Nitrous question for curiosity sakes

[02sixxer]

Had a discussion with a buddy of mine who races sb mopars has a duster with a sweet 360 pushing 2 stage 250 shot of nos. an 8.5- 9 second car. I have nothing that fancy.

I have a 74 duster with a ford 9" and 3.89 gears. I am running a magnafuel QuickStar 300 fuel pump and regulator. My engine is 383 with stock bottom half 915 heads with the intake valves of 2.08 and exhaust of 1.74 no work done. I have a purple shaft cam with 248 duration and 509 lift. I have a team g intake with with a speed demon 850cfm carb. The top half was just rebuilt and being put back in next weekend. Just have to make the descision on what headers from tti to buy.

Now with that info here is my question. Can I run a NOS sniper system with a 100 to 125 shot of nos without damaging the pistons. My compression ratio is measured at 8.8:1. Buddy seems to think there will be no problem with it. Since the engine does not run lean and cr is right on. What do you think. I have a sniper system minus the bottle. It's a bit old but considering it once I tune the Engine back where it was running before. It averaged 12.5's but would like to see faster. Next build will be a 512 stroker but can't afford it right now

 

[crackedback]

Get it tuned up right on the carb FIRST!

You could hit that with a 100-150 shot no problem as long as, like the carb, the tune up is right. Proper fuel pressure and pull timing, about 6-8 degrees to start. Lean out the system til max mph is found then start turning in timing 1 degree at a time until MPH slows down. The jetting on the plates as recommended from the manufacture are DEAD RICH! Any time the fuel jet is same or larger than the n2o jet, it's rich. Rich is as bad or actually worse than lean. If your buddy that runs the fast car is around have him help you pick a jet package. My 2 cents pick you n2o jet and pick a fuel pill 7-10 sizes smaller. Put a .045 n2o jet in, use a .035-.038 fuel jet. Talk with Monte Smith about jetting if you don't believe me.

If you have a wideband A/F sensor that will help too. Hope you know how to read plugs, you'll need it!

Here's a good thread at moparts about this. Big Squeeze is very good and works pretty close with Monte Smith.
http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Board=Racer&Number=7204348

 

[BBBCUDA]

A friend of mine has been running a 175 shot on a cast piston 413, no issues, and a tremendous gain in power. Drops from mid-high 12, to VERY low 11's.

 

[345man2]

get it tuned right on motor then put a hundred shot on the way it is and spray it, with no further adjustment, you could retard timing 2 degrees if wanted to just for good measure, after 100 shot retard 2 degrees for every 50 hp jet increase, it a good rule of thumb, make sure you put a fuel pressure safey swiitch on the fuel side to prevent fuel pressure drop and leaning cond, should be good to go good luck:blob:

 

[02sixxer]

Thanks so much for the answers. Once I get it back in and run it a few times and get it tuned I think I will run some nos. want to hit mid to low 11's.

 

[JoeDust451]

Thanks so much for the answers. Once I get it back in and run it a few times and get it tuned I think I will run some nos. want to hit mid to low 11's.

If your wanting mid 11s you'll need at least a 150 shot, maybe with what you have. At this point you'll need a better fuel supply, IMO, anything above a 150 shot requires a deticated fuel system for the nitrous, or a VG single set-up on a 150.

If you do it right & have all your ducks in a row, that stock 383 block will take a 200 shot, but you need to really pay attention to the tune.