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Chevy 350 Small Block Supercharger - Boxing The Power Curve
Our 350 Test Mule Takes A Pounding As Trick Flow Specialties' New Carbureted Supercharger Kit Adds Mountains Of Torque.
Sep 1, 2009
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Chevy 350 Small Block Supercharger - Boxing The Power Curve
We couldn't slap this blower on possibly the ugliest motor on the face of the planet, so we did a little bit of dress up prior to heading to the dyno.
First and foremost, we ripped off the stock balancer and broke out the flat black paint to cover up the off-shade of orange. This is a quick and cost-efficient way to dress up your engine. We used quick drying paint so we could quickly tackle some of the other goodies we had prepared.
Summit Racing sent us a lot of chrome, including a set of valve covers, a fuel pump block off, timing chain cover,...
...balancer, oil pan, water pump, alternator, and a whole lot more...
...Check out superchevy.com for a web-exclusive look at everything we installed...
...to get our engine ready for a car show.
Then it was off to B&B Automotive Machine. Using B&B will give us consistent results, as this is where we did our previous testing. Glenn Briglio has been more than helpful through the entire process. As usual, we were on and off the dyno in no time and they were prepared to try anything to make sure our engine was making power and making it safely.
As few have had their hands on this blower kit prior to us, we mocked up as much as we could before hitting the dyno room to make sure we didn't waste our time if a problem was to arise. We did have to do a little grinding, and it was...
...great we found this out when all was apart. The water neck we used needed a little more room to fit flush and some minor grinding took care of that. Also, out back we had to make some modifications to our distributor as it would not clear the back edge of the base plate. Two small speed bumps, and two easy fixes.
The base plate simply installs to the block and cylinder heads using the same holes as the intake manifold on a naturally aspirated engine. Trick Flow supplied...
...all the hardware we needed for the kit, which saved us a great deal of time since much of the...
...hardware is metric. We placed some silicone around the water jackets and across the front and rear rim of...
...the block and positioned the base plate into place.
Once evenly tightened into place, we made sure the rubber seal that sits between the base plate and supercharger was firmly in its groove, and set the blower into position. If this rubber seal were to move out of place, an air leak could occur, affecting boost levels and impeding our ability to tune the engine properly.
The Magnuson 122 super-charger is available in this satin finish and it comes in a short or long neck design to clear the water pump on your combination. It is even available for Vortec cylinder heads. The kit runs $2,899 in any of these forms and includes a crank pulley, idler assembly, distributor hold down, gaskets, and all the necessary hardware to bolt directly onto your engine.
Proform's 950cfm race series carburetor was bolted atop the supercharger and looked great to boot. Hand assembled in the U.S. of A., it features high-flow main bodies, screw-in air bleeds, solid billet construction, and power valve blow out protection. We could not have been more pleased at how the Proform carburetor performed. We planned on having to mess with jetting to achieve optimal performance, but literally did not touch the carb the entire day. Before some of the pulls, we brought rpm down past 900 and the engine had a beautiful, consistent idle.
Next, we bolted the crank pulley into place and using a straight edge, ensured the blower pulley, idler pulley, and crank pulley were in line. Supplied with the kit are two small shims if all the pulleys do not align. Luckily, we did not have to use them.
When we first fired up the engine, the crank pulley was obviously not spinning true. Turning to 6,500 rpm, this is one issue we wanted to resolve, and could with a little know-how. We loosened the three bolts and mounted a dial indicator on the block. We set the indicator to zero on the inside edge of crank pulley and rotated the engine till we found the highest number on the indicator which happened to be +0.080-inch. This indicated that the crank pulley was spinning 0.080-inch out of center. Using a rubber mallet, we gently persuaded the crank pulley 0.040-inch in the opposite direction of the high point and tightened the bolts. This made a world of difference when engine was running and could eliminate belt loss in the future.
Our first pull was made with the 3.250-inch blower pulley in place, which nets approximately 5 pounds of boost across the rpm range. We had timing set at just 22 degrees and were staying extremely safe as all we were doing was making certain all systems were go. Max torque was 481 at 3,000 rpm and horsepower was 458 at 5,400 rpm. More importantly, the spark plugs looked clean, the engine ran through the rpm range very smoothly, and our brake specifics (the measure of fuel rate over power) maintained a safe reading.
We then switched to a set of plugs designed for a forced-air application. We went to a non-projected Autolite 3910 plug gapped at 0.030-inches that burns colder than those in N/A motors, helping to eliminate detonation, and ensure the quick rush of air does not blow out the spark.
B&B's shop is state of the art with fresh air flow, ambient noise reduction, quick disconnects, and most importantly, triple-paned bulletproof glass separating us from the engine in case of a major malfunction, Also, while making pulls, we made certain to use noise reduction ear protection as the decibel level in the dyno room can reach unhealthy levels.
As the BSFC (brake specific fuel consumption) and spark plugs stayed on the rich side, we decided to change pulleys from 3.25-inch to 3-inch, taking our boost level from 5 to 7 psi. At the same time, we also turned the timing up to 25 degrees. The change netted us 530 lb-ft of torque at 3,100 rpm and 517 hp at 6,000 rpm. At this point, we...
...pulled all eight spark plugs to ensure we were not doing any damage to the engine. Note that all pulls were made on the "cool" side with our water temperature at 130-degrees and oil temperature at 140. Once we find a home for our supercharger small-block, this is probably about where we will run the set-up: 7 pounds of boost and approximately 25-degrees of timing.
Last but not least, we decided to go for broke and turn up the wick. At 7 psi, we were encountering some belt slip through the higher rpm range, dropping boost approximately 1.5 psi. If we were trying to make power and turn this into a drag-only machine, we would go back and install either an 8 or 10 rib pulley system to help...
...with the pressure loss. We then installed the 2.8-inch pulley, increasing boost to 10 psi and also increased timing to 27 degrees. Our first pull went smoothly, and before even looking at the dyno graphs, we backed it with another pull with a little more temperature in the engine. The results were outstanding. We made max torque of 581 lb-ft, and max horsepower of 555, an increase of 138 lb-ft of torque and 87 hp.
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