Smog ‘Em If You Got ‘Em: Adding Emissions-Legal HP With ProCharger

If you live in California and you’ve looked into bolting horsepower to your late model car or truck, you know it’s not simply a matter of finding a part number in an online catalog and clicking the “Buy” button. While other parts of the country see ostensibly no difference between a modern daily driver and a purpose-built racecar when it comes to emissions compliance, it’s a different story in The Golden State, where any 1976-or-newer gasoline-powered vehicle is required to pass smog checks regularly to be legally registered.

The California Air Resources Board (or CARB as it’s colloquially known) defines these vehicle emissions standards. Any modifications made to a street car that’s required to pass smog inspection must be approved by CARB (as indicated by a CARB sticker in the engine bay or near the component in question) for that vehicle to comply with the law.

CARB certification can often be a long and expensive process. As a result, finding performance parts that pack a meaningful punch while keeping a vehicle smog-legal can be a tall order for enthusiasts in California. Fortunately for us, companies like ProCharger have come to the rescue.

“We’ve had CARB-legal systems for a while now, but this has really become one of our most significant areas of focus over the past few years,” said ProCharger’s Erik Radzins. “And perhaps the best news is that, since we’ve been working with CARB so much recently, the process has been streamlined significantly. I think it helps that our systems tend to pass with cleaner results than the baseline factory setups. Ultimately, everybody wins – CARB is happy, our customers’ vehicles are emissions legal, and the horsepower gains are exactly where they should be.”

 

With late-model vehicles like our 2014 GMC Sierra, finding meaningful power gains while remaining above-board with emissions compliance can be challenging here in California. But even with horsepower increases of more than 40-percent over stock, Radzins tells us that ProCharger’s systems often end up being cleaner than the factory setup when tested for CARB certification.

As such, when we were looking to wake up the L83 engine in our 2014 GMC Sierra, we reached out to ProCharger for its 5.3-liter high output intercooled system with P-1SC-1 (PN: 1GV213-SCI). These systems promise reliable horsepower gains of more than 40-percent over stock in a kit that’s straightforward and mercifully free from installation hassles.

Here we’ll check out the particulars of the kit we chose, bolt it up, then hit the dyno and head to the drag strip to see how it performs out in the real world.

Emissions-Friendly Supercharging

“There’s a big misconception that if you have a CARB-compliant system, it makes less power or is somehow different from a non-compliant system that we offer,” says Radzins. “With our kits for a truck like this, there’s fundamentally no difference between the smog-legal system and the ones that aren’t CARB compliant. Basically, one has gone through the certification process, and the other has not.”

Radzins says that this is possible due to ProCharger’s overall approach to its supercharger kit designs. “We’re extremely fortunate that we don’t change the intake manifold or have to relocate catalytic converters and that sort of thing. We have a very emissions-friendly supercharger system – you don’t have to swap out a bunch of factory components to get results here. Such trucks like this one are a slam-dunk for us.”

Before installing the ProCharger kit we put the truck on the dyno to see what kind of power we were working with. Although 260hp and 281lb-ft provides enough grunt for this full-size pickup to get out of its own way, it's not particularly lively by today's standards. Good thing the Sierra's spacious engine bay offers plenty of room for a forced induction system.

Developed for use with the factory fuel injectors and delivering substantial horsepower gains at just 8 psi, ProCharger’s centrifugal blower employs a self-contained oiling design that eliminates the need for external lines. The kit also comes wholly complete with a three-core air-to-air intercooler, a ProFlow anti-surge/bypass valve, and everything you need to install a blower-ready tune. It all adds up to a job that you can legitimately do in your garage.

There’s a big misconception that if you have a CARB-compliant system, it makes less horsepower or is somehow different from a non-compliant system that we offer. With our kits for a truck like this, there’s fundamentally no difference between the smog-legal system and the ones that aren’t CARB compliant – Erik Radzins

Radzins also notes that while they’re not currently available as of yet, CARB-legal ProCharger kits are on the way for 2019 and 2020 model year GM pickups, as well. “We basically apply and then wait our turn to go through that certification process, and sometimes that takes a little while. They’re currently being tested, though, and we expect that they’ll be added to our catalog very soon.”

The Install

“It’s so ridiculously easy to do,” Radzins  explained. “You’re bolting the blower to the cylinder head and mounting the intercooler, the latter of which isn’t much different from changing the front grille.” 

And indeed, we did find the installation to be refreshingly painless. “The kit fits really nicely, and I like that the air inlet and filter are moving away from the headers to grab cooler air by the fender,” says LSX Magazine’s Scott Parker. “The ECU was one of the few things that needed to be relocated, and only slightly.”

Following ProCharger’s detailed directions made for an install that was free from headaches. Since we were mounting up a three-core air-to-air intercooler as part of the kit, the front fascia, grille, and radiator shroud need to be removed in order access the area where the intercooler would live. ProCharger provides detailed, step-by-step instructions for the entire process, and we didn't run into any surprises along the way. We opted for a satin finish for the supercharger housing and the associated brackets, but black and polished finishes are available as well.

