3 replies to this topic

[Terry Haines]

The subjest of pistons and material has gone round and round for years. Most owners who have T/C or S/C engines,on the whole, feel that the stoc piston is OK for boosted engines..a view I have never subscribed to!!

Take a look at this info...


http://en.wikipedia....eutectic_piston


Note the text that says..

The biggest drawback of adding silicon to pistons is that the piston becomes more brittle as the ratio of silicon is added. This makes the piston more susceptible to cracking if the engine experiences pre-ignition or detonation.


... this tells you that if you hit any det on a boosted motor you could be in trouble..I should also add that hyper pistons do not conduct heat away as well as performance units..another drawback in stoc pistons in a boosted engine..All just FYI for the masses!!

[SDK]

BULLITT, on 19 March 2010 - 01:44 PM, said:

all the mustangs from 1996 to current mustang MINUS 03-04 COBRA. all have the hyper pistons.

boost on those motors is limited to 8-10 psi and max out at 425 hp(breaking point for powered steel rods and hyper pistons) so these pistons can take some power under the right configuration 10 psi is the most i would run i have seen people run more then that over time. And they have had a metal down running like 12-14 psi on stock hyper pistons in a mustang..... Plus YOUNEED A WELL THEN STANDARD FUEL SYSTEM. if you have a fuel system that can support ur popwer and boost all the way to REDLINE you will just about be ok. And set a rev limiter AT THE REDLINE. not past that...

HEAT AND NO FUEL ARE THE WORST FOR THESE PISTONS. But if you run N/A and make a shiz ton of power ull be just fine. Mustangs have run na with stock pistons at like almost 500 hp and not had a issue. Ur not adding anymore pressure like as BOOST would. So its not making that big of a issue. also on hyper pistons I WOULD NOT run anything more then a 125 SHOT ON STOCK hyper pistons. anything more then that UR ASKING FORA MELTDOWN. and on a 11.1 compression motor, i would not go over 75 shot.. cuz ur just be asking for trouble on these 3 liters.

I dont know the exact compression on these motors. But i think the escape one like i have is 10.1 maybe a tad higher dont know. But these motors with that kinda compression will not take much boost or N20 before they pop. TUNING HAS TO BE CRITICAL AND DEAD ON

Agree that if you are building a motor for boost/nitrous you really should go for the forged rotating assy. However, the 92.5-95 cars with the 5.0 motors also had hyper pistons and provided you have a good tune you can run up to 500+whp which is about when the block lets go. Again, this is with a spot on tune and obviously detonation will be bad in any situation. At least a forged piston can take a bit whereas a hyper will give up the ghost almost immediately. The main weakness in the 96-up Mustangs is the rods which are made out of that pile of shiz powder metal or whatever it's called.

So basically I'm agreeing with everything mentioned in the above 2 posts, just throwing my $.02 in.