hypereutetic piston
 

I've been wondering about hypereutetic pistons and what benefits/problems they offer. They seem to be pretty big with the hot rodders, why haven't I heard of them in Porsches?

------------------
plain fan

Cause they Suck. It s a fancy term for Cast. Steve

Not quite Steve. I'm running KB hyperutectics in my 360 MOPAR. They're cast alright, but with a higher silicone content than normal "cast". Damned near as strong as forged. But WITHOUT the "slap" problems of forged when you get to larger diameter pistons. In other words, hyperutetics don't expand and contract with heat as much as forged pistons do. Not nearly as much. That means you can build an engine with closer piston/cylinder wall clearances than you can with forged pistons, but still end up with a much stonger piston. Ever watch dirt track sprint cars, alcohol burners? You'll find hypereutectic pistons in most of 'em. They are a lot stonger than stock cast pistons. Hey, they work in fuel dragsters, running nitro. Keith Black proved that years ago. All that said? With the itty bitty Porsche pistons, and yes, 3.6 liter engines are itty bitty compared to USA V-8's, go with forged, you'll be happier. But when the bores get bigger, hypereutectics are well worth considering, IMHO...

[This message has been edited by pwd72s (edited 10-24-2001).]

I wasn't considering putting them in my engine, I read an article about the pistons, but had never heard of them before so I decided to ask. Are there drawbacks to using this type of piston? Thanks to replying.

------------------
plain fan

PF,
I have a pair of 10:1 Keith Black hypereutetic pistons in my '96 FLHR Harley-Davidson. They are set up to run at about 0.005 piston to wall clearance, and therefore, are very quiet, much more so than a forged piston. One thing I noticed in using these pistons is you can dial back the advance by 2-4 degrees without loosing any power. This made my motor less prone to detonation on unleaded gas.

I'm not a metalurgist, but I read that the pistons are made from a T-6 aluminium alloy, then treated to a molten salt bath, a process which imparts some special qualities to the alloy.

------------------
'81 SC Coupe (aka: "Blue Bomber")
Member: SCWDP
Canada West Region PCA
The Blue Bomber's Website
"If it ain't broke...we'll help you fix it 'til it is!"

[This message has been edited by Doug Zielke (edited 10-24-2001).]

My sister is hypereutectic. With the proper medication, and some protective head gear, she's doing just fine!

------------------
Tyson Schmidt
72 911 Cabriolet
92 C-2 Cabriolet

When I get hypereteutic, I just breathe into a paper bag for a while.

Both my cars have "hyper-teutonic" pistons!

------------------
Tyson Schmidt
72 911 Cabriolet
92 C-2 Cabriolet