Alan said.... (1 Viewer)

[Cliff]

Was listening to comments by Alan yesterday at Wild Horse. He said that gasoline was actually more powerful as an energy source than nitro. The reason the nitro cars run so quick is that they run so much fuel through the engine on a run. Plus nitro is an oxygenated fuel. (I hope I'm saying this right) So, made me wonder, what if you could run the same amount of gasoline through the engine as they do with nitro? Would gas make more power than nitro if they could do that? I know squat about running a nitro car, but that really surprised me about gasoline. What do you guys think? (And don't tell me I'm nuts, cuz I already know that. HA)

 

[Jeff]

problem with gasoline it that you can't get enough oxygen in the cylinders at the same time as the BTU's of fuel. That's what nitrous oxide attempts to do, but get's physically stopped way short.

You need to go to Nitro School cliff ....

 

[TSK]

Here’s a short article about the thermal output for gasoline, methanol and nitromethane.
http://www.smokemup.com/tech/fuels.php

 

[Jimbo]

Interesting I did not know that!
This site is full of information and facts.

Jim Hill
www.nostalgicracingdecals.com

 

[none]

And with twin 44 amp magnetos wait until you hear how wide the spark plug gap is to light all that fuel.......

Alan

 

[flapjack]

And with twin 44 amp magnetos wait until you hear how wide the spark plug gap is to light all that fuel.......

Alan

Those magnetos are like arc welders, that's for sure. I've heard of spark plugs having the electrodes melted off.

 

[none]

problem with gasoline it that you can't get enough oxygen in the cylinders at the same time as the BTU's of fuel. That's what nitrous oxide attempts to do, but get's physically stopped way short.

You need to go to Nitro School cliff ....

Jeff is exactly right, (and he should be he runs one of them) to make more power with a gas burning engine you need to add more air (oxygen) Nitrous oxide isn't flammable, but it has a much higher oxygen content than ambient air, so you are adding more oxygen and you add more fuel to make more power. What a blower or a turbo does is force more air (oxygen) into the engine then you can efficiently burn more fuel to make more power.

Alan

 

[none]

Those magnetos are like arc welders, that's for sure. I've heard of spark plugs having the electrodes melted off.

And yet still sometimes the fuel volume in the cylinder will drown the spark out. That's what a dropped cylinder is.
As I tell everyone at Nitro School try to wrap your mind around this. Set your arc welder to 88 amps and strike an arc, now try to drown out that arc by pouring a flammable liquid on it. (Please don't try this at home, it won't end well.)

And Tom, it's the tune up that melts the electrodes, if the engine is happy the spark plugs will come back looking good. But if it's a little lean on the top end the electrodes are the first thing to go.

Alan

 

[Jeff]

So now I've got to ask Alan ... what gap on a fuel plug? Our nitrous oxide set up (let's call it 2000 to 2500hp) with a MSD Power Grid/HVC2 coil ignition set up (nothing special but adequate), the cylinder pressure is high enough that we only run a plug gap of .017" to get the spark to jump across the plug gap. Any more than that and the spark is going to find an easier place to jump (inside the rotor/cap, etc. MUCH larger gap, but no cylinder pressure to overcome) and shortly after that we tend to see the intake scoop shooting a fireball to the front tires.

I'm guess that those high amp mags can jump a larger gap.

One side note on the blower/turbo comment .... those engines are generally burning methanol (alcohol) which is a highly oxygenated fuel .... doesn't compare to nitro, but WAY more than gasoline (which is why E85 cars get less MPG than running on gasoline ... oxygen takes up room in the fuel).

 

[mick]

physics dictate there is only so much volume in a cylinder head. you can burn about 8-9x more nitromethane than gasoline in a cylinder with a given amount of air.
but.....nitromethane does have a lower specific energy than gasoline. so when you do the math. the energy (or btu's) created with nitromethane is somewhere a little over 2x that
of gasoline......this is kind of what's been told to me over the years. i think the numbers are pretty close.

