Im rebuilding my beta with hypereutectic pistons. I was reading about them and many people say they are really bad for boost...



What is the reason???

 

Hypereutectic pistons have a-lot of silicon in them. The silicon makes them very wear resistant, and very brittle. Having a brittle piston in a boosted engine is not a good idea because they are more prone to cracking if you get any detonation, which is more likely in a boosted engine.

 

Hyper U pistons are a good compromise between stock cast and more expensive forged pistons. They don't expand as much as forged due to the high silica content so you don't need to overbore your engine. Plus they can be quite a bit cheaper. Ultimately they have a lower peak pressure threshold than forged but that only matters if your going for BIG power. Otherwise its all in the tuning. A poor tune can grenade even forged pistons in a heartbeat.