Nitrous Oxide with Methanol

[Alky V6]

I thought I would post this realization I recently had.

Using nitrous with methanol can net more or less power depending greatly on the temperature of the mixture during the compression cycle. Nitrous oxide used together with methanol yields a super cool intake charge. Since nitrous oxide must reach a certain temperature before it will dissociate into oxygen and nitrogen so that the oxygen can be used to burn fuel, if during the compression stroke some of the nitrous oxide has not dissociated, it will dissociate during the combustion process. Since the dissociation in itself absorbs heat, some of the combustion process heat will be absorbed affecting the resulting power level. The same holds true for the methanol fuel. There must be enough heat during the compression stroke to vaporize the methanol before the spark ignition event. I had read that some that had used methanol with nitrous experienced a horsepower level of about half of what the system was rated at, so I went with that assumption. I created a port injected nitrous system with a rating of 190 horsepower using the nitrous oxide jets as a reference. I have found that less than traditional ignition retard, while the nitrous system is activated, will have a great affect on the resulting power level. Possibly caused by creating more heat during the combustion process to overcome the heat lost by some of the nitrous oxide that is still dissociating during the combustion process.

 

[jwillettgn]

Thanks Don, good info. My son had been wondering about this effect and thinking about not using an intercooler, thus having less restriction in the intake track. We will be running methanol one day as that is the direction my son wants to go.



Jim

 

[Alky V6]

Thanks Don, good info. My son had been wondering about this effect and thinking about not using an intercooler, thus having less restriction in the intake track. We will be running methanol one day as that is the direction my son wants to go.



Jim

You bring up another point that is not well understood. Aftercoolers and methanol.

Aftercoolers have the same affect on a turbocharged engine running on methanol as it does on the same engine running on gasoline. That is, it cools the intake charge which 1) makes for a denser air/fuel charge, creating better volumetric efficiency and hence power, 2) moves the mixture further from detonation/preignition limits, allowing more static CR and/or more boost, hence again, more power.

The reason you commonly don't see aftercoolers on some sanctioned racing venues that burn methanol is because aftercoolers aren't allowed in the rules, or the boost level is controlled by the rules to such a low level that aftercooling isn't necessary. This is something I just recently learned myself.

 

[BillyRValentine]

Been doing it for years now both with and without turbos. I believe that the reason this path hasn't been more widely used is because of the limitations put on turbos by organized racing. I have built my own N2O systems with alchy injection instead of fuel. One would be amazed at the amount of timing that can be run on PUMP GAS and a 200 shot at 10.5:1 compression and only 221@.050 of duration in 346-c.i. (Stock heads, LS6 intake) I also ran a system I built on both of my turbo Buicks with great results. The one I am building now for the LS1 turbo project will use one of Julio's kits and a 150-shot with my FJO controller to spool and cool the 88-mm turbo. The compression on it is 9.5:1 with a camshaft that is 218/214@.050 and again a stock LS6 intake. I went through several intakes before I found the timing limitations. I don't like all of the classroom engineering arguements so I stopped posting any of the results years ago but will say this - 8 years ago I was able to go 11.16@126 on a BFG 275/60-15 radial. That's right a touring radial not a drag radial. There were several witnesses to this that still remember it to this day. There were other key factors involved but at the time I was doing allot of street racing and had the car set up to run as I drove it day to day. I believe it would have went 10's but I picked up false knock on one of the shifts and started to lift when I realized what it was. I got back in it and the time above was the result. I sold the motor that night after returning to the pits to a local here (David Tibbs) and built a twin turbo 406-sbc. On slicks the car did run 10.52 leaving at 2 lbs and rolling into it. I believe that it would have went faster had I left on the trans brake but at the time I was still fiddling with it. I have run 10.79@127 in my LS1 on pump gas and a 200 shot with the tranny slipping. I am setting up another one with my old setup and will see what we can get out of the factory long block on a 200 shot and alchy soon.

Jim C.

 

[Alky V6]

If people gain a better understanding of using methanol and nitrous together, I'm sure we'll start to see more people doing their own experiments with it. In my opinion, it's much safer than using nitrous with gasoline. The usable mixture tuning range is so much broader with methanol which would help keep some out of trouble. In fact, a person new to nitrous would be better off using methanol than gasoline if their afraid of burning down their engine.

