hardcore91LX

I was wondering what is the highest compression ratio I could go with and still run nitrous. I wont to build a 331 N/A and run nitrous on it sometimes at the track.

Thanks in advance for the help.

tinman

N2O knows no compression limits. Just don't get carried awy with it......
Use forged pistons/good rods and all........

hardcore91LX

I was thinking of rebuilding the stock block and use all forged interalls. I thought you could not run nitrous and real high compression.

waxyourboard

Nitrous will cool down your air charge... kinda like an intercooler/aftercooler for a turbo or supercharger (which allow you to use more boost).. Going off this principle, your engine should take a pretty healthy shot of nitrous without pinging or detonation... you just gotta watch out for running lean

Someone correct me if i'm wrong

silver91gt

sounds right.

but I would stay under 13-1 compression, unless you have o-ringed heads.

with compression that high you will probably blow headgaskets often.

frop

Also depends on what type of shot you want. Little shot works better with more compression, bigger shots work better with lower compression simply to keep things together, also, two-stage & progressive systems are easier on the motor/tires.

hardcore91LX

I was not planning on going to high since the car is drove on the streets the most. I wanted to run a 100 or 125 dry shot. I thought you had to run lower compression with nitrous as with a supercharger. Thanks for the replies.

roughneck9725

You didnt say if you were wanting to run pump swill or race gas? I would say 10.5:1 is the highest with pump gas you should go for reliability. Race gas you can go higher of course. Would be a good idea to retard the timing too, especially with higher compression, even with race gas. detonation with nitrous in the cylinders is BAAAD. I have read (going from memory) that 2 degrees per 50 HP of Nitrous is a good place to start. Good luck.

C/Note

old motor>>> 351w 10.7to1 with 175 shot..pump gas 11.7s on motor and 10.59 on 200 nos.

angcobra

agree, Nitrous loves higher compression (CR).
Make decision based on octane gas you want to run and how the bottom end is built.