Nitrous Fuel System Questions......

I have a 76 Camaro that I am installing a new engine in.. The engine is a 10:1 383 stroker with JE nitrous pistons, JE HNS rings, 4340 crank, 4340 rods, and Dart 215cc Pro1 Aluminum Heads.. I built this engine for the soul purpose of running on large doses of nitrous. I have already purchased a NX Gemini Quad dual stage kit, and plan on a stage 1 of 150hp, and a 2nd stage of an additional 150hp (total of 300 shot). My question to you is mainly about the fuel system. I was planning on running a sumped stock tank feeding into dual Holley Blue's, and Y'ing into one large fuel line going to the front to my fuel pressure regulators. According to NX, the dual stage system must have a seperate regulator for each stage, so I will have a total of 3 fuel pressure regulators... My question is: should I run dual holley blues, or just one big badass fuel pump??? I know that if I run a dedicated system to the nitrous that I will have to run a return line to the tank. On a 300 shot on a small block chevy, a single badass magnaflow electric pump should flow more than enough fuel for the carb, and both stages of the nitrous system correct??? I am kinda leaning away from the dual holley blue's idea, and towards just one big badass pump... What do yall think???? Any input would be greatly appreciated.

Originally posted by MEAN_SBC
I have a 76 Camaro that I am installing a new engine in.. The engine is a 10:1 383 stroker with JE nitrous pistons, JE HNS rings, 4340 crank, 4340 rods, and Dart 215cc Pro1 Aluminum Heads.. I built this engine for the soul purpose of running on large doses of nitrous. I have already purchased a NX Gemini Quad dual stage kit, and plan on a stage 1 of 150hp, and a 2nd stage of an additional 150hp (total of 300 shot). My question to you is mainly about the fuel system. I was planning on running a sumped stock tank feeding into dual Holley Blue's, and Y'ing into one large fuel line going to the front to my fuel pressure regulators. According to NX, the dual stage system must have a seperate regulator for each stage, so I will have a total of 3 fuel pressure regulators... My question is: should I run dual holley blues, or just one big badass fuel pump??? I know that if I run a dedicated system to the nitrous that I will have to run a return line to the tank. On a 300 shot on a small block chevy, a single badass magnaflow electric pump should flow more than enough fuel for the carb, and both stages of the nitrous system correct??? I am kinda leaning away from the dual holley blue's idea, and towards just one big badass pump... What do yall think???? Any input would be greatly appreciated.

Here is what I am doing:

1 gallon jaz nitrous enrichment fuel cell in the engine compartment
Holley Blue pump with a holley regulator with return line to fuel cell feeding the fuel solenoid
Holley 110 gph mechanical fuel pump feeding the carb

Cheap and easy, and you will have a nice dedicated fuel system. Also, you can fill the 1 gallon fuel cell with some potent race gas :).

And btw, on a 300 shot you better be running some potent race gas anyhow heh.

This I know... the race gas thing... I'm currently running low 11's on 175 shot on a stock bottom end.. lol :) How large is your return line??? Do you have any pictures of your dedicated fuel system??? I would love to see them...

Originally posted by MEAN_SBC
This I know... the race gas thing... I'm currently running low 11's on 175 shot on a stock bottom end.. lol :) How large is your return line??? Do you have any pictures of your dedicated fuel system??? I would love to see them...

Its all in pieces in my room at the moment, but I have a pic of what I am copying:

http://www.thirdgen.org/techbb2/attachment.php?s=&postid=1442150

I planned on running a -6 AN return.

Originally posted by 12Second3rdgen
Its all in pieces in my room at the moment, but I have a pic of what I am copying:

http://www.thirdgen.org/techbb2/attachment.php?s=&postid=1442150

I planned on running a -6 AN return.

How safe is that under-hood setup?

Is it more efficient than running a second line from the gas tank?

Good question.. If you run a dedicated fuel pump for the nitrous, then you HAVE to run a return line (I've heard), so I'm trying to figure the best options for the fuel system on a 300 shot...

Hey 12second3rdgen, what kind of fuel pressure regulator is that???? It is running a bypass, correct??? What exact parts did you buy????? I appreciate it...:bow:

Originally posted by MEAN_SBC
Hey 12second3rdgen, what kind of fuel pressure regulator is that???? It is running a bypass, correct??? What exact parts did you buy????? I appreciate it...:bow:

In the picture that is a mallory 3 port regulator. I will be running a holley $22 3 port regulator (the one that comes with the holley blue pump). You want to run a return so that you dont get air in the line before the fuel, otherwise you will go extremely lean whenever you first apply the squeeze.