Nitrous/Methanol factoid:
Start with a nitrous to methanol ratio of 2.4 to one. This ratio is very safe.

Jim C. Are your systems port injection systems or single nozzle?

 

[BillyRValentine]

Jim C. Are your systems port injection systems or single nozzle?

They have been both on the turbo setups, controlable progression is the key in my opinion and the tunablilty only gets better the further along the digital technology comes. The LS1 system is actually a plate system with an alchy solenoid, electric pump and 1 gallon tank. Take care.

Jim C.

 

[Dust]

Really would like to hear more about you experience with this stuff, and why you think it's safer to run methanol than gas with N20.

 

[bobc455]

They have been both on the turbo setups, controllable progression is the key in my opinion and the tunablilty only gets better the further along the digital technology comes.

True to a point, but with the sluggish solenoids that most US suppliers use the digital technology can only get you so far.

What are you using for solenoids?

-BC

 

[BillyRValentine]

Really would like to hear more about you experience with this stuff, and why you think it's safer to run methanol than gas with N20.

Be glad to answer any questions you have to the best of my ability. I do believe it is easier, safer and better to use the alchy with N20.

Jim C.

 

[BillyRValentine]

True to a point, but with the sluggish solenoids that most US suppliers use the digital technology can only get you so far.

What are you using for solenoids?

-BC

I prefer the NX solenoids.

Jim C.

 

[Alky V6]

If anyone is truly interested in pulsing solenoids, you need to check out the Wizards of Nitrous site. They are the state of the art at present, and with the development work they're doing, they'll probably stay there. You just don't see any radically new solenoid designs here in the U.S. They're pretty much all the same.

I'm using NOS solenoids. For the fuel side, the Alky solenoid. As long as you stay away from pulsing, you're pretty safe.

Some of the many reasons why it is much safer to run methanol than gasoline with nitrous is the superior cooling effect the fuel has. Due to its high latent heat of vaporization value, it cools the charge as it vaporizes during the compression stroke, and during the cumbustion process if some hasn't vaporized by that point. This cooling value is very much higher than it is with gasoline. This property can actually be detrimental to power output if too much hasn't vaporized by the ignition cycle. The vaporization during the combustion cylce will tend to quench the heat of combustion lowering power output. This is probably the main reason why you need to jet larger to get the equivalent power output as you would with gasoline. Some may look at this as a bad property of using methanol with nitrous. I look at it as one of the tuning safety blankets available to you with burning methanol instead of gasoline.

Of course, as with gasoline, if your mixture is too lean, you will have some melted aluminum to deal with, if not worse. This just brings up another of the wonderful things about burning methanol.

The tuning range or window for gasoline is very narrow when compared to methanol. When you go to the track with gasoline, you'd better adjust for weather. Once you've found the midpoint of your tuning window with methanol, don't worry about it. Let the other guys play with their jets.

I have learned that the tuning window or range for gasoline is 10% a/f ratio for max power. Where as methanol is 30%. You can actually go so rich with methanol that it starts pouring out the exhaust, and you don't have to worry about fouling plugs! We all know the story with gasoline. Another thing. That 30% range? There is not much of a power difference throughout much of that range. So you can do a 'close enough for government tune' and end up with a decent run.

Methanol is a beautiful racing fuel. One of the main reasons it took me so long to get this project tuned in was because I didn't realize just how broad the tuning range of this fuel was. At the beginning, particularly with the first engine, I always stayed at the dangerously lean edge of the range. After a few blown engines, I started going richer, which was safer. Then I went richer, and richer, and richer, and richer, etc... It was amazing how after a point I could keep going richer with practically the same power level. Of course, I backed it off after discovering how much the oil would contaminate with the super rich mixtures.

When you run methanol in the super rich ranges, as in the case of top alcohol cars, the high latent heat of vaporization value allows the fuel to be run in conditions that would require a fuel octane of between 125 to 130+. How much is that import VP fuel?

 

[Alky V6]

An interesting point about my tuning experience with methanol. Although it has taken quite a bit of time for me to find a safe a/f ratio for the engine fuel system in general, with the nitrous/methanol injection system, I have yet to make a jetting adjustment to the nitrous system after I've done the initial math to come up with the initial nitrous and fuel jet sizes. That's a testament to the wide tuning range that methanol posseses. Granted the math was done to come up with a nitrous/methanol mixture that was plenty on the safe side.