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From the edelbrock website

 

NITROUS SYSTEMS - Intro - Tech TipsIntroductionTypes of SystemsScience of N20Tech TipsEdelbrock Nitrous Technical Tips and DiscussionThis technical information is to be used as an aid in helping to tune our nitrous oxide systems. Before addressing the nitrous variables, be sure that you have properly tuned your engine and that it's working at peak efficiency without nitrous. Our goal is to provide reliable horsepower gains without sacrificing dependability or reliability. To achieve the gains that we did, you need to eliminate variables that could cause less-than-ideal operation.BOTTLE PRESSUREBottle pressure is one of the most important factors in tuning a nitrous oxide system. Many people feel that if a bottle is full then the pressure must be right, however, that isn't always true. Pressure has a direct relationship to temperature. A full bottle can vary from 750 to 1200 psi. All Edelbrock nitrous systems are tuned utilizing liquid nitrous, which is denser than gaseous nitrous and more stable. Nitrous becomes a liquid at a temperature of -127°F at atmospheric pressure. Since this temperature is nearly impossible to sustain and there would be no pressure to carry the nitrous where it needs to go, we use the alternate method to change the phase to a liquid by pressurizing it to a level of 735 psi or greater, ideally 950 psi. At 950 psi nitrous has a density of 5.44 lb/gal., bottle pressure is more stable and can easily be sustained with the use of a bottle heater. A common misconception is that running bottle pressure greater than 950 psi will generate a much higher flow of nitrous, however, this is not the case. At excessive bottle pressures as bottle volume decreases the rate of pressure drop increases and it becomes harder to maintain a stable pressure. A consistent bottle pressure provides a consistent amount of nitrous delivery during a given period of time. It's also good practice to top off the bottle when it reaches a volume of less than 40%. FUEL PRESSUREA commonly overlooked problem is insufficient fuel pressure. To maintain consistent fuel pressure and delivery we must determine if it is adequate for the task. Most modifications will be fine on factory fuel delivery systems. On highly modified engines that horsepower levels exceed 40% over the manufacturer rated hp level, modifications like the addition of an in-line booster pump or dedicated fuel system is recommended. The purpose of a booster pump is to work in conjunction with the stock pump and maintain a more consistent fuel pressure. The booster pump allows the factory pump to provide its maximum volume capacity; the booster pump then increases the fuel pressure. In racecar applications with a direct port nitrous system or wet nitrous system, a dedicated fuel system is recommended. A dedicated fuel system consists of a fuel pump, fuel pressure regulator and feed line to the fuel solenoid. The purpose of a dedicated fuel system is to provide fuel enrichment for the nitrous system independent of the primary fuel system. A dedicated fuel system offers a greater degree of tune-ability and eliminates problems that might arise from sharing a fuel pump with the engine. TIMINGWhen we set the timing on a car we are actually finding the point in which the engine will initiate the burn so that at about 15° After Top Dead Center (ATDC) peak cylinder pressure can occur. Depending on combustion chamber design and cylinder filling, this point can be anywhere between 30° and 45° Before Top Dead Center (BTDC). The reason we retard timing with nitrous injection is that the air charge becomes more oxygen dense, causing the air/fuel mixture to burn at a much higher rate. In other words, accelerated combustion occurs. This acceleration in combustion causes peak cylinder pressure to happen much earlier. The problem with this is that instead of using the energy generated by combustion to give the piston momentum we are transferring that heat energy onto the rotating and reciprocating assemblies, and possibly hurting them. In the process we are losing torque and horsepower. To prevent this, we recommend that you retard the ignition timing 1-1/2° to 2° for every 50 hp added through the nitrous system. This will ensure that peak cylinder pressure occurs at the same point it did before the nitrous was injected into an engine. Also keep in mind that retarding too much timing will also hurt you. If you retard more than the recommended amount, peak cylinder pressure can occur much later in the combustion cycle and that energy will be wasted. In most cases, avoid aftermarket chips or computers that are not designed for use with nitrous. They typically add more ignition timing, which could lead to power loss and engine damage. SPARK PLUGSThe last frequently misunderstood factor in adapting a nitrous system to your engine is the spark plug. Three important aspects of spark plugs must be looked at: their heat range, reach and gap. We advise lowering the heat range of your spark plugs 1 step for every 100 hp added with nitrous. The other aspects of a plug that must be looked at are the reach and gap. It is best to use a non-projected type plug. Projected plugs allow a greater portion of the electrode to be exposed to combustion gases and possibly cause pre-ignition. The spark plug gap also plays a large roll in nitrous engine performance, because increased cylinder pressure from the additional nitrous and fuel makes it harder for the spark to jump the gap. The same gap that worked for a non-nitrous set-up may be too much for nitrous, leading to excessive misfires and loss of power. Also, we recommend that you do not use platinum plugs. The platinum tips can get extremely hot and will cause detonation. Plus, there is a chance the tip may break off in even cases of mild detonation and can severely damage the engine.Ideally a gap between .025" and .035" should be used on high horsepower applications where an inductive style ignition system is utilized. Engines equipped with capacitive discharge ignition systems may use gaps larger than .035". It's very important to learn how to read the plugs after a pass. A plug can tell you a lot of what is happening in the combustion chamber. CLICK HERE to view spark plug heat ratings.Edelbrock suggest an NGK Spark Plug with a heat range of -9 to -11 depending on the nitrous power level being tuned. When in doubt, always go to the next colder heat range plug. 