Mean SBC,
With that size shot you have moved up to the point of making sure you have enough fuel.I would run two seperate systems.One pump for motor and one for Nitrous.You can run a small fuel cell for just N20 or you can tap a seperate spout in your stock tank. The holley blues will work. Make sure you have a return line for the N20 or the pump will burn up.The holley blues are decent pumps but if you can afford it use the Holley Blacks.If you were running a small single stage kit one big fuel pump would work.But you will be safer this way.

The fuel cell in the engine compartment is the easiest and probably the best way to go. I would run the Holley blue on the nitrous, UNLESS you are using the 10psi tuneup. I have found that the holley pump is very inconsisant at that pressure. I have used it on many many kits though that use the standard low pressure tuneup. These low pressure tuneups are very safe, and are actually what the kits were designed for. If you have any questions, feel free to hit me up, and I can answer them. As for the return line, I would use a cheapo Holley regulator. 1 IN and 2 OUT. 1 Out would go to the fuel solenoid, and the other out, you would put a small jet into, and return it to the cell. You only need a small jet to clear out any air bubbles, and to keep the fuel pressure from creeping. Have used this in low 9 high 8 second cars, and it works great. Feel free to ask me any other questions about the Gemini Quad. I have tuned many of them, and they are very good kits.

Scott 925-998-1517

Thanks for the info guys... I have decided to go ahead an do a 16 gallon summit cell in the trunk, and also a Jaz 1 gallon cell under the hood for the nitrous. The nitrous kit came with the 10psi tune-up specs, and that's what I was planning on using..

Scott, I may hit you up tomorrow, and ask you a few more questions...

Is it true that on the Gemini Quad you have to have a seperate regulator for each stage??? And if so, do you have to have a return running for each regulator???

Thanks.

Yes, you always want a seperate regulator for each nitrous kit, and yes you would want the bypass I was talking about for each stage. You could Y them together though and run 1 line back to the cell.
Feel free to call me.

Originally posted by 12Second3rdgen
Its all in pieces in my room at the moment, but I have a pic of what I am copying:

http://www.thirdgen.org/techbb2/attachment.php?s=&postid=1442150

I planned on running a -6 AN return.

What size line is that??? I was planning on going out to the fuel pump with 1/2" 8AN, out of the fuel pump and y'ing it into 2 6an lines to two regulators, and then to the solenoids.... 6an line is sufficient isn't it???

FYI: Those Holley Blue Pumps SUCK!!! Not to mention the blue pumps are prone to breaking the internal plastic pump vains. It doesn't take much for one of these pumps to take a dump. I've seen these pumps die more times then I care to say. These pumps are dog S H I T!!!

If your not in favor of running two fuel systems then my advice would be run one big pump. Your on the correct path regarding pump manufactures, go with a Manaflow Quick Star 500. This pump will in deed provide enought fuel flow for the engine and for the nitrous kit in your car. I know of on person in fact that uses this same pump in a frt mounted system that feeds both the motor and nitrous kit. Car runs mid 7.50's in the 1/4 mile.

Stay away from those cheap a s s Holley Blue pumps if you value your engine.

Good Luck!

Originally posted by JWINN
FYI: Those Holley Blue Pumps SUCK!!! Not to mention the blue pumps are prone to breaking the internal plastic pump vains. It doesn't take much for one of these pumps to take a dump. I've seen these pumps die more times then I care to say. These pumps are dog S H I T!!!

If your not in favor of running two fuel systems then my advice would be run one big pump. Your on the correct path regarding pump manufactures, go with a Manaflow Quick Star 500. This pump will in deed provide enought fuel flow for the engine and for the nitrous kit in your car. I know of on person in fact that uses this same pump in a frt mounted system that feeds both the motor and nitrous kit. Car runs mid 7.50's in the 1/4 mile.

Stay away from those cheap a s s Holley Blue pumps if you value your engine.

Good Luck!

The blue pumps are not junk, but they can easily be damaged if incorrectly installed. I have 3 friends who run them in their street cars without problems.

Originally posted by JWINN
FYI: Those Holley Blue Pumps SUCK!!! Not to mention the blue pumps are prone to breaking the internal plastic pump vains. It doesn't take much for one of these pumps to take a dump. I've seen these pumps die more times then I care to say. These pumps are dog S H I T!!!

