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1971 Buick Skylark - Wheel To Wheel Powertrain - Chassis Dyno Testing

How To Get The Most From Your Time On The Dyno

By Johnny Handzel, Photography by Johnny Handzel

The W2W dyno can record air/fuel ratio O2 sensor data during a run, but this vehicle did not have an O2 sensor bung in the headers. To assist in the tuning, Denny Dera from the W2W fab shop installed a bung in the passenger header. This would prove to be valuable later on.

The Findings
Check out the photos and sidebars to see how the testing went and what you can learn from our pain. Without a doubt, the chassis dyno testing discoveries were more than just horsepower-the car is much safer and consistent. Now, the car should be able to make some laps at the dragstrip with the focus being on getting the car to hook at the line and using all the power it is making.

Kunkle is planning a new engine to produce the 600 rear-wheel horsepower W2W says he'll need to run in the 10s. He's a believer in chassis dynos and looks forward to coming back to the dyno rolls with his new engine installed to debug it before heading out to the dragstrip.

Dyno Testing Results
The chassis dyno is a brutally honest piece of equipment, but it tells you much more than just power output. If a vehicle is unsafe or unreliable, the dyno will expose it. We ran into multiple issues that needed to be resolved, and the vehicle is better for having corrected them. They are listed along with the power improvements because of their value to the overall performance of the vehicle.

TEST STEP RESULTS DIFFERENCE
Performed baseline testing 320 hp n/a
Checked throttle travel at WOT 320 hp 0 hp, but peace of mind
Checked timing 326 hp +6 hp, set to 35 BTDC
Tuned carb setup 326 hp 0 hp, but smoother idle
Fixed vacuum/pressure leaks 350 hp +25 hp, blown-out gasket
Fixed underhood oil leak 350 hp 0 hp, minimized fire hazard
Fixed leaking transmission pan 350 hp 0 hp, durability improvement
Fixed slipping blower-belt tensioner 350 hp 0 hp, improved reliability
Repaired blown transmission 370 hp +20 hp, replaced torque
converter
Increased boost with Dyer's pulleys 390 hp +20 hp, 1.5 pounds of boost
Horsepower results from testing 390 hp +70 hp
  • Chassis Dyno Strapping Vehicle
    W2W chassis dyno operator Rich Gala is skilled at strapping vehicles to the dyno. The positioning of the tie-down straps and the tension on them is critical to keep the vehicle in place during the testing. Various recording connections are also hooked up at this point, like engine rpm, manifold vacuum/boost, O2 exhaust gas, and others that the dyno records along with power output for future reference in problem and power research.
    Chassis Dyno Strapping Vehicle
    W2W chassis dyno operator Rich Gala is skilled at strapping vehicles to the dyno. The posi
  • Chassis Dyno Air Fans
    Since vehicles are designed to shed heat via the air rushing through the radiator and under the vehicle, a chassis dyno needs to have a dramatic amount of air pushed through the radiator and under the vehicle. The W2W dyno uses a series of these high-volume and high-pressure squirrel fans and has a large fan pulling air throughout the entire dyno cell.
    Chassis Dyno Air Fans
    Since vehicles are designed to shed heat via the air rushing through the radiator and unde
  • Chassis Dyno Throttle
    As Gala put it, "I always make a baseline run without looking at anything as long as the timing is safe, then immediately check that the throttle blades are opening 100 percent. I've had some great finds. On a recent 450hp vehicle test, we gained 30 hp by getting the throttle fully open. I usually find single-digit horsepower with this one check." In this case, Kunkle had addressed the issue the previous year, and the throttle blades were opening 100 percent.
    Chassis Dyno Throttle
    As Gala put it, "I always make a baseline run without looking at anything as long as the t
By Johnny Handzel
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