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If I was unclear, the whole time I was speaking of a 1 step colder plug regardless of the gap.

 I should have made that clearer, if I didn't.

 

I'd ask those with nitrous experience with these engines on the gap but that article said for that little a shot, though it's more comparatively to a 3.7, that the gaps wouldn't need adjusting down. I think what you are suggesting is the safest route to go when in doubt. Again, the upper isn't too difficult to remove to regap if needed.

 

Done a bit of nitrous work over the years, cautious is always the best approach. Engine builder love nitrous because people are not cautious with it and that makes for repeat business for a builder.

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From the edelbrock website

 

NITROUS SYSTEMS - Intro - Tech TipsIntroductionTypes of SystemsScience of N20Tech TipsEdelbrock Nitrous Technical Tips and DiscussionThis technical information is to be used as an aid in helping to tune our nitrous oxide systems. Before addressing the nitrous variables, be sure that you have properly tuned your engine and that it's working at peak efficiency without nitrous. Our goal is to provide reliable horsepower gains without sacrificing dependability or reliability. To achieve the gains that we did, you need to eliminate variables that could cause less-than-ideal operation.BOTTLE PRESSUREBottle pressure is one of the most important factors in tuning a nitrous oxide system. Many people feel that if a bottle is full then the pressure must be right, however, that isn't always true. Pressure has a direct relationship to temperature. A full bottle can vary from 750 to 1200 psi. All Edelbrock nitrous systems are tuned utilizing liquid nitrous, which is denser than gaseous nitrous and more stable. Nitrous becomes a liquid at a temperature of -127°F at atmospheric pressure. Since this temperature is nearly impossible to sustain and there would be no pressure to carry the nitrous where it needs to go, we use the alternate method to change the phase to a liquid by pressurizing it to a level of 735 psi or greater, ideally 950 psi. At 950 psi nitrous has a density of 5.44 lb/gal., bottle pressure is more stable and can easily be sustained with the use of a bottle heater. A common misconception is that running bottle pressure greater than 950 psi will generate a much higher flow of nitrous, however, this is not the case. At excessive bottle pressures as bottle volume decreases the rate of pressure drop increases and it becomes harder to maintain a stable pressure. A consistent bottle pressure provides a consistent amount of nitrous delivery during a given period of time. It's also good practice to top off the bottle when it reaches a volume of less than 40%. FUEL PRESSUREA commonly overlooked problem is insufficient fuel pressure. To maintain consistent fuel pressure and delivery we must determine if it is adequate for the task. Most modifications will be fine on factory fuel delivery systems. On highly modified engines that horsepower levels exceed 40% over the manufacturer rated hp level, modifications like the addition of an in-line booster pump or dedicated fuel system is recommended. The purpose of a booster pump is to work in conjunction with the stock pump and maintain a more consistent fuel pressure. The booster pump allows the factory pump to provide its maximum volume capacity; the booster pump then increases the fuel pressure. In racecar applications with a direct port nitrous system or wet nitrous system, a dedicated fuel system is recommended. A dedicated fuel system consists of a fuel pump, fuel pressure regulator and feed line to the fuel solenoid. The purpose of a dedicated fuel system is to provide fuel enrichment for the nitrous system independent of the primary fuel system. A dedicated fuel system offers a greater degree of tune-ability and eliminates problems that might arise from sharing a fuel pump with the engine. TIMINGWhen we set the timing on a car we are actually finding the point in which the engine will initiate the burn so that at about 15° After Top Dead Center (ATDC) peak cylinder pressure can occur. Depending on combustion chamber design and cylinder filling, this point can be anywhere between 30° and 45° Before Top Dead Center (BTDC). The reason we retard timing with nitrous injection is that the air charge becomes more oxygen dense, causing the air/fuel mixture to burn at a much higher rate. In other words, accelerated combustion occurs. This acceleration in combustion causes peak cylinder pressure to happen much earlier. The problem with this is that instead of using the energy generated by combustion to give the piston momentum we are transferring that heat energy onto the rotating and reciprocating assemblies, and possibly hurting them. In the process we are losing torque and horsepower. To prevent this, we recommend that you retard the ignition timing 1-1/2° to 2° for every 50 hp added through the nitrous system. This will ensure that peak cylinder pressure occurs at the same point it did before the nitrous was injected into an engine. Also keep in mind that retarding too much timing will also hurt you. If you retard more than the recommended amount, peak cylinder pressure can occur much later in the combustion cycle and that energy will be wasted. In most cases, avoid aftermarket chips or computers that are not designed for use with nitrous. They typically add more ignition timing, which could lead to power loss and engine damage. SPARK PLUGSThe last frequently misunderstood factor in adapting a nitrous system to your engine is the spark plug. Three important aspects of spark plugs must be looked at: their heat range, reach and gap. We advise lowering the heat range of your spark plugs 1 step for every 100 hp added with nitrous. The other aspects of a plug that must be looked at are the reach and gap. It is best to use a non-projected type plug. Projected plugs allow a greater portion of the electrode to be exposed to combustion gases and possibly cause pre-ignition. The spark plug gap also plays a large roll in nitrous engine performance, because increased cylinder pressure from the additional nitrous and fuel makes it harder for the spark to jump the gap. The same gap that worked for a non-nitrous set-up may be too much for nitrous, leading to excessive misfires and loss of power. Also, we recommend that you do not use platinum plugs. The platinum tips can get extremely hot and will cause detonation. Plus, there is a chance the tip may break off in even cases of mild detonation and can severely damage the engine.Ideally a gap between .025" and .035" should be used on high horsepower applications where an inductive style ignition system is utilized. Engines equipped with capacitive discharge ignition systems may use gaps larger than .035". It's very important to learn how to read the plugs after a pass. A plug can tell you a lot of what is happening in the combustion chamber. CLICK HERE to view spark plug heat ratings.Edelbrock suggest an NGK Spark Plug with a heat range of -9 to -11 depending on the nitrous power level being tuned. When in doubt, always go to the next colder heat range plug