If your not in favor of running two fuel systems then my advice would be run one big pump. Your on the correct path regarding pump manufactures, go with a Manaflow Quick Star 500. This pump will in deed provide enought fuel flow for the engine and for the nitrous kit in your car. I know of on person in fact that uses this same pump in a frt mounted system that feeds both the motor and nitrous kit. Car runs mid 7.50's in the 1/4 mile.

Stay away from those cheap a s s Holley Blue pumps if you value your engine.

Good Luck!

That is the first I herd of someone having a bad experience with the Holley pumps. And it sounds like you had a handful of occurances which really sucks!
I am running the little Holley on my 383 currently, it's the RED model and I have had NO problems or hickups whatsoever.
I will be setting up a secondary fuel system utilizing the Holley Blue and regulator. It will only be in use while spraying.

Damn, I hope the blue ones aren't junk!!! I just bought 2 of them.. lol... :D

The two things I always hear (whether they are true or not) about holley blue fuel pumps is that:

They are pushers, not pullers, so you want it as close to the fuel source as possible.

Without a return on the regulator, you will burn the pump up.

Ok a little test to figure out if those hot ticket blue pumps are worth even the $100.00 or so dollars they get for them? Plus a little info for ya:

How much fuel flow is enough?

The correct volume of fuel is that which is required to support the amount of horsepower that the engine can produce. Most engines that are using gasoline burn approximately .5 pounds of per horsepower-hour. This is sometimes called BSFC (Brake Specific Fuel Consumption). What this means is that for each horsepower (HP) produced, it takes 112 pound of fuel. This is a general statement and sometimes engines can be a little more efficient than .5lb/hp-hr., but it is a good practice to plan and measure fuel system operation using this number. Carburetors must have a stable supply of fuel in order to maintain the correct liquid fuel height. This is most difficult with drag racing vehicles that sometimes have forward acceleration and wheel stand at the same time. Each time that a nitrous system is engaged, additional fuel supply demands must be met or melted parts can be the result of "system lean-out", because the fuel required is in excess of the .5 lb/ hp-hr. for normally aspirated conditions. The additional fuel requirements for nitrous system planning is about .7 lb/hp-hr.

How much fuel pressure is necessary?

First, the fuel system pressure (provided by the fuel pump) must be enough to oppose the effects of gravity during the launch and during the run for drag racers. The system pressure of at least 8 to 10 psi per g is generally adequate. That's why a high end pump offers a 25 to 30 psi by pass as to help the return fuel back to the tank and at all time maintaining 6.5 to 7.5 psi WITH FUEL FLOWING at a rate of about 112 cc per second (that's about 10 drops per second). Higher fuel pressure will generate more foam in the float bowl.

Use a hand held calculator and plan on .5 lbs/hp-hr (gasoline). Use .7 lbs/hp-hr when planning a gasoline system for nitrous assist.

EXAMPLE: You have a 650 hp engine. 650hp x .5 = 325 lbs/hr (gasoline). Although you need to know how much your fuel weighs, assume for this example that it weighs 6.2 lbs/gal. 325 lbs/hr 6.2 = 52.42 gal/hr. Dividing by 60 (minutes per hour) yields .847 gal/ min (GPM).


A performance fuel system should always be plumbed with a return line to the fuel tank?

IMO a pump without a external by-pass system is just asking for trouble.

That's why any well engineered racing fuel system should not use internal by-passes because all they do is heat up and add foam (bubbles) to the fuel. Yes, it is a little more difficult to plumb, but it provides a better and more efficient system.

I'm guessing if your car should make on the spray say 600hp even using two Holley Blue pumps I would figure even the two pumps don't even flow enought fuel for that power level assuming the Blue pump is still a 140?

It never pays to strimp on your fuel system. If Holley is your company you want to use then by all means purchase one of there upper end pumps then like there Billet 350 or 500 race pump. Now that pump I do know will feed anything just about.

Its not the nitrous the makes power but the fuel and with a lack of it why then spend big money on rebuilds and nitrous kits to have it all hindered by a cheap $100.00?

My advice go with the Magnaflow I run there Quick Star 300 for my nitrous system and I also use there new EFI 600 pump for the motor, yes the 600 is way more pump then I need to feed my SBC but I for one am not going to waste $10,000.00 on a engine because of a pump that can't handle g's on launch. The motor will get fuel for sure!

Some people do get by with these small pumps but like I said is it worth the chance? Its your money.

