the great oil debate
- Thread starter SIRCHOPALOT
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Sorry, posted that before finishing all posts...If you don't like my math then do it your way, no skin off my back. Us Certified Professional Engineers probably don't know what we are talking about anyway.
Blowdown1
ArboristSite Operative
PE eh? Yeah, I deal with you guys fairly regularly reviewing site plans for development. And guess what, a bunch of you don’t know what you are doing. Whether it is applying formulas incorrectly, calculating the wrong things (as in your case), or simply committing numerous math errors. PE after your name is worth squat on this issue.
Now, since you have escalated this to a personal issue, why don’t you take a look at the previous posts and maybe you’ll see why your numbers are BS. Once again, you are calculating a change in the ratio, NOT the amount of gas in the mix. That would be a change in respective VOLUMES that you should be calculating. I’m not saying your math isn’t right. You are calculating the wrong thing. Get it? And that is problem; you are thinking like an engineer and complicating matters. By the way, you went around you’re a$$, no make that my a$$, to get to your elbow. You took a basic math problem and turned it into an algebra problem.
Now, sit back, take a breath and think about it. You have a gallon of mix, all of which but a couple ounces is gas. You add a couple more ounces of oil to change the ratio. Do you honestly think you are reducing the amount of gas by 36%-50%? Well, do you? Of course not. Now, I’ll let you figure out how to calculate it, but I have already provided the answers. Let us know how you fare.
I think thats a pretty fair assumption in this case.....
I have really tried to be nice till now but... This is why I am an engineer and you are not. If you go back to page one and look at what I have put down as a percent decrease you will see it is of OIL and not GAS. The percent increase in gas for my original comparison problem (From 32:1 to 50:1) would be about .00107 gal. Also, I didn't use ratios for this problem but assumed a desired outcome of 2 gal. of gas.
If your where such a smart engineer you wouldnt make statements like the above which are based on false ASSumptions on your part. The differance between a 50:1 and 32:1 ratio is a meager 1%. 4/128=.031=3%, 2.6/128=.023=2%. :angel:
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SIRCHOPALOT
ArboristSite Operative
VTMechEng said:
this is exactly why all the engineers I know have to send their motor to me to build. they can't seem to get out of their own way. not saying they are all like this, but its these ones that make the whole lot of them look bad. :blob5:
Engineers where responsible for the Tacoma Narrows bridge and the Chevy Vega!
SIRCHOPALOT
ArboristSite Operative
VTMechEng said:
and thank goodness! I don't think even a lowly hillbilly like me could mess up as much stuff as a "professional engineer" could.
SIRCHOPALOT
ArboristSite Operative
No offense to TONYM, as you seem like you have a good amount of sense. But this seems to be the kind of engineer crap I always get to deal with! so now you know why I feel the way I do about them.
woodshop
Addicted to ArboristSite
exactly... I remember all the hype and fluff when the Vega came on the scene with all its (then) high tech parts, its lightweight aluminum block. Motor Trend magazine named it "Car of the Year"...when was that, think 1972?. Buddy of mine bought one of the sport models. Wasn't long before he found out that that high tech engine lasted about as long as his original set of cheapo bias ply tires did. His experience, that single experience with the Vega, tainted me for life. I was never as naive since, and it made me a bit more cynical. NEVER buy a car the first year it comes out.. its a crapshoot, even today. The engineers are not dummies, but they still have a bottom line to deal with and there is still built in planned obsolescence, perhaps more today than before, not sure. However, I think the world is just too complex to cover every single circumstance. Look at the reams of data all those NASA engineers came up with telling us that chunks of foam flying into the shuttle wings would do no harm. Well... they did.bwalker said:
Oil mix... 3oz/gal Stihl (43:1) all saws under 90cc... 3.5oz/gal(36:1) for my 395XP. Only use premium gas, and only gas thats less than a month old due to the alcohol compounds mandated by EPA possibly mixing with water. Alcohol absorbs water and gets "burned" in 4 cycle engines with relatively no harm long as it doesn't freeze in the lines or collect and lay long enough to rust metal. In 2 cycle mix, different ball game. Oil and gas mix and stay mixed. Oil and small quantities of water in your gas do not. You don't want little bits of gas/alcohol/water sans oil going through your saw. Therefor I use fresh gas that has not sat long enough to absorb any water. If my mix is more than 8 weeks old, like if I had a saw that has sat that long with mix in tank, I pour that into my car gas tank and pour in fresh gas. The little bit of oil mixes with the 20 gallons gas in the tank. No problem. No waste except the 3 oz of oil mix. Compared to the price of my saws, nothing to worry about.
bwalker said:
If you will please note, I already acholadged that the post you quoted was incorrect. Please look at the new posts of mine where I properly calculated the percentages where a .107% loss in gas could be found for a 2 gal amount. (I didn't mean to put the "gal" after .00107 before, 0.00107 = 0.107%, I was getting a little hot and started to rush) Yes, I make mistakes and I am sure you do to but please don't start saying things like the POS Vega are my fault. Just a little reality check for you, I rebuild my own engines and have not taken a vehicle in a shop for more then a yearly inspection and an alignment. Don't assume things about people, it isn't much better then me assuming you are a hack that tops and uses spikes to prune just because you climb trees.
