Ok, the Vette is an American icon, and it comes from the factory as a pretty damn good performance machine. We wanted to know if the performance of an “out of the showroom” Corvette could be improved by adding one of the most common upgrades that engine builders start with: a new intake. After some research, we selected an intake from VaraRam. VaraRam’s VR-SCI Gen 2, better known as the “Snake Charmer,” was a perfect modification for our 2008 C6 Corvette. Our goal? To find out whether or not the new system would increase the Vette’s performance, both on the dyno and seat of the pants.
There are a couple schools of thought regarding Ram Air induction. Opponents of Ram Air say that it is simply a cold air induction system and nothing more. Those who favor the use of Ram Air Induction use Newton’s second law of motion, the Bernoulli Principle, and aerodynamics to explain the actual horsepower gains in a Ram Air system. We’re not airflow engineers, but we know that some of the OE’s have built factory ram air systems. The question is — what difference will it make for us?
The VR-SC1 Gen2 SnakeCharmer Intake System
Upgrading the intake from the stock system to the VR-SC1 Snake Charmer is one of the easier performance upgrades in terms of horsepower gain vs. manpower spent. The entire install can be performed in a leisurely couple of hours, and that includes time spent taking photos of the finished product to upload onto your favorite internet message board.
You don’t have to be a rocket scientist or an engineer to determine why the VR-SC1 system will increase performance. To start with, the stock air system is virtually blocked off from the ambient outside air. While a good case can be made that the stock system isn’t pulling heated air from the engine compartment, there do seem to be more efficient ways to route the intake duct to draw inlet air in more easily.
VaraRam President Patrick Ledford explains: “The Snakecharmer Intake, like all VR units, was not designed for the dyno which requires the engine to pull air. The SnakeCharmer was designed for ramming air. The aero package and shape of the unit are designed around this”. Based on this, we deduced that our real measure of the intake would be on the street and the track. It only seems right to quote Bob Dylan here: “the answer my friend, is blowing in the wind”. That given, we wanted to dyno test it at the wheels and see whether we would pick up any power.
We pulled the stock plenum chamber out of its resting place located above and in front of the engine’s radiator, and were stunned by the airflow design. In order for air to be pulled into the plenum chamber, it has to be drawn by vacuum around the plastic shroud that serves to block off the intake from the ambient outside air. We presume that it was designed this way to not only prevent the intake from ingesting dirt and debris from the road surface, but also to lower the car’s drag coefficient. Whatever the reasons, this shroud design makes the air move in an awkward and less than efficient flow.
Pulling the stock system was easy, and the step-by-step photo instructions from VaraRam make this a virtually foolproof disassembly. Each step was detailed and photographed, from disconnecting the MAF sensor to removing the entire plenum assembly out of the bay. Once the stock air intake was removed from the vehicle, we could start installing our VaraRam intake. Thankfully, the first step in installation was cutting a hole in the shroud to mount the new air intake scoop.
We discovered that adding tape to the enclosed template strengthened it up so that it would lay flat against the shroud. The template was clearly labeled, so it was no problem laying it on the shroud and tracing around the template. All that we needed to do during the first stage of the shroud modification was to score the plastic shroud with an X-acto knife or something similar. We found it easier if we didn’t apply a lot of pressure and worked in a three or four inch area at a time, retracing the score line a couple of times to make sure that it would be visible when we lifted up the template.
We began cutting the shroud on the scribed line, using a box cutter and moderate pressure. It’s important to take your time when cutting the plastic. Keep the cut area workable by not trying to take too much material off at a time. A simple steady pull with a good grip on the box cutter is all you need. Personal preference can dictate the direction that you choose to cut in, but we found it was easiest to position ourselves at the fender and pull the blade towards us. This allowed for maximum control of the box cutter.
Once the plastic shroud was cut we could move on to installing the lower duct to the shroud. If you’ve done a good job of using the template and cutting the shroud, the lower duct will slide in the opening that you’ve just created with only a little bit of pressure.
We wanted it snug so that the air would go through the duct and not take the path of least resistance around it. The duct drops in just in front of the oil cooler and some caution needs to be exercised so as not to damage the cooling fins. The lower duct is then secured into place by putting plastic pins through a pair of holes in the frame.
VaraRam’s instructions then guide us through the MAF sensor installation. The sensor is directional and needs to be installed in the proper direction. You must reuse the MAF sensor that was in the stock housing, so take note of the direction in which the sensor is installed before you remove it from the housing. Make sure you install it the same direction in the housing supplied by VaraRam.
