about a Nitro cackle engine

[nitro2]

I won't disagree with that summary, as the quantity of nitro that can be put into a cylinder and fired off effectively is not limited by the air fuel ratio as it is with other fuels.

However, when one talks nitro, everyone automatically thinks "blown TF car". But, a blown TF car is just a very extreme and very short lived example of what can be done with nitro at the outer limits.

NA nitro engines are a different beast. Peak cylinder pressure on a 5x power NA nitro engine can easily be made to be less than peak cylinder pressure on a high boost methanol engine.

The only way to know the pressure is to measure it and the cool thing with nitro is that once you measure the combustion pressure in the cylinder you can shape/mold the combustion process pretty much like you can on a turbo diesel engine. Instead of the combustion pressure rising to peak pressure and going back down quickly, you can tailor it so that you never exceed a pre-determined peak pressure and have the combustion pressure maintained near peak pressure for many degrees of crank rotation down the power stroke. This makes for a lot more power without ever having excessive peak pressures, and is very reliable.

What tends to bite nitro engine owners hard and keeps everyone scared of blowing things up on nitro should they experiment, is this. A well tuned boosted methanol engine will only make a modest amount more peak pressure (ballpark 20%) if it was improperly tuned (assuming no detonation or pre-ignition) than when it is properly tuned, whereas with a nitro engine this is absolutely not the case. A powerful NA nitro engine can be running at 3500 psi peak pressure, or 5000 psi peak, or 8000 psi peak, or be blown to bits at some even more astronomical peak pressure. All 4 scenarios can be had putting the same amount of fuel into the engine and there is no great difference in power because power is primarily tied to nitro quantity, but peak pressure is primarily tied to HOW the nitro burns in the cylinder. How the nitro burns is dependent on many things. It can even change drastically with modest changes in engine speed (something that is not common knowledge I suppose).

Changing the how the burn happens in a nitro engine, or turbo diesel engine, or very high boost conventional fueled engine, is the way towards adding more nitro, or more boost without getting into reliability issues. Peak combustion pressure is never allowed (at any point in the race) to exceed what the engine will take, or what the owner thinks the engine will take.

[Dave Koehler]

I could be wrong but I think your last sentence is the same thinking as when we teach nitrous oxide users NOT to turn it on below WOT.

[nitro2]

I could be wrong but I think your last sentence is the same thinking as when we teach nitrous oxide users NOT to turn it on below WOT.

Most nitro engines are operating on nitro the whole time not just at WOT. They only start them up on methanol.

Depending on the answers to my questions about Bonneville, I was going to suggest running a set up whereby the nitro was used for only part of the run, not the entire run. Perhaps they already do that.

[Belgian1979]

A question came up with what was written. Maybe a dumb question but here goes : how do you control the burn of a nitro charge. I don't know much of a nigfo engine but unless like a turbo diesel engine where you would directly inject into the cylinder in several injection events, I do not see how you could spread that burn in an engine that gets its fuel in the intake tract.

[nitro2]

A question came up with what was written. Maybe a dumb question but here goes : how do you control the burn of a nitro charge. I don't know much of a nigfo engine but unless like a turbo diesel engine where you would directly inject into the cylinder in several injection events, I do not see how you could spread that burn in an engine that gets its fuel in the intake tract.

Nitro is a peculiar fuel in practically every aspect, and the way it burns is dictated by several things. You don't have to control how the nitro gets into the engine in order to adjust the burn, whereas on a turbo diesel controlling the injection is one of the main ways, (but not the only way), to control how the burn proceeds. At the end of the day the burn can be readily tailored in both types of engines, but by different mechanisms.

[Truckedup]

I'm not familiar with the rules at Bonneville, the "3 miles" you mentioned I presume that is the distance between take off and shut down or are you saying they are going 185 mph for 3 miles i.e. 185 mph for about 60 seconds?

The short track is 3 miles from start to finish...Considering traction problems, that means the engine is full throttle for perhaps 2-1/2 miles...reliable running of these old 1930's technology turds with 90 degree valve angles and deep hemi chambers with marginal air cooling using a lot of one off parts is no easy task...

[nitro2]

I'm not familiar with the rules at Bonneville, the "3 miles" you mentioned I presume that is the distance between take off and shut down or are you saying they are going 185 mph for 3 miles i.e. 185 mph for about 60 seconds?

The short track is 3 miles from start to finish...Considering traction problems, that means the engine is full throttle for perhaps 2-1/2 miles...reliable running of these old 1930's technology turds with 90 degree valve angles and deep hemi chambers with marginal air cooling using a lot of one off parts is no easy task...

The thing about nitro is that it is not concerned about technology. Nitro can be used successfully in anything that has a spark plug, assuming appropriate mods. What sort of displacement/power(gas)/peak revs are we talking about? Same peak revs on nitro?

[Truckedup]

The thing about nitro is that it is not concerned about technology. Nitro can be used successfully in anything that has a spark plug, assuming appropriate mods. What sort of displacement/power(gas)/peak revs are we talking about? Same peak revs on nitro?

I don't run in fuel classes so I just saying what the fuel guys tell. Racers been doing it for 60 years and there's a huge knowledge base on this stuff for LSR situations...But very few to none will say anything other than "I run 98% nitromethane".. If you're really intersted there's a forum called Land Speed Racing

[FC-Pilot]

There is some good info being shared here, but for the cackle deal I think it is being overthought. As I see it he is going to put together a SBC with injection and zoomies and light it off in a crowd so people can smell it and hear it. He will rev it four or five times and then turn it off. So put a decent powered mag on it, have it nice and fat at idle to give plenty of the smell and have it rev quick and you are good to go. That is my understanding of what the OP was looking for. OP, am I right?

Paul

[Dave Koehler]

Got a bit carried away didn't it?
The original poster asked if it could be done. Certainly.
Does he want to go through with it? no idea
Does he already have a running injected engine? no idea
Has he priced nitro lately? no idea
Will it be worth the time and expense to impress the natives? who knows?

[Dave Koehler]

It should be noted that IF nitro flames is the most important then it can only be done at night.
IF Flames is all that is required faking it is a possibility.

[CamKing]

Just inject the nitro, straight into the exhaust pipes, and ignite it.

[Dragsinger]

Thanks to all for your thoughts. It might be a fun project for an old [age 72] engine builder. When I was a youngster when u-control plans were very popular. After I crashed a model and before I could get another built, I would mount the engines on scraps of wood and just run them.

And through my adult years of racing one of the things I enjoyed most was simply listening to the engines.

Someone said, once an adult, twice a child.

[Dragsinger]

and of course, those model engines ran a mix of methanol and nitro. And for the last 15 years, I have raced both carb and injected methanol. The smell reminds me of the young years and those model engines.

[FC-Pilot]

and of course, those model engines ran a mix of methanol and nitro. And for the last 15 years, I have raced both carb and injected methanol. The smell reminds me of the young years and those model engines.

I can appreciate that. My oldest sisters favorite smell in the world is the exhaust of and alky burner. Running an alky funnycar for years and also going to the drags as a very young girl she learned to love it. Now when she announced at a church gathering that her favorite smell was alcohol she did not understand why people gave her funny looks, until back at home that night when she realized most people only knew about alcohol for drinking.

Paul