SharkSkin

Seconded!

Nitrous on a 928 carries the same risks and benefits as on any other car, though the block design imposes an upper limit. I'm guessing that part of the general aversion to "gas" is that the car was designed to run flat out for hours on end... people enjoy that, and tend to prefer carrying their power trip along without having to worry about running out(strokers, forced induction).

Hey, got any "before" pics to post? We all love pics....

jserio

Right on David. NOS, SCing or pushed by Godzilla, Man it's all relative.

Garth S

, not bad - think I'll have another sniff - ahaaaa

Well, now that the nitrous has worn off - it is perfectly safe in metal containers: it is the oxidized combustion products plus water that form the atacking nitric acid varients. Similarly, if 'sulfur' is added as a mercaptan (see 'skunk'), the sulfurous acid by- products are equally corrosive: Enough chemistry, time for another sniff ....

Gretch

Man, you learn quick. A thick skin and a sense of humor are almost requirements for membership here. However, properly used these two characteristics will result in not only your own enjoyment of this mad house, but the rest of the inmates will find you entertaining as well.

I include my welcome to the chorus.

Re NOS, the real beauty of the 928 powerplant is the sustained torque delivered in every gear. The car just does not need a rocket strapped to its *** to provide occasional fun, it is fun all the time. For example, say some weenie insists on attaching himself to you on the highway, for what ever reason those loosers do that.......When you get tired of it you can just increment your speed, at what ever pace you choose, until said parasite is forced to detach himself. And it really pisses them off if you do it slowly, refusing to actually "race" them.

The kind of cars a 928 finds itself going up against who qualify as "worthy" have the same kind of power, ie sustained torque over a wide rpm range.....So what you may want to do, budget permitting, is make more of what you already have......

I have a Supercharged 928 GT......I have not come across any thing yet that has had the sack to stay with me, (when I choose to flex a little muscle). And even from a standing start, the car is an ANIMAL, frighteningly fast..

Many, but not all, of us here feel NOS is for ricers, and they are the evil empire.....so we would rather build our power in a more reliable, respectful way. Think about how you will feel when you go up against a 928 powered that way, and you run out of NOS......And you WILL run out of NOS.

ViribusUnits

You know, you could always put together a car with a stroker crank, twin screw blower, and a nice big bottle.

That way, you've got more power than you'll ever need w/o the bottle, but just in case you need that extra 400, you can hit the butten, and make big clouds of tire smoke on the highway.

mark kibort

Carl, yes, Superchargers are the way to go, but there is ABSOLUTELY NOTHING wong with NOS, other than the fact that you have to fill up a bottle every so often. I successfully used NOS on the street and in my racing until it was banned by the racing organizations. (however, TouringCarClub still allows it) I certainly would have used it in SCCA PRO World Challenge GT if i still had the kit!!! It worked Great!!! No isssues, fuel air ratios were exactly at 12.5:1 and i used the system through out my sprint races where the 10lb bottle lasted 10 laps and i used it on all straights (with my idea of a engagement switch on the dead pedal so you would have no chance of overrev) the engine doesnt know whether its expanding gases are supercharged or NOS!! in fact, NOS is actually better as it is very cold to begin with and has a cusioning effect and a more control expansion upon ignition. supercharging has to deal with the heat and sometimes can lead to detonation. NOS is pretty easy and very safe. NOS is just AIR, but very cold . In fact folks tend to view NOS as Nitro methane in their discussions. its not. its practically the same composition as plain air. 80% nitrogen 20% oxygen. the little sulfure added is only so you cant use it like the dentists do without throwing up if inhaled!

So, no coorosive issues to worry about, no mixture issues to worry about, (unless you use the wrong jet size to begin with) and filling up a bottle at the local speed shop for $30-40 is not such a big deal for 50-100hp, when you think of $7-8.00 a gallon for race fuel to have a motor that has 100 more
hp and needs this every tank!! ( $7 x 20gal = 140 bucks!!!!)

