What are the benefits of Split Duration Cams?
What are the benefits of Split Duration Cams?
What are the benefits of having split duration cams? Would the exhaust cams be the longer duration or the intake cams? And are they better for higher horsepower track applications or are they pretty good for a weekend street performance car?
The big power domestic guys I consulted before buying my cams said this about forced induction and the cams:
It's not hard to get air into the cylinders, but getting the air out is another story. Look for longer duration exhaust cams to try to get more of that combusted mix out rather than going with same duration cams.
It's not hard to get air into the cylinders, but getting the air out is another story. Look for longer duration exhaust cams to try to get more of that combusted mix out rather than going with same duration cams.
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PROJECTRB240SX
- Posts: 3673
- Joined: Fri Jun 13, 2003 5:33 pm
- Car: 1972 DATSUN 240Z W/ SR20DET
ITS MORE FOR STREET CARS.... BECAUSE RACING CARS ARE DESIGNED TO MATCH ALL ASPECTS OF THE ENGINE. IF THEY INCREASE EXTERNAL FLOW (TURBO, MANIFOLDS, ETC.) THEY MATCH CAMS TO IT (UNLESS RESTRICTED).
SPLIT DURATIONS ARE FOR WHAT'S MENTIONED ABOVE.... GETTING MORE AIR OUT.IF YOU CAN COMPLETELY CLEAR A CYLINDER YOU CAN ALSO COMPLETELY FILL IT (MAKING MORE POWER WITH LESS DETONATION BECAUSE LOWER INITIAL TEMPS).... THE DOWN SIDE IS IF ITS NOT TIMED RIGHT YOU CAN GET TOO MUCH OVERLAP WHICH HURTS A FI ENGINE.
I HAVE ALWAYS BEEN A FAN OF HIGH LIFT SHORT DURATION INTAKE CAMS WITH LOW LIFT LONG DURATION EXHAUST CAMS. THIS ALLOWS FOR A GOOD AMOUNT OF AIR INTAKE IN THE CYLINDER WHILE THERE IS GREAT VELOCITY AND CYLINDER CLEARING ON THE EXHAUST SIDE.
SPLIT DURATIONS ARE FOR WHAT'S MENTIONED ABOVE.... GETTING MORE AIR OUT.IF YOU CAN COMPLETELY CLEAR A CYLINDER YOU CAN ALSO COMPLETELY FILL IT (MAKING MORE POWER WITH LESS DETONATION BECAUSE LOWER INITIAL TEMPS).... THE DOWN SIDE IS IF ITS NOT TIMED RIGHT YOU CAN GET TOO MUCH OVERLAP WHICH HURTS A FI ENGINE.
I HAVE ALWAYS BEEN A FAN OF HIGH LIFT SHORT DURATION INTAKE CAMS WITH LOW LIFT LONG DURATION EXHAUST CAMS. THIS ALLOWS FOR A GOOD AMOUNT OF AIR INTAKE IN THE CYLINDER WHILE THERE IS GREAT VELOCITY AND CYLINDER CLEARING ON THE EXHAUST SIDE.