a cinch we’ll be doing more testing when this hits the market in midwinter or later.

Horse Sense: While these Mustangs show there is still some pony work going on at Paxton these days, the R&D shop is actually full of trucks. From SuperCrews to Navigators, Paxton is putting blowers on them.