I used to keep 2 bottles filled at any given time so i never was in need.

think of NOS as a liquid stroker motor on demand or a liquid supercharger.

if the engine can handle 500hp via a stroker or supercharger , it certainly can handle NOS. the forces are the same on the rotating components.

after running the NOS on my 4.7 for a couple of seasons, i pulled the motor apart and everything looked very good. IN fact, it was also on a 170,000mile motor with a previous head gasket leak that i stopped with barrs stop leak until the rebuild to the 5 liter. (where i used the NOS there too!). There were was nothing corroded!! looked very normal in there, including rings, bearings , valves, etc.

so, in summary. NOS is fine. no issues, especially if you use 50-75hp shots.
you get about 14, 14 second uses (if you are drag racing) or lots of 60-100mph runs (closer to 25-30)

I used the wet system and a single port mixing NOS and fuel tapped from the main fuel rail. as you go up in hp, there are many other considerations such as engine strength and individual port injection. But, its a very safe way to gain 50-100hp at the push of the (dead pedal ) button.

mk

Garth S

Ah, not quite: NOS is Nitrous Oxide, or N2O - it is not compressed air in a bottle that cools on release due to Joules-Thompson adiabatic expansion.
NOS ("laughing gas") is flammable, and its oxidation products are corrosive in the presence of water ( of combustion); It is a mild anesthetic ( Dental use), and a great fuel - when mixed with air at the correct stoichiometric ratio ... BOOM!!!

mark kibort

It is not flammable! it is an oxidizer, but so is air. when mixed with fuel at the right proportion, it is flammable. it is compressed air and i also use NOS in my tires, as it is easy to get, has simular non moisture properties as Nitrogen, and it lasts me all season long. I blow off dust off rotors, and try not to breath it in! ha ha .

it is just as corrosive as air in the process of water, as air is in the process of water. (see steel brake rotors turn orange after you wash your car. rust)

NOS is a TERRIBLE fuel. try and burn some sometime. its air, and very cold too. (and yes, its cold due to it being in a liquid state, under 500-1000psi) when it is released from the bottle in the pressurized state, it gets very cold, just as Nitrogen does. now, nitrogen doesnt help a fuel burn, but it does stablize the burn when its in its chemical structure of NOS, simularly to air.

who told you that NOS is flammable??? why are you posting this as a fact when it is very very wrong? NOS mixed with air is diluted air with NOS, and nothing more. the stoich ratio i think your talking about is that of 15:1 of that of Air or NOS to gasoline or other REAL fuels. (that are flamable) . NOS is not a fuel nor is it flammable.

better do some research on this before you post back
and please post a corrective post too. we dont want to make folks parinoid
of NOS for the usual wrong reasons.

MK

from a common informative website:
....N2O, or Nitrous Oxide, also known as laughing gas, is a weak anaesthetic gas that has been in use since the late 18th century. Common use includes both surgical and recreational purposes. Most people have experienced nitrous in the context of dentistry. Nitrous oxide chargers are also used to make whipped cream. The dairy industry uses nitrous as a mixing and foaming agent as it is non-flammable, bacteriostatic (stops bacteria from growing) and leaves no taste or odour. Nitrous is sometimes used in auto racing to speed engines. Nitrous is even used in diving to prepare divers for nitrous-like effects.

Legality of Use

Nathan Valles

I have to go with Mark on this one.

NOS works because of 2 reasons. First is that it absorbs heat (drops the temp) as it expands, creating a much colder and denser charge in the cylinder.

Second, it has a higher density of oxygen than plain air does. That additional oxygen is used to burn more fuel than can be burned with regular air entering the cylinders. That's why you need the extra fuel to keep the engine from a lean condition which can generate heat, pinging and engine demolition.

NOS is definitely not a flamable gas, at least not by itself. It is not the same as propane or natural gas which are fuels that need Oxygen. NOS supplies extra oxygen so that you can burn more fuel.

