What pistons to use

[Excaliber]

Sorry, I'm not well versed in this subject to render a worthy opinion as to pros and cons. I'm just going on a 'gut' feeling from what I've gleaned here and there. For instance, at one point I was considering a 'blower' for my Excalibur. During that 'research' phase I heard from several sources that the hyper pistons I was running were not strong enough for boost, let alone a 'bottle'! Perhaps a mild boost, but care should be exercised or the pistons should be changed.

If there not strong enough for boost or a bottle, how would they stand up to a 'lean' condition or 'pre-ignition'? Not as good as forged I'm thinking, so 'get that motor right', right from the beginning!

I came across an article at some point addressing 'piston slap', complaints from NEW car owners on a warranty level. Turns out hyper pistons, commonly used in new cars, do tend to 'slap' more than other pistons. No big deal, not a warranty issue, but it 'bothered' me.

Manufacturers like them for various reasons, ease of installation and price I suspect are big reasons why. I guess the real question is: Are they strong enough for YOUR intended use? There certainly cheaper than forged, so when you consider 'cost benefit analysis' they might be a good call for you. LOTS of people like them for various reasons.

[ffindling]

Hyper pistons are cast, the main difference between hyperuetectic pistons
and conventional cast pistons is the silicon content of the alloy. Hyperuetectic
alloys contain as much as 16% silicon. The higher silicon content alloys have
lower thermal expansion rates and as such can be installed with tighter clearances than pistons made with more conventional aluminum alloys. This
is why they have become popular in the car industry because emission control
becomes easier with "tight" fitting pistons. If there is a problem with "piston
slap" or rattle it is most likely due to the manufacturer fitting the pistons
with excessive clearances. Since they "grow" less with heat working into them,
they may not quiet down once the engine is warm because they can't fully compensate for the cold installed clearance. In application terms, hyper pistons can generally be used in applications where cast pistons are appropriate,
but they should never be considered as an alternative in an application that
calls for forged pistons. If your application calls for forged pistons, then that
is what you should use.