Anyone using NOS in their A4. What the downside.

 

Use it too much and you'll melt your pistons

 

It's perfectly safe as long as you don't overpower the engine. You should buy it in a kit form. All NOS does is allow more fuel to be burned in the cylinder by introducing an oxidizer. It's the same thing as getting a bigger turbo, or adding a supercharger, or porting a manifold. NOS doesn't burn it is an oxidizer.<p>Just make sure you have a whopping amount of fuel being pumped into the engine with the NOS. If you lean the mixture say goodbye to your motor. And pray you don't have a nitrous backfire. If it's installed right you shouldn't.

 

I was interested in NOS on my 1.8t. A few months ago I asked around and searched the archives extensively. Installing and using NOS in the 1.8 is not as easy as it sounds because of the complications of the fuel maping issues. Try searching under nitrous in the archives and you will come up with tons of information. You don't want to mess around with this stuff unless you know all the risks involved.<p>Chris K<br>98.5 1.8TQTS Tap Stage II

 

Nitrous oxide is not fuel and does not burn of its own. It is, as the name describes, Nitrogen and Oxygen. The Nitrogen is inert and just takes up space in the combustion chamber. The Oxygen is an oxidizer and needs fuel to burn. Sufficent additional fuel must be added with nitrous to maintain a decent air/fuel ratio. Burnt pistons are the result of a too-lean ratio (pporly designed nitrous system), not excessive use of "the button".<p>Been gassed, but not on my A4.

 

Not a favor of the juice myself but several magazines quoted that the safe horsepower increase with Nitrous on a 3.0L V6 is 75 hp. Any higher, engine works need to be done to sustain the large force - i.e. forge pistons and crank rods, crack shafts. Down side, on a very high output NOS system, you'll need a timing remapper to make sure that the timing is as retarded as needed when NOS comes in. Also, when the bottle is out, time to go home as stroker motors or forced induction will blow the empty NOS person far away =)

 

NOS involves retarded timing and extra fuel injected. Also nozzle tuning to make sure that you don't over power the engine is tricky. Stick with a chip and forced air induction. There was more though put into that.

 

my vehicles (not My A4, though). Most fuel injection systems<br>operate in closed loop mode (part throttle where the ECU<br>reads the O2 sensor and adjusts fuel delivery to maintain the<br>proper ratio). This involves the fuel mapping. At wide open<br>throttle (WOT) most fuel injection systems go into open loop<br>mode and no longer use the O2 sensor to correct fuel mixture.<p>According to a person I talked to at Dicks Audi Performance<br>(a TAP dealer), the A4 1.8 also operates this way under WOT.<p>Vehicles that switch to open loop mode work perfectly well with<br>nitrous oxide. The nitrous is usually injected with fuel already at<br>the proper ratio (usually slightly rich to be on the safe side) by<br>using replaceable jets on the nozzles. Some more advanced<br>systems inject the nitrous only and increase the stock fuel pressure<br>to prevent leaning out of the mixture (similar to using a rising<br>rate fuel regulator to handle increased boost).<p>There is nothing inherently wrong or dangerous about nitrous<br>oxide. It's only when used incorrectly that you have problems.<p>As to whether to use it on your A4.... I believe the A4 would work<br>great with nitrous. The engine is already overbuilt, and there's no<br>reason why you couldn't set the kit up to produce the same kind<br>of power increases that other tuners are getting with bigger<br>turbos. For my money, though, I think I'd go with a chip. It's a<br>little less than a nitrous system, and you get almost as much<br>power ALL THE TIME. Besides, are you drag racing your A4?

 

check this out...<ul><li><a href="http://www.momentummotor.com/a4pics.htm">http://www.momentummotor.com/a4pics.htm</a></li></ul>

 

NOS in a low pressure turbo does some neat things. First, the expanding gas increases intake and combustion pressures, effectively raising the level of boost when engaged. Second, the expanding gas cools quickly and serves to cool intake temps dramatically, making the engine much less susceptible to detonation and octane intolerance when under boost. With chipping, you increase the boost but also increase the intake temps.