what would tha best pistons to use with a 300 shot of nos and be safe...for a .060 over 383 street/strip car

 

Assuming everything else is able to handle the needs of a 300 shot, then I would suggest JE, Ross, or Mahle. They all should have a set of pistons designed for heavy duty N2O. I think any decent piston manufacturer will have a set that will fit your needs.

 

Agree with the above. "Safe" is a relative term with a 300hp nitrous shot. One of the keys to making it (relatively) safe is to not bring it all in at low rpm. Either use a multistage system, or don't turn it on below 4,000rpm or so. A 60 over production block may have big trouble with cylinders splitting, let alone the usual problems with piston damage from very high cylinder pressures.

Rich

 

Not going .060" over on almost any 350 would be safer as well. I'd also hard block the SOB as well.

For lots of N2O a custom piston is the way to go.

Bret

 

What block are you using? Gen 1, LTx, LSx??????????

 

The pistons will handle that shot no problem if the tune and ring gaps are correct. Like has been said, I would be most worried about the block. Say your motor makes 400 N/A, then you dump a 300 shot...that's 700 at the flywheel and after-market block territory.

We use sets of custom pistons from JE with a dimpled crown, specifically made for heavy nitrous hits.

 

its a gen 1 block and i pulled it out ma camaro its already .040 over and its been sittin up 4 6 years wit a blown head gasket so its gotta go .060 and whats a safe shot ma block? (everything forged)

 

How do you like those dimpled pistons? I haven't played with that, but Jim McFarland seems to think that has merit. Have you torn the motors down and looked at the burn patterns with them? Have you noticed any changes in timing with them? or less detonation? or lower BSFC?

Bret

 

All the motors which are out with those pistons have not come back for re-fresh yet, so unfortunately I have not gotten to look at the burn pattern which I would suspect to be the biggest advantage along with it's collateral gains. I don't do the day to day tuning, and only work on the dyno when we're changing engine parts around. I will have to pull up the notes to see if there was anything noticeable.

 

MachiniseOne:

Have you used glass-beading on any of your piston crowns?

 

Fred, after I radius everything on the pistons I do exactly that.

Your block can look like this but the piston crowns shouldn't!

 

Only as prep before coating. Radius work and scotch brite pad otherwise.

What is the theory behind that? I would think that would just aid in carbon buildup.

 

Yeap, and a light coat of carbon actually aids combustion as goofy as that sounds it's true. Well at least some single cylinder R&D tests have showed that.

 

I don't know the exact benefits. That's why I was fishing for info.

It was a concept sold to me by a shop with significant experience with large shots of nitrous. I thought they were doing it for heat transfer purposes. They didn't want a crown coating. But the idea of building a thin layer of carbon would not promote heat transfer. And a high percentage fo nitrous in the mix is not going to need any sort of "aid" to combustion, unless its just more uniform mixture. So maybe they were trying to keep the piston cooler by insulating the crown with carbon, as an alternative to a coating.