I have a 1985 with 95k Miles on it, I am considering a NOS Shot for the track, and lets face it it looks way cool.

So what is the real deal I know my Motor is 9:5:1 ad from what i read Occasional NOS will not hurt the motor.

I have also heard the stories of "it will blow out your bottom end" and "Nos will melt the valves" and "You'll Put an eye out"

Maybe that last one was my mom talking about my red rider bb gun....

So does any one know for sure, Once again this is just for some occasional tire melting at the drag strip.

Please let me know

 

Nitrous is an outstanding power adder and when done prudently, it's the best bang for your buck by far. You will often hear horror stories, but they'll always be "I heard" or "a buddy's friend's brother-in-law's neighbor" kind of stuff. When tragedies do occur and you can track them down to a real person, they're almost always directly related to an improper installation or somebody taking a shortcut to save a buck.

Just my two pennies........

PS: the bb gun thing was true for me too! My mom was ALL over me about that thing.

 

i ran many, many hits of 100 shot wet nitrous on a NX system on my 93 lt1 without incident.

Nitrous gets a bad rap from the older guys who remember when it first came out. They didnt know how to use it and understand that it needs additional fuel to work. Nitrous itself is not a fuel, its an oxygen adder that allows you to burn more fuel. A lot of people leaned their motors out and melted stuff, or detonated and broke ring lands. If you use a wet system, you wont have any issues. wet means it sprays the required fuel into intake, alongside the nitrous. I didnt even have to back off my timing at WOT.

A few people on here, with lt1's, ran great at the 100 shot level. However, when they switched to 150 shot, they blew their motor the first time around. Its my theory that the stock fuel pump was the weak point. It was ok with supplying the fuel needed to their wet system at 100 shot, but not at 150 shot.

Its this reason, I recommend replacing your stock fuel pump with a racetronix walbro 340 255 liter/hour pump and hotwire mod relay (they sell the kit, plug and play). Replacing the stock fuel pump is cake.
Although I ran my stock fuel pump for many 100 shots and didnt have any problems.

Theres other safety items I recommend:

1. a window switch (only allows nitrous to operate in a preset RPM window - this is a MUST.....one time i hit wheelspin that shot my RPM well over 6000 and if I didnt have that window switch shutting off the juice at 5800 rpm, I would have surely thrown a rod!!!)

Also, you want the 'off' rpm of nitrous, on a window switch, to be something below your rev limiter. Why? because your rev limiter cuts fuel. very bad when you are spraying nitrous.

2. fuel pressure safety switch (though I didnt run it because it sometimes acted goofy when the nitrous first hit due to an initial drop in fuel pressure as the fuel solenoid opened up)

3. new fuel filter (dont want anything to impeded fuel flow when you need it).



In combination with heads/cam, I got 445 rwHP and 525 rwTQ on my 93lt1 on the dyno. I also needed to switch the fuel side jetting of the wet nozzle such that it was a little bit leaner than what NX recommended.

While those numbers may sound great, keep in mind nitrous TQ hits real hard at first, on a full bottle, and then falls off quickly towards redline. Its not a flat torque curve! Its a downhill slope.

However, heres the #1 thing I HATE about nitrous:
1. If you have a half bottle at, say 1100 psi, it will not hit as hard as a full bottle at the same psi. Essentially, you will be richer. Theres less driving force, less compressed 'liquid' nitrous flashing into gaseous state in your intake.

Its like saying: my car wont accelerate as fast on a 1/4 tank of gas as it does on a full tank. Wouldnt that be annoying if that were true? Well it is with nitrous.

Now, I had a 'tiny' 10 lb bottle. If I had a 15 lb bottle, or twin bottles, Im sure the difference wouldnt be as bad or would take longer for me to notice.

#2 thing I hate is that its expensive, i almost felt 'guilty' everytime I hit it.

Im now running a blower setup and like this way better. The blower's torque curve increases towards redline. Max power is hit at redline now making the thing just a thrill to drive.

