How Much Nitrous Can The Stock Pistons Handle?

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Possibly in the future I might want to experiment with power adders, like nitrous. I have a 1972 or 73 318 LA which is now a 323 with replacement cast pistons, a stock crank, stock rods and moly rings gapped within spec, but more towards the higher side (I forgot the numbers). The recommended safe shot from Nitrous Express is 100HP, which they told me over the phone years ago. But how much further can these cast pistons for the small block Mopars be pushed before they give up? And with addressing the ring gaps too?
I have no idea where to buy it.
BUT,
After you gap your rings appropriately,
After you research adding fuel to your nitrous ‘shot’ in order to avoid going lean-

Research a ‘Progressive Nitrous’ system or valve which doesn’t ’SLAM’ the rotating assembly and bearings with 50, 75, 150, 300 horsepower shot of nitrous oxide.

The valve opens at a controlled rate.

Originally this system was created by a British guy in the late 80’s I believe but also David Vizard used this system on “STOCK BRITISH 4/6 cylinder cars that typically made 90-100hp with the equivalent of a ‘300 shot’ volume of nitrous.

You can Google this as well I believe. But I am sure that this type of system is sold here in the United States.

It should extend the life of your engine, wallet, and fun.

Best wishes
 
Engines for pure stock drag racing are Engines that are blueprinted and highly tuned. As I've said several times before they are totally stock.
...... except for the cam, carburetor, pistons, light crank, rocker arms that have had 200 checked for the best sixteen, transmission and converter, gear ratio, and tires. Totally stock!
 
I had a car I would love to have used nitrous on, ladders and big slicks, good 60 foot, but the forged pistons it had had the rings too high, not gapped enough, thin wall piston pins, and a cast crank.
Better safe than sorry, my bottle got nowhere near it.
 
I thought NOS was like torque for a bolt you tighten till it brakes then back off some.
Oh well guess I was wrong.,
Sorry......
Since I have absolutely no idea myself I've been watching this thread and just waiting for an answer like this!

So in that spirit (and just for the sake of levity)...

To the OP: Build two identical motors, stick one on the shelf. The other is your "test mule". Throw it in the car, add a 50 shot, and run 'er. Still good? Go for 100. (And so on and so on....) Once you blow it up you'll have your answer!

:thumbsup:
 
Since I have absolutely no idea myself I've been watching this thread and just waiting for an answer like this!

So in that spirit (and just for the sake of levity)...

To the OP: Build two identical motors, stick one on the shelf. The other is your "test mule". Throw it in the car, add a 50 shot, and run 'er. Still good? Go for 100. (And so on and so on....) Once you blow it up you'll have your answer!

:thumbsup:
Build? The question is for stock pistons. So I’d assume stock engines. So maybe we should change your statement to;

“To the OP:buy two identical junkyard engines……”
 

Build? The question is for stock pistons. So I’d assume stock engines. So maybe we should change your statement to;

“To the OP:buy two identical junkyard engines……”
Good point! But then this opens up a whole 'nother can 'o worms regarding variances and differences between JY motors, and since this thread has already gone off the rails a few times (DTM's "stock" engine, for example), I'll just STFU, go lay down by my dish, and just watch!

:lol:
 
Good point! But then this opens up a whole 'nother can 'o worms regarding variances and differences between JY motors, and since this thread has already gone off the rails a few times (DTM's "stock" engine, for example), I'll just STFU, go lay down by my dish, and just watch!

:lol:
No no don’t do that. Your topic was worth discussing. Dan’s not so much.
 
The article came out in Car Craft magazine first. They didn't do article sharing like they do now, but the Car Craft guys got a stone stock 360 out of a junkyard with the intent on eventually blowing it up with nitrous. They kept putting more and more on it and I think they got it over a 300 shot. On a stone stock engine. It never broke. I'm sure some of yall remember it. The name of the article escapes me.
 
Wow, that's more than I expected. Maybe my next motor will be a cheap stock-ish beater with just rings opened up more, or maybe something something built to handle abuse, it depends on funding and time.

As for my current motor, I've put too much effort into it to blow it up. From the ring size calculations, a 50hp shot should be ok. I assume because while I don't remember the exact ring gap measurements, I do remember that they were at the large end of the spec, like .020" or so. I figured that would be fine for a hotter street engine and even though I was told it should be tighter, but Installed them anyway.

Of course there is the curiosity of how much can the stock junk handle, with proper ring gaps and a proper tune. :p
I HAVEN'T TRIED IT YET, it might blow up the second I touch it with 150 shot; but if it does blow up there I won't be concerned. I have a bluetooth distributor and I will be able to change timing curves on the fly while tuning so I hope I can step up the nitrous slowly and change around timing slowly to find the absolute limit. But I have the rings set so they won't butt together immediately. I'm not saying they will live at a 250 shot. (yet)
 
Since I have absolutely no idea myself I've been watching this thread and just waiting for an answer like this!

So in that spirit (and just for the sake of levity)...

To the OP: Build two identical motors, stick one on the shelf. The other is your "test mule". Throw it in the car, add a 50 shot, and run 'er. Still good? Go for 100. (And so on and so on....) Once you blow it up you'll have your answer!

:thumbsup:
I did that to a 225 once, for a "Let me see". Run the motor in the car at 1500 RPM's, without oil and water. Ten minutes later I increase the RPM's to 2,000. Ten minutes later I went up another 500 RPM's, to 2,500. Ten more minutes I went to 3,000 RPM's. The motor stopped after ten more minutes at 3,000 RPM's. The cam broke in two, the rest of the motor looked fine. They don't build them like that any longer.
 
Something many people don't relate to is HP/CID. Spraying 200 hp shot on a 170 cid engine is the same as spraying is the same as 517 hp shot on a 440 cid engine, as far a the strain on the engine. Back in the mid 80's I sprayed 125 HP on a 100,000 mile 318 engine in a 74 Dart. Car was totally stock except for a LD4B intake and a Holley vac sec 4 bbl. Car ran 13.0's with just a open single exhaust, and 23 in tall slicks. I think the rear was a 2.9x, if I remember right. Plate N2O system.
Also ran a 66 Cuda with a 170 slant stock rotating assy, milled head, mild cam, 500 Holley 2bbl carb on a modified stock 1 bbl intake, with a fogger system. Sprayed a 225 shot. Both cars hit the bottle on the line. at time stamp 21.00
 
If you really want to know how much nitrous a stock replacement cast piston can take find Doc Baker from Judsonia, AR on FB and ask him. He street raced a small block 4spd Challenger. He split blocks on several forged piston, steel crank 340's. While searching for another block he threw in an Auto Shack (remember them) 318 shortblock. Retuned and kept going. Swears he never blew that one up. Removed the laughing gas and sold the car when he started racing his Orange Studebaker truck in the "fastest street car" stuff in the early 90's. If I recall correctly Doc was pushing more than 300 worth of N2O through that poor 318.

There was a dummy bottle in the trunk, sneaky Pete though the china wall, up through the breather and into the air cleaner, and a fogger setup mounted to the bottom of the intake supplied through the heater hoses plumbed through the intake bottom. The bottle was inside the heater box. Doc was and still is crazy, but an awesome machinist and fabricator.
 
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I have hit several different 440's in my big ole C Bodies with a 250 shot plate and never had any issues. Mind you these were not 1/4 drag cars. Just hit it long enough to take out the usual Mustang, Camaro, Corvette weenies.
 
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