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Performance & Hotrod Business - April '15

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82 n Performance & Hotrod Business n April 2015 2 n PRECISION ENGINE n April 2015 PRECISION ENGINE Once the oil and filter were replaced, and as long as the Holley carb was still in place, Scott Koffel pulled two dyno runs with the carb to establish a base- line. While I had initially set timing at 32 degrees, Scott advanced timing further to 34 degrees, with a distinct improvement in horsepower and torque, moving from 638 hp at 32 degrees to 644 hp at 34 degrees. While our carb-equipped numbers put a smile on our faces, (quite frankly, I was quite happy with our first numbers), we couldn't wait to try out our new Holley Terminator EFI system, which proved to be a real eye-opener, ramping up to 657 hp with ease. Our Best Numbers Take a glance at the dyno sheets included in this article for the details on both initial pulls. These first two pulls were done with one of Koffel's known-good dyno shop carbs, a Holley 4150 series 900- cfm model. This is a carb that has been massaged, tweaked, tuned, cuddled and kissed for years—and kicks butt. We started with a carb for two reasons: to break-in the new cam, and to obtain some baseline data prior to testing the Holley Terminator EFI system. WITH THE 900-CFM CARBURETOR: At 32 degrees timing, she pulled 638 hp at 5,500 rpm, and 641 foot- pounds of torque at 4,800 rpm. At 34 degrees timing, she pulled 644 hp at 5,800 rpm, and 639 foot- pounds of torque at 4,800 rpm. The initial results were not bad at all for a fully streetable motor. It was obvious at this point, considering the torque output, that she would be a real stump-puller. Next, we turned to the Holley Terminator EFI system, installing the throttle body unit, the Holley harness (which connects to the Holley Terminator kit's controller), coolant temp sensor, oxy- gen sensor and plug-in handheld tuner module, along with connecting the fuel system using -6 plumbing from the throt- Koffel's dyno drive plate installed to adapt the engine to its DTS dyno. Koffel's in-house long-tube headers were in- stalled for the dyno runs. After base runs were accomplished with Koffel's 900-cfm carb, the Holley Terminator EFI throttle body was installed, plumbed with -6 AN fuel feed. Holley's O2 sensor was installed to the dyno header left bank. The water temperature sensor, supplied with the Terminator EFI kit, was installed to the Meziere water pump. Fuel pressure was obtained with an Aeromo- tive electric pump, A1000. This pump is rated to handle up to 1,300 hp on a naturally aspirated, fuel-injected application. An Aeromotive 13109 pressure regulator was installed, adjusted to 45 psi for the runs made with the EFI system.

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