They say that living in California means paying the “sunshine tax” – while you can drag race year round and visit the beach and play in the snow up in the mountains on the same day, you pay for it with the fact that there aren’t many dragstrips left thanks to noise and zoning regulations, and you can’t always see the mountains looking east from the beach thanks to the smog that still hangs low over the metropolitan areas on many days.

Of course, it’s nothing like it was in the bad old days of manual chokes, untuned Quadrajets, and leaded gas. The price we pay for cleaner air is the strictest emissions laws in the US, and many other states have followed California’s lead in that respect. Once every two years (or every year, if your car is classed as a particularly likely polluter) you have to get your car smogged, and the process is about as much fun as a prostate exam. A visual inspection makes sure you haven’t disabled or changed any of the factory emissions hardware, a tailpipe sniffer test on the dyno ensures your exhaust is squeaky clean, and they even pull off your gas cap and test it to make sure you’re not letting even a whiff of unburned hydrocarbons loose.

Against that backdrop, trying to squeeze more power out of a tightly-regulated car like the new 5th-gen Camaro SS while getting the seal of approval from the California Air Resources Board would seem to be an impossible task, but there are companies that are doing it. Turbonetics, based in California’s Simi Valley, has a vested interest in keeping the Golden State’s air clean, since they’re breathing it themselves every day. Coming off of their successful, CARB-approved turbo kit for the ’05-’10 Ford Mustang GT, they decided to tackle the new LS3 Camaro, as shown in the following video:

Per Turbonetics’ president Brad Lewis, the experience gained navigating the bureaucracy with the Mustang kit was a big help when it came to getting the Camaro system approved. “The Mustang kit took us probably 8-9 months and about $30,000. The Camaro happened significantly faster than that, but we had them included in part of the design process up front,” he explains. “We kept them in the loop as we got going, to know what they would accept and what they wouldn’t. We still have a significant investment in doing this, but the time frame was much shorter. We got most everything done in about 120 days. Part of it was because we had just finished the Mustang. Our guys are real familiar with the guys who run the AAA lab, and that seemed to help a little bit.”

Engineering the Impossible

In order to receive the blessing of a CARB Executive Order number, the magical code that turns the smog check guy’s frown upside down when he sees a turbo under the hood of your Camaro, one of the requirements is that everything that touches the airflow from the filter face in front to the tail of the catalytic converters in back must remain as supplied by the factory. Per Lewis, “The biggest challenge is that you can’t change the catalytic converters – you can’t go to a high-flow cat, you can’t change the relationship of the cat position to the exhaust valve, which means the only thing you have left to do is grab the exhaust after the cats. You cannot do away with the airbox and the carbon trap.”

To meet that criteria, the Turbonetics kit intercepts the exhaust flow just behind the stock cats, and returns it to the stock exhaust system once it has been run through the turbo. On the front end, the stock airbox is relocated to inside the front fascia and a new clip arrangement retains the flat panel air filter, essentially turning it into an open element for better flow. To make room under the hood for the new plumbing, Turbonetics also supplies roto-molded washer reservoir and coolant recovery tanks to replace the stockers.

The need to make the kit work cleanly in all operating conditions, from idle to redline, meant that extra attention was paid to every aspect of the design. It’s easy (relatively speaking) to make a turbo system work properly at wide-open-throttle, but sweating the details of things like cold start performance and transient response were also necessities.

“There’s quite a bit of work that went into getting a clean signal to the airflow meter,” Lewis explains. “We’re blowing through the meter – we put it in the pipe just ahead of the throttle plate, so we did a bunch of playing with tube shape and diameter. We have kind of a unique flow-straightener internally in the tube, so that again we have a real clean signal, and a lot of that had to do with the cold start and idle.”

On the fuel side, some changes are also necessary to keep up with the additional horsepower while staying clean. “We were trying to find a bigger injector for the Camaro when we started doing these kits,” says Lewis. “Naturally, you’d think of getting the stock injectors out of the ZR1 Corvette, because they’re supercharged. The problem is that the injector out of the supercharged engine has a 10 degree spray angle change, because the injector lays over slightly on the manifold to clear the blower. Put that injector in the Camaro and it works good for making power, but at idle it won’t pass the cold start test. There’s just enough of a change in angle that the spray touches the manifold wall and won’t atomize. You make good power, get a little hesitation at idle, and just flat won’t pass cold start emissions.”

In the end, 630cc/min Bosch injectors, along with a reflash of the stock ECU via a Diablosport programmer included with the kit, were the solution to the fueling puzzle. Timo Trevismo, Turbonetics director of sales and marketing, explains, “We also have a tuner/off-road version of that kit available that doesn’t come with the usual parts that are required for street legality – fuel injectors, stuff like that. That allows people to use other turbos as well, all the way up to 80mm. That opens up with that for pure race applications.”

