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Showing results for tags 'Duration'.
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I while back I took my car, (280z) to a dyno the result, (discussed in separate thread,http://forums.hybridz.org/topic/127636-thoughts-on-my-dyno-result-280z-triple-webers/?hl=%2Bdyno+%2Bresult I contined the investigation regarding the strange figures. I surely have jetting isusue, I however also discovered that my cam was way to retarded. After several measurements with degree wheel and indicator clock I decided to move the cam one notch forward. After this the measurements look quit ok, would probably be a even better with adjustable cam sprocket After advancing the cam these are the figures i got. Max lift intake lobe at 105 degres, approx 12,3 mm, defined max lift according to cam card 12,57 mm at 104 degreess Max lift Exhaust at 111 degrees, approx 12,3 mm, defined max lift according to cam card 12,57 mm at 108 degreess Intake lift at overlap 4,5mm Exhaust lift at overlap 3,5mm Below are figures I measured when camshaft mounted in engine. At 0,05 inch. Exhaust opens 65 degree BBDC Exhaust closes 17 degree ATDC. Intake opens 27 degree BTDC Intake closes 51 degree ABDC Overlap 44 degrees Overlap according to cam card 32 degrees The Duration I get with measured figures Intake 258 degrees Exhaust 262 degrees. Figures according to the cam card. Exhaust opens 50 degrees BBDC Exhaust closes 14 degrees ATDC Intake opens 18 degrees BTDC Intake closes 46 degrees ABDC Duration according to cam card. Intake 244 Exhaust 244 What I don´t understand is the differences in Duration and overlap when comparing to the cam card, this is very strange to me. I´m measuring this with valve play at 0,08 inch as stated in cam card and at the valve retainer. There are certainly some degrees here and there that are incorrect, but as whole I think this is correct. The big picture is showing a quit a big difference in Duration and overlap. I´m I missing something when measuring? The feedback I get from supplier are more aiming towards that the Max lift should be at the correct timing, and not focus on Duration and Overlap. For me this is a bit strange, I would like to know the actual Duration and overlap of the cam in the car. Grateful for any help. /Henrik