We installed the MAF sensor housing on the upper duct before installing it in the Vette. We started by attaching the supplied silicone hoses to the housing with clamps. VaraRam instructions provide a helpful tip: “locate the clamps so the tightening screws are on the driver’s side. The ETC motor will interfere with the closest clamp to the throttle body”.
Once the MAF sensor housing was attached to the upper air duct, we inserted the filter assembly into the ductwork and installed the entire assembly into the car. The upper air duct is attached to the lower air duct by means of two rubber anchor straps on the lower housing. In the interests of full disclosure, we weren’t thrilled with the method of sealing the air filter. We experienced a mild amount of dust accumulating on the outer edge of the seal. Not enough to make us worried about using the Vararam, but we’d prefer more of an OEM-style “LIP” sealing system.
That being said, Vararam has sold thousands of intakes with no complaints, so we’re sure it’s not an issue. On the other end of the duct, we attached the duct to the throttle body and intake manifold. We stepped back and admired the installation after a quick check of the clamps, the MAF sensor wiring and vent pipe tubing.
We’re going to address the before and after seat of the pants feel, but first – let’s talk numbers. Generally, numbers don’t lie. They don’t always tell the whole story, but numbers don’t lie. We’re fortunate to have an accurate measuring stick in our shop to track and record our project upgrades. Our Dynojet four-wheel drive chassis dynamometer is the ultimate judge for most high performance upgrades. In this case, where airflow plays such a key role in the performance of the ram air induction, the dyno will tell some of the story, but it will not show the entire picture.
Now, Vararam told us not to expect much on the dyno. But we had our fingers crossed. By cutting out the shroud, and with the free flowing intake, there just had to be less intake restriction.
We can, however, look at the static number and judge how much we gained simply by getting cooler outside ambient air into the engine. So, we strapped out project car on the dyno, made a couple of pulls, and compared the newest dyno runs against the base line run. Our baseline (benchmark) run that we were measuring against is shown below.
Our Dynojet chassis dynamometer features a weather module that takes both barometric pressure and temperature into account to provide an industry standard corrected measurement. The corrected measurement makes it possible to compare dyno runs taken at different times and during varying weather conditions and keeps the data on a level playing field. As a result, we were able to compare apples to apples and oranges to oranges without bias.
While we expected to see a change in horsepower and torque numbers, we really didn’t know how much of a change we would see. We were surprised to see a horsepower gain large enough that you could feel inside the car. The dyno run with our VaraRamSnake Charmer Ram Air Induction is shown below.
We’ve found it helpful to download the dyno numbers into an Excel spreadsheet for a side-by-side comparison because any changes would show immediately. When we performed the side-by-side comparison we saw gains throughout the entire pull, with one exception at 3,800 rpm. Even with that one anomaly, we saw gains at every data point through the run. See our side-by-side comparison of the data in the spreadsheet below.
We proved to ourselves that our new intake provided an increase in performance in a static condition on the chassis dynomometer. Then we really wanted to know how the VaraRam would perform on the street in real world conditions, so we happily rolled our Vette off the dyno and out of the garage.
Driver Impressions On the Street.
Real world driving tests and track testing are going to produce the best evaluation of performance because of VaraRam’s design.
Over the stock intake, there was a dramatic and profound performance improvement that was most noticeable to our driver over 40 mph and 4,500 rpm. It is difficult to determine if this was due simply to the reduction in restriction that the VaraRam offered with the trimming of the shroud, or due to the cooler air offered by the ram air/cold air induction system.
Our driver reported that previously the Vette would chirp slightly between shifts in 2nd and 3rd gear. After the VaraRam was installed, those chirps turned into full blown “blowing off the tires” shifts between 2nd and 3rd, and we even got noticeable spin on the 3 to 4 upshift. The power increase was substantial and was very evident.
An increase in the magnitude of 10-12 rear wheel horsepower in real world conditions is not going to produce that additional power gain. We determined that the horsepower gains were higher than the numbers produced on the dyno.
Driver Impressions At the Track
In terms of track times, we were very pleased with the performance of our C6 at the local Irwindale 1/8th mile Dragstrip. With the Doug Stalter tune, our best pass during a Thursday night test session was a 7.95 at 94 mph, which equates to a 12.30 at over 119 mph when compared to other C6 1/8 to 1/4 incrementals.
We incurred heavy wheel spin in all 3 gears, and our driver felt that we could have easily run in the mid 7′s with decent traction and sticky tires. According to VaraRam’s Patrick Ledford, “the SnakeCharmer was designed where overall peak performance would show up in torque, and lots of it.”
Our driver verified this. We had torque, and lots of it.