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The COMP Cams billet aluminum belt tensioner is adjustable for belt tension and offers rock-solid serpentine belt guidance.
The tensioner is adjustable via a locking bolt. A convenient 3/8″ square drive hole offers a tension pull point with a 3/8″ drive ratchet or bar.
The tensioner/pulley attaches to the water pump’s OE tensioner bolt hole locations on the right side of the pump.
The damper hub on the left is P/N 91643-A, which measures 4.350″ long. This is for a truck/SUV application. For a Camaro/Corvette pulley setup application, you need ATI’s P/N 916032 (seen here on right). The shorter hub measures 2.770″ in length.
For our dyno run, we only needed to run the water pump, so we installed a Goodyear belt (P/N 4060435), which is 43.5″ long. Naturally you’ll need a longer belt to run accessories such as an alternator, power steering pump, etc.
This side view (with the shorter ATI damper hub installed) placed the serpentine belt in perfect alignment with our belt tensioner pulley.
In order to send the firing signals to the coilpacks, you’ll need a pair of GM coil harnesses (one harness shown here). This is GM P/N 12582190. Be sure to pay attention to color coding in order to install the harnesses in the correct firing order positions. The MSD timing control kit instructions clearly identify the wire colors.
In order to monitor engine oil pressure on the dyno, I removed the OE oil pressure sender from the rear of the engine valley cover plate. I purchased a spare 16mm straight-thread plug from a local GM dealer and drilled/tapped the center to 1/8″ NPT to accept the dyno’s oil pressure sender. In this photo, a 1/8″ NPT plug was installed simply to seal the hole during engine transport.
While not absolutely necessary, I installed a MAP sensor. Since the manifold offered no vacuum hole location, I jerry-rigged a MAP sensor to the carb’s full-vacuum rear port.
Setting up the LS2 engine on the dyno was fairly straightforward. Gressman’s already had LS exhaust headers and a dyno-friendly flywheel on hand, since they’ve been testing several LS engines recently as part of a corporate client’s R&D program.
Scott Gressman used the MSD software (mini CD provided with the timing control kit) to set timing mapping and to move the rev limiter.
I know it’s difficult to see the screen on this laptop computer, but the MSD software is fairly easy to use. You can re-program the timing box at will, and you can leave the laptop connected to the timing box during engine as an extra data monitor.
A few minor adjustments to the Edelbrock carb’s mixture settings was all that was needed to tune this carb to our motor. This carb’s performance was very impressive.-no problems whatsoever and the throttle response was outstanding.
With the air tunnel hat installed, the engine was ready for official pulls.
Our first pull netted 537 horsepower, and that was hitting a rev limit.
The first pull showed 537 horsepower at 6,330 rpm and 445 lbs./ft. torque.
It’s really difficult to photograph a computer monitor screen due to screen pulse (a dark bar moves along the screen because monitors flash so quickly that you can’t see this with your eyes but a camera freezes this). Plus, the data appears and disappears quickly, which makes it tough to capture exactly the display that you want to capture. This second-pull reading shows 560 horsepower and 520 lbs./ft.
This display (also during the second pull) shows 589 horsepower at 6,650 rpm. Unfortunately I wasn’t able to catch the 625 horsepower moment during the final pull, but at least I have printouts of the run.
Our 403 CID LS ran like a monster. We were thrilled with every aspect of the engine’s performance.
Tags: ATI, BALANCER, CARBURETOR, COMP CAMS, DYNO, HORSEPOWER, INTAKE MANIFOLD, LS, LS2, MSD, TORQUE
