i just got my nitrous system and need some fuel system suggestions. heres what i was thinking. i have a holley red. i will get a holley blue and use that for my engine and transfer the red to my nitrous so it has a dedicated fuel supply. should i use 8an line or would 6an work? i have a cell so it has 2 outlet.

I use 2 blues(had them) a #8 for the carb and #6 for the N20. I have the N20 pump come on with the N20 arming switch. Use a bypass regulator for the N20(if not it could go lean on the hit)

thanks very much your help is greatly appreiciated. i dont wan this ting going lean

You can't use a red for nitrous. It is designed so that it does not need a regulator with a carb and will not generate enough pressure to run for nitrous which needs 5-7 PSI on the fuel side. You'd have to run a blue with a regulator.

so ill probly need to get two blues? what would you recomend i use? the max i can go is 150hp shot but i wont do that til i get forged pistons.

You can use whatever pump flows enough fuel at the pressure you want to run. A blue pump would work as should some of the properly rated Mallory's that require a regulator. Most pumps for a 150 shot will be overkill, but you need a pump that has enough flow at 5-7 PSI which the red pump doesn't.

Depends where you are getting fuel from as well... if you are pulling it from the back or a stock tank you will need more of a pump then say if you have a seperate 1 gallon cell up front.

Get the Blue pump of one of the Mallorys. My nitrous pump is a Mallory 250.

what if a ran out of my two cell outlets to my holley blue and my red then to a y fitting into my 1/2 line up to the regulater then have one outlet got to the carb and one to the nitrous.

I suggest a complete separate fuel system for nitrous, with a Blue, 3/8 line (5/16" would probably be fine too) to the front of the car.

Then at the front, the fuel should enter a regulator, a Fuel Pressure safety switch (you're a fool without one), then the solenoid.

Do not regulate at the back, especially if you use 5/16" line.

If you were gonna go for 250HP or more, then I'd suggest 3/8 line, but 5/16" should be fine. You could probably use a 1/4" in theory, but let's stick with the 5/16".

Carb will use the same system that it always has, leave it separate.

-Bob Cunningham

could i use the stock fuel line. its 5/16. i have 1/2 to the carb now but i left the stock line in there.

For a 150 shot you should be fine IF there are no restrictions in the 5/16 line and you run a regulator up front as mentioned.

I'd recommend using the red dome topped NOS brand fuel regulator with the dedicated Holley Blue pump or any other good quality ele pump that can supply 15psimin @ 12VDC. The regulator they give with the new pump is not very good at regulating on off type fuel control. Took me almost a year to find this on my dragster using a data collector system quikdata. Holly reg worked great standing still was crap going down track. #4 An is just fine for the fuel feed to the plate and gas from bottle and than to plate. Maybe a AN 6 to feed the pump no larger for sure

How is the red dome NOS regulator at controlling pressure creep? The holley regulator I am using now pegs the fuel pressure until activated, then is very consistant at dropping to the set pressure when the system is engaged, but I beleive the initial high pressure when activated is too rich and giving me some tuning issues.

Use the cheapie $20 holley regulator you get with the blue pump. It is by far the most accurate,repeatable,and quick acting regulator out there. I use them on everything. Carb,plate,and fogger. I modified mine to increase the pressures to a high pressure tune-up on the plate and fogger. I also run up to 35 psi to each regulator. Yes, on the initial hit the reg. will be a tad rich, but this is a good thing as the nitrous will beat the fuel to the fuel bars as it is under a lot more pressure than the fuel.This will introduce a lean condition on the hit if you have a lazy reg. I don't worry about the pressure creep while the system is off and the reg is not flowing. I only care about when it is flowing and what the pressure is. Now if it is taking a long time for the reg to recover there is something wrong with the reg and would warrant a look. BTW, take a look at any serious pro-mod,outlaw 10.5 car and you will see many of the same regulator- if it works for them using 3 stages and up to 700 hp, hey it will work on a plate shooting 100.

