Messin" with dope

I first got involved with dope when I was about 10 at the Minnesota fair grounds.. I was with two guys who had an older Offy 270 powered sprint car.. By then the small block Chevy's pretty well dominated the big main events..

Imagine dirt flying 20+ feet high and more than 50 feet off the knobby back tires of a sprint car. The smell of Castor oil and the deep bark of an Offy compared to the roar of the Chevy's. Life doesn't get much better for a serious gear head..

To be competitive they pulled the pill and with an hand cranked drill bored out the jet, The hood came off and timing was changed on the magneto to some mark on the block. Then some Nitromethane was added,... maybe a 1/2 gallon or so? to the nearly full tank. With that the car buttoned up while the driver stepped into the seat and sat down.. No seatbelts back then.. Of course there were a lot of one armed former drivers working as mechanics. On a regular basis the newspapers splashed the death of some poor racer in the sports section...

The push truck shoved off the sprint car tires dragging. As they eventually started turning the engine over, first the fuel valve was opened up followed by the ignition switch on and a moment later the car sprinted away while the push truck went to start the next guy..

Anyway I want to mess with a little nitro. I'm not ready to rebuild the motor every 1/4 mile so it won't be the 90%+ the dragsters are using but maybe 2%, 5%?

But what to do about mixture?? How much richer? Will Nitro mix with ethanol or am I condemned to use methanol? What about timing? Spark plug heat range?

Where can I go for such information?

Im interested in this discussion.....

Cause i could have the first nitro challenge car!!!!

To The InterWeBB and Beyond!!!!!

Isn't nitro about $100 a gallon?

I am very interested. I looked into this a while ago, but found only hearsay.

Something something nitro adds its own oxygen. Something something, richer doesn't always mean richer... something something lean is death. something something.

Basically it looks like you have to find a first-hand drag racer who has done it, because they probably paved the way with broken blocks. A nitro engine with a turbo should be able to basically make as much power as you want before things break though, so I can understand the draw.

$1068.00 per 55 gallon drum from VP fuels

759NRNG wrote: $1068.00 per 55 gallon drum from VP fuels

Fuel doesn't count towards the GRM budget. That's only $19 per gallon!

tuna55 wrote:

759NRNG wrote: $1068.00 per 55 gallon drum from VP fuels

Fuel doesn't count towards the GRM budget. That's only $19 per gallon!

Sooo if it is $19 per gal when you buy 55, would it be fair to say it would likely cost you $30 for a single gal (if you know someone who would sell it).

Slightly on this subject.......... back when I owned my 1970 1800E, I could get different kinds of race fuel, or av gas. I do remember getting "Blue Thunder" (106 octane leaded) and mix a gal in with the super unleaded and the engine did run a bit better/stronger.

But don't you have to pay for nitrous refills in challenge? It would seem to be same difference with nitromethane..

Ovid_and_Flem wrote: But don't you have to pay for nitrous refills in challenge? It would seem to be same difference with nitromethane..

No they do not, and it's most certainly not the same thing anyway.

http://www.grmchallenge.com/rules/

Ovid_and_Flem wrote: But don't you have to pay for nitrous refills in challenge? It would seem to be same difference with nitromethane..

I think (didn't check rules, so shooting from hip here) opposite. You do have to pay for the tank with budget, but not the 'fluid'.

There's a reason I don't mess with laughing gas. LOL

Don't some model airplane motors run with a nitro mix?

Probably not the cheapest way to get it in quantity.

aircooled wrote: Don't some model airplane motors run with a nitro mix? Probably not the cheapest way to get it in quantity.

Typically 15% Nitro about 25$ a gallon for it. It has a ton of lubricant in it as well though. Like 20% of the total weight is lubricant.

So... good for a rotary then.

Most of the model engines are 2 strokes, so that does make sense.

tuna55 wrote: I am very interested. I looked into this a while ago, but found only hearsay. Something something nitro adds its own oxygen. Something something, richer doesn't always mean richer... something something lean is death. something something. Basically it looks like you have to find a first-hand drag racer who has done it, because they probably paved the way with broken blocks. A nitro engine with a turbo should be able to basically make as much power as you want before things break though, so I can understand the draw.

