New Guy Nitrous ??? - Page 3 - Chevelle Tech
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post #31 of 33 (permalink) Old Apr 26th, 19, 9:32 PM Thread Starter
Join Date: Jun 2018
Posts: 24
Re: New Guy Nitrous ???

Originally Posted by ddeennis View Post
Keep it simple.

I have ran nitrous for over 5 years on the street and well into the 10's with it.

Some real world key points:

The kits ( standard 125 plate deal) are designed for 4.5 psi fuel pressure minimum, when you hear folks jetting down fuel side that's because there fuel pressure is higher than what the kits was designed for and this was a factory protection built in. they assume the worst customer just bolting in a kit with stock style fuel system- after all most give you a "t" to cut into your fuel system.

It is really best not to purge, really need to ignore these folks, you do not want the nitrous to beat the fuel to the intake manifold- that is just plain stupid. Purging is really for the high output systems that have super higher fuel pressures and these guys have their zhit together. They have a specific system. The basic kits do not need these purge kits.

A basic system you want that protection of the fuel to get there first. So just don't buy into the purge kit yet.

I ran for over 5 years with no heater, little common sense goes a long ways. Best performance at 900- 950 psi. to cold let the sun soak on it heats right up or even a heat lamp. I normally had issues keeping it cool. using ice to cool the bottle, or running cold water from a hose over it before I staged.

If nitrous gets to high in bottle pressure it turns to a hot air and it won't make you go faster it will just buck and kick down the drag strip, you will run super rich, the higher you get away from 950 psi your nitrous starts to degrade. Of course to cold and the bottle pressure to low, you won't flow enough nitrous and run to rich and bog.

typical 10 lbs bottle you get about 6 passes. you will never use all the nitrous normally couple lbs left you can never use.

I would do my burnout and I would do a dry hop with the nitrous, active nitrous above 3000 rpm and full throttle. I did this to make sure all was well. Pull up to the line bring my rpm up to 3000 and when the second amber came on hit the nitrous and floored it at the same time.

125 kit took a 14.99 car to 12.69, 175 kit took a 12.19 car to 10.80 using this method.

I ran 1/2 inch fuel line from tank pickup to holley mechanical fuel pump. 3/8 " line to a fuel regulator and one side went to 850 double pumper and the other side went to fuel side of the nitrous kit. I set fuel pressure at 7 psi at wot and when the nitrous kit was activated with a push button the fuel pressure would drop to 6 psi wot.

I had a fuel pressure gauge I could read at all times just outside my windshield.

during the 125 to 175 hp usage I ran same stock plugs with projected tips, I would run 6 degrees timing less from 36 to 30 total.

I did make a run on 150 hp jets with 36 total timing and it did chip some of the porcelain on the plugs. I did make a run on full timing on 125 jets and didn't hurt a thing.

At some point you do want to read plugs and understand whats going on, I never hurt my car or blow anything up, biggest key to all of this is to have fuel pressure. You can be off on the timing some and not have a carb totally dialed in as long as you got good fuel pressure.

After 125 hp the 150 and 175 came real quick, nitrous is to easy once you get it installed, I would spend money all on fuel line, fuel pump and fuel pressure gauges and make sure you have a gauge on the bottle. All that "extra crap" can wait spend money on the fuel side of things first.

I tried a few micro switches but they was short lived, they would burn up. I just always went back to the blue push button the nitrous kit came with.

Another tip, shift lower rpm and you will go faster, my bbc ran best at 7200 rpm for best e.t. and mph naturally aspirated, nitrous did best at 5500 rpm. So shift lower rpm or at least play with your shift points.

My experience - never broke anything because of nitrous.
Thanks Dennis great read.
So don't know where I got the idea that the fuel supply was 5/16 IT IS NOT. It is 3/8 line from stock gas tank.
Every thing that you are saying above is in line with my research from manufacturers..
I am not looking to get to greedy here. I know that the temptation can become irresistible to some but I think I can stay on task here.
Really appreciate your put here thanks Again..
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post #32 of 33 (permalink) Old Apr 26th, 19, 9:54 PM Thread Starter
Join Date: Jun 2018
Posts: 24
Re: New Guy Nitrous ???

Do I am getting some great information here. Would dome one walk me thru some street car use procedures.
So you would you want to have the bottle turned off during normal street car cruising?
And if you wanted to do a run with the nitrous included would you simply pull over, go to the bottle turn it on, turn on power supply switch, check fuel pressure gage, and if all is good then say run the car up to 3000 rpm bump the button once or twice? Then at this point you would be in line to make a run by hitting the button at the same time as matting the pedal? Or even to stay on the safe side hit the button at the same time as shifting into second gear? Does this sound right?
Then what about from there?
If you want to curise some more on the street what then? Turn off power switch, Do you have to pull over and shout of the bottle again? Anything special to make sure no nitrous gets to motor at low rpm?
Do you really have to keep bottle turned off when not in use or just make sure power supply switch is off?
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post #33 of 33 (permalink) Old Apr 26th, 19, 11:25 PM
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Re: New Guy Nitrous ???

Originally Posted by ddeennis View Post
The kits ( standard 125 plate deal) are designed for 4.5 psi fuel pressure minimum, when you hear folks jetting down fuel side that's because there fuel pressure is higher than what the kits was designed for and this was a factory protection built in.
Fuel and nitrous pressure affect the tune which is why I asked at least twice now what kit he is looking at. Different manufacturers and different kits are calibrated differently. The NOS Big Shot plate is calibrated for 6PSI fuel. Twenty years ago the factory tunes from NOS had a larger fuel jet than nitrous jet. Then they squared them up and now the fuel jet is smaller than the nitrous jet. Thoughts on timing have also changed during that time. The old 2 degrees per 50HP is not the way to time an engine on nitrous.
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