Power Junkies! 2-stroke Chambers (Domes) for Real Power on Pump Gas.. What if?

[gtfoxy]

this is a very interesting concept. I believe its do able too. It gets done every day on many cars like subaru's. Pump fuel and turbo's.

I think in the sled industry, everyone has opted for leaded fuels rather than the right intercooling setups and proper ratios with readily avalible head designs.

Intercooling I feel is a big part of this. Air to Air exchangers are the only real common place system in sleds. Or non at all. Only one consumer kit has Liquid to air intercooler.

There may be more costs from pumps, plumbing issues and an exchanger in snow contact, but to me it just makes too much sense. What better cooling medium than snow?

Air to airs just aren't really practical. Sure they do work with snow on them. But how effective is it then? The majority of the exchange medium isnt being cooled.

I've talked with a few individuals about head design in this. All three guys seem to agree that a larger squish, a ratio in the 10 to 11 range, retarded ignition timing and an effective intercooler will make a pump fuel turbo develop very good power.

If there was a head avalible that could keep high ratio's and still do pump fuel, turbo or non turbo at whatever elevation....... man you would sell a bazillion of them.

I would buy 3 right now. Its the one thing keeping 2 stroke turbos from being in every garage. Fuel cost and reliability. Everyone has nuked a motor on a trip some where and everyone can agree how un-fun it is.

Price of Race leaded fuels are crazy. Av is somewhat effective alternative price wise. In the mid 4 dollar range most places. Sunnoco 110 in bulk locally is in the $6.25 range. If you want 112 or other specialty fuel its even higher. Not hard to spend $70-90 in fuel on day for one machine. Not to mention if you put alot of miles on in a season. I had one day i used 14 gallons of fuel to ride 130 miles. Race fuel doesn't excite me much at all.

They work so why wait? I said very plainly anyone with a sled and EGT/ Wideband can volunteer. I've gotten a few requests so people better hurry, I am only doing 5 for FREE... 6 total and 1 is for my sled.

 

[CBX]

you have a PM.

 

[gtfoxy]

you have a PM.

Back at ya! TTYS

 

[winter brew]

What engines has this design been used/tested on and what were the results.....forgive me for being skeptical....open minded, but always skeptical

 

[gtfoxy]

What engines has this design been used/tested on and what were the results.....forgive me for being skeptical....open minded, but always skeptical

So far small bore, square displacement, engines.

I know where you are heading with this and believe me it has been addressed. Increased bore diameter does have an impact on pressure wave to surface area interaction. What is important though is that the design allows, to a point, and as I illuded to before, an increase in wave speed. Not propogation or burn rate, but simple wave speed. That is not to say that certain piston interaction caused by a given rod to stroke ratio do not impact this, because they will. All that can be done is an adjustment in chamber diameter to suit a given compressed height. Asside from that all the pieces simply have to fall where they may.

If there is a fundamental flaw in the bore/ stroke or rod/ stroke ratio, no design will totaly eliminate this. That is not to say it won't still outperform what ever else is out there...


All this is where proper engine dynamics come into play. Nothing by itself is the be all to end all. Not even this design. It needs to be viewed as simply a step in the right direction toward an undertsanding of what dynamics need to be paid attention to and which ones are secondary.

I actualy enjoy the scepticism, now just apply it to convention...

 

[DaveB]

http://www.snowestonline.com/forum/showthread.php?t=151153

Are you heads better than these? LOL "head wars" on SW....

 

[rocket]

Heads

A neat head design is all well and good, but I think you're forgetting that a naturally aspirated 2-stroke depends on the PIPE to make power. It won't matter what head you put on it, if your pipe sucks, your power is going to be limited. These aren't 4-strokes, nor are they automotive style 2-strokes (supercharger scavenged like an old Detroit). Further, your motor will only support as much power production as the motor has capability to dissipate the heat generated. That is a function of the engine design, not the head. Again, this imposes a limit irrespective of head design. Last, I'm going to suggest you're also failing to take into account the physical issues created by extreme compression ratios. Every try to rope-start a cold 800cc full race mod motor at sea level? Better eat your Wheaties......

 

[gtfoxy]

A neat head design is all well and good, but I think you're forgetting that a naturally aspirated 2-stroke depends on the PIPE to make power. It won't matter what head you put on it, if your pipe sucks, your power is going to be limited. These aren't 4-strokes, nor are they automotive style 2-strokes (supercharger scavenged like an old Detroit). Further, your motor will only support as much power production as the motor has capability to dissipate the heat generated. That is a function of the engine design, not the head. Again, this imposes a limit irrespective of head design. Last, I'm going to suggest you're also failing to take into account the physical issues created by extreme compression ratios. Every try to rope-start a cold 800cc full race mod motor at sea level? Better eat your Wheaties......