Horsepower in a Box

The Turbonetics Camaro kit is designed to be complete and as easy to install as possible. Lewis says, “We did it so that there is no cutting necessary, other than the pipes behind the cats. It’s literally all bolt on.” No specialty tools are required, and as far as the time involved, “We’re guessing about ten hours,” Lewis estimates. “Our technicians can do it in seven because they’ve done it before, but it will take the first timer between 10 and 11 hours.”

“We supply a new set of colder plugs, a 180 degree thermostat, a programmer that has our emissions tune already loaded,” Lewis continues. “We tooled up to supply roto-molded windshield washer and radiator overflow tanks. It’s all T304 stainless TIG-welded piping… it’s a pretty clean kit.” Here’s a partial list of what you get:

• T76 Ceramic Ball Bearing turbo
• Spearco Front Mount Air to Air Intercooler
• Dual Evolution 35mm external wastegates
• Turbonetics Duo 35 bypass valve
• Diablo hand held ECU re-flash tool
• All exhaust and intake plumbing
• All mounting hardware included
• 50 state emissions legal (EO D-99-7)

But How Much Power Does It Make?

In dyno testing, the Turbonetics kit takes the stock LS3 Camaro from 365 horsepower and 337 pound-feet of torque to 560/537 at the wheels, for an estimated 600 horsepower at the flywheel. An important thing to consider is that for any given power rating at the tires, a turbocharged engine will be under less total stress than an equivalent mechanically-supercharged engine. That’s because the power to drive a turbo’s compressor comes from energy extracted from the exhaust gas, where a supercharger is spun by power robbed from the crankshaft.

While a blower kit, either centrifugal or positive-displacement, offers somewhat simplified installation compared to a turbo, it will require that engine to make 600 horsepower at the crank, plus whatever additional power it takes to turn the blower itself, which can be considerable. That’s easily seen in the fact that the Turbonetics kit makes that level of power with only 7.5-8 pounds of boost.

“We have enough turbo on the car to go to about 850 horsepower.” Lewis claims. “It has a 76mm ball bearing turbo on there now. We have plenty of turbo on there, and we are making 600 horsepower with roughly 7.5 pounds of boost. Of course with that 76mm we can make 35 pounds of boost.” All that headroom means that should an owner decide later on that he wants to take the car off the street for good and dial it up, there’s plenty of performance still untapped.

With an extra 170 or so horsepower out of the CARB-legal kit, you might be wondering if you’re risking parts failure elsewhere in the drivetrain, but Lewis assures us that a stock SS shouldn’t have any problems with the extra muscle. “We haven’t hit the weakest link yet, and we have hundreds of hours of dyno time on ours,” he attests. “We haven’t gone through a clutch, we haven’t hit anything yet. But we haven’t really cranked it up yet, either. I think the next thing we are going to play around with is some cat delete pipes – and this is for our own purposes, not to release it – just to see how far we can go.”

Per Lewis, experimentation with and without the stock catalytic converters there at the Turbonetics shop is necessary to determine how much of an effect the cats have on peak power and transient response. While turbo lag is minimized due to the fast-spooling ball bearing center section (and the fact that the LS3 is a torquey, powerful engine to begin with), Lewis admits that it’s hard to quantify at this point.

“It has some effect, and until we pull these cat pipes off and start testing, we won’t know what that is,” he explains. “One of the things we found was that the cats really need to be warmed up. If we made two or three pulls on [our Dynojet], the second and third are where it starts getting consistent. The first one where you don’t have heat in the cat yet, the boost pressure will be about a pound or a pound and a half low.” On the street, this should never be an issue – once the engine is up to operating temperature, the cats will be lit off and ready to go.

Other LS3 Kits on the Horizon?

While having a 50-state-legit turbo kit for the LS3 Camaro SS is great in and of itself, it was only the first stage of a master plan. Owners of two-pedal 5th Gen Camaros will be pleased to know that Turbonetics is working on adapting the kit for the L99. Per Lewis, “We have a car here now. It looks like it will be very similar, but the problem we have is that they spread the catalytic converters wider apart to go around the transmission, so we have to re-do the Y-pipe that goes up to the turbo. We have to do some dyno testing with the turbo we are using now to make sure it will work right with the automatic, number one, and two, we’re not sure how we’re going to address the Displacement-On-Demand yet. We aren’t sure if we have to leave that intact, or the details of it yet.”

What may actually gain approval first are kits for LS3-powered 6th Gen Corvettes, and for cars using the CARB-approved GM Performance Parts E-ROD crate motor. “When we filed the application, we included the E-ROD as well as the Corvette. We haven’t gotten an answer back on anything other than the Camaro yet, but at least we have our foot in the door, and GM just got an EO number on the E-ROD in naturally aspirated form in December, which had been over a year,” says Lewis.

For the time being, 2010-up Camaro SS owners will be the first to experience the added horsepower of Turbonetics’ smog-legal turbo kit – it’s a no-compromises way to boost your new Chevy while still keeping on the good side of Mother Nature and Al Gore.