Do you need dome pistons for hemispherical engines?
About the only engines that really need dome pistons are those that use hemispherical combustion chambers; in this case, the chamber roof is so high and peaked that you almost can’t maintain a decent compression ratio without a dome piston head.
Which is better dome or peaky dome pistons?
One of our steps with a dome piston is to radius it and keep it as low and broad as possible. Low, wide, broad domes are definitely more in favor than a tall peaky dome. Such challenges are not limited to conventional big-block Chevy heads with open combustion chambers over 100cc.
Why are compression pistons set to 10.5 to 1?
However, having said that, if you decide to go with the 10.5:1 setup, the Sportster Performance Handbook states that if you set the squish height close enough (distance between the top of the piston and the head) it is supposed to improve the engine response and reduce preignition.
How much pressure does a dome piston have?
If your combustion event gives you 200 lb. of pressure per square inch, you end up with 2,512 lb. of force pushing down on the piston. Now, put a triangular dome on top.
About the only engines that really need dome pistons are those that use hemispherical combustion chambers; in this case, the chamber roof is so high and peaked that you almost can’t maintain a decent compression ratio without a dome piston head.
One of our steps with a dome piston is to radius it and keep it as low and broad as possible. Low, wide, broad domes are definitely more in favor than a tall peaky dome. Such challenges are not limited to conventional big-block Chevy heads with open combustion chambers over 100cc.
What’s the compression ratio of a domed piston?
72 Change to a domed piston. This method of increasing compression is more expensive, but more flexible than milling the heads. Most high compression pistons will come with valve relief’s allowing the use of high lift cams. This JE domed piston raises the compression in a stock combustion chamber to 10.5:1.
How are high compression pistons used in H-D engines?
Most high compression pistons will come with valve relief’s allowing the use of high lift cams. This JE domed piston raises the compression in a stock combustion chamber to 10.5:1. JE and Wiseco both make high compression pistons for H-D engines that do not require machine work on the heads.