I am a big fan of the "Pass Time" show on the Speed channel. What are they talking about when they mention spraying nitrous during the pass? Thanks.

 

There are three points. First, nitrous oxide is comprised of 2 parts nitrogen and one part oxygen (36% oxygen by weight). When the nitrous oxide is heated to approximately 572F (on compression stroke), it breaks down and releases its load of extra oxygen, However, it is not this oxygen alone which creates additional power, but the ability of this oxygen to burn more fuel. By burning more fuel, higher cylinder pressures are created and this is where most of the additional power is realized. Secondly, as pressurized nitrous oxide is injected into the intake manifold, it changes from a liquid to a gas (boils). This boiling affect reduces the temperature of the nitrous to minus 127 Degrees F. This "cooling affect" in turn significantly reduces intake charge temperatures by approximately 60-75 Degrees F. This also helps create additional power. A general rule of thumb: For every 10 Degrees F. reduction in intake charge temperature, a 1% increase in power will be realized. Example: A 350 HP engine with an intake temperature drop of 70 Degrees F, would gain approximately 25 HP on the cooling affect alone. The third point, the nitrogen that was also released during the compression stroke performs an important role. Nitrogen acts to "buff or damper" the increased cylinder pressures leading to a controlled combustion process and better slower heat release

or,

It's a gas thats sprayed/injected into the engine to make a whole lotta power......

 

I couldn't have said it better myself.....

 

When they mention spraying during a pass, what they're meaning is that they are going to allow a car that has a nitrous system to use it when they run or not use it.

 

Thus you hear the terms "on motor" meaning no N20 and "on spray" meaning N20 being used.

 

I'm pretty sure the German WWII Fouke Wolf fighter used nitrous for short burst of combat power during dogfights.

It is essential to inject additional fuel with the Nitrous or you will melt the pistons with too lean a mixture. So in addition to spraying the nitrous there is additional fuel sprayed in with the nitrous.
LJ

 

Thanks so much for the info. Now, I feel a little smarter about drag racing.

 

I have heard that too much can NOS can cause engine damage. Is this true and if so how much is OK on a Vette?

 

Lots of ways N2O can damage an engine.

Not enough fuel for the amount of N2O; You run lean and melt a piston.

Not enough fuel for the amount of N2O; Get a lean backfire that blows the intake manifold.

A lot of N2O with the correct amount of fuel: Cylinder pressures go too high and you destroy rods, bearings and pistons.

Lots of ways to do N2O wrong, lots of dicussions on this Forum on "Wet" or "Dry" systems and what HP shot is safe. A search will give you hours of reading.

 

So, in short you better have a clue on what the heck you are doing before you give it a shot

 

Anything you do to an engine to make more power puts more stress on the engine and increases the potential for damage. N2O injection is no different than a blower or radical cam in this respect. However, it is easy and cheap to make huge amounts of power with N2O injection. The temptation to do so, power greed, can be intense. Some people can't resist, turn up the wick too much, and blow their engines. But used conservatively, N2O is no more hazardous to your engine than any other power adder.

On a pure stock engine, a properly setup 100 hp shot is generally safe. If you want much more than that, and nitrous can give you much more than that, you're going to have to do things to make the engine live with gobs more power and torque. These are things you'd do with any high performance build up, such as forged internals. You also want to make sure your nitrous controls and safeties are up to snuff. The system must shut down immediately in the event the mixture goes wonky.

 

Great info.

 

 

Interesting that you would know a bit about the history, Larry, (not many folks do), but nitrous oxide injection was an American invention in WWII.

The Focke-Wulf and Messerschmidt fighter planes in the Luftwaffe used nitromethane to achieve a much higher cruising altitude since it's an oxygen-bearing fuel. Germany's nitro technology came from the government-backed Auto-Union Formula One teams of the '30s which utilized nitro, (as well as dozens of other exotic blends), during their dominance of F1 racing.

To achieve similar performance in U.S. fighters, the P-51 Mustangs were equipped with nitrous oxide cannisters which were manually operated by the pilot; the Mustangs were able to hit the same altitudes at the FWs and ME109s and also gained superior acceleration.

Insert Paul Harvey ending here.

 

Definately, it should be installed and tweaked by someone that has experience doing it. Way too easy to bump it up too far and kaboom if you don't know where to draw the line.

 

The P51 Mustang actually achieved air superiority over the FW190s and MEI09s when the US Allison engine was replaced with the British Rolls Royce Merlin engine. The nitrous oxide cannisters provide that extra boost of power to over take or to escape ones enemy.

Edward R Merle reporting.

 

Ed, was the Merlin equipped with the centrifugal superchargers or am I confusing it with the Allison used very late in the war?

 

Both of the engines that you referred to were fitted with a centrifugal supercharger.In fact those were the two engines that the Gold Cup hydroplane race boats used back in the day.The Merlin was still the superior engine and generally dominated the boats that were equipped with the Allison engine.