hypereutectic pistons in 3.1

Jbrogan · 11-18-2008, 02:34 AM

are the hypereutectic pistons any good? i was reading a forum on another site that said forged pistons are not necessary and you can use these hypereutectic pistons in a turbo motor and they are better than stock. is this true? or should o just stick to spending $650 on wiseco forged pistons?
The pistons i found and i was thinking of using can be found on summitracing.com, p# ZH692CP. is this a good idea or no??

loner666 · 11-19-2008, 01:00 PM

Do it right and use forged. For your setup though you should be fine on 9psi for a while. My stock bottom end has seen ALOT more abuse then yours and Im still running strong. Its seen a taste of 20+psi a few times. From this point on its getting a minimum of 12psi with more coming when I get a better controller or another spring and I STILL have optimize my tune yet. Yours its probably safer then mine with the way I did it (unless you've changed it)

Jbrogan · 11-20-2008, 12:09 AM

no but, i figured that the hypereutectic pistons are stronger and hold up to heat better than stock cast aluminum. what happened was i put some methonal in with my race fuel and the combustion chamber got too hot and melted part of one of my pistons, but this time around im still going to run 9 psi but no methonal and im going to put a cam, valve springs, pp heads, pp exhaust manifolds, 65mm tb, chromoly pushrods, and im going to use a 2000+ 3400 intake manifold for better air distribution. i just figured that the hypereutectic were better than stock and alot cheaper than wiseco. just wanted to get some other opinions.

IsaacHayes · 11-21-2008, 12:37 PM

Some say hypers are brittle. Though I think one OEM uses them in a turbo auto they produce.

loner666 · 11-21-2008, 02:00 PM

You can try it but like Isaac said, Some say they are too brittle some say they will work. I have some stock ones here from my '94 3100 you can have if you want them. Been sitting in the block open to weather for almost 2 years but the pistons themselves should be fine.

Also get Meth injection instead of putting it in your gas like that and dont use 100% meth when doing so

Jbrogan · 11-21-2008, 07:32 PM

well according to the description, most people ive talked to and the guy i talked to at summit, the all say that they are stronger and hold there shape much better because they are bonded with silicon. i just figured if they are stronger than stock then id try em, so i guess well see what happens.

loner666 · 11-22-2008, 12:15 PM

I suppose for the price its worth a try

1988GTU · 11-22-2008, 12:34 PM

Hypereutectics are FINE! If your tune is not safe/setup properly or something is out of line making for engine concerns, you will have problems no matter what and using forged will just hide it longer.

Go for it and dont look back.

torq455 · 11-23-2008, 03:16 PM

hypers are stronger, more heat reflective, self lubricating due to the silicon, but they are more brittle. my Dad had a 350 TPI with 8.8 CR and 7 psi and ran great! even stood up to horrible detonation several times at 4000 + RPM. the water injection nozzle got clogged a few times. however, for a few hundred more, and while you are there, it'd be better to just put in the forged. they are good insurance.

Joseph Upson · 11-23-2008, 09:37 PM

Nearly all of the production forced induction U.S. cars use hypereutectic pistons. They are fine as long as you don't subject them to detonation. The top outer perimeter of the naturally aspirated fwd pistons are rather thin and therefore the first thing to go with excessive detonation under boost, otherwise if you tune it carefully and avoid detonation they will stand up to well over 10 psi. I have read several high boost on stock, naturally aspirated piston stories and have a copy of an 1995 article on a stock street legal 93 mustang GT with a paxston supercharger running mid 10 sec quarters using slicks at 14 psi in an old Turbo magazine. Technology has improved a bit since then.

The newer forged pistons are actually closer to hypereutectic pistons in composition and that's part of the reason they are capable of running much tighter clearances which is an attribute of the hypereutectic piston. Years ago forged pistons were not recommended for daily drivers because of the need to warm up to reach proper shape for the cylinder. The Ferrari Testarossa had a required warm up time because of the forged pistons.

If you can tune it without "knocking" it they should work fine. The Syclone/Typhoon and Grand National owners have run their hypers up to at least 18 psi, but they also have a piston built with boosting in mind so I don't know how far you could push it.