Thread: Engine help...

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Ok, my other thread didn't get answered so i'll ask another question.

How much nitrous is safe with cast pistons/rods?
How about with hypereutetic pistons/forged rods?
How about with forged pistons/rods?
What kind of nitrous can be run with cast steel crank/production cranks?

The reason i ask this is because i have a complete motor that came out of the car with cast crank/stock rods, the pistons will be replaced but I'd kinda like some opinions on what stock crank/rods can do before i go buy new crank and rods...if i don't have to buy a new crank and rods i can splurge for forged pistons. I REALLY need help here because it is my understanding that i can use up to 150 shot on cast/hypereutetic pistons and up to 300 on forged pistons.

The reason I am looking at nitrous is because i can build a motor that makes good power and build it on a budget, and then when i need that extra oomph, it is there at the push of a button. But i want it to be safe.

Also, before i sign off, what kind of precautions are necessary when dealing with nitrous? what about the msg timing retarders and other electronic nitrous control aids?

What size motor? What's the compression ratio? Need more info before I can give you any real advice. A 100 shot on a chevy 289 at 12:1 compression will do a helluva lot more damage (ie: you'll need stronger parts) than a 100 shot on a 502 big block running 9:1 comp.

whew....that was a read.

with the cast pistons, I would think that the tops you would want to do would be about 125. Above that is kinda risky unless it is efi.

with forged pistons I personally have gone as high as 250. (ARP rod bolts, ARP main bolts, GOOD head gaskets, and a quality fuel supply) once again it depends on the tune you have.

I wouldn't even worry about the crank unless you go over 200.

probably your worst enemy on this motor would be too many RPM's and the nitrous. as for the timing controls and nitrous controllers, you can get away without using them if it is mostly street driven. The main reason for them is to eleminate variables while you are trying to do bracket racing.

Simple and clean with the right supporting systems is the way to go no matter how much nitrous you use.

Just my .02

I'm sorry, i should have specified what engine size.

The motor is a 350 4bolt @ standard bore (will be taken over size for cylinder wall cleanup)

I'm not sure what compression it will run because i was trying to choose a piston material before i chose flat, dished, or domed... I'll be running a 76cc 441 casting GM cylinder head.

I'm not exactly sure what to build. If i were building a non nitrous engine it would be another story. I don't know what cam specs to look for when using nitrous. I'm shooting for a bracket/street car if that helps. I know sometimes what your going to use it for really helps to decide what goodies to stuff into the motor.

I guess that real question i should be asking is: What is the engine requirements for a nitrous build? For example, what kind of compression is ideal to run on pumpgas/race gas, what cam specs are ideal for nitrous, ect...