That's exactly where I'm at. Years ago I tried the same thing and everybody seemed to have a little knowledge which might or might not be wrong.. Last time I talked to a top fuel guy he knew nothing about fueling an engine that wouldn't self destruct or be on the edge of self destruction..

I know the unlimited hydro boys played with it in the 70's and 80's but that was on Rolls Royce Merlin or Allison's..

If I buy a gallon or two it won't break the bank.

I would also say that if GRM staff is smart they would disallow it as the exhaust gases contain an acid with the following warning:

Exhaust gas from an internal combustion engine whose fuel includes nitromethane will contain nitric acid vapour, which is corrosive, and when inhaled causes a muscular reaction making it impossible to breathe. People exposed to it should wear a gas mask.

Funny fuels are a fast path down a slippery slope. Many avenues to more power exist, but many of them are dangerous.

Stick to Nitrous.

If you cant be dissuaded

Heywood Text

May have the math and solid backing you are looking for. I can dive into my copy in a few days looking.

Hope you took a course in Differential Equations though...

Wikipedia has a good section on it. Wiki

Do basically, you need to figure out the percentage you want to run based on the properities (not so much it breaks the engine) and use the math to get the right air/fuel ratios/etc.

You would still not be fully optimized, but that is unlikely to happen on a challenge budget.

(edited; because Dr. Strange points out that warnings should come before how to do it...)

Joe's right; nitromethane's combustion gasses are highly toxic and corrosive. Don't the top fuel guys actually have helmets with built-in filtration for that reason? Those things look like something from a Fallout video game.

Sky_Render wrote: Joe's right; nitromethane's combustion gasses are highly toxic and corrosive. Don't the top fuel guys actually have helmets with built-in filtration for that reason? Those things look like something from a *Fallout* video game.

The drivers do not, the crew people wear respirators.

I ran 40%-60% nitromethane in radio controlled race boats for 10 years. It is not a good fuel for longevity of engine components. We would rebuild engines annually at a minimum because of the corrosive nature of the fuel and the ridiculous RPMs we were running.

Another issue I foresee in full scale, is the sheer amount of fuel that will be needed to feed a large engine. nitromethane does release oxygen as it burns. It's a viscous circle, the more fuel you need, the more oxygen that is available. That makes chasing carburetor settings a little tricky.

Also, the higher percentage you use, the more finicky jetting gets. We would start the morning with one needle setting, and by afternoon be upwards of a full turn different. To say the least, twisting a needle is a lot simpler than rejetting a carburetor because a storm dropped the temps by 20 degrees.

It would be interesting to see how a modern EFI system would handle it. Maybe it would add fuel as necessary.

tuna55 wrote:

Sky_Render wrote: Joe's right; nitromethane's combustion gasses are highly toxic and corrosive. Don't the top fuel guys actually have helmets with built-in filtration for that reason? Those things look like something from a *Fallout* video game.

The drivers do not, the crew people wear respirators.

Do the drivers not use this type of helmet anymore?

Sky_Render wrote:

tuna55 wrote:

Sky_Render wrote: Joe's right; nitromethane's combustion gasses are highly toxic and corrosive. Don't the top fuel guys actually have helmets with built-in filtration for that reason? Those things look like something from a *Fallout* video game.

The drivers do not, the crew people wear respirators.

Do the drivers not use this type of helmet anymore?

I though it got a lot more difficult to purchase after OKC went up 20 years ago.

Dr. Hess wrote: I though it got a lot more difficult to purchase after OKC went up 20 years ago.

I don't think so, although I expected that.

The memorial they have in OKC is really pretty touching, FWIW.

aircooled wrote: So... good for a rotary then. Most of the model engines are 2 strokes, so that does make sense.

Before I knew anything about cars, I had an '80 RX7. I worked at a hobby shop and dabbled in RC boats, at that time. One day, I ran out of gas, about a mile from the station. I had my boat box in the car...

It went like stink. Emphasis on "stink". But it ran like a scalded cat, too.