Quote:
Originally Posted by Formulas
What do the numbers in the L/H column represent the 20-101 ? just trying to learn how to read the graph
|
Left hand column is MAP (manifold absolute pressure) reading in kPh. Lower MAP is lower load and typically higher vacuum.
It is possible, but unlikely to see values as low as 20 and higher than 100, but most naturally aspirated engines will not produce those types of results. MAP readings above 100 indicate pressure above atmospheric, typically from turbo or supercharging.
To see numbers below 20, you'd have to have an incredibly efficient engine at low rpm. Idle MAP values in the 30's to low 40's for most stock or mildly upgraded camshafts are normal.
Altitude increases MAP values as well. My 465 with a 242/248 on 112 LSA hydraulic roller at 4500 ft of altitude idles right at 50 kPa.