It looks like you live close to me and if it is close enough I invite you to come and check out what I am doing, maybe we can go for a ride...We got snow now!

I appreciate your input so I am going to be as patient and as brief as possible. If you take what I have to say to heart then so be it, if not, I can only say you need to learn a little more before making blanket statements. It only identifies that you do not fully understand what energy conversion is all about and how it truly effects engine power output. That being said I can tell your concepts in thinking, as related to engine heat, are based on a skewed view ofconvention with little in the way of understanding of what proper fundamental engine dynamics are and can do. That is not a slam, just an observation. Go back and re-read what I have written thus far.

I fully understand the function and incompassing importance of a tuned pipe. Pipes are important yes. They are however one piece of a very extensive puzzle. If you have a puzzle with a say 20 pieces and some are bigger than others, when you have all the big ones, and parts of others, in the proper place you can still tell what the picture is... Understand?

Maximum cylinder filling is effected by a "perfect pipe". But you need to first identify what is "perfect" and what is not. Perfect to one person could be a pipe that produces a broad useable owerband over a wide RPM yet not making as much peak power. Others may view it as producing a maximum power yet narrow powerband. There are also other criteria in this "perfect" scenario all too imprtantly overlooked. There is not a "perfect" pipe made for a sled chassis, in relation to proper flow dynamics and sound wave distortion, in the US that I have come accross. Close maybe, but no where near perfect. I do not need to explain myself here, it would simply take too long. It just needs to be taken at face value. ANd NO I have not tested every pipe there is. But I can still look at a Dog and tell its a Dog whether it barks or not...

I asked "what if" a certain compression ratio was possible. Not that poeple need to run it to get the power they require. People pull start 14.5:1 engines and that compression ratio is more than enough, with proper engine dynamics, to put any stock engine into pieces. People can also buy starter kits, and they do.

If there is a particular statement you have a question on then I will be glad to address it. I want to educate people here but I am not going to spoon feed people who have a set ideal on what they percieve as correct. Especially when they do not want look at things as they really are. I hope you want to learn and not think I am just being a D.H. because that is not my intention

 

[gtfoxy]

http://www.snowestonline.com/forum/showthread.php?t=151153

Are you heads better than these? LOL "head wars" on SW....

I am not on here to battle anyone or be caught up in a war of any sorts.


I have reviewed that thread and I wish him well with what he is trying to work out. Atleast he is DOING something and trying to come up with a new concept.

 

[MCIVER]

so heres a question, will your dome increase power output if the compression is left the same ?

 

[gtfoxy]

so heres a question, will your dome increase power output if the compression is let the same ?

Good one...

The answer is simply yes, but to a certain point. It all still boils down to energy conversion while maintaining certain dynamics before the chambers were changed.

If we go back over what exhaust heat is and where it really comes from we can easily tell if it is indeed doing a better job at energy conversion by simply monitoring EGT's. If EGT's drop after a particular chamber is swapped for another one then we know there is more Kinetic enegry from the combustion process being turned into useable torque. Torque increases, at any RPM, equate to more HP.

There is a line here though that depends on one variable. That is to say if the Pipe is very sensitive to heat changes and it causes a drastic change in cylinder filling the total gross gains in energy conversion will result in maybe a lower net gain, but a gain should be seen none the less.

A bigger question yet would be if A/F ratios can be leaned to create a more "efficient" or maybe even a more overall powerfull scenario.

Much of the fuel enrichment at WOT in a sled is to cool the chambers down with gas. If there is less residual temp in the gases before the next combustion cycle, then a reduction in "fuel cooling" can be implemented. In all actuality this would lead to an additional increase in power because the gases will be in a closer stoich ratio to fuel and will be able to phase their molecule formations more fully and use less energy. Improper A/F mixtures lend to partial molecule formations, that when they do not form into the next phase, because of a lack of the poroper atomic ratio, and the time for energy input into the piston has past, heat energy is given off. Thus kinetic energy has been wasted once again.

It is important to note, however, that how close to a stoich ratio can be ran depends thusly not only on chamber design, but also on vaporization and distribution and homogonization. In otherwords, for a given engine, with a given state of these things, a point in leaner A/F mixtures may only be able to be driven to a certain point before a detonation threshold may once again be reached. This is clearly not by the limitation of the chamber design then but the emulsification and distribution capabilities of a particular engine.

In this case of leaner A/F ratios, less fuel at the same power equates to increased efficiency. Also having a A/F ratio closer to stoich, as stated above, leads to less energy loss, thus another increase in efficiency. Also less fuel with an increase in energy conversion automaticaly results in an increase in fuel effciency... or MPG!!

