Ok. Here Goes. I have a 1965 Dart Wagon, with a 360. It has speed pro .030 over hypereutectic pistons, eagle I beam rods, stock crank, and big valve heads. The motor runs great, but I am looking for that little bit of extra power at the track. I have seriously been considering a 150-250 hp shot of nitrous, but I have heard that the hypereutectic pistons don't like it. I've also heard that they are fine. The only thing I know is that they really don't like detonation. What do you guys think? Can I safely run that power level with my setup? I do know that Hypers are considerably stronger than regular cast pistons, but not as good as forged slugs. The only problem is that they are more brittle.

Start off with a 75 shot, and work your way up and don't go more than 150 and you should be fine. We have run 100 to 150 on cast pistons.  

MAKE SURE YOU BUY A COMPLETE KIT AND FOLLOW THE INCLUDED INSTRUCTIONS TO THE LETTER !  IF THEY SAY HOP AROUND ON ONE FOOT AND ACT LIKE A GORILLA..... DO IT (YOU CAN FEEL STUPID BUT DO IT )todays n2o kits are well enginered and a very affordable power adder but can also bite you on the a$$ if you start to think it wont happen to you. make sure your motor is in good shape, keep your tune conservtaive and have fun. i am using the edelbrock performer rpm kit and love it!  also make sure you get a kit from a well known supplier  not some guy on the corner by the way make sure your fuel delivery system is up to the demands going n2o rich and fuel lean is deffinatly NOT fun   my nephew found out the hard way in his 5.0 stang (want a paper weight?)  dont be scared but be cautious and hit the switch soon

Just out of curiosity, does the gorilla hopping occur before or after you open the N20 bottle?  

(I'm thinking the Chinese dude who translated the instruction sheet in to "American" was a little confused)

during installiation.    it was used as an example to state if the manual says do something that you feel unnessacary do it any way just to be safe and make sure your not turning your very reliable motor into a grenade when you spray it for the first time... by the way if the rear only has radials on a worn out suspension it will hop like a raped ape

I have a carter high volume fuel pump, plus, I am thinking about running a dedicated 5 gallon fuel cell and electric pump for the N20. That way I can run 100+ octane with the Nitrous system, and still run 92 octane when cruising. I definitely don't want any detonation, because it will shatter Hyper pistons. I am looking at the NOS Cheater kit, but several people have said this is too much and I should look more towards the Powershot or Super Powershot systems. And as for the rear, I have BFGs, and superstock springs with caltracks.
Mopar or Nocar

i wont tell you not to run it but the dedicated fuel system is a bit of overkill at this level with a 150 shot you can still run 92     dont quote me but at 150hp you need 7 psi for my edelbrock kit your carter should supply that with no problem and if you use the extra cell i reccomend you activate the fuel pump on the same circuit as the juice arming switch so you dont get excited and forget(its possoble anyone can do it so dont be offended)to turn it on also with it set up that way you MUST make sure the extra tank isnt low, with one tank your fuel level gauge will tell you.    alot of people like to run just 1 switch that they hit with their thumb... i strongly advise aginst that for a few reasons1 hit it before wot=broken parts2 back peddle and forget to let go of the button and some thing is going to scatter3 accidently hit it and some thing bad will probbaly happen    i run my system with 2 switches 1 on the dash that is lit(came in kit)and clearly labled on and off and a micro switch on the carb that ONLY activates at WOT it only takes a couple more mins to set it up this way and is worth a ton of assuranse. for a few bucks more get the preformer rpm kit its adjustable from 100 150 175 200 250 hp and i can highly reccomend its quality ease of install and consistency    if you have any more questions feel free to e mail me directly off my profile on here

The problem with your hypereutics pistons is that they are more brittle, they don't expand and contract like forged or cast pistons. Hypereutic means they have more silicon in the molten aluminum during the manufacturing process. The biggest concern is keeping the silicon well mixed while in the molten state. If the silicon bunches up before the aluminum cools then it becomes a severe weak spot in the piston. If a detonation hits the weak spot, BOOM!

I read all this about ten years ago, so hopefully they have improved the manufacturing quality in the mean time. Seeing how the car manufacturers now use these pistons in many of there engines, I betting they have. Theres no way GM would risk engine replacement warranties on a inferior piston.

All else fails call the Nitrous manufacturers tech line and talk to them.

I would talk to the piston manufacturer.  KB has a nice write up on nitrous.

http://kb-silvolite.com/article.php?action=read&A_id=7

Steve

GM doesn't factory-install nitrous and is unlikely to warranty a motor that they thought had it.

Back to the question of h.e. pistons...I've no personal experience there but have a freind who routinely tears down Corvettes for his business, he says shattered pistons are common and his description for hypereutectics involve a stream of profanity not acceptable here.  I think even cast pistons are more ductile than h.e. and because someone succesfully uses them on a nitrous motor does not mean that you can use hypereutectics.  Caution advised, and of course ask the piston company.

Ha ha, one of the funniest stories I have at working at a Pontiac dealer is once a Grand Prix (98-02) was towed in with the hood majorly bulged up. When we finally got the hood open the whole upper intake (plastic) was blown apart.  If the little red button on the dash wasn't enough of a giveaway it was still an obvious N2O backfire. We pulled the carpet in the trunk and found where a bottle had been mounted and a red wire. The owners insisted for 2 weeks that all they did was turn the key, they heard a bang and the car wouldn't start (the friggin  hood was bulged up I wonder why the engine wouldn't start) and wanted the engine replaced under warranty. We laughed and eventually they purchased a new engine.  

Ahh, just their dumb luck that they towed their car to a dealer that had service guys wise to the N2O thing...  

"Theres no way GM would risk engine replacement warranties on a[n]inferior  . . . ."

How soon they forget the 301 Pontiac, the 305 SBC, the 151 "Iron Duke," the 140 SOHC Vega . . . .  

. . . the Oldsmobile 5.7 diesel . . . .