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153 - Rod to Stroke Ratio

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Did I hear wrong ... about half way through the webinar Andre said we want to achieve max cylinder pressure 16* to 18* 'AFTER' TDC?

Should this be you want max cylinder pressure 16* to 18* 'BEFORE' TDC?

I guess I'm having a hard time mentally conceptualizing this ... if anyone could help me out

Much appreciated

If the max cylinder pressure is before TDC the piston will have to push through the pressure to get to the top of the compression stroke. By having the max pressure after TDC, the piston is pushed down with the cylinder pressure.

Thanks for the clarification ... so then this is after spark/ignition?

Yes

thumbs up ... much appreciated - it didnt click, it does now

If max pressure was occurring before TDC, the engine would run backwards :)

I would like to ask in motorbike for Drag Use only with revlimit about 12500rpm the Rod to Stroke ratio is 1.72 rod length is 99.4mm and Stroke 57.7mm is this Identical for that?

1.72 is probably a little on the low side if you're talking ideals but certainly not outside the ballpark of what can be achieved reliably. If you can increase the rod to stroke ratio without any drastic measures then I'd attempt to do so however if not then I wouldn't be concerned about it at 1.72.