I was under the impression that nitrous does not effect compression ratios. I mean I don't see how it could effect compression the way a turbo or sc would. Nitrous isn't "forced air" is it. Also, what's the scoop on running 100+ octane when on the spray? Is it a safegaurd to run high octane when spraying? What octane is ideal, 100,104,108?

 

they call nitrous chemical supercharging <img src="images/icons/grin.gif" border="0"> basically you are spraying something very cold, dense and combustable in to you motor and mixed with fuel it is very explosive, and expands 10 times what that went in the motor(estimate)when ignited and raises your CR dynamically, since its so cold it cools the fuel and detonation is quenched if you well with the fuel its mixed with. on a shot bigger than 150 I would try to run about a 100 octane, or retard your timing, on LS1 without LS1edit readily available you cant retard timing so add octane. i think you want to run octane because on shot bigger than 150 the cylinder pressure gets really high and heat overcomes the cool features or nitrous and your friend detonation is back to play.

[ December 09, 2001: Message edited by: Nickn20 ]</p>

 

"Chemical Supercharging" Hmmmm, interesting. So nitrous does effect compression. I take it the higher the spray of nitrous the higher the CR increases. Are we talking high enough CR that we might start blowing head gaskets?

 

[quote]Originally posted by Big Mike:
<strong>"Chemical Supercharging" Hmmmm, interesting. So nitrous does effect compression. I take it the higher the spray of nitrous the higher the CR increases. Are we talking high enough CR that we might start blowing head gaskets?</strong><hr></blockquote>

I think this is something MTI could give you a really clear answer on, since that is where you are gettig some motor work done.... as a general rule they say anything over 450 rwhp you are pushing it on cast pistons and rods, the limitations on the crank I dont think anyone has found yet.... also there are a few people way over 450 rwhp on stock motors look around the site. also I dont hear or too many people blowing heads gaskets, but i do remember some poeple mention heads start to lift at ~650rwhp mark....
<img src="images/icons/shocked.gif" border="0"> <img src="images/icons/shocked.gif" border="0">

 

Yes it does affect compression more importantly it effects cylinder pressure. BUT cylimnder pressure has alot of variables involved with cam timing. Bottom line is anything over 150hp shot and you are pushing the limit of stock components. Above a 200hp shot you should be considering O-rings. Pushing a gasket out or lifting a head is very nasty and can cause very severe damage to the head when the pressure is vented out of the wrong place.

 

It does not effect compression ratio. CR is the ratio of cylinder volume at BDC to cylinder volume at TDC. Using nitrous does not effect this physical ratio. However, your cylinder pressure will rise dramatically. Also, just a factual correction, nitrous oxide is not combustable, it does not burn. N2O is an oxidizer and works by supplying additional oxygen to the combustion process, thereby increasing the rate of combustion in the cylinder and allowing additional fuel to be burned, and burned more quickly.

[ December 11, 2001: Message edited by: spiesscj ]</p>