Cam and compression ratio compatibility
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An engine having a high performance cam (later IVC point) needs a higher SCR in order to keep the DCR within an optimum range. Because the late IVC point can cause reversion (along with an increase in overlap and/or a tighter LSA), this type of tune can cause the engine to idle rough (have a lot of lope). Idle vacuum will be lower and if you were to put a compression tester on these engines you would see something in the 125-150 PSI range. | An engine having a high performance cam (later IVC point) needs a higher SCR in order to keep the DCR within an optimum range. Because the late IVC point can cause reversion (along with an increase in overlap and/or a tighter LSA), this type of tune can cause the engine to idle rough (have a lot of lope). Idle vacuum will be lower and if you were to put a compression tester on these engines you would see something in the 125-150 PSI range. | ||
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| + | ===Dish volume=== | ||
| + | Most dished pistons have published volumes. Those that don't or with pistons that are unknown as to brand can be estimated by using the following formula: | ||
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| + | {{Note1}}All measurements in inches. | ||
| + | *3.14 x [radius of the dish]² x depth of the dish x 16.4 (converts cubic inches to cc) = Volume in cc | ||
| + | **Add 2 or 3cc for the valve reliefs if they extend beyond and/or below the dish. | ||
===Compression calculators=== | ===Compression calculators=== | ||
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