Thread: Quench and soup bowls

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I know the importance of a good quench area and run some high end street engines such as iron headed 10.9:1 383 with 200psi cranking pressure on pump gas. I like to zero deck my block and run a .039 gasket with flat tops and 64cc chambers. I understand the quench concept to help swirl the air/fuel mixture in the chamber.

My problem now is I have never ran a soup bowl piston. I love flat tops for max power and second best is inverted dome/D-shaped for lower compression.

Now, what about soup bowl turbo/blower type pistons. Will the tight quench area actually help anything when you have a negative 34cc bowl type piston top. Seems to me like it would be the same as running a loose quench. Any thoughts/experiences?


These are to be used in a blower application and it seems to me that they will not benifit from a tight quench. Maybe a thicker gasket to reduce CR would be better in this application???

My pistons are 9.0:1 inverted dome and they reap the rewards of the tight quench being able to run 6+ lbs boost on pump gas. Will soup bowls do this under the same circumstances??

"My problem now is I have never ran a soup bowl piston. I love flat tops for max power and second best is inverted dome/D-shaped for lower compression."

I haven't either and I don't intend to at this late stage of my life. Same as you, flat-tops and D-dishes work well, why change?

"Maybe a thicker gasket to reduce CR would be better in this application???"

Wrong approach. CR should be set with the combustion chamber volume and the piston crown configuration. Then a gasket of the proper thickness should be chosen to work with the deck height of the motor to set the quench figure at 0.035" to 0.040".

Quench can't be all that important, Hemis don't have any! haha.

Originally posted by R Pope
Quench can't be all that important, Hemis don't have any! haha.

With a hemi, you have a centrally located spark plug and it's the same distance from the plug to the farthest point in any direction, so you have no hot and cold areas of the chamber and the flame front has an equal chance of firing off in all directions.