"The Fast And The Furious" was just a movie....

mark kibort

think of NOS is Precompressed air, without all the heat of compression of a supercharger. net effect is that there is more air (oxygen) and you match that with the same amount of fuel that you normally have with your engine's mixture setting. there are more oxygen atoms per molecule in NOS than air, but that just adds to its efficiency to burn.

also, its not lean that kills engine or detonation. its Stoich!! 14.7:1 or near about. anything leaner than 16:1 or more is generally no problem, you just loose power. aircraft engines have been running lean passes stoich for 50 years without hurting the enignes (see lycoming engine operation manuals)
"lean of stoich" is a common term in aviation, calling for lean mixtures, just before missing, to get best fuel economy at partial throttle settings for REDUCED cylinder head temps.
mk

DoubleNutz

Thirded!!!

DoubleNutz

Hey Grarth, pull my finger...

ViribusUnits

Seriously, ya'll are both right, and both wrong.

A simple google search will indicate that what is commonly called "NOS" is really nitrous oxide. A quick reference to a chemistry book tells you that nitrous oxide is abbreviated N2O, where the "2" is a subscript. (It appears the board won't handle a subscript.)

Nitrous Oxide and N2O have fairly similar mass compositions. Air is right at 79% weight N, and 21% O, while N2O is 63.6% weight N, and 36. % weight O. Air is a mixture of N2 and O2. Each is a separate molecule. In N2O, each molecule contains 2 atoms of nitrogen, and one atom of oxygen. However, this diffrence in the composition is what makes all the diffrence for adding power with N2O. When you inject nitrous oxide into the intake, your displaceing some of the air and replaceing it with N2O on a molecule for molecule basis. Thus your adding O to the intake gas because your replaceing a gar with 21% O, with a gas that has 36% O. Higher precentage O, the more O for a given pressure and volume, the more you can burn, and the more power you can make.

That said, they do NOT behave the same, and are NOT the same thing. N2O has a MUCH higher boiling point than either N2 or O2. As a result, you can liquefy N2O fairly easily; liquefaction of N2 or O2 is very difficult. Also, N2O can make you high, while air generally doesn't.

Next, N2O IS NOT inflammable. It is an oxidizer. In other words it can supply the oxygen side of the combustion reaction. For combustion to happen you need a fuel, and an oxidizer. O2 in the atmosphere makes a great oxidizer, so we generally control the fuels to control combustion. The fuels are labeled as inflammable, but not the oxidizers.

Most hydrocarbon fuels have the greatest risk of detonation right at stoichometic. Anything richer or leaner of stoichometirc is more resistant to detonation.

If N2O is placed in the presence of water, and if I recall correctly O2, it can and will form HNO3, or nitric acid, which can be nasty. All of these are present inside the combustion chamber, so yea that might screw up your engine; however, acids are formed in your engine simply because of the combustion it undergoes. The oil is there to remove, and hopefully neutralize the acids. This really shouldn't be an issue, simply because of all the acids that are normally formed by combustion in the first place.

Garth S

Mark, you are correct in pointing out an error above - and I am pleased to attempt to correct it!

NOS is not directly flammable - actually it aids 'flammability' by thermally decomposing to produce additional oxygen and nitrogen [2 N20 -> 2 N2 + O2] in the heat of the combustion chamber. In that context, it acts as an oxidant ( additional oxygen), so the last sentence should read, " .... and a great oxidant - when mixed with fuel at the ..."
Nathan is closest in his post , because NOS does quench/cool the mixture - and in doing so, absorbs the heat and decomposes to release additional oxygen/oxidant.
So, with more fuel, NOS quenching ( Joule - thompson effect), and additional oxidant from NOS decomposition ... more power!!

Still, NOS is NOT compressed air, and equally, should not be presented as such: you may wish to revisit that statement - which prompred my too hasty response.
NOS may thermally decompose into oxygen and nitrogen, but it is a distinctive compound with established physical and chemical properties.
No reaction is perfect, and the slight amounts of higher oxides of nitrogen produced from N2 and NOS in the combustion chamber are acidic/corrosive as are the oxides of sulfur containing compounds.

jserio

Holy ****...... I feel like I should be walking up to the Dean for my Deploma. If you guys actually know what you are talking about you be smart some bitches boy I'll tell you what. Seriously it is very interesting to say the least.