I would like to run a mild nitrous kit. Like 100-150 shot. My motor wasn't built with nitrous in mind.

10.7:1 383ci. fully balanced
Eagle crank
GM rods
Speed Pro ceramic coated hypereutectic pistons.
Pro Topline Lightning 200cc
Full MSD everything
The rest really doesn't matter...

Anyways, I've heard that "hyper" pistons expand and retract under heat, and that the rings would need to be gapped specially in order to run nitrous on them. I'm just wondering if this is true or am I safe to run a mild/moderate shot of juice. Anybody running this now?

 

I never heard about that i just heard they crack at the pin.
I think youll be fine.

 

i'd say a 100-150 will be fine.. What kind of block are u using? If your only using a two bolt block i'd be careful, even the good 4 bolt blocks are only good for around 600hp, i like how i said OnLy lol :lala:

I'd personally prefer better pistons than you have, but i can't say i've heard any details about them, good or bad.

Mike

 

4-bolt main.
This is good news. I'd really like to run some occasional juice.

 

Hypereutectic pistons don't expand and contract under heat. Forged pistons of yesteryear do. (Newer forged pistons don't seem to expand and contract as much as older ones.)

The problem with hypereutectic pistons is the fact that they are very resistant to heat. Because of this they cause the piston rings to run hotter. Then, because of operator error, the gaps aren't increased to compensate enough for the expansion that takes place.

Then the rings butt up, crack and/or bind, shift the piston and the pistons crack/break.

Another problem is, because people are too used to forged pistons, and think hypereutectic pistons are "similar" they run the same piston-to-bore clearance as a forged piston would use. That's the last thing a hypereutectic piston needs.

Because of it's ability to resist heat, hypereutectic pistons don't expand and contract hardly at all. AAMOF, the clearance can normally be run tighter than a standard eutectic piston (aka cast). If the clearances are left loose, then the pistons will shift around, get cocked in the bore, and more than likely crack.

Anyone that has broken a hypereutectic piston(s) has done so because they're under the impression that they're stronger than cast pistons. They aren't. They simply resist heat better, keeping the chamber temperatures higher. That usually means more power.

They are a little stronger than cast pistons, but not much. Not enough to be able to run more boost or nitrous than a cast piston can tolerate.

 

The rings were thrown on already pregapped(I'm guessing standar fitment) right from Speed Pro. So, because they are to be treated like regular cast pistons, I should be OK?

 

Well, I think you could use hyper pistons with a propely tuned nitrouis system but "Deto" the eng. just once and it will sound like glass breaking. Use forged pistons.

Auggie

 

That's what I have also, and from what I understand, Speed Pro says their hypers don't require more ring gap over standard cast pistons in N/A engines.

Using nitrous is a different story. The increased cylinder pressure will increase the amount of heat in the combustion chamber when the fuel is lit off. (I know nitrous cools the intake charge, but once the spark plug lites, there is quite a bit more heat generated.)

It would lead me to believe that (just like building any nitrous/forced air engine) it would be wise to run a larger ring gap.

Or, as Auggie says...
You'll never regret buying forged, but you may regret NOT buying them. Which way would you rather have it?