High compression with nitrous? Safe or not?

[blackbombshell95]

I know that when having boost it is recommended to lower compression a bit. But what does compression have to do with nitrous? anything? I'm curious.

I have a 75 shot wet. Zex kit with racers tuning kit. Would 12:1 compression be fine with nitrous?

[Doubt_Incarnate]

nitrous is a form of boost. anything extra put in that the motor wouldnt normaly draw, is boost. turbos cram in more oxygen in the form of air. nitrous is craming it in as a cold fluid that is drawn in and vaporizes in the chamber(the nitrogen is there to stabilize the gas i belive). both methods require added fuel to prevent burning up. In my opinion, there is no difference. but all my knowledge is from what i read, i have no personal experiance in either.

I wouldn't bosst anything over 10:1 unless you have a lot of money to spend on special coatings and stuff to hold up to extreme tempuratures.

[blackbombshell95]

Here is what is being done to the short block when my heads come back from ben.
I hope what i'm listing is enough to Keep the motor safe with high compression 12:1 and nitrous. Of course before I drive the car or use juice, it will be professionally dyno tuned. So this is what I have

Main bearing hrated(the quote was hand written and is very hard to read.)
rod bearing hrated?
cam bearing
Camshaft roller
oil pump
timing chain
o ring block
line hone block
knifeedge crank
assemble motor
bore+hone
hottub
arp rod bolts
arp main bolts
forged pistons
shot pinging
turn crank
presize or pb or pie rods?(can't read what he wrote)
mollyring(what is this)

I don't see on the quote about balancing the crank. I wonder what that will cost me.

[Doubt_Incarnate]

mollyrings are the piston rings. he's going to put in a set of race quality rings. some of that is obvious stuff and the stuff you dont understand, i dont either, never heard of a pie rod. if he's going to shot peen them maybe he's doing a heat treatment as well. they should be much stronger in the end. aside from the 12:1 i'd say it should handle boost ok. if you really want to use the nitrous, you may want to look into ceramic coatings for the piston tops, valve faces, and combustion chamber. i'm not trying to be negative, nothing is more depressing than getting a motor together and finding out the hard way that it wasn't ment to be.

for nitrous its similar to turbo or super charing is several ways. you have to retard the timing and add fuel among other things. the benifit from nitro is the charge is cold to start with, so you have that working with you. It may work fine, but you need to check out a setup similar to what you want to do and see what has happened. learn from the mistakes of others, its cheaper.

there are strange differences in tuning things out per induction type. for some reason. a car that has 8:1 cr, with an 8psi of boost its getting 54% more air, that has to be compressed into the same space as the original 8:1. so now its actually cramming like 12:1 but is seemingly easier to tune than a NA motor doing 12:1. now check out a 15 psi setup, thats a 2.02 Pr. twice the air, like 16:1cr NA. not possible unless your using something other than gasoline, but in a proper tuned turbo setup it seems to do great. I dont completely understand it all myself. Research research research.

[Guest]

Nitrous loves high compression. You will make good power.

Just get it tuned properly. Use 93 at a minimum and if you plan to spray it prob would be safe to run some race gas.

You can run high compression and boost too. Its all in the tune. Some honda guys run 12:1+ and boost at the same time on pump gas.

[SHOoff]

Lets relate the turbo and nitrous together for a second.

"Can I turbocharge my engine"
Yes, regardless of the make or age of the engine

"How much power can I get from it"
As much as the engine can stand

Any automobile or motorcycle engine can be turbocharged (i'd assume about the same for nitrous) Results of it all depend on how strong the engine is and how well of an installation is done. Cuz there isnt an engine in the world today (or ever) that can be boosted past it's physical capabilities.

[FastGT31]

I plan on using nitrous as well with my car. I told that to the guy at the machine shop and he advised me to run stainless steel valves as well. i dont know what nitrous does to stock valves but i picked up the stainless ones from SI Valves. What would nitrous do to stock valves?

[614streets]

Stainless steel is more stable or stronger at higher temperatures. However it is weaker than some conventional steel at low temperatures. Nitrous engines create a wicked fast flame front , faster burn rates and thus more heat.

[StudlyCamaro]

Nitrous loves high compression. You will make good power.

Just get it tuned properly. Use 93 at a minimum and if you plan to spray it prob would be safe to run some race gas.

You can run high compression and boost too. Its all in the tune. Some honda guys run 12:1+ and boost at the same time on pump gas.

race gas is over kill, however i will agree that its all in the tune for boost and high compression though

there was an article a while back in mustangs and fast fords IIRC of a guy running 25 lbs of boost on a 302 with 10:1 compression (or something just as insane as that) on pump gas

[Nightingale]

probably using water/methanol injection with that much boost that or a really efficient intercooler.

[bszopi]

90ci, 11.2CR, 27psi of boost, 500+HP and 25mpg...

[hamondale]

From what I've read, nitrous (nitrous oxide) is effective for several reasons.
Quoting from an MSDS sheet at http://www.airliquide.com/safety/msds/en/093A_AL_EN.pdf

Item #10, "Stability and Reactivity"

"Violently oxidizes organic material. At temperatures over 575 degC... nitrous oxide decomposes into nitrogen and oxygen. Pressurized nitrous oxide can also decompose at temperatures equal or greater than 300 deg C.... Nitrous oxide disassociation is irreversible and exothermic, leading to a considerable rise in pressure."

So here's the thing... at your nitrous injectors, you get tremendous cooling from the phase transition from high (bottle) pressure liquid to the N2O gas. That cooling helps give you a lot denser charge. Once in the combustion chamber, under compression of the piston and heating from all of the chamber surfaces, you get the disassociation into N2 and O2 near the top of the compression stroke. Because of that disassociation, now you have more oxygen available to burn more gas. Isn't it true that when you run guys nitrous, you have to inject more fuel? That's why - if you don't, you're running lean because of the extra O2 available from the nitrous breakdown. Plus you're getting the boost just from the change in gas pressure from the nitrous breakdown as well. I believe it is a 50% boost if measured at constant volume and temperature. (2N2O => 2N2 + O2).
So nitrous boosts with three different effects.
Chow,
Geek of the Week

[RidgeRunner]

That's an interesting little factoid there... I didn't think about the increase of gas volume from the N2O separating.

Good old PV=nRT

[blackbombshell95]

Nitrous loves high compression. You will make good power.

Just get it tuned properly. Use 93 at a minimum and if you plan to spray it prob would be safe to run some race gas.

You can run high compression and boost too. Its all in the tune. Some honda guys run 12:1+ and boost at the same time on pump gas.

good to hear

[TurboGTU]

LOL... Like said you'd be fine.

Another reason I like quench...improving the BSFC. Im also going to run high comression (14:1) and boost. Glad to see your not alone in this high compression with power adder.