Collect some good quality pressure data going down the track and only than will you learn how poor that "give away" Holley regulator really is. Or you can just forget I gave you a big gift. It's easy to run slow for sure... lol

i always hate to get into the nitrous talks but it is hard for me to stay out of them...........i have found myself to be like a king guru of nitous plate systems to the 175 hp mark.

because i have ran them so long and i know what works and what problems you can encounter with them.........since i went thru my share.........i'm glade to report i have never toasted a motor to nitrous or broke parts.........

when i first started in with nitrous i started out with a basic NOS kit that was adjustable to 175hp with there jets........it cost 336 bucks delivered to my door with a full bottle of nitrous.........

i had the system on my car and working in an afternoon.......i did a basic set up......my car had 3/8 fuel line from gas tank to stock fuel pump and 3/8 line from fuel pump to carb............i put the nitrous in and i spliced into my fuel line with the "T" fitting in the kit.........for the nitrous plate.

i then went down to the local parts house and bought me a fuel pressure gauge and mounted that..........took the car out for test run i had found my stock pump combined with activating the fuel on the nitrous gave me way under the required 4.5 lbs of fuel pressure.......i was running the car up to 5500 rpms and hitting the nitrous button to find out my fuel gauge would take big nose dive........i didnt have the nitrous bottle open yet.......

i then went back to the parts house and got me a holley mechanical strip pump with a holley regulator.......i installed that with the regulator and gave one side to the nitrous plate and the other side the carb. this provided me with no less then 5.5 lbs at wot with nitrous engaged.......i went ahead after i installed everything to make my first pass down the highway with 100 hp jets........no timming retard and no special fuel.........things looked great.

after several trail passes down the highway with 100 hp i decided to go 125 hp....and at the same time i ran 1/2 alum. fuel line from the gas tank to the fuel pump (mechanical holley) just with the increased fuel line dia. this allowed less of a dip in my reading of the fuel pressure gauge........with 125 hp jets at wot the pressure was at 6 psi at 5500 rpms my regulator was always set a 7 psi........and with 150 hp jets it was just just shy of the 6 psi mark................

this set up provided me 6 years of endless runs on and off the track......this set up work with no other changes.and it worked well for running in the low 12 sec range with nitrous and the 150 hp pills

after i did a complete engine hi po rebuild that included 11.7 to 1 compression huge solid cam and more stall......my car was running deep in the 12's on street tires and mufflers. i added a holley blue pump to the back of the tank along with the mechanical fuel pump.


i ran the 175 hp jets with this set up but to some who might know allready the 175 jets dont show much more gain over the 150 jets because the system is pretty much max out at the solenoids.

the extra fuel pump allowed no change at all at the fuel pressure guage it stayed stuck at 7 psi even with the initial opening of the fuel solenoid when the nitrous was activated.

this set up allowed me to run another 4 years turning a few violent 10 sec passes off a 12 sec motor . and alot of low 11's run when it just wouldn't hook.

some of the problems i ran into was bottle pressure......early on i found out when the bottle got to hot it would just blow hot air out of the nitrous bottle......i put on a pressure gauge on the nitrous bottle and thru help from NOS hotline i was to keep the bottle pressure at 850 psi at all times........so i made sure the tank was out of the sun on hot days and if the bottle pressure was to high use some cool wet rags to bring it down.......on cooler days let it have some sun........i also found out the braided steel line will leak over time......i had put my nitrous bottle and braided steel line and nitrous solenoide under water in the bath tub and found that millions of little air bubbles comming from the braided steel line.......so i changed it over to just regular brake lines that i had bought from the local parts house to fix that problem...........


i have for several friends installed and used very similar set ups on there sbc and they have enjoyed many years of use with out ill effects............i have double stacked nitrous plates use 150 hp off the line and hit another 150 just past the 60 ft marker......using a dedicated 3/8 line with a holley blue and regulator just for the second hit of nitrous carrying 114 octane fuel.

The bubbles were not coming from gas inside the hose, I promise. That was most likely air bubbles trapped by the surface tension of the water.

Everyone with nitrous should always maintain certain bottle pressure, as recommended by the manufacturer of your system.