 

[RIDECATS]

How low of BSFC runs "safe" for say a WOT run >60sec?

 

[RudeAwakening]

i hope what you have come up with pans out to be true! it will be great for everyone with a 2 stroke engine. you will always incounter those who are disbelivers no matter what info you give them. just make sure you dont get screwed over like Tesla by big business if it works

 

[crazysledhead]

You have a pm

 

[gtfoxy]

How low of BSFC runs "safe" for say a WOT run >60sec?

Man, Talk about a loaded question!

To be honest that would depend on so many variables that I could not begin to give an estimate on BSFC vs time at specific load/ RPM.

All I could do is give a base comparative as it relates to many various operating conditions and engine dynamics.

One way to look at it though, providing many variables were taken into account such as RPM threshold for sustainable engine durability, if the pre-known causes for engine detruction that are heat related then failures from those cuases would then be eliminated.

I hope that is close enough to satisfy yuor question.

 

[gtfoxy]

i hope what you have come up with pans out to be true! it will be great for everyone with a 2 stroke engine. you will always incounter those who are disbelivers no matter what info you give them. just make sure you dont get screwed over like Tesla by big business if it works

That is the reason I am doing this. So that everyone can benefit from what has been discovered. We then need to be very cautious of people who would try and corner this for themselves to simply make a buck. It is much too important of a discovery, in my opinion, to be left in the hands of individuals such as that...

Have no fear though, this design was created nearly 20 years ago, and I have now made sure it is open source for all to share...

 

[Anylizer]

Quote:
If we go back over what exhaust heat is and where it really comes from we can easily tell if it is indeed doing a better job at energy conversion by simply monitoring EGT's. If EGT's drop after a particular chamber is swapped for another one then we know there is more Kinetic enegry from the combustion process being turned into useable torque. Torque increases, at any RPM, equate to more HP.

While I might agree w/ this statement...... couldn't it also be the case that less energy was converted, causing a quench and excess "unburned" fuel cooling the EGT's??

 

[gtfoxy]

Quote:
If we go back over what exhaust heat is and where it really comes from we can easily tell if it is indeed doing a better job at energy conversion by simply monitoring EGT's. If EGT's drop after a particular chamber is swapped for another one then we know there is more Kinetic enegry from the combustion process being turned into useable torque. Torque increases, at any RPM, equate to more HP.

While I might agree w/ this statement...... couldn't it also be the case that less energy was converted, causing a quench and excess "unburned" fuel cooling the EGT's??

This is an easy one...

If raw fuel is left in the chamber and exhaust gas temps were over ~500deg F, the fuel would be excessively burning in the exhaust. Causing a rise in EGT, not the other way around. That is one of the reasons why these engines present excessive heat in the exhaust. It is from too rich a mixture to begin with and the proper gas formation can not occur at such low compression ratios. Then add to it shorter than optimum power strokes, do to a basic flaw in Bore/ Stroke arcitecture.

Besides any unburned fuel present in the exhaust, as in the scenario you present, would immediately be detected by the wideband as an increased lean condition.

 

[Anylizer]

I guess an A/F gauge would be the tell tale at this point.

EGT's actually have a bell curve to them, in some cases.
If we say, for instance, 1250 deg. is the peak, you can have 950 deg. on either side of this peak. A rich cond. showing as 950 on the front side, and an extremely lean condition after the peak also showing 950. In most cases the eng. will seize on the lean cond. eventually. Depending on how hard it is forced to run. If you go lean enough it will actually survive much longer than you would think, but it runs like chit! starving for fuel, but it will run. Seen this happen alot, guys says, I'm not making any temp. must be too rich...not.

 

[gtfoxy]

I guess an A/F gauge would be the tell tale at this point.

EGT's actually have a bell curve to them, in some cases.
If we say, for instance, 1250 deg. is the peak, you can have 950 deg. on either side of this peak. A rich cond. showing as 950 on the front side, and an extremely lean condition after the peak also showing 950. In most cases the eng. will seize on the lean cond. eventually. Depending on how hard it is forced to run. If you go lean enough it will actually survive much longer than you would think, but it runs like chit! starving for fuel, but it will run. Seen this happen alot, guys says, I'm not making any temp. must be too rich...not.

the wave seen in your scenario is because the combusting wave is moving past a stationary sensor probe. Not necessarily an indication of what is going on in the pipe per say.

You have opened a whole new can of worms with your second part of the statement. That scenario presents itself as a lack of vaporization, distribution and homoginization. When those things are correct then stoich or near stoich ratios are the result with increased power and lower EGTs yet...