We really dig the black satin finish on the blower and piping, and we also opted to get ProCharger’s optional helical gear set to reduce noise. With the quieter gears, you still hear the blower at idle, and the blow-off valve makes all the fun noises, but it’s not obnoxious. We’d consider that just perfect for a daily driver.

Our only deviation from the kit was a switch to NGK Iridium plugs (.024-.025-inch gap), which are two steps colder than stock. ProCharger often recommends colder plugs like TR6 or TR7, which we are more accustomed to using, but Josh Epstein at JEP Autoworks suggested these iridium plugs for improved longevity. Keep in mind that a special tool is required in order to gap them properly.

After bolting everything up and installing the tune, the engine fired right up without incident.  A word of caution before embarking on this endeavor, however: we’d recommend downloading the stock tune onto your Diablosport tuner (which is included with the ProCharger kit) before you touch anything on the truck and send it to ProCharger. This action will allow them to get the ball rolling on creating and sending you back a supercharger-ready tuned file. This process may take up to 48 hours, so plan accordingly.

A Diablosport inTune hand-held tuner is included in the ProCharger kit. We suggest uploading the stock tune from the truck’s ECM to the Diablosport tuner before doing anything else so that it can then be emailed to ProCharger for modification. Turnaround time is typically between 24 and 48 hours, so you may want to wait until you’ve received the modified tune before diving into the rest of the upgrade.

Putting Down Numbers

Before installing the system, we established baseline dyno numbers for the truck in factory-stock form. After we bolted up all the new hardware from ProCharger, we headed over to JEP Autoworks in Hemet, California, to put the Sierra back on the dyno to see where we were at with forced induction as part of the mix. Although the truck put down solid numbers, we theorize that there’s still more here than meets the eye. We struggled to get the GM transmission to hold a gear during testing, something that Radzins points out is very common with modern full-size pickups.

The stock baseline dyno test (left) yielded rear-wheel horsepower numbers of 260 horsepower and 281 pound-feet of torque. Even running at just 8 psi and with no other supporting mods, the ProCharger system ramps things up significantly, dishing out 419 hp, 422 lb-ft. Still, we feel like this system should be good for 440 horsepower or even a bit more under similar conditions, so we're going to head back to the dyno again soon to see if we can't dial this in a little bit more. We expect that by adding octane, wrangling the unruly transmission, and putting a few other emissions-legal tricks to work, we may pick up some additional ponies.

“When you’re dynoing a GM truck these days, you have to be really good at slowly and progressively rolling into the throttle and knowing when you’re past the downshift point,” Radzins says. “When you have a transmission with six, or eight, or even 10 gears and no manual mode that allows you to lock it in a specific gear, it can be tricky. So ideally, you’d select the gear that you’d like to start in, and then you’d slowly roll into the throttle to the point where you know it can’t downshift – around 3,000 RPM – and then you can go wide open.”

Regardless, gains of nearly 160 horsepower and more than 140 pound-feet of torque on an otherwise stock 5.3-liter L83 are nothing to scoff at, and we wanted to see what the newfound grunt would translate to behind the wheel.

We compared the before and after 0-60 times which served as a harbinger of what was to come at the drag strip. The truck was definitely traction limited, but even with massive wheelspin, we were able to drop that sprint to 60 MPH from 7.7 seconds in the stock form down to 6.6 with the ProCharger.

The Sierra’s 0-60 MPH time dropped by roughly a second after installing the ProCharger system. Running a conservative 8-pounds of boost, the blower provides reliable horsepower gains without tripping the emissions alarms or stretching the factory fuel system beyond its limits.

We didn’t have baseline, factory-stock 1/8-mile e.t.’s to compare when we headed to Irwindale drag strip, but we did have a leisurely 15.7 at 89mph 1/4-mile pass to use for comparison’s sake. With the ProCharger in the mix, the truck requires gentle throttle application off the line to prevent all the torque from going up in tire smoke, and even on this prepped surface, putting the power down was easier said than done.

Whether it was the lack of traction compound, the tires, the gearing, the fact that this truck sends the power exclusively to the rear wheels, or something else, we had a tough time figuring out how to get the Sierra to put the power down at the drag strip effectively. Oil-downs and a few on-track incidents limited the number of runs we could make, so we didn’t have a chance to do much experimenting with our launch technique to see what the GMC likes. But we’re planning to head back to the track soon to see if we can get that 60-foot time down to a respectable range.

We have no doubt the truck would put down much better times with better track prep and a sticky tire, particularly in the 60-foot, and moving from the 3.08 factory gear set to the 3.73s that come as part of GMC’s towing package would improve the e.t.’s even more. But don’t worry – we’ve got a few CARB-legal tricks up our sleeves for this one, so stay tuned.

In the meantime, if you’re looking for a way to seriously wake up your late model GM vehicle without running afoul of smog laws, ProCharger has just the thing for your LS or LT-powered whip.

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About the author

Bradley Iger

Lover of noisy cars, noisy music, and noisy bulldogs, Brad can often be found flogging something expensive along the twisting tarmac of the Angeles Forest.
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