 

[none]

So now I've got to ask Alan ... what gap on a fuel plug? Our nitrous oxide set up (let's call it 2000 to 2500hp) with a MSD Power Grid/HVC2 coil ignition set up (nothing special but adequate), the cylinder pressure is high enough that we only run a plug gap of .017" to get the spark to jump across the plug gap. Any more than that and the spark is going to find an easier place to jump (inside the rotor/cap, etc. MUCH larger gap, but no cylinder pressure to overcome) and shortly after that we tend to see the intake scoop shooting a fireball to the front tires.

I'm guess that those high amp mags can jump a larger gap.

One side note on the blower/turbo comment .... those engines are generally burning methanol (alcohol) which is a highly oxygenated fuel .... doesn't compare to nitro, but WAY more than gasoline (which is why E85 cars get less MPG than running on gasoline ... oxygen takes up room in the fuel).

Jeff,
You were on the right track, then derailed..... LoL Every Nitro team has a plug gap of .012 to .015 lot's of fuel in there and huge cylinder pressure so just as with your car you have to tighten up the gap or it will find an easier place to jump. Another thing that you have in common, just a little lean and your electrodes disappear first, don't they?

And you are correct on the fuel run at your level, I was referring more to a street application, that the power adder was in actuality just adding more air.

On a personal note What happened to my RED??????? EEK!

Alan

 

[Jeff]

Being a UT fan I sorta favor your new "burnt orange" Alan. But I'm sure the "red writer" will return.

Tuning a racecar has taught me a ton about being wrong ... while I'm clearly not surprised given the cylinder pressure, it was hard to guess "4 pieces of cheap printer paper" was the gap!

You may recall from the flames coming out of the header pipes even on daylight runs, that I try to stay away from lean (not that rich is without risks), but yes I've trimmed an electrode or two!

 

[Cliff]

OK, THIS is my nitro school!! Thanks so much for the great info. OK, I have one other question. Supposed nitro is outlawed. Now you have a 500" alky motor, screw blower, no limit on heads or fuel pump, etc etc. Nitrous would be allowed. Would it be possible to run, say, 8 stages of nitrous? I know some Pro Mod nitrous cars run 4-6 stages now. If the engine would handle that, how close could you get to the power of a nitro motor? I've always been curious about this. Some years ago, there was a serious shortage of nitro, & I remember Don Prudhomme saying they were ready to go to alky. If that had happened, I still think you'd see 4 second runs in the 1/4 mile at 300 plus, but... how close could you come to nitro?

 

[Jeff]

Cliff, you would really enjoy nitro school at an event. If it doesn't conflict with our class (it usually does) I will attend every time ... we compete in 5 or 6 nationals a year so I make it at least once a year. I don't even want to admit how many times I've walked away from listening with an idea about how to improve our program.

Even at over 900 cu in nitrous/C23 can't compare to blown alky or turbos. This is pretty clear in ProMod nowadays. You can make the engine think it's about 1.5 times bigger than it really is with nitrous , but that's about it. As a sportsman, my wife runs three stages of nitrous and we make roughly 1350 hp with 762 cu in naturally aspirated (less than optimal head set up to be optimal for nitrous) and we can make almost that much again with nitrous & extra fuel. The pro's have better everything and make way more hp with nitrous that just with their base 900+ cu in motor.

A super/turbo on alcohol is probably the highest output possible (supercharger with turbos pushing on the top end) but it would pale to nitromethane.

Check out a Proline turbo set up some time. One of the prettiest pieces of billet aluminum you'll ever see. The turbo plumbing looks awesome too.

 

[Cliff]

Thanks Jeff. My wild hair combo was a 1000CI engine, twin turbos, alky & nitrous. Had never thought about running both supercharger & turbo. (I know Chase Knight did this years ago in Pro Comp). I didn't think my "combo" would run close to nitro, but it was just my thoughts. Now that I think about it, would probably be more expensive to run "my" combo than a nitro engine. I do love to see the Pro Mod cars run; watch them a lot on computer (PDRA, etc). Never really get a chance to see Pro Mod here in Arizona. The ones I have seen look like a plumbers nightmare (Turbo), with all the pipes and various parts & pieces, but boy do they run! Did get a close up view on Hrudka's turbo car at Wild Horse, when Bo Butner was making license runs. Oh yeah....