I'm in the process of preparing my fuel system for nitrous use. Right now I'm wondering if my plans will be good enough? I'm running the stock 3/8" lines with a Holley Blue pump into a return-style regulator for the motor fuel system (pump gas). For the nitrous I'm going to be installing a 1 gallon fuel cell under the hood and using another Blue pump and return regulator (race gas). Would this setup be safe with my 430ishHP motor + 175-200HP shot of nitrous? Or would it be a better idea to keep it simple and upgrade to like 1/2" line with a better pump and run the nitrous and motor fuel all off one?

Any ideas would be helpful. Anyone with a similar setup have opinions?

Thanks,
Chris

I don't like the idea of mounting a fuel cell under the hood. You want to keep the fuel cool and away from ignition sources, and I don't think there's any worse place to put it than under the hood.

I would run a -8 line from tank to your carb, and remember this is an area that you can go overboard and come out OK. -8 line should be plenty, but if you are in doubt of the pump, go up a notch. Are are some good mechanical pumps out there too that can handle the flow.

The thing is, 3rd gens dont have trunks so unless I build a rear firewall, under the hood is the safest and NHRA legal way of doing it. The spot I want to put it in is far away from the motor and in a spot where it can be air-cooled. Maybe this sounds stupid of me but I'd like to do it 1 way or another. Either 1 great fuel pump with 1 huge line for both, or 2 decent pumps and 3/8" lines. I know it'd be MUCH safer if I upgraded the regular fuel lines and pump AND did the independent system but is it really absolutely neccessary?

Heres a shot of exactly what I'm going to do. If you're fimilar with under the hood of a 3rdgen, this is the place up front where the cruise control and charcoal canister usually is:
http://chris.tetro.net/pics/fuelcell.jpg

What's wrong with the stock fuel tank? Keep in mind, I'm not too familiar with 3rd gens.

IMHO.... I would put a sump in the bottom of your gas tank. Have both pumps pull from the ports on the sump.

That's what I was getting at.

I can't run a sumped tank due to my exhaust being underneath the tank (thats the stock location). The main reason I want to run a completely seperate fuel system is because

1) I have the 1 gallon cell
2) I have 2 new fuel pumps
3) I have tons of 6AN fittings and hose
4) I wouldn't wanna have to constantly mix race fuel into my tank - just to wind up burning it all for no reason.

So, basically it would be cheaper for me to do the independent system then it would for me to have to redo my entire fuel system: pump, regulator, lines, a zillion fittings, ect. I guess the main question is, would this supply enough fuel? 2 Holley blues, and the 2 sets of 6AN lines for motor and nitrous?

Thanks,
Chris

#6 will do. Just make sure that 1 gallon cell has plenty of fuel in it before you sqeeeze that trigger.

I noticed you installed a sump.
sump (http://chris.tetro.net/images/thumbsump.jpg)

Yeah I had one for awhile but I'm installing a Mufflex single 4" exhaust system so I put a stock tank back in.

no need for race fuel with nitrous
you're not anywhere near the danger level
window switch and some timing retard and you're all set

There's no problem with running the fuel system just as you planned. I know several guys with 1 gallon cells tucked in front of the fenderwell of their cars.

And I would run race gas on 'the hose' just so you can be more aggressive with the timing and not worry about detonation. That is if you're gonna try and wring it out. ;)

ditto on joesmiths statement. thats actually a very common way of doing it, and i know a few of my buddys cars are exactly that way. one of them is the 70 nova i help wrench on, its an 1100 horse 632 (motor only) with the capabilty of over a 500 horse nitrous tuneup. we've gone with just shy of 400 horse tuneup just because of chassis limitations, and trying to take it easy on the motor. its gone 7.80 @ 173, and that fuel setup works flawlessly.
now granted the nova has bigger primary fuel line (-10), but the nitrous fuel is only -8. my first concern with yours would be the 3/8 from the tank, but i think your fine there for now, imo. this would be a fine time to invest in some fuel pressure gauges, if you don't already have them.
the one thing about the picture you have is i'd try to get the pump below the cell if possible, but otherwise i think your all good graemlins/thumbsup.gif

Thanks, that was my main concern weither or not the 3/8" stock lines would be alright as long as I used a seperate system for the juice. I'm still not 100% sure what I'm going to do, maybe I will replace them with 1/2" line just to be safer.