Now where have I heard that? lol

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So between 0.25" and 0.35" so what should I gap at 0.30"?

I'm not the nitrous expert but I don't think you'd see much if any measureable power difference is what I would guess.

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Bumping an old thread. I'm looking for some NGK iridium stock replacement plugs for some spring maintenance. All the vendors seem to only stock colder plugs for FI/nitrous applications. I'm having a tough time finding stock replacement iridium plugs, not really interested in simply stock plugs from Motorcraft unless that happens to be the best choice.

 

AM, LMS, Lethal, all have 1 heat range colder plugs as the only options:

http://www.americanmuscle.com/ngk-iridium-6510.html

http://www.americanmuscle.com/ngk-iridium-3789.html

 

I went to NGK's website and I'm hoping to verify the stock heat range.

http://www.ngk.com/product.aspx?zpid=9887

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Bumping an old thread. I'm looking for some NGK iridium stock replacement plugs for some spring maintenance. All the vendors seem to only stock colder plugs for FI/nitrous applications. I'm having a tough time finding stock replacement iridium plugs, not really interested in simply stock plugs from Motorcraft unless that happens to be the best choice.

 

AM, LMS, Lethal, all have 1 heat range colder plugs as the only options:

http://www.americanmuscle.com/ngk-iridium-6510.html

http://www.americanmuscle.com/ngk-iridium-3789.html

 

I went to NGK's website and I'm hoping to verify the stock heat range.

http://www.ngk.com/product.aspx?zpid=9887

 

Im no pro, but my belief is unless you are running FI/nitrous, nothing aftermarket beats the OEM Motorcraft plugs.

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Im no pro, but my belief is unless you are running FI/nitrous, nothing aftermarket beats the OEM Motorcraft plugs.

 

 

The local parts store has Motorcraft plugs for $6.70/ea, so if all else fails I'll pick those up for this Saturday.

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The local parts store has Motorcraft plugs for $6.70/ea, so if all else fails I'll pick those up for this Saturday.

 

Advance carries the Motorcraft SP-519 - which I believe are OEM - for $6.99 each.

 

If you buy x 8 you can use either of these codes to get the OTD price to $38-40

 

TRT25: $20 off $50

TRT30: 30% off $50

 

Only catch is that few Advance stores have them in stock, I think the one in Herndon does, if thats close to you.

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Give me a complete nitrous kit, plus an extra one for my girl so she doesn't worry about it(wink wink, nudge nudge).

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Give me a complete nitrous kit, plus an extra one for my girl so she doesn't worry about it(wink wink, nudge nudges

speaking of your lady.. she doesnt FFM anymore??? did you ban her lol

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Advance carries the Motorcraft SP-519 - which I believe are OEM - for $6.99 each.

 

If you buy x 8 you can use either of these codes to get the OTD price to $38-40

 

TRT25: $20 off $50

TRT30: 30% off $50

 

Only catch is that few Advance stores have them in stock, I think the one in Herndon does, if thats close to you.

 

 

This is what I ended up using thanks to Eric's discount codes. Saved $20 even compared to the parts store that I get a discount at.

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