yldouright
Wrench Pro
I had hoped to end up with a DIG-T-R but failed so I'm looking at building one up from the DIG-S. What are the challenges I'm likely to run into?
@obi_wayne
The DIG-S has two versions, one with 12:1 and one with 13:1 compression but when you extend the bore to ~4", the compression drops to 9.5 on the 12:1 engine. I'm looking to push 40lbs of boost on the 3 cylinder.
Increasing the bore increases the volume of the cylinder for the same stroke so the CR is lowered. The "bowl crown" pistons are also increasing the cylinder volume for the same stroke and that also lowers the CR.TCJBOLDIE said:IF you increase the bore size then you will be increasing the swept volume of the cylinders so you will be compressing more air into the same combustion chamber in the head so your CR will be higher not lower
Increasing the bore increases the volume of the cylinder for the same stroke so the CR is lowered. The "bowl crown" pistons are also increasing the cylinder volume for the same stroke and that also lowers the CR.
It's not the same space when you increase the bore. The increased diameter increases the volume displaced. I don't know how I can state it any more plainly. If your race engine builder agrees with you I don't want his enginesTCJBOLDIE said:So can you tell me by what type of logic or math tells you that having to compress a larger volume of air into the same space actually lowers the CR ????