Hyper pistons= bad?

[CTX-SLPR]

Howdy,

Whats the deal with hypereurtectic pistons in a turbo motor? I managed to get a set of the speed pro's for my 4.1 project for really cheap so I would like to use them. And as an add on questions, whats the difference between the rockers on a 3800 Series II motor and the classic 3.8/4.1?

Thanks,

 

[Quick89]

Hypers

Not bad, TTA's came with hypers

 

[CTX-SLPR]

Thats reassuring to know actually. But how much booste can I stuff into this thing with those pistons if I'm on the war path against detonation? I'm talking for serious booste, race gas and alky injection.

Thanks,

 

[NC87GN]

I have had many discussions, on this topic, with the best in the buick business. You will hear about 5% say good things about hypereutectic pistons and 95% say NO WAY, not in my motor!. Stock pistons are hypoeutectic design and without getting into detail, it is a unique piston. The problem with hyper pistons is they do not stand up to detonation under high boost and they do create quite a bit of heat. This is my .02 and if you wanna expert opinion call GSCA club, TA performance etc..

Mike Banas
87GN

 

[machinegun]

I have talked to a number of people and some who have used the hypers and a few with success. However the hyper pistons are more brittle than a forged piston and as such can be more severly acted upon by detonation. They could break easier in essence. I personally have never used them and I wont, seen and heard of too many issues. I would like to say that the stock pistons are not anything like a hyper piston. They are unique in their manufacture though and is why they have proven to be very reliable and resilient to detonation due to their manufacture. I hope this helps.

 

[TurboDave]

Stock pistons are hypereutectic??? Nah, not on your life. They're cast, and have a special steel insert in the head and pin bosses.
Not sure where that info came from that they're hypereutectic, but they're not.

Maybe some people confuse the issue because of the "Hepolite" marking inside. That's nothing more than a manufacturer's ID marking, not the process.

 

[RobR]

Hyperubreakems just don't seem to hold up to any amount of boost. I've had several buddies with other cars, either turbo or blower, rebuild with hypers and the ring lands don't hold up.

I'm with TurboDave, stock was a cast piston.

 

[CTX-SLPR]

I went and looked at the photo guide on www.gnttype.org for the Buick v6 pistons. While its no forging the 4.1L hyper does seem to be a stouter piston than the 3.8 Hyper. If I could get forgings without having to get custom ones for the 4.1 I would. I've considered using sbc pistons but then I would need custom rods... more money. If anyone has a better cheap solution I'm all ears.

Thanks,

 

[sowle]

.02, Let's think about how much boost you can shove in a 4.1. Is that a production block? Or a stager? The past has proven how much the factory pistons can take. You haven't mentioned the level you want to take this.

 

[CTX-SLPR]

Oh I am sorry about that, I am remiss in telling that. I'm using a production block, hopefully an 84, still combing the yards for it. I'm planing on maxing out the components reliable capacity, like ~24 psi maybe more. I'll be using the front 3 billet caps, ARP studs top and bottom, cometic head gaskets, twin turbos, twin intercoolers, alky injections, ported heads and gasket matched all around.

 

[broke1]

Go on the other board,post this and ask Jesse aka Call Me Mud,he runs hypers and loves em. He used to be on this board as Intercooler and was banned or chose not to come back after all the post deleteing,no idea ,seems like a great guy ive talked to him at length. Hes run the hypers into the 10s many,many times and at over 25 lbs of boost and never holed a piston. I garuntee you he knows more about hypers than most.I also think hes got a 4.1 shortblock fresh and ready to go for like $2200.HTH

 

[GrndNatnl]

Ask J Banning too. Jesse did his motor. Banning has beat the living crap out of his motor, to a melodic tune of 10.97 @ 120 on hypers, as well as other NA (non-turbo) internals.

Hypers are perfectly fine as long as you keep the detonation away. Thats the bottom line. My current motor has hypers.

If you have the money to blow on forged, then go forged.

 

[CTX-SLPR]

Surprise!

Howdy,

What a surprise I had today when I opened the package containing my new pistons! They are not the speed pro's I was expecting but instead Sealed Power units. I'm not sure what to make of them, they use a full skirt, actually good for a turbo motor I think, have somewhat of a pin reinforcement on them, huge slots behind the oil control ring for oil draining and what looks like a nicely reinforce crown. The bad thing is that the crown isn't fully machined and is slightly rough. Anyone know a thing about these?

Thanks,

 

[JCotton]

whats the part number?

 

[CTX-SLPR]

Sealed Power 6-9006P .030 I know they are .030 over already though

Thanks, if anyone will know it would be you.

 

[JCotton]

H521 is the number for the Fed Mogul hypers, were you expecting the trw forged?

 

[CTX-SLPR]

I knew I was getting hypers but I thought I was getting the more common speed pro hypers on these sealed power ones. I'm hoping that no one has used them and found them to be complete junk!

 

[JCotton]

They don't add up to any numbers I'm familiar with, I'll have to check to see if they have been superceeded tomorrow

 

[CTX-SLPR]

Thanks a ton, I'm pretty sure they are out of production now but any information on how good or bad these things are would be greatly appreciated.

Thanks again,

 

[chevyII]

I think speed pro bought TRW or the other way around,maybe federal mogul too?