-Bob Cunningham

Hey Flyboy's where'd you find the spring for the Holley regulator?

Here is what I did. Right or wrong, but it works. The spring stays the same. When you take the reg apart the diaphram will have a little metal tit on it. I slowly ground down the tit until I could get the reg to adjust to what ever pressure I want. I can now run as much as 18 psi if I want. You can buy these deals already modified from Pro-systems,Jeff Prock, and many others if you choose.
To the other post about having datalogging info on the cheapie regulator. I wish I had one in the car. I would love to see some data on this setup. If you have any, any chance of me getting some from you? I am always open to new information.

Thanks Flyboy for the info on the regulator, I figured it needed a different spring. I'll have to try your trick out.

Hey pcs0snq, just curious as to some more info on your combination. Do you run an alternator? fuel pressure set to the regulator. Dia. of fuel lines. Just trying to compare apples to apples here with what I have. I would also like to bend your ear on dataloggers. I have been in the market, but unsure of what I exactly need to monitor. THanks

Originally posted by Bob Cunningham:
The bubbles were not coming from gas inside the hose, I promise. That was most likely air bubbles trapped by the surface tension of the water.

Everyone with nitrous should always maintain certain bottle pressure, as recommended by the manufacturer of your system.

-Bob Cunningham no it wasnt from surface tension..........after wiping the line several times by hand to rub off what i too thought was from surface tension those bubbles was comming for minutes that it was underwater............i had the whole thing under water for long time...........i did this because i was losing line pressure after the bottle was shut off.........

Hey Flyboys. I have a 555 with a Ron 2100 Terminator injected methanol. 14.4:1 CR Dart 320 heads ported to flow 394 at .7 lift and 28in-wg. Belt drive pump. -10AN suction -6AN discharge. -6AN normal bypass from the valve. I also have a hi speed lean out with -4AN back. It comes on at 6400 and works great. Looks like a small NOS purge solenoid. Ye I have been running an East Coast full size alternator for about 8 years. It's the only way to fly. The NOS system is a dominator cheater plate with 175HP pills (conservative NOS tune up) I use the Summit billet ele pump rated at 140gph It's really an Aeromotive pump but only $100. Way better the Holley Blue. Way smother flow. I have the NOS red top regulator set for 5.5psi measured flowing. 7.5psi flowing is just wasting good gas. The pump takes suction from a 1 qt Jazz Jr dragster fuel tank on the rear firewall. One little trick I added and will share with you guys is I added as very small bypass from the regulator output back to the tank using -4AN hose. I used a NOS jet holder and a jet soldered closed and a very small hole drill in it for the flow restrictor, pin size flow. This helps the regulator deal with the fast on and let's me not worry about leaving the fuel pump on when trying to think about other things like winning. That little flow keeps the pump from heating up and the better regulation is a bonus. I use RED race fuel the highest Octane at the track. The control is off a timer on my delay box. I delay 0.1 sec after trans brake release and spray from 2 to 4 sec depending on what the Field is like. This 222" Horton runs 7.50's on HP and 7.20's with the 4 sec dose of Mr Frosty. I have a 12DC NOS bottle heater and try to maintain 1000psi. It hard in the summer here when it's a day race. Bottle is up front as far as I could put it and still have good angle. It let me remove the weight bar. For me the Edlebrock Quikdata was a great deal. Pretty easy to use and install. When it came out the factory support was really good. Not so sure anymore. I measure Oil P and Fuel Press. (I move the fuel to read NOS Gas fuel or Injection pump pressure). I have one temp T/C in the oil block galley and 3 egt's in the headers. G force is built in as well as voltage and rpms..I have about 4 digital channels. TB on, NOS on and Shift ON and glide output rpms. Can do more, but I had plenty. I will see if I cant find a way to make some ele images of the data I collected when I was doing my NOS gas fuel effort. Gotta find the data files also. It was amazing how well the NOS fuel system worked perfect in the trailer as compared to the crap going done the track. Nice crisp square wave with one or two small rings standing still. +/- 4psi on the track!!! BTW the 60 footers are 1.04 and about 3.5G's, that may have a little to do with it plus it's a hard tail digger. Hope this helps. If you go to the Edelbrock web site you can download the quikdata software for free. If anyone does that I can send you some data sets to look at. email me for them after you get it up and running.
Horton 222"
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A few crapy shots of eng area:
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I am curious as to how much pressure the enrichment pump you have puts out to the regulator. I use a single Magnaflow 500 set to 35 psi to the regs. I monitor fuel pressure at the float bowl on the dominator and fuel pressure on each system with pressure guages mounted under the cowl induction hood. I have not seen any fluctuation in pressure readings down track with this set-up. I use the regs on the plate (Big Shot 250hp setting @10 psi don't ask about the jetting it will scare you) and a fogger using a 300 shot@11 psi. I use a holley reg on each float bowl also. I calibrated the fuel pressure guages on the car to a set of known calibrated guages that I have here at the shop. We work on aircraft so everything has to be calibrated yearly. I don't doubt your findings one second. Just curious as to the different setups and how they react to different conditions ie- g-forces,vibration, etc. My above psi readings on the NOS are for a high pressure tune-up. The jetting is no where even close to a stock fuel map, in fact I don't even keep one in the trailer. I am curious though as to why the small heads on that size cu. inch motor. Was it a set that you already had or do they help in any way for you combination. Most 550 on ups I see lately either use a Dart 360 or go with a big duke, big chief set up. I have 2 engines with Dart 320's one is a 510 and the other a 477 deal. This is why I ask.

