Holly Blue / Nitrous / air fuel

[Daveeed]

I purchased a Holly blue fuel pump with regulator after
hearing it mentioned many times on this list and others.
I was under the impression this was going to be a constant
flow system rather than a dead head system.
OK so I make all my brackets and I'm dam near done when I
read the Holly install sheet, saying basicly plug the second output
line in the regulator if not running a two carb system...
So I call Holly and yup - It's a deadhead system. Plug one of the lines.
The guy sez it will pump up to max (14lb) while in the staging
lanes but will quickly drop to whatever I set it to (5.5lb) when it squirts.
He also said for Nitrous I want a deadhead cuz it's better.
Everything I've read sez the constant flow is better.

With the Holly Blue, what jets should I use for 80 or 100hp.
I'm thinking 26 nos / 22 fuel @ 6 lb or 13.2 air fuel ratio?

[hawkwind]

starting point  80 hp   fuel .021   n2o .023  100 hp  fuel  .023 n2o .025  fuel pressure = 6psi n2o = 900psi these give a nitrous /fuel ratio around 5.5
 I run a holley blue  BUT I use a Mallory  return to tank reg or an Aussie made Madden , piss off the dead head ,as you stated high psi untill you hit the juice  then sweet FA  goes below set pressure , you need to run some fuel tests and check what your system is doing ,check dynamic pressures and fuel flow volume ,IMHO you need constant fuel pressure at all times and place a fuel pressure switch in series with the power to the solenoids a very important safe gaurd
Hawkwind

[Daveeed]

Hawkwind, Glad you replied. I was gonna ping ya.
>I run a holley blue BUT I use a Mallory return to tank reg.

Egg frickn zackly. I was in the belief that I was buying a return system with the holly blue. Heck, wasn't it your bike that had the holly regulator on it? How did it run?
What model Mallory regulator you running?

What nozzles you running NOS or NX? I got NX.

But let's think about this. The lines between the solenoid and head will become emptyer after a run.
Fun Fact!!  normally after a nitrous run my bike will stall when I pull the clutch and chop the throttle at the 1/4 mile. I attribute this to the fuel in the lines draining into the cylinders.
The bike will always start when I'm pulled off the track in the return lane, or if I bump start the bike as I'm rolling down the track...

Anyhoo, I believe consistent pressure is what we want, but is a 14lb hit a bad thing at the start until the pressure stableizes. I'll probably go out and buy the mallory regulator anyway, cuz I want to see my dialed in pressure on my gauge while staged.

[Daveeed]

OK, I called NX support line and talked to the man.
He said to run 26 nos, 24 fuel and set the fuel pressure
at 5 lb. for a 100 hp squirt.
He has no real matching jets for a 80 hp squirt.

Said the deadhead Holly Blue will work well with the holly regulator but will need to check the deadhead pressure a couple times before the pressure creaps to max at 14psi, but so what, the pressure is good
for when it starts squirtn.
Also said flowing pressure will be about 4.5lb
He said my target air/fuel under nos should be 12.5 ish,
But best to do a plug chop and look for coffee W/Cream color.
Retard about 5 deg, running C12 with colder plugs.