I was wondering why stock bottom ends will hold up to 100 to 150 shots of nitrous, but tend to not hold up to boost very well. I know bearing clearances and compression come into play, but I dont know exactly what all the variables are. Just tryin to learn a little bit here, if anyone knows, please teach me.

 

I would guess that it is because under load, you will always have boost, while you decide when to use the juice, and it is not used as much as you would see boost.

Both can wear your stock bottom end the same though.

 

Very true

 

heat of the intake air charge is a big deal... it's much colder with nitrous than even intercooled boost. a hotter intake charge is more prone to detonation.

 

This is true, however you can reach detonation with the juice as well if you are running too lean. Either way, if you get enough detonation, it will only take one time and your motor is done.

 

That plus the fact that the nitrous kits add thier own fuel and are typically tuned rich for safety. Also, if you have a blower you are probably gonna see boost a LOT more that you use nitrous if you have a nitrous system.

 

All great answers. Are there any mechanical reasons?

 

Only in how they add power. They both accomplish the same thing (adding more oxygen to the combustion process allowing more fuel to be burned). The thing that kills pistons with either is detonation.

 

Awesome, could 8 lbs of boost be ran on a stock bottm end if you had an ignition box that pulled timing constantly like how my mallory box pulls timing when I am spraying?

 

If you are going to run any boost on a stock bottom end, the safest way to do it would be to have a good intercooler, and even better, have a good methanol injection setup, or run race gas and have a good dyno tune. Even then, the stock bottom ends won't hold up over time with 8#'s IMO. I have seen some that will make it as long as 25,000 miles, but most don't make it that long without seeing some form of issue with the motor.

Spraying seems to be a little safer, although you can hit detonation with either, and detonation = rebuild.

 

Supercharging is like increasing compression moreso than nitrous oxide is. Nitrous oxide is composed of more oxygen than atmospheric air, and it's temperature also increases the density, as was mentioned. Of course, the fact that a street car is going to see WOT nitrous hits less than the boosted car is also a note-worthy factor.

 

because the motors were built to be N/A... too much compression to be boosting...

when you build a high horsepower nitrous motor you always have lots of compression... the opposite of boost... simple as that.