Topic: Nitrous Oxide fogger nozzle location, CB750

[cb650]

What about jetting?  Going fatter?

[Hondell]

Yes, the foggers are actually long tubes that extend into the carb mouths just before the slides.  There are custom rapid prototyped velocity stacks inside each pod also. I'm working on an airbox solution that will be less restrictive. I need some sort of filtering on the street because our roads are really filthy with small rocks left over from winter. I agree that a progressive setup would be worthwhile for racing.    CB650:  not "fatter jetting" per se.  Additional fuel is mixed with the nitrous at the end of the fogger and is metered by a jet(s). You can see the fuel octopus with the yellow lines just under the tank. During normal running the regular carb jets are used.

[cb650]

Are you ussing a pump for the extra fuel or just gravity?

[Hondell]

No pump. The combination of the low pressure of the carb mouth and the venturi effect of my nozzle design seems to meter the extra fuel flow quite well. I think a pump would be best but I'm running out of room under there. There's 2 solonoids, relays and my electronic ignition box taking up space.

[cb650]

Cool thanks.  I always had a idea like that but just never did try it.  Mostly figuted I would need a pump.  Thought of the little cheater bottle also.  Be a little smaller.

[dragracer]

On our wet systems, we use the small NOS pump. We sometimes pulse the fuel in conjunction with the nitrous progressively or go 100% depending on the need. Fuel pressure is a direct determination of final horsepower and jetting size. Having constant fuel pressure eliminates chances of melt down from a dry shot of nitrous. Gravity does work for very small jets. Paul Gast tried it on his pro mod till he started stepping up the nitrous jets and began the meltdown process. He was getting left behind by the rest of the field then.  He now runs a full wet system with a large pump. 4.0's in the 1/8th mile.

[Hondell]

Yes , my setup is conservative. If I was going more radical I would use a pump. It was really just an exercise to see if I could get nitrous to work on a street CB. Most bystanders think it is fake or the bottle is used as a catch can or something. The bike is really a leftover special--- parts left over from my restoration and vintage speed stuff collected from junk yards. Still looking for a junkyard turbo

[scottly]

No pump. The combination of the low pressure of the carb mouth and the venturi effect of my nozzle design seems to meter the extra fuel flow quite well. I think a pump would be best but I'm running out of room under there. There's 2 solonoids, relays and my electronic ignition box taking up space.

I experimented with some hashed together siphon nozzles about 30 years ago. My goal was to improve fuel economy by improved vaporization of the fuel, using compressed air to provide the siphon, rather than nitrous. My inspiration for the design was a paint spray gun.
The air was fed into the threaded fitting and exited in the gap between the inside of the outer tube and the outside of the inner tube, creating the siphon. The small inner tube was plumbed to a dip-tube in the float bowl. The flow of fuel was roughly proportional to the flow of air.

[BLUE71TURBO]

On our wet systems, we use the small NOS pump. We sometimes pulse the fuel in conjunction with the nitrous progressively or go 100% depending on the need. Fuel pressure is a direct determination of final horsepower and jetting size. Having constant fuel pressure eliminates chances of melt down from a dry shot of nitrous. Gravity does work for very small jets. Paul Gast tried it on his pro mod till he started stepping up the nitrous jets and began the meltdown process. He was getting left behind by the rest of the field then.  He now runs a full wet system with a large pump. 4.0's in the 1/8th mile.

                  Never run Nitrous without an electric fuel pump !     You need the high pressure for the fuel " gas " side to keep up with the Nitrous high pressure side of the system.   

              This is what happens  when using Nitrous Oxide when a lean condition occurs. It only takes a couple of seconds and makes for a real bad noise.   

             

[dragracer]

On our wet systems, we use the small NOS pump. We sometimes pulse the fuel in conjunction with the nitrous progressively or go 100% depending on the need. Fuel pressure is a direct determination of final horsepower and jetting size. Having constant fuel pressure eliminates chances of melt down from a dry shot of nitrous. Gravity does work for very small jets. Paul Gast tried it on his pro mod till he started stepping up the nitrous jets and began the meltdown process. He was getting left behind by the rest of the field then.  He now runs a full wet system with a large pump. 4.0's in the 1/8th mile.

                  Never run Nitrous without an electric fuel pump !     You need the high pressure for the fuel " gas " side to keep up with the Nitrous high pressure side of the system.   

              This is what happens  when using Nitrous Oxide when a lean condition occurs. It only takes a couple of seconds and makes for a real bad noise.   

             

No arguments from me on the use of a fuel pump. Nitrous is not a fuel, its an oxidizer. It adds you in being able to add more burnable fuel to increase cylinder pressure resulting in more horsepower. Most dry systems sold for cars and bikes state that you should increase your fuel flow in proportion to the nitrous jet size.

I'm going to look at tapping the intake runners on the head somehow so i can screw in my fogger nozzles. As long as i have room behind the block to take the nozzles in and out, i'll be fine. I don't want to spray through my carbs or drill into those 35 year old rubber boots. My bike is drag only so i have a lot of room for the solenoids and the fuel pump. I'll add a bung/petcock to the tank for my seperate fuel source. I already added in a cross brace for my bottle in the extended swingarm when i first built the bike 18 years ago.

[Sam Green Racing]

Question (not arguing) If you pump fuel into the system, then it will be going in at a constant pressure.
How do you not get a rich (fat) condition when the pressure in the nitrous cylinder is falling with every spray ?

Sam.

[joe p]

You use the largest bottle you can get on the bike, and you keep your eye on the pressure gauge. In the old days you would see guys running around with turbo-torch heating the bottle up to get the pressure up. to much damn trouble for me! Thats another reason I stop using it.

[Greg H]

Question (not arguing) If you pump fuel into the system, then it will be going in at a constant pressure.
How do you not get a rich (fat) condition when the pressure in the nitrous cylinder is falling with every spray ?

Sam.

Hi Sam . I've found that running a 5lb bottle and bottle heater works on the Busa over the mile . I'm spraying for the whole mile , the 2lb bottles which most use just won't hack it over that sort of distance .

[afkrejci90]

Could a progressive feed box be used instead of having a fuel pump?

[TurboD]

I have been lurking on this site for a while, This is my first post. That said, I have owned and worked on SOHC Honda's years back, With a big Vintage bike scene in my area lately I have caught the SOHC bug once again.

I would like to help a little reguarding Nitrous use. I have been using Nitrous since 1984 on both cars and bikes, since that time I have used 100's of pounds of nitrous and been involved with a number of Fast 'Street Car Shootout" wins. One thing that I see is that there is still much confusion about its use. I will try to help people to understand a little about Nitrous use.

Things to think about.
1 Nitrous can be completely safe, IF (the big IF) used within limits of the engine design and strength and NOTHING goes wrong.
2 (in simple terms) Nitrous does NOT burn, It does not add power by itself. It allows the use of additional fuel which actually makes the added power.
3 When Nitrous is used, the engine requires added fuel from somewhere, be it a pump and injector or a overly rich mixture to start with.
4 "Dry Shot" systems don't use a pump but still needs extra fuel to make more power, so typically the carb is jetted rich to start with.

I will try to help any way I can.