Lets talk nitrous...

[my66coupe]

In my quest to find more power, I've decided to look into nitrous set up for my car. Ok questions I have.... I know that i will have to rejet the carb in order to run richer to compensate for the nitro, but will i have to get a higher than stock flow fuel pump? How many degrees of timing do i have to retard? With the new jets and timing retard, will the car run like crap when the nitro is off? I have a mexican 302, its known that these blocks are tougher than the stardard 289/302, its .04 over and does still retain the thick main bearings....stardard rebuilt flat top pistons w/valve reliefs... hyperutectic? The edlebrock performer Nitrous system is adjustable from 50-75-100 i would probably run the 50 to be safe.......Are my pistons at risk with a proper tune? Ive heard that high compression pistons (flat tops) will be fine in proper tune, but some say no. Benefits of a purge valve? WOT switch or just a toggle? Bottle warmers? When they say i would have to run a colder/hotter plug, does that mean the gap is changed on the stock plug or would I actually have to buy a different plug??? Check my sig for details on the rest of the engine...does my cam check out? Any other points that i missed would be appreciated. Thanks guys

Mike

ps....Do i absolutely need a single plane intake?

 

[ForceFed70]

Wow... that's alot of questions. Possibly you need to do some research and answer these questions on your own. But here is some quick answers.

1) You do not need to rejet the carb. If you want to change fuel mixture, do it with the jetting on the nitrous kit.

2) A rule of thumb is to retard your timing 2* for every 50HP of nitrous. (IE 4* for 100hp). But there are ways around this.. for example, if you have a MSD ignition, you can set the system up to automatically retard the timing when the nitrous is flowing.

3) Better pistons is a good idea but may not be absolutely necessary. For example, I'm running stock style cast iron pistons in my engine with a 150HP shot. My original plan was to run the stock pistons until they melted and then replace with something better. That was 3 years and many bottles of nitrous ago...

4) You may or may not need to install a better fuel pump. It really depends on what your fuel requirements are. The nitrous system is designed to work with a certain fuel pressure. If your pump can maintain that fuel pressure with the nitrous system in use, then you do not need to upgrade. If the pressure starts to fall too low, then you need to upgrade or else run into a lean condition and start melting stuff.

Now before I answer anymore questions.. let me explain something about nitrous... Nitrous is no harder on your engine than something else that would create the same amount of additional horsepower (IE a supercharger). Provided you run the propere tune. There are 3 things that will destroy your engine fast. Detonation(pinging), a lean fuel mixture, and finally a nitrous backfire.
Your "tune" revolves around these issues.

Each of these issues needs to be addressed in order to have a healthy tune.

 

[WORTH]

Why would anyone want to do that to a perfectly good engine?

 

[jbsteven]

Why would anyone want to do that to a perfectly good engine?

because you can.

 

[94CobraPace]

More Power... ARG arg..
Do some more research on this. You can get a wet kit that spray NO2 & fuel so you do not have to rejet the carb. You don't need a purge kit. You do not need a bottle heater, but for more consistant power, it is best to have the same pressure. Lower pressure when cold = less power. You will need different plugs, 1 range colder, possible 2 if you use the larger jets. You do not need a single plane intake.
70 N E covered a lot with good info.

 

[my66coupe]

Thanks guys... 94cobrapace, the kit is wet and it arrives in a week. Does anyone know the specs on the stock fuel pump on a 289/302? The edlebrock tech says I require around 110 gph at 15 psi. 15 seems quite high for me, since all the pumps they offer run at about 6-8 psi....at either 110/130 gph. Thanks guys


Mike

p.s. I got one hell of a deal, the kit itself, a WOT switch, an RPM Switch, pressure guages and more for only $330.

 

[66P51GT]

Benefits of a purge valve? - Keeps the supply of nitrous at the solenoids for instant and repeatable results. It bleeds accumulated nitrous vapor from the supply lines.

WOT switch or just a toggle? - I'd go with the WOT switch. This ensures the butterflies are open and you get plenty of air flowing through the carb with the right fuel mixture. Use this in conjunction with an arming switch.

Bottle warmers? - Nitrous works best when pressure is at or near 900 psi. The warmer is used to maintain the pressure and maintain consistency with your runs.

Another item to consider is a fuel pressure safety switch. This stops the flow of nitrous if your fuel system falls under a defined threshold. This keeps lean conditions from frying your pistons.

If you use a high pressure fuel pump (15psi in your post), you must run at least one fuel pressure regulator.

 

[10secgoal]

You more than likely will not need a change of heat range or timing until 125 shot. 2 deg. is a rule of thumb to be safe. You do want to be safe, but I run stock heat range and no timing retard on pump gas with no problems. If you got instructions with the kit it will tell you the same. My kit (NOS) said stock or one colder for 100hp shot. Stock works for me. And if you run a 50, you should have no problems. If you chose 50 for fear of breaking something with more nitrous,keep the 50 jets and throw away the bigger jets, or sell them. Once you feel a 50 shot it will be very tempting to stare at those jets and have the will power not to use them. Have fun !!