What I envision is using nitrous for starting power off the line and having it shut down by 4000 RPM, then the blower purely takes over.

Who knows if the stock bottom end could stand that?

 

Besides the THOROUGH informative post above, the best/straightest advice I recall on the subject was:

Stay with 50lb boost if pistons are cast, --or--
100lb boost if pistons are forged.

The advice above was present for (conservative) safety concerns vs how to make max power.

From the movie "Gone In 60 Seconds", I agree NOS is cool. In practical terms, my opinion is different. The couple of times I've seen a vette with a tank (in the back), I've said to myself "What at PITA!". Losing all the room and paying for a shot each time has gotta to suck. Plus, think about the increase in odds of someone wanting to smash/grab your tank.

I decided to go another route because of that.

 

Its not a corvette, but on my mustang I had a 125 shot on a stock motor, stock fuel pump everything. Any higher and I wouldve had to change things. But the motor STILL runs strong.

 

If the engine is built well and you take good care of it otherwise, theres nothing wrong with nitrous addition.

A stock 85 with lower miles that had been maintained and had the fuel and ignition system checked out regularly should be fine with up to a 100 shot. You have a forged bottom end in 1985. I think it will be fine.

Personally, and I'm not a big proponent of juice, I would not run that much unless I had the engine rebuilt and blueprinted, just because of age, but 50-75 I wouldnt hesitate to run.

 

Well Speaking as one of the "old guys who remember when Nitrous first came out.. hes right.. we blew stuff up left and right.. we were learning.

An official "back in the day" story..73 pinto with mostly (we built these for formula ford racing) stock 2300cc and manual tranny and a Horrendous amount of nitrous and fuel. ran a 13.40 at 5300' ft above sea level in denver.. that would be like a 12.40 at sea level, we ran it for a few weeks then pulled it apart and did rings and bearings..and went back out and did it again. we tore up the clutch broke the bellhousing countless times and grenaded rear ends.. we did burn up our share of pistons and valves, but not as bad as you might think

Get a quality wet kit with limit switches..and resist the urge to beat on it at every opportunity..(good luck with the last one).

Now having said all that, do I own anything with nitrous on it now? Nope.. and I havent for years now. but I did laugh all the way thru the fast and the furious if that counts.

 

Mine was a dry kit, just FYI

 

I ran 100 shots on stock 1.6 liter Honda motors...if a Chevy V8 can't handle it there's something SERIOUSLY wrong.

My advice is simple:

1. Ensure proper installation
2. 2 degress of retard per 50 shot. I saw the guy above that had no timing retard....I wouldn't do it personally. You'll get away with that more on a v8 because your essentially dividing the shot into more cylinders therefore it's less volatile of a mixture. In a 4cyl, if you ran a 100 shot with no timing retard, the motor would go bye bye.
3. Avoid the rev limiter
4. Don't do extended pulls (like from a dig to 165mph). 1/4 mile length and that's it. Anything more and the pistons will potentially struggle with heat buildup and possibly fail.
5. Use a wot switch not some "press here" button like the movies. You want to ensure your at 100% wot when spraying.
6. Avoid spraying at too low of an rpm


To clarify something above, nitrous sprays 100% therefore the longer your valves are open, the longer the opportunity to ingest nitrous oxide. This is the reasoning behind "torque in a bottle" versus "horsepower in a bottle". Cylinder fill will occur more at lower rpm than high, though you can use nitrous controllers which will slowly modulate the solenoid like an injector and spray an increasing shot vs. rpm. This would feel much more like a turbo or centrifugal blower style of power delivery.

 

I have probably run more that 100 bottles thru my car sparying a 200 shot, on pump gas, and never hurt anything.I recently added a secondary fuel system for the NOS, and can up the octane when spraying to prevent pre-detonation. For a small shot like a 100 shot, it is really is nothing! I personally don't think you need to change anything. Run full timing on pump gas, and the fuel pump should be able to keep up (on a stock motor). But running bigger doseages, pulling timing, and making sure the fuel system is up to par is important. You need to make sure the fuel pump will be able to support the hp of the engine, plus the hp of the nos added to that. Fuel and timing problems are what gives NOS a bad name. But it is up to the installer/tuner to make sure everything is good. Like I say I have probably run over 100 bottles thru my car, and everything is perfect, and never hurt anything!

