Kadorja

Anyone on here running a centri setup with nitrous? I've been back and forth on setting up my system but I'm confused on how it will work with a boost referenced pressure regulator and nozzle kit.

The fuel pressure will be fine but how does the nitrous pressure compensate for the boost pressure increase? I've been looking into controller kits that will ramp the nitrous (probably a small 30 shot up to a 150-200 shot) but will that be enough for 12-15 psi of boost pressure on a nozzle setup?

schpenxel

Nitrous bottle pressure is so high the small amount of manifold pressure doesn't even matter. You're talking 500 psi+ vs. 12.

It matters on fuel pressure because you're talking 58psi of base pressure, 12psi of boost, which effectively brings down fuel pressure to 46 psi, which is over a 20% decrease.

12psi vs 500 is only about a 2% change.. so not really a big deal

In reality the bottle pressure could be 750+, making the net change even smaller

ZincGT

As the boost increases so will your fuel pressure. If you are teeing after the regulator for your nitrous setup then the fuel pressure at the solenoid will also see this increase and your jet size will be "incorrect". It will run richer, which isnt bad.

I see 3 solutions:

get fuel before the regulator, might have to play with jet sizes if you dont know the pressure there.

run a jet for the overall pressure, could be lean on initial hit, but can be tuned to help.

run a stand alone fuel system for the nitrous with its own pump.


You dont need to compensate nitrous pressure...

neverstop

that's a good point on the fuel pressure but if you're boost referenced i'd think you'd just be a bit rich and in the end you'd be fine. if you're running dual nozzle methanol though I personally would not be comfortable with that much stuff in the intake manifold

Kadorja

On meth nozzle would be removed for the nitrous nozzle so I wouldn't be super concerned. I can always just turn down the meth as well... it's a good safeguard under high boost since it's just there to add to octane level and not essential for my level of boost.

Thank you all for the replies I completely forgot about this thread. It's good to know that the nitrous won't need any help I didn't even think about the bottle pressures being around 750psi.

I may set up my system when I get back and finally get my hands on a good 8-10 rib setup.

gotjuice?

This is the way I have it on my Z. Still using dual meth nozzles. Fuel comes off the rails.

neverstop

nice setup gotjuice! more details on whp level and fuel setup?

I've been long researching this and I think that this kind of setup should be fine in short bursts but I have serious concerns about fuel distribution issues with dual nozzle meth, pump gas AND a 100+ shot of nitrous/fuel in the intake so I am wondering how long these setups last when the spray is used often.

so far the only one i've seen who runs their car hard and sprays often with dual meth and pump gas and 100 shot is SloPoc

c5mtl

I love it ...one big salad ....meth ,pump gas , nitrous , talk about mixing fuels. My question is how can you get an accurate afr mixing all that stuff?
Nuts to me but wish you the best

Slo-Poc

Start small and make small adjustments as you go. Stay safe and test it before making huge jumps. I don't make much more on spray according to the dyno results but ask those cars making more than me what color my car is

schpenxel

As long as it comes on consistently it shouldn't be that much different to tune.

And just dump enough meth in and you'll be fine.. lol

gotjuice?

I have run this setup about a dozen time at the Texas Mile, Best is 215mph. I have had no issues, If something was not right it would not have lasted. I shift into 5th gear before the 1/2 mile mark. Stay WOT with juice for the last 15 seconds. It would of melted down by now if something was not tuned correctly. Horsepower is around 1100 or so at the wheels. I made my own fuel setup, Magnafuel 750 pump along with the factory pump for normal daily driving. It is a street car.

schpenxel

How long is a full run?

gotjuice?

28 to 30 seconds.

schpenxel

That sounds pretty rough on engine parts

Chris Stewart

I run a NX plate with turbo and boost referenced regulator, figure it's the same concept. Single nozzle meth too lol. With 20spi boost I see about 75psi fuel pressure. If I use the recommended jets for 150hp, my AFR ends up a full point rich in the 10's. Target is mid 11's AFR. If I back off the fuel and use the 100hp fuel jet, I end up a point lean in the 12's. So I got a jet in between them and puts the AFR right where I want it. I can't spray on pump gas tho or it rattles, gotta have good gas for that.

neverstop

that's pretty impressive you can pull that much fuel through the rails and then throw the kit on top. nice work! would be cool to see some vids on some mile runs. 215mph is gnarly.

neverstop

just judging from reading on here and how reliable Unreal's 1,100whp setup has been it seems like the key to keeping these LS motors happy at >1k whp is to keep them pretty rich. good stuff.