See Ya,

Ok, you are partly right, but what you fail to realize is that a holley blue pump will easily supply enough fuel for a 400hp motor. How many people on this board are going to spray 400hp worth of nitrous? The nitrous fuel pump only needs to supply the fuel for the amount of nitrous you are going to use. Make sure the pump on the "motor" is enough to supply the HP the motor will produce. I have an 8 second 350 chevy, with 300hp worth of nitrous, in a 3250lb car. I ran 8.90 at 152 with 2 Mallory Comp 140s. Basically same pump as the Holley blue. I wouldnt recomend it though, cause we were on the edge with those pumps. Once we switched to a Magnaflow 300, on the motor, the car picked up another 2 tenths, and about 3 mph. This is just an example of what those small pumps can handle, if watched very closely. One thing I dont recomend is using a holley blue if you are going to use the 10psi tuneups. At 10psi, the pumps GPH drops WAAAAY down, which wont supply you with enough volume of fuel. This was another problem we ran into with the Mallory pumps. They are designed to operate at about 7PSI, and when jacked up to 10, they are basically free flowing, and the volume drops dramatically. Absolutely no problem with a traditional NX tuneup at about 4-7psi though. Dont get me wrong, Magnaflow pumps are the ****, but for somebody who just wants to put 200hp worth of nitrous to their motor, its a little pricey, and often times overkill.

Scott, (CustomN2O)
One more question about the regulators.... Many people have told me that in order to run the holley regulators correctly using a bypass that I would have to drill a hole in them..... Is this true?? From you're previous post I conceded that all I would have to do is use the extra outlet with a compression fitting, and a jet for the return line.... This is the way that I would really like to do it.. Also, do you have the jet numbers for the low PSI tune-ups??? The only specs that my kit came with are for the 10psi setup. Sorry I haven't gotten the chance to call you yet... I appreciate the help!!!!

Brant

Well, you have to at least modify the fitting that you put into the regulater, to allow you to install a jet into it. Thats about all the custom things you have to do to it. Yes, I have all the jets, and the low pressure tuneups. If you are interested in any of them, you can give me a call. You can also buy the regulators already set up for the bypass pill, for less then 50 bucks. Give me a hollar any time, or email me. Im glad to be able to help.

I think I may go ahead and buy those regulators from you here in a week or two... I also need to ask you what size jet to put in it..... Thanks.

great info JWINN and CustomN2O !!

I feel very confident about being able to setup my car with the nitrous system and all it's supporting casts?

I have posted the following message on another forum and have only recieved limited responses. Can anyone shed some light on this for me? Thank you !

[B]Been shopping for a new adjustable ignition system with rev limiter and single stage retard for nitrous. Can anyone recommend a solidly reliable system!

Choices:

MSD Digital 6plus #6520 ($280)

ACCEL 375+ #49375 ($200)

MSD 6AL #6420 ($196) and start/retard control #8982 ($119)

CRANE CAMS Hi6S #6300 ($140) and TRC2 timing retard control #6425 ($118)

If there is another brand, please mention it.

Anyone using any of these setups ?

I know ALOT of people use the 6AL and think they are great.
But if you are going to comment on the 6AL; I want to know about it in combination with the retard box.

thanks[B/]

I was planning on running the MSD Digital 6 Plus because of the retard capabilities. It's 279 (which is cheaper than the 6al and ignition retard module. I am going to order it here in the near future. I was also thinking of running MSD's new digital multi-stage retard box too... That way I could run the timing for max performance all motor, and have 2 stages of ignition retard. The Digital 6 Plus would be perfect if it only had dual stage ignition retard capability. Unfortunately it only has single... :( lol..

Yeah, I am leaning towards the MSD 6+ also because of it's single stage retard and digital circuitry. I will only be spraying 1 shot of juice so it will be all I need. If you are spraying dual stages then you need to get the other box like you said.

I am just real curious if some people have used some of the other systems I mentioned.

Originally posted by HeavyChevySS
Been shopping for a new adjustable ignition system with rev limiter and single stage retard for nitrous. Can anyone recommend a solidly reliable system!

Choices:

MSD Digital 6plus #6520 ($280)

ACCEL 375+ #49375 ($200)

MSD 6AL #6420 ($196) and start/retard control #8982 ($119)

CRANE CAMS Hi6S #6300 ($140) and TRC2 timing retard control #6425 ($118)

If there is another brand, please mention it.

I'd also look at Mallory ign boxes. They have some decent ones as good or better than MSD (reliability wise, plus you won't need 3 different parts to run one box) :bow: