WHat's the biggest shot I can trigger at 15psi??

JQmile

JQmile

Comp Diesel Sponsor
Going to the dyno next week with more nitrous....was wondering what the biggest jet anyone has used triggering at about 15psi without putting the fire out. I'll have plenty of fuel. I was thinking about starting with a .99 first stage, .135 second and going up from there.
 
That should be ok as long as you start your pull around 2000 and how does your second stage go off
 
I tried a .120 jet in each stage on my duramax once (2 stages) and all went well. I would imagine common rail injection pressures ( I was commanding 27,000 at the time if I remember right) would hold up better to VE injection pressures.

Does that sound right? Would the fire be harder to put out at 5000 psi than it would be at 26,000 psi?
 
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In mu experience, it has more to do with turbo selection than fuel systems. Small turbos can take bigger shots earlier. My theory being that they heat the air up more.
 
GRotman said:
In mu experience, it has more to do with turbo selection than fuel systems. Small turbos can take bigger shots earlier. My theory being that they heat the air up more.
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That's my thinking too....and the fact the truck is non-intercooled, I figure I'll be able to run a pretty big shot without putting the fire out...especially if I brake boost a little on the dyno.
 
I never had problems as long as I was above 15-18 psi, if you are under you get a nice nitrous backfire. I was hosing 3 stages without any jets at just over 15 psi, then 2 more after that.
 
Red Stroke said:
I never had problems as long as I was above 15-18 psi, if you are under you get a nice nitrous backfire. I was hosing 3 stages without any jets at just over 15 psi, then 2 more after that.
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I figured if anyone would know, you would.....thanks for chiming in. Looks like the .156 jet it is!! :bow::nos:
 
Did you pin out your solenoids? Thats why I didnt use jets, the solenoid is already the restriction, and most of the time the solenoid is smaller than the jet you are trying to use.
 
The NX kit has two .157 solenoids with twin -4 lines, so flow shouldn't be an issue. Where was your bottle pressure at when you made those runs Adam? Did you have heaters on all of them?
 
i have 2 200 hp stages and if you fire them once you are under boost it works fine but if you need it to build boost useing them use them in stages because once you fire the first itll start into boost then the second will be fine
 
JQmile said:
The NX kit has two .157 solenoids with twin -4 lines, so flow shouldn't be an issue. Where was your bottle pressure at when you made those runs Adam? Did you have heaters on all of them?
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If you are only making one nitrous run you dont really need the heaters. I used a pressure switch hooked up to the heater relay and it kicked off the heaters at a preset pressure dont remember what that was though...
 
You will be more than fine with that set up, I would hit your second stage at 2500rpm. Running to shots that big it can be easy to put the fire out spraying the second too soon. I know this is why Adam Winslett and I changed our set ups when we started playing with that much n2o and we would hit our second stage at 2500rpm
 
RPM has more to do with the size jet you use than boost. Don't hit a .157 too early, it could be catastrophic if you do.

I usually run a .088 first stage triggered at about 2k and a .125 second.
 
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