Polaris 2003 Pro X - Formulas

ENGINE
2.4
Bore = 6.5 cm. Stroke = 6.0 cm. IHV = 17.1 cc
Displacement = SBore  Stroke


S 
Displacement = 199.098 cc
R=
IHV + Displacement
IHV
R = 12.643
Full Stroke Compression Ratio
To calculate the Effective Compression Ratio, substitute the exhaust port height for the stroke in the
formulas above:
Exhaust = 2.95 cm.
Exhaust port height 29.5 mm
Eff Disp = SBore  Stroke


Effective Displacement
Eff Disp = 97.89 cc
Eff Comp =
IHV + Eff Disp
IHV
Effective Compression Ratio
Eff Comp = 6.725
In order to increase the Full Stroke Compression Ratio to 13.6, how much material do you need to
remove from the cylinder head?
R=
IHV + Displacement
IHV
You know that:
, and you want to find out IHV.
Displacement = 199.098 cc, and we want R = 13.6, so then
IHV2 =
Displacement
(R -- 1)
IHV2 = 15.801 cc desired IHV to have 13.6:1 Full Stroke Compression Ratio
IHV = INSTALLED HEAD VOLUME [CC]
DISP= CYLINDER DISPLACEMENT [CC]
R = COMPRESSION RATIO
S = FULL ENGINE STROKE [CM]
I = INCHES PER CC OF IHV
B = CYLINDER BORE [CM]
PI = 3.1416
R = (IHV+DISP)
IHV
I= S
(DISP*25.4)
DISP = (PI*B*B*S)
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