How many HP?
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,171
From: Hermosa
I’m going to lay a new idea on you if you have not found it yet.
lower octane fuel for a given cylider pressure will create more HP .
so if we get the squish right and prevent detonation then we can run lower octane fuel.
a good squish means I can run a higher CR/DCR to make power extraction from each power stroke more efficient then.
in addition since the lower octane burns faster and produces more cylinder pressure
via a more complete burn I can now reduce ignition lead.
by retarding ignition I can light the fuel when the piston is just a little higher up in the cylinder. This produces less negative cylinder pressure as the fuel begins to burn during the pistons ascent to TDC.
Now peak pressure is reached just on the other side of TDC and more of the fuel that was provided is burned because of the volatility of the fuel used.
this in turm can allow for different valve timing events that will better optimize the various valve openings and closings. Which will produce more usable power.
so yes, squish is very important, as is any other effort put forth to prevent detonation.
one other point, we run carbs. Fuel atomization is important for us. As is keeping the fuel in suspension during it’s trip to the head. A more volatile fuel atomizes more readily. So again, better.
lower octane fuel for a given cylider pressure will create more HP .
so if we get the squish right and prevent detonation then we can run lower octane fuel.
a good squish means I can run a higher CR/DCR to make power extraction from each power stroke more efficient then.
in addition since the lower octane burns faster and produces more cylinder pressure
via a more complete burn I can now reduce ignition lead.
by retarding ignition I can light the fuel when the piston is just a little higher up in the cylinder. This produces less negative cylinder pressure as the fuel begins to burn during the pistons ascent to TDC.
Now peak pressure is reached just on the other side of TDC and more of the fuel that was provided is burned because of the volatility of the fuel used.
this in turm can allow for different valve timing events that will better optimize the various valve openings and closings. Which will produce more usable power.
so yes, squish is very important, as is any other effort put forth to prevent detonation.
one other point, we run carbs. Fuel atomization is important for us. As is keeping the fuel in suspension during it’s trip to the head. A more volatile fuel atomizes more readily. So again, better.
Last edited by REELAV8R; Apr 8, 2019 at 02:58 PM.
