bru91

iTrader: (3)

While searching the web about nitrous i came across this site that had true and false statements about nitrous. One of the statements was this-

FALLACY: Premium fuel must be used with N2O injection.
FACT: The purpose of N2O injection is to support the combustion of extra fuel, thereby releasing more work-producing heat in the combustion chambers. Consequently, maximum cylinder pressures with N2O will be higher than when it isn't in use. Extra cylinder pressure does tend to cause pre-ignition and uncontrolled combustion, but as previously described, N2O injection also tends to suppress detonation. With most street N2O systems, these two opposing forces tend to cancel each other out, which means you can continue to use the same octane gas that was acceptable before the N2O was added. Because competition N2O systems inject a greater quantity of N2O and gasoline than do street N2O systems, cylinder pressure is frequently raised to the point where a higher octane fuel (or anti-detonation additives) must be used.

Does anybody know if this theory is true?

streetzlegend

iTrader: (8)

Seems like b.s. to me. the purpose of nitrous is not to support combustion for extra fuel! its the opposite, extra fuel is being provided because of the nitrous. Not going to get all chemical here but an idea is, nitrous enters the cylinder and once there is a spark and combustion, the nitrous molecules release doubled or more oxygen molecules therefore increasing the pressure of the cylinder. Now since extra oxygen is being produced from combustion, there needs to be extra fuel to support that oxygen. Thats why with wet kit you spray fuel with nitrous, and with dry extra fuel delivery is increased as well. I think that entire paragraph is false. and also, iv never heard of "anti-detonation additives". The only thing people do or add to prevent detonation at higher shots of nitrous is higher octane of fuel. But thats when you are at like 100 shot or higher.
also nitrous does NOT suppress detonation lol, that is why you put 1 or 2 step colder spark plugs, because nitrous injection causes higher EGT or cylinder temperatures to increase..

bru91

iTrader: (3)

Yeah that's what i was thinking. You'd think if that theory was correct it would be well known among nitrous users. This was the first time i've heard of it so it seemed suspicious.

Donkeypunch

Injecting liquid nitrous will keep detonation down
compared to useing gas nitrous (vapors).

The nitrogen acts as a buffer, and absorbs some of the heat.
Without the nitrogen, the motor would melt
(why people don't just use oxygen).

That probably is ment for turbo users since higher octan is use anyway
and they're talking about small shots.

Is the glass half empty or half full?

GTRJazz

Not sure of the Science behind it, but my GTR has less pre ignition when I am using a 125 hp shot of NOS with standard ignition settings.

grey99max

iTrader: (12)

My personal opinion:

It's not all-or-nothing, it's a matter of how much nitrous and how much ignition advance is being used.

A little nitrous (ex: 50-shot) and stock everything is OK. Go higher and problems begin to develop - you run lean 'cause fuel pressure drops 'cause fuel volume has gone way up. Cylinders run hotter, spark plugs get hotter, valves get hotter, until something gives and you get serious detonation and/or preignition. Either one can destroy your motor. Spraying longer, like at the strip, just makes combustion temperatures keep climbing until something fails.

You can get fuels with additives that prevent detonation and preignition. Any real drag strip sells several - usually Sunoco. Google-search for Sunoco 104 GTX unleaded and VP Racing fuel Street Blaze 103. ( The Sunoco 104 is $32 for five gallons at KCIR). They are made for racing and support very high compression and supress detonation. Read up on these fuels - they will save your motor.

Retarding your ignition advance is another solution to melt-down, but on 4th gens you gotta have a piggyback unit of some type controlling your ignition, which is expensive, means dyno tuning and experimenting for a solution. I use the stock '99 ECU.

Some folk make a religion out of "running on 91 octane with a 150-shot", like that's a big deal. If you want your engine to live through a full 1/4 mile of a 150-shot over and over again, then cut back your grounds on your 2-step-colder plugs and side-gap them (so they don't glow in the dark and cause preignition), install a Walbro 190 or preferably a 255, and a FPR, use Sunoco 104 GTX (the light-blue stuff you get at the strip), or use VP Street Blaze 103 (red stuff) if you can find it. It's usually available at drag strips hosting National events - that should be a clue...

The right fuel pump, side-gap cold plugs, and the right fuels "get 'er done" - at least for me, all this season....and I sprays a bit...(at least a 125-shot all the way, several times per event)...

My old 3.0 takes a lickin' and keeps on tickin'