Is there a calculator to figure out how long a 10lb bottle would last @ a given shot? I'm trying to figure out if I want to bump up to a 15lb bottle with my new direct port setup.

 

you will use 1# of nitrous for every 100hp in 10 seconds

A 10# bottle will last 100sec if you are jetted for 100hp

You can typically use 75-80% of the bottle if you do not have a push system, A 15# bottle gives you 50% more volume but can be harder to have stable bottle pressure.

I am going with a 15# bottle and a Nano system in my 94 formula and am planning on hitting it with a 300 shot

 

so I could get 2 good runs out of a 10lb bottle on a 250-300 shot or 3 good runs if using a 15lb botlle. hmmm...thanks for the info. It's kind of a toss up still. I'm leaning toward 10lb to help keep weight down and then I guess just having 3+ bottles on hand for every trip to the track. The cost of the n2o is gonna be the same either way.

What about line size and length? If I jump to -6 for the bigger hit and the bottle is mounted mid car would 2 runs on a 10lb bottle be inaccurate due to extra nitrous needed in the line?

 

a 300 shot on a 10# bottle will net 1 solid run, the 2nd might see pressure drop on the big end and a 3rd would be unable to finish because of pressure drop. This is assuming no pressure compensation system.

A 300 shot will use ~3# of nitrous in a 9-10 sec pass.

Should make a difference between -6 and -4

On big shots is where the NANO kits will really start to shine, as they will maitain pressure and give you more runs per bottle. With a NANO you could easily get 3 9-10 sec passes on a 10# botle assuming you dont purge more than 1 pound

 

Yes.... 2 full passes on a 10# bottle with a 300-shot. On the third pass, bottle pressure will start to drop too much. Swapping out 10# bottles frequently is the lowest "weight" solution. With the Nano system, you should get 3 full passes with the weight of the Nano system added. That would be preferable to going to a larger bottle, IF you want to minimize weight.