I have run 12.45@109 with 75HP (NOS) 12.40@110.6 with 100HP
and 13.17@104 on motor. Its a 2 bolts main stock rods cast crank and Speed pro hypertectic piston.All stock nuts&bolts.I open the nitrous at 2400RPM....Does it will survive 125HP or 150HP my goal is 11.9X@11X....

Car wheight around 3650LBS

 

not very many more

 

id stop at 12.5 Nitrous HP/Cylinder on hyper.pistons, you could 'push' it to 15 hp/cyl(120 shot) but not much more.
what AFR you running?
id shoot for 11.2-11.8 on the juice.
and i would up the RPM to 3000,
500 RPM is not a lot but could save you from damage or a nitrous backfire.

 

AFR I think that its 12.00 @ 5.5 psi of fuel pressure...I know someone with a Zex kit the nitrous open as soon as the tps get 4.6Volts no mathers what rpm ..

 

Just to warn thoses of you running speed pro hyper piston ....100HP of nitrous is the MAX you whant to go...I put 125HP and piston no 4 and 6 are now in pieces (yes the fuel pressure was good) .So now i got my ansew Times for a forged 383

 

I prefer no more than a 125 hp shot on cast/hyperuetectic pistons with a 4" bore and no more than a 200 hp shot on a forged 4" bore unless other items on the engine are considered/built.

My friends 302 in his stang lasted 3 years on a 125 shot on hyper pistons. Many have lasted longer.

I know it may not be what you want to hear but ring gap, timing, and fuel is more likely what killed your engine. you have to run what some people would consider a massive ring gap when running nitrous with a hyper piston.

read this

https://www.thirdgen.org/techbb2/sho...light=ring+gap

and this

https://www.thirdgen.org/techbb2/sho...light=ring+gap

and this

https://www.thirdgen.org/techbb2/sho...light=ring+gap

 

Yeah i know about ring gap, timing, and fuel...The fuel & timing where ok but not the ring end gap... When i built the short block i set the top ring gap at around 0.012 i was not supose to run nitrous then goes 75hp 100hp finaly i told myself 125 hp should not hurt 11s where so close

Thanks for the ring tread

 

well atleast it gives you some closure to know what caused the death.

 

just put a turbo on there or run a twin turbo setup they dont harm your car plus they are lighter than a blower and dont require your engine to spin it with the right set you could hit mid-high 11's. dont keep uping your nitrous because it can only take so much i wouldnt expect to see those times on just nitrous alone

 

um...how about no

 

I had a 350 with hypereutectic pistons that I sprayed a 125 shot on quite often. I also didn't let the nitrous hit below 3000 rpm. I eventually went to 150 shot on the pistons with no trouble. I was worried though. I guy in my town has put a 300 hp shot on some hypereutectics before.

 

I ran over 175 hp on hyperthetic pistions no problem. my car has forged now (way cheaper deal for some reason?) anyway I called KB and they said running 200 hp nitrous would be fine. I think there was a post someware on here that had all the technical garbage about the hypers vs the forged and it said that the hypers are stronger than the forged but, are brittle. where the forged are very strong but, will flex and give more when you get knock. on a hyper it just breaks up like hitting a rock with a hammer, where the forged will take some knock before the metal gives