The discharge pressure at 14VDC, with car running is about 17psi. It's a little $100 pump. I use less than a cup of fuel in a 3 sec blast. The heads started at 320 casting, but intake runners are poured at 355cc's. Sorry to miss lead. I'm a two finger typer and....... I could do many things to the base engine HP, but it's hard to go regular bracket racing with a sub 7.5 race car at my local track. The way I have it now I'm sorta consistent on HP (if the track is decent) and I only use the NO to make the 16 car field quick race. The bump spot here can be 7.65 to 7.30's and given night, so the spray let''s be deal with just about any event... so far. My friend that runs the top sportsman IHRA events runs the hi pressure lean jetting nitrous tune up also. He typically melts something every year on his 700ci engines. My short wheel base car is about at it's limit with what I do now so...

BTW I have to also share that that all pressure Gauges have built in dampening by design and you will never see the real hi frequency pressure swings going down the track. It takes an electronic transmitter and pretty fast sampling to OPEN your eyes. The 1st time you see it you'll be sick and than maybe like me possessed about making it better... or not. I ran this Cheater plate for 3 years with a 540cid and a Holley Blue and there free regulator with no issues. Than I started looking at the data and shazam I found almost a tenth.

BTW++ Do you check your Nitrous GAS fuel pressures (to the plate and nozzles) with the system ON and flowing and at the same voltage you race at? A 7AL can suck some power and pull the voltage down at hi RPM's. The pressure drop is way different flowing.

Actually, I plug in a battery charger to 'simulate' the car running while flowing the 2 systems. I run a volt meter at the back of the car to monitor voltage. I found out early on that motor rpm in the pump vary's greatly with voltage ie pressure changes.I marvel about guys not running an alternator and running multiple kits and can't figure out why things change. The rpms in the pump motors will start to decrease almost immediatly after startup without and alternator. I run a custom made 160 amp one-wire alternator. I also use a digital7 which is not so bad on amps. Your comment on the datalogger has just made my decision a whole lot easier. Now to wade through all the bull to find one that will suit my needs. I really like my high pressure tuneup stuff. Once you get the hang of the N/F ratios it starts to come together what you can get away with. I think also that cylinder head,combustion chamber design has a lot to do with how well the 'tune up' needs to be. The conventional headed stuff like I run I can get away with being waaay off and still not hurt parts. The 14 and 12 degree stuff makes more power but needs special care. But by looking at the difference it only seems to make sense look at the burn rates across the piston between the two! Thanks for the information.