Dry Shot? Bottle pressure?

[Thumper]

I just hooked up a dry shot to my GTO but was curious how much bottle pressure effects a dry shot. I know a wet shot its huge because less nitrous or more nitrous effects afr's. But since a dry shot uses the maf to adjust I think that the only thing bottle pressure effects is the amount of nitrous it feeds thus the power of the shot.

 

Since its cold out and I don't have a bottle heater "yet", I'm going to run a .003 larger fitting to compensate for the 650-750psi bottle. Good idea? Thanks

[jbc3]

The dry shot I use (NOS 5176, LT1 125Hp dry kit) has a solenoid that increases the fuel pressure to compensate for the nitrous, by bleeding nitrous pressure to the fuel pressure regulator. The less bottle pressure, the less nitrous into the motor and the less FP increase. It is proportional.

The LS1, thru the MAF, dry kit has the MAF adjust the fuel. The more it sees, the more fuel is added by the computer... similar in the fact that it is proportional. The LS1 fuel pump/regulator maintains a constant FP, and can not be adjusted like the LT1 set-up.

IMO, .003 increase in a nitrous jet is not significant and is not giving you that much more flow to notice. The only issue would be if your GTO was highly modded and you were already near or past the limit of the MAF. I have seen people take a dry kit with a .67 nitrous jet and replace it with a .90 and get away with it... a different guy has a melted head to show for his jet testing. Short answer to your question... safe; Yes. Good idea; shrug. Worth the effort; No. Get the bottle heater and move on.

The reason the bottle pressure is so important in a wet kit, is the fuel pressure is constant, making the fuel added with a nitrous kit a constant. If your bottle pressure goes down, less nitrous is added throwing off the optimum balance.

 

Jody

 

 

I just hooked up a dry shot to my GTO but was curious how much bottle pressure effects a dry shot. I know a wet shot its huge because less nitrous or more nitrous effects afr's. But since a dry shot uses the maf to adjust I think that the only thing bottle pressure effects is the amount of nitrous it feeds thus the power of the shot.

 

Since its cold out and I don't have a bottle heater "yet", I'm going to run a .003 larger fitting to compensate for the 650-750psi bottle. Good idea? Thanks

[Guest Gr8White]

I just hooked up a dry shot to my GTO but was curious how much bottle pressure effects a dry shot. I know a wet shot its huge because less nitrous or more nitrous effects afr's. But since a dry shot uses the maf to adjust I think that the only thing bottle pressure effects is the amount of nitrous it feeds thus the power of the shot.

 

Since its cold out and I don't have a bottle heater "yet", I'm going to run a .003 larger fitting to compensate for the 650-750psi bottle. Good idea? Thanks

 

I used to have the 5115 kit (stage 2 upgrade added, 150 hp) on my Mustang ( a dry shot) and bottle pressure is absolutely huge in terms of power output with that kit, I would assume the kit to be very similar- 600 psi in the Winter= dead meat. I invested in a bottle heater the first time I experienced this low pressure problem. In the 1/4 mile, this 600 psi would cost at least 0.30 seconds in my combo.

 

NOS will tell you 900 psi to be optimal, I have found that 1000-1050 to be the optimal pressure, at least with my car. I have several friends still running the 5115 kit with the updated stage 2 (150 hp) and they concur.

 

Depending on your solenoid, most of these kits free flow with a .073 jet. ( I believe the 5115 uses a super power shot solenoid, somebody correct me If they know differently)..Once you free flow the solenoid it doesn't matter what size you increase the jet to, there won't be any more nitrous injected past the free flow point of the solenoid. The .073 jet is about 175 hp I believe with this solenoid..

 

As mentioned above, it is the "fuel" jet that spikes the fuel pressure to around 80 psi to give the extra fuel. The smaller the jet, the higher the spike in fuel pressure. Tune in small increments using your plugs. A dry shot is great, but you have to watch the tune. I used a 73/42 combo and got away with it. NOS advertises the 150 as a 67/42....

 

Don't heat the bottle with a torch to raise pressure, do it right and get a bottle heater!!!!!!