looking into nitro

Sorry if this is a stupid question, but I'm looking into running 20% nitro in my blown injected bbc. I've been doing some research and cant find a definite answer on this. I see it with running more % but just wondering if its required on 20%. thanks.

 

Here's a good place to start...
http://www.fuelinjectionent.com/nitro_new.php

 

Yea I seen that page, but it wasn’t specific on the percentages. I’m looking for when it’s too dangerous and you need to start with a different fuel.

 

Theres alot to it. That link he posted above is a good read and does talk about percentages around 10 to 20%. Spud is great to talk to about this topic.
We have run 15% and it worked. I now run in the 90% range.

 

I've read through it a couple times now. When you were running 15%, did you start it on that or a differ fuel?

 

Started on 10% if i remember correctly. And if you mean starting it with a primer, we use alcohol.

 

Here's what you need to consider. As you add nitro, you are adding oxygen (nitro carries 2 oxygens, methanol carries 1 oxygen). By adding nitro % and leaving everything else the same (jetting/compression) you are effectively leaning out your mixture. It will run better to a point; that point is detonation/too lean. The heating value of nitro is less than that of methanol so as you add % (leaving everything else the same) you are also slightly lowering your power available. Seems counter intuitive doesn't it. The power gained by a leaner mixture (heat) is greater than the power lost by less heating value, hence the slightly increased power. In order to effectively gain even more, you must richen the fuel system so you can burn more fuel (at the correct A/F ratio with the added oxygen the nitro % brings). The more fuel you burn, the less room in the chamber there is so ultimately you will need to lower compression as the nitro % goes up. It comes down to the proper balance of fuel %/jetting/compression/timing. Small amounts won't hurt. Make a % change, run it, reassess, adjust, run it again. Or find someone doing EXACTLY what you want to do (and doing it successfully) and copy what they are doing.

 

I have run my injected aka not nlown Hemi at 30% and actually had to lean motor a little bit. Et dropped .27 with 30 and would have probably dropped more except my stall went up about 600 rpm. I am thinking that as you add you need tighter converter bec ause of increased TQ. Looking into bolt together converter for just that reason.

As far as safe amount before firing off another source I can not really say.Due to working with A/Fuel car and hearing half dozen stories of little nitro in cylinder or bolt hole causing big problem .I just start off primer system on alky and turn nitro on after running. I also blow lines out after run.Just habit and probably not needed.

 

Biggest challange to nitro is stopping the percentage.Once you try it you will want more.

 

Dumb question. What happens if you inject a small amount of nitro through seperate nozzles along side a alcohol or gas system instead of mixing with the base fuel?

 

Unless you have super accurate nozzling, you will have an uneven mixture cylinder to cylinder which will cause bad things to happen as the oxygen content per cylinder will be uneven. Mixing with the base fuel gives you even oxygen distribution across the mixture.

 

In a NA application has anyone tried seperate nitro injection or in other wards using similar to NOS?

 

I'm not sure, maybe. Seems like a lot of work to have a complete separate system just to inject nitro. It's much easier just to mix the fuel and use a singular delivery system. If nitrous could be handled easily in liquid form, I'm sure they would just mix it in instead.

 

It was the end of the season and some stink and thunder was deemed the order of the day.

FED injected alky w 4 stages n2o/alky. Ran 20% without giving a whole lot of thought to the mix.
It was impressive and way cool for about 700 ft until the flames went up about another 6 inches and turned green. uh oh.
As I prepared to click it an oil leak out the manifold ensued and fed the headers. Lit it and me up.
Clicked it and it went out. whew. Elvis was nearby.

Autopsy. 8 pistons, 6 broken and/or bent pins which took out the rod ends. Fortunately it didn't ventilate the block.
Anyway, the fuse is short and tricky with the bottle involved. Too much oxygen. Tread carefully.

Note: If you want to play with it, leave the nitrous off. Once you get into nitro you may find you don't need the bottle. By then you are addicted. Seek counsel.

 

Tuest statment so far. Nitro is addictive like drugs. You start out small and if not carefull you endup on 95% and craving your next fix.

 

You are likely on a safe tune. 20% will require no changes in your tune. Depending on your setup it might be a bit aggressive at the hit. Some will say richen it up but remember that also adds more nitro volume.
I would make the change on a day where you and your tune are familiar with current weather conditions.

 

20% a waist of time..if it's not a nitro deal leave it out of the equation all you will do is confuse the motor..went we went to nitro we started at 85% now run between 88 and 95

 

Look into airdensityonline .lots of good info there and the guy is very helpful. Very accurate calculator and informative books also. Not free but not super expensive.

 

I think there is one important point not being discussed here.

"Molar Expansion".......

When reactants are brought together, and a chemical process is triggered (could be combustion OR conversion), those reactants dissociate into products. This causes not only heat, but also increased volume of gasses, or molar expansion, through the resultant products.

The molar expansion of nitromethane is 3 times that of methanol (roughly).

Manage your heat, make sure your engine is strong enough, and manage your cylinder pressures.

Oh, and run more nitromethane !

 

Yes, and it works very well !......

What this allows you to do is launch on your base fuel, and then roll in/out the nitro as needed. The problem with mixing the nitro in the same tank as your base fuel is that you are tied to a fixed % mixture all the time.

Why do you say "small amount" ? Think BIG.

There are different ways to accomplish this depending upon MFI or EFI. Hint, NOS nozzles are compact, dual channel, and discharge at one point.