Don Terrill’s Speed-Talk

Hi Don,

Could you tell me the general range(i know it will vary with the combination)in degrees that the piston speed just starts to have and affect on the air column when scavenging is done or as it is ending


Thanks

Well, it's somewhere between TDC and when the exhaust valve closes. Exactly where, I have no idea. Maybe engine simulation software can help. Look for one that will display the cyl. pressure / volume graph (data). What are you trying to figure out? Thanks, Don

I understand the benefits of different rod lengths depending on the engine combination. I was wanting to get a general idea of when piston speed starts to have an affect to get me in the ball park and give me a starting point to get the most out of any particular combination. I dont have access to a flow bench or dyno but my intuition is usually pretty good.

Thanks