 

[my66coupe]

66P51GT.... If I did go with the WOT switch, and the arming toggle, what would I be arming? The solenoids? The only thing i can think of arming would be an electric bottle valve which I dont have. I forgot to mention to you guys that the kit also included a NOS purge valve. I might as well install it. The purge mounts where though and where do you recommend I shoot it? Ive seen pleanty of cars at the strip that have it in front of the windshield. I live in arizona, our temperatures can get insanely high during the summer, I would not go for a bottle warmer due to the fact that its already warm outside. I beleive 85* will get me 900psi on the bottle. Do bottle blankets work? Will they keep my nitrous cold when its 120* during the summer? or warm when its 55-65 in the winter? 10secgoal, I have thought about what you said about the jets, for now im definetly running the lowest shot (50) to ge a feel for the system. 75, and the 100 are tempting but do scare the crap out of me, Just think a 1/3 of my power instantly added on top of what i have.. that has to feel pretty crazy. Speaking of the feeling, I've never been in a rig with nitrous, when you activate it, how does it react? Is it an instant jump in RPM and thrust you in your seat? Or is it more like a turbo/supercharger that slowly progresses the RPMs? Thank guys

Mike

 

[10secgoal]

It is instant and the ride is outstanding.Imagine being in first at 3k at 1/8 throttle and stabbing it. Add full throttle and a 75 shot and that's what it feels like. I was in 29 palms for a few years with the same weather you have there. You will HAVE TO have the purge in the summer. Nitrous boils at room temperature. And at 120 + degrees out side, it won't take long for it to boil in the line. When it boils it turns to gas, causing nitrous lag. You will not get that instant kick in the pants. You will if you purge the gas, and get the liquified nitrous right up to the soleniod. If there is enough gas in the line, it may even backfire out the exhaust. The motor will be very rich because the there is more fuel then there is nitrous to burn. This is why foggers are far more efficient nitrous kits. There is less time from injection of the nitrous into the cylinder. It has more time to boil and turn to a gas, and the cylinders don't fill with as much nitrous. Ok I've gone of on a different subject. I would HIGHLY, HIGHLY recomend getting the nitrous book summit has and reading it in it's entirety before the install, to prevent any foolish, preventable mishaps. Nitrous is safe and effective witht the right knowledge. Done lecturing.
I have my purge going thru the windshield squirters. It looks awesome when you purge. Two plumes of nitrous 4 ft over your car. You will probably have to sand the squirtes a little. It's a tight fit.
One last thing. When you get the bottle filled,freeze it and don't let them pump it in. You will be paying for air. I picked up almost a tenth in the 1/8 when I stopped pumping.

 

[my66coupe]

"When you get the bottle filled,freeze it and don't let them pump it in. You will be paying for air. I picked up almost a tenth in the 1/8 when I stopped pumping."

Freeze the bottle bottle before or after i get it filled? The nitrous place will let me pump up the bottle? Maybe you wrote the last sentence wrong but why did you stop pumping?? I understand that the bottle must be at 900 psi for best results, If i only have 1 lb of nitrous left in the bottle, how the hell is it going to be 900psi? Is it still pressurized to the last drop?

ps i found this on google, this can't be safe....

Mike

 

[10secgoal]

"When you get the bottle filled,freeze it and don't let them pump it in. You will be paying for air. I picked up almost a tenth in the 1/8 when I stopped pumping."

Freeze the bottle bottle before or after i get it filled? The nitrous place will let me pump up the bottle? Maybe you wrote the last sentence wrong but why did you stop pumping?? I understand that the bottle must be at 900 psi for best results, If i only have 1 lb of nitrous left in the bottle, how the hell is it going to be 900psi? Is it still pressurized to the last drop?

ps i found this on google, this can't be safe....

Mike

Freeze it before you fill it. You want your bottle pressure to be lower than the fill bottle. That way it is force feeding pure nitrous into your bottle. If it is pumped, normal air goes in the bottle along with nitrous and you pay for breathing air.
The bottle won't come close to reaching 900 psi with only 1 lbs. Even if you use it a the 300lbs that it might have, there is not enough pressure to turn the nitrous to liquid. Then you have the same problem as you had before when you don't purge.

 

[my66coupe]

Do you have any pictures on how you mounted your switches? Im thinking, an arm switch that feeds power to the relay....a purge switch, and then a nitrous switch. Not sure if I should go with dash mounted switches, floor mounted etc.... I know that i will probably be buying the B&M handle with the button for my megashifter for the nitrous, but what about the others?

Mike

 

[Darkhorse845]

Why would anyone want to do that to a perfectly good engine?

Because you just can.

 

[10secgoal]

Do you have any pictures on how you mounted your switches? Im thinking, an arm switch that feeds power to the relay....a purge switch, and then a nitrous switch. Not sure if I should go with dash mounted switches, floor mounted etc.... I know that i will probably be buying the B&M handle with the button for my megashifter for the nitrous, but what about the others?

Mike

I have the nitrous hit in the shifter,for now. It will go to a WOT now that I have a holley. The rest are mounted on the plastic piece between the dash and the plastic above the glove box. Honestly can't remember what yours looks like. But sorry dude, no digital camera.

 

[66P51GT]

66P51GT.... If I did go with the WOT switch, and the arming toggle, what would I be arming?

If you only have the WOT switch, you will get the Nitrous shot every time you floor it. The arming switch overrides this and allows you to control whether you use the nitrous or not. For instance, you would disarm when driving on the street.

I disarm, run hotter plugs, and increase my timing when on the street. I run cooler plugs, reduce timing, and arm when at the track.

$.02