C4VetteLS1

Geez, its rare i care much about a random honda dynoing. But i had a group of guys that are pretty high tech in thier honda building (Another speed shop about 1 hr away.

They brought down a custom nitrous motor setup in a integra.

They built it at 8.5:1 compression so they could run more nitrous on it. (which ive always thought nitrous likes compression). The motor only made about 150 rwhp or so on motor. On a 2 stage dry setup, they made 360 rwhp on nitrous. It kicked on pretty low and went from about 100 rwhp to 350 rwhp within 200-300 rpm. geeezsus.


Anyone ever seen the ability to run alot more nitrous with low compression motors?? hmm i always just figure put more octane in it and keep spraying.

Zo6Killer

It's always been my understanding that nitrous, like boost, increases cylinder pressure. It stands to reason that a lower static compression ratio would allow more safety when using a big shot. I could be wrong, but thats what I've always thought.

Strahley

iTrader: (4)

Integras are rear wheel drive now?

Draco

I think nitrous acts a little differently. First with boost you are cramming more air/fuel volume into the cylinder, so when the piston compresses the mix there is more pressure prior to ignition. With pressure comes heat also and thus a tendency to detonate. Nitrous on the other hand results in less volume of nitrous/air/fuel sucked, and in addition the nitrous cools down the mixture making it denser and maybe a little more resistant to detonation due to heat/pressure.

I'm no expert but this makes the nitrous setup seem friendlier to a high compression motor, but could result in the same power output.

Cmarsh93z

I have seen it before. I had a Mustang coupe that was a 306 with ported heads, cam, carb intake. It was 8.5:1 compression....made 330rwhp on motor. Ran 11.7@114mph on motor. With a 150shot, it would go 10.5 @ 130...which I thought was a pretty good increase. Nothing dramatic, but the lower compression seemed to really pickup on the bottle. I would imagine if you sprayed a well built blower motor, it would make really good power

Chris

383LQ4SS

iTrader: (33)

I think some of the guys that run HUGE shots of juice on a purpose built nitrous motor actually go with lower compression in a max effort. I think you will reach that mythical area that will max out available octane requirements and your ability to retard timing in order to keep detonation under control sooner with high compression. But also from a purely dimensionsal standpoint..... If you have a larger combustion chamber to begin with and then raise cylinder pressure to X amount (using the correct octane fuel, timing, and nitrous)...you will have more crank rotation before that cylinder pressure halves.... equaling more power.

Kind of like when your a kid and you had those little red and white water rockets that you filled with water and then pumped up with air. You needed to save about half the volume for water and half the volume to pressurize with air. That combo went the highest. If you filled the volume with 95% water and pumped the crap out of it to the same pressure...it didnt go anywhere...because the air pressure dissapated very quickly since it was actually a smaller overall amount of stored energy... even though you started at the same peak pressure.

Granted you need to spray more nitrous in that scenario but at the extreme limits...I have always heard less compression and more nitrous. Im sure there is a "perfect" combo with stroke, Combustion chamber CC ( compression), timing, fule octane to control burn rate, etc etc.

At those levels its all about maximizing cylinder pressures...not just peaks..but optimizing cylinder pressure over as much crank rotation as possible. Too much peak cylinder pressure at the top of the stroke will ultimately be your limiting factor. I think this may all come into play when building a max effort purpose built nitrous motor and the reason for using lower compression.

And that honda motor being of small displacement may be in that catagory.

383LQ4SS

iTrader: (33)

TTT...I want to hear some more ideas and thoughts on what the best course is for building a max effort nitrous setup?

Anyone have actual knowledge or experiance in designing such an engine?