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Refrigerator Raider Hater
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11,719 Posts
Discussion Starter #1
Read the other day that a 200hp nitrous shot will add 200hp at every rpm. Since it's spraying the same amount of N2O and fuel at all rpms, it will add the same amount of power. This would mean that a 200HP shot adds 200lb-ft at 5252rpm. It also means that at 3000rpm, it would add 350lb-ft and at 2000rpm would add 525lb-ft!

Does this seem right to you N2O users?
 

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West Virginia Chapter Director /, MA Drag Race Te
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2,643 Posts
No way thats gonna happen.

You have several factors to consider besides the shot size. The EEC determines the fuel pressure/trim levels on our cars. Most nitrous systems richen as the nitrous system bumps pressure to handle the nitrous. Now, it will follow the engine powerband curve but not at maximum power level, IE 200 difference or whatever.

Bottle pressure also makes a difference. The lower the pressure the more it will affect that power curve. If what you are hearing were the case it would stay the same clear to the time the bottle runs out. That's not so. Down track pressure down track is usually lower than when you leave the line, so its likely putting out less down track. Its got to affect something.

I'd have to see something definitive otherwise to believe that statement. Its not been proven on mine for sure.
 

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Refrigerator Raider Hater
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11,719 Posts
Discussion Starter #3
I thought about the pressure dropping in the bottle, but figured for one run on a fairly new bottle it wouldn't drop all that much. I was skeptical, hence the post. Would the shot be better represented by torque?

Steve, you probably have dyno graphs handy for motor and N2O?
 

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West Virginia Chapter Director /, MA Drag Race Te
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2,643 Posts
Regardless of where you start with bottle pressure and if the bottle is full I've seen at least a 50 PSI pressure loss by the time the run is completed and I'm back in the pits turning the valve off. It subsequently drops more each pass even at peak pressure when you leave the line. Thats part of the reason some some folks use double bottles to help equalize the pressure. However, as the bottles empty its harder to get the pressure stabilized and you will see it gradually in ET as well, therefore the power is droppping.

Whatever the case, a 200 shot generally from what I've seen does not equate to 200 HP at the wheels. At the motor, maybe. I'm speaking from experience and with a dry shot. I've seen Wet systems put out more power to the wheels but even on dyno's I haven't seen them put that power to the wheels either.

Now a built car, with high dollar wet Port injected system maybe. Again, I'd have to see it and in back to back runs at that on a dyno to prove it.

I'd have to check and see if I still have an old Dyno sheet around with mine.
 
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