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Hypereutectic Cast Pistons


RedFive

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I would keep looking there, they pop up all the time.

Sounds like someone is using too long of a connecting rod......

 

 

 

 

 

GROAN...... :mparty:

Still plenty of those pistons in stock from ITM last I checked, and they are what i am going to run as soon as I get my head reassembled.

 

I wouldn't bother trying too hard to press this point. The more people you convince, the more people you will be competing with for pistons. Kinda a lose/lose situation.

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My point is with well over 40K miles on a set of used N42 N/A pistons which have seen their fair share of detonation over the years, I'm still running with virtually the same compression and about 5% more leakdown than I had when I started.

 

Actually, on #5, due to some stuck rings from extended storage before I installed the engine, I am up 10psi and down 20% on leakdown from when I originally started the engine the first time and took basealine readings.

 

The N42 N/A piston is very durable. Nissan narrowed the rings to give 300,000 mile durability on an engine which was known for this kind of mileage lingevity by the time the turbo came out. It was an engineering decision to not compromise any longevity AT ALL when adding a turbo that may see constant borderline detonation for thousands of miles due to poor maintenance...and still hold up.

 

We are not talking about that situation here. We are talking about seriously increasing the specific output of the engine well above the 200HP Nissan Designed around (yes, 200, not 180---the pistons in Euro Turbo Cars are the same P/N as North American Models...and they are 20HP more!) Under that assumption is that we will be running considerably more cylinder pressure, and if the fueling goes off the resultant detonation will be FAR more severe than what Nissan Designed the pistons for in EITHER case.

 

If you ever heard Japanese LPG powered Bluebird Taxis and how they were lugged by the drivers, you would realize that the N/A pistons were designed around some SERIOUS parameters in regards to detonation.

 

Make a stronger ring land, break the piston ring. Make a stronger piston ring, break the head gasket. Make a stronger head gasket, break the piston. Go forged pistons with even THICKER lands, THICKER rings, and O-Ring the block: BULLETPROOF?

 

Detonate: Still break the piston.

 

Detonation WILL break things, period. The difference between the turbo pistons and N/A pistons in service to 350HP to the rear wheels has been indecipherable to me to this point. If you are going higher than that, maybe turbo pistons are a good thing because of ring loading on the lands due to higher sustained cylinder pressures. But realistically do you see yourself running that build even 100,000 miles before expecting to overhaul or freshen it up? If not...

 

But in either case, both machines will blow the ringlands when you detonate.

 

I remind you JeffP ran lean at 8psi on two successive dyno pulls. TWO PULLS. Never heard it detonate or anything. Sunk 5 of six pistons rings and lands out of those expensive forged pistons. If it had a weaker head gasket, it would have blown. Maybe the rings would have held, maybe they would have gone... who knows, but if you make everything else airtight and 'bulletproof' you detonate and you will kill either piston: N/A-Cast, Turbo-Cast, Superdooper Unobtanium-Forged-Custom 6 Month Leadtime from Cosworth Racing-Forged.

 

"You canna fight the laws of physics, Jim --- it's gonna blow!"

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My brother, running 10:1 in a b16a broke ring lands in 2 pistons.

 

He was with a great tuner and did a couple of street pulls for a tune and pooof!

 

Those were forged.

 

He currently is running in the neighborhood of 9:1 with some ls pistons that are ceramic coated, (as a Christmas gift from me), and has dynoed 350 and is the longest running engine he has had to date.

 

Burnt his fingers seeing how well that coating works, tee hee.

 

I know there is some disagreement on coatings, however, I BELIEVE! Seen some increadable "saves".

 

This is why I will stick with flat tops, P79 block, ceramic coat two, and meth with no intercooler.

 

I will consider running the head cooling by drilling the water jacket.

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One reason, learning curve.

 

If you are successfull with a cast, then you don't need a forged.

 

If you melt a stock cast, you are not out that much money;)

 

 

thats the moral of the story... id rather be out 300 bucks for cast ITMs from 1 fast z than 700 bucks for forged ross pieces from MSA. bottom line, i think under 350-400 hp if you beak one, youll probably have broken the other with your poopy tuning skills.

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