And the instant torque is what is amazing. Everybody talks about the hp added, but the tq is even greater. A 100 shot will probably add about 175 ft/lbs TQ. A 200 shot on my car added 330 ft/lbs TQ to the tires. That is what you really feel. And there is no waiting for it to ramp up. It's game on! Instant power!

 

the reason i ran no timing retard w/ 100 shot nitrous was because the MSD digital 6 plus box I bought was a piece of crap that malfunctioned constantly - stopping the car on the highway a couple times. (That MSD box had a retard feature that I used when spraying nitrous.)
I called the techs at NX and they told me that with their kit you didnt need retard because it was so well designed. When I asked them to elaborate they said that their nozzle 'atomizes' the fuel and nitrous mixture better.

All this said, I would use timing retard (and a bigger fuel pump) for shots above 100 if I were to do it again.

Again, everything ran without a hitch everytime on the stock bottom end motor. Dyno runs, drag runs, on-ramps....etc. I never tried to top end it on nitrous. Id typically get it to 120 MPH and shut it down...

Thats a good point about how you only want to spray it WOT. If your not at WOT, that can be very dangerous because you dont have all the fuel you need. If you really want that little button, NX shows a WOT throttle switch that must be tripped first then a button you can press to activate the system.

oh yeah, and colder spark plugs. I ran NGK TR6's.

 

My #1 Post of the week. Great info on NOS...Thanks

 

Ive probably ran 50 bottles thru my basically stock 86 engine that has over 100k miles on it. This is my setup :

NOS plate wet injector that goes between the throttle body and intake plenum (comes with a relocation kit for your linkage).
WOT switch (I bought a bracket that would fit the L98, but didn't because it hit the neck of the water return on the top of the engine but if you mount the bracket upside down, it still works and clears the neck.)
NOS brand fuel and nitrous solenoids
NX 10 lbs tank
Harris Speed Works purge solenoid
Dynotune bottle heater w/ fittings for the pressure switch
Switches from Radio Shack for the Arm and Purge
Wiring from radioshack, and Relays/fuses from Autozone
3000 psi pressure gauge from AirHydroPower (local industrial shop)

all together it was about $500, filling it is $50 a pop and I usually use it all up on a test and tune night at the track. I did not retard the timing at all.

I started out with a 50 shot, then switched to a 100 shot...thats when the bad things happened. I have slicks on my car, so it hooks pretty well. Well, that was the end of my 700r4 after about three runs down the track with a 100 shot. I was able to get it home, but the tranny was toast.

I ended up getting a built turbo 350 tranny with a 3000 stall in it. On pump gas, does 8 flat on the 1/8th mile track. Fun as hell!

http://www.youtube.com/watch?v=cps2e...eature=related

 

Good info, I have been pondering a wet setup to play with and was wondering how it was injected. This would be the first power adder I have played with. I figured it made sense to go behind the TB.

Do they have a rev limiter kit to prevent spraying while hitting the rev limiter?

 

That's the function of a window switch...

Here's some reading for you: http://advancedautocc.com/page--Nitr...formation.html

 

very informative, thank you.

Can anyone recommend a kit for the LT1?

 

I don't like nitrous because I consider it too expensive for my liking. I don't feel I have maxed out my motor yet so I will not consider it.

I like to romp on my motor so if I use it every time, say 3 or 4 times a day, it will get expensive fast.

So, IMO, it is cheap only if you don't consider the long term cost

 

85's were 9.0:1 and had forged pistons. Unless your motor is not stock

 

$500 give or take for a hundred HP? And, it's on demand........not used all the time

 

That is what has always kept me from it. The initial price, plus the %50 fillups, quickly add up to major mods, or even an SC over time. Then you can stomp all day for no pay.