You should have know problems doing it the way that you plan to. We did it that way with my '67 when it ran the 427 and Fogger and we do it that way with the Super Bee (picture of install at www.adivanman.com/beespecks.html (http://www.adivanman.com/beespecks.html)). The only thing that you need to watch is that the cell is full (especially on the street). If you are going to run on the street and pull the trigger on a regular basis, you may want to consider plumbing in a mechanism to fill the cell on "the fly". Good luck.

Tp prevent accidentally running dry. Just install a fuel pressure switch. That will dis-arm the N2O if your cell runs low. I have seen many guys run the system the way you have planned. Should work fine. Make sure you filter the fuel line.

I plan on doing as many saftey things as I can think of and triple checking everything but how often do you think the fuel cell will run out? I'd assume the bottle would run out before the cell?

I'd also like to hear some opinions on how much nitrous I should use. I'd obviously like to use as much as possible :D My kit (NOS Cheater) is adjustable up to 250HP. Would it be stupid for me to go that high? Keep in mind I'll probably only use the nitrous once a week if that. My internal specs are:

-355 studded 4-bolt mains
-Childs & Albert forged I-beam rods
-TRW forged pistons (10.3:1)
-Eagle cast steel crank
-ARP studs and hardware throughout

The one thing I'm worried about is my rings. They're not gapped for nitrous and they're pretty much stock replacements. Now with all the safety features, quality fuel, ignition and careful tuning would I be able to pull this off?

Sorry for all the questions, but like the most of us, I'd like to get as many opinions and tips as humanly possible before tackling this project.

Thanks for all the help so far,
-Chris

Did you file fit the rings? If they are out of the box pre-gapped rings I bet the gaps are pretty wide. Just like anything else you should start with a mild tune up and work your way up. Start at 100HP, watch your plugs. I think the bottle will out last a 1 gallon cell. Also follow the timing retard guidlines. N2O can be fun and gives you instant cheap power. The bad thing is if something goes wrong it is usually to late. That's why you have to follow the guidlines and not get to carried away. As long as you are careful I think your engine will live with a 200HP shot. Just error on the rich side and be conservative with the timing. Once you get it dialed in you will be pretty safe.

as long as your fuel and timing is up to the task, you could get away with 250 horse, imo. i'd be careful above 200 with that 3/8 primary line though, it will likely be ok, but at that level one hiccup and your motor is all done, seriously. just be darn sure you take enough timing out to go with the level of nitrous you are running, and always try to err on the side of slightly rich on fuel, your motor will thank you. and as for the motor, if its a well assembled piece it will live at 250 i'm sure, but if there are any weaknesses in it, nitrous has a nasty habit of exposing them.
as for the fuel cell, 1 gallon will live quite awhile, but you do not want to run out. for an example, in the nova i referred to we ran 36 square jetting on a fogger system, and two bottles. at the end of each pass both bottles were about half full, and the nitrous fuel tank was about at half as well. so it would seem at least on this combo, a bottle would equal half a gallon, with square jetting. so it will last awhile i would say, but again, dont let it go lean on you, or all you'll find left of your pistons will be aluminum slag in the oil :eek:

The concern that you will have in a street driven application is not always consumption, but evaporation. We find with the Bee here in Florida that evaporation from the front mounted cell can be sigificant in the heat of the day. Any assumptions about fuel vs nitrous consumption can go out the window if you lose fuel when you are not using the system. It is important to keep an eye on it whenever you think you might squeeze. One of the first rules of nitrous is to assume nothing.