The fact remains, 2 cycle engines are made to be run with a certain amount of oil and gas at a certain rpm and load. This is mostly governed by their material makeup but also things like port size. Just do what the owners manual says and lets drop this $h!t.
Oh and BTW, the mistakes of people like the NASA engineers with the foam are now used to show engineers what not to do. I agree that there are too many engineers that can't even chainge there own oil but please dont assume that all are like that. Remember that is was an engineer that made the Stihl 200T and Ford GT40.
bvaught
ArboristSite Operative
VTMechEng why do you get pi$$ed off so easily. I cant understand why you would take comments from a weblog so seriously. Do you have some kind of "complex".
As far as oil mix goes, the argument that "just do what the manual says" is pretty weak. Are you saying there isnt even a hint of a chance that oil mix ratios havent been influenced by emissions standards in the past 20 years? Metallurgy surely hasnt changed. If the ratios the manufacturers recommend are so perfect why dont you hear the factory giving a rational explanation of why they recommend a given ratio, especially given the obvious desire by consumers to understand "what is best for my motor". The manufacturers web sites that I have read simply say "use this mixture".
As far as oil mix goes, the argument that "just do what the manual says" is pretty weak. Are you saying there isnt even a hint of a chance that oil mix ratios havent been influenced by emissions standards in the past 20 years? Metallurgy surely hasnt changed. If the ratios the manufacturers recommend are so perfect why dont you hear the factory giving a rational explanation of why they recommend a given ratio, especially given the obvious desire by consumers to understand "what is best for my motor". The manufacturers web sites that I have read simply say "use this mixture".
SIRCHOPALOT
ArboristSite Operative
VTMechEng said:
engineers didn't make either one of those products. the tool and die makers and machinist and other skilled trades did.
You are correct, the engineers don't make them they design them. I was actualy a machinist, working on mills and leaths, and while this work is difficult and takes a great deal of knowladge it was still an engineer that gave them specs. Without the engineer there is no way for a machinist or die maker to know what demensions and of what material to make a part. In the end neither are more important but both need the other.
SIRCHOPALOT
ArboristSite Operative
VTMechEng said:
this is where your thinking is flawed. 2 cycles are not made to run a certain amount of oil and gas. they are made to run a certain amount of oxygen and gas. the oil is just for lubrication. think of it this way: don't mix your oil with your gas, but mix it with your air. It would be the same thing. so if the oil is mixed with the air it wouldn't matter how much oil you used it would still make max power because you are getting max gas flow right? this is basically what you are saying. it proves to me that you don't really comprehend the basics of jetting.
you see, I started this thread hoping that someone like you would chime in on this subject. someone who really doesn't know, but for some reason likes to confuse everyone that really just wants an honest answer and a good explanation.
that being said, I will have to say that all above are wrong. it has been figured on this thread (with great discomfort to the engineer) that at 32/1 vs 50/1 the decrease in gas volume will be 1%.(I think ben came up with that number). that is not correct. the fuel volume is actually decreased 1/2% and the AIR volume is decreased 1/2%. once the carb is rejetted for the proper combustion chamber heat. the extra oil does not displace only the gas in the fuel mix, but also the air. of course the only thing in the air that we really need is oxygen. wich can also be displaced by a number of things such as humidity. or it may just not be as plentiful, such as high altitudes. that is why seriuos racers know their air density gauges very well. that is also why I say that you will not really notice a power drop when going from50/1 to 32/1. it will not affect the power as much as the normal day to day air density changes. and I will bet a thousand bucks that it will also last longer.
Blowdown1
ArboristSite Operative
I appologize...
for dragging this out, but you are an embarrassment to your "profession".
There it is, your own words. TWICE. 36% less gas to combust.
Huh? Changing your tune again? And what is that .00107? The increase in gas by volume is 1.16%. (which is equal to ~1.5oz gas per gallon)
Really, where?
So now it is a .107% LOSS. A percent loss from one volume will not equal a percent gain from another number due to the fact that you are taking PERCENTAGES of different starting amounts.
Oh, but you assume you know about all of us and take your little "I'm a PE, I know what I'm doing and you don't" stance? You are joke dude. You don't know squat about anyone on here in terms of what their aptitude is or whether any are PEs. You're living proof that having your engineering degree is worth a bucket of warm spit. You can't put together a word problem and solve it properly and you keep changing your tune (and still get the wrong numbers).
Ben Walker already came up with the same numbers I did. BTW, you still haven't come up with the actual % increase in oil volume by richening the mix to 32:1 ( hint, it isn't 36%), and you are still arguing the point. You have done more to discredit engineers in one thread than all of NASA in recent years.
That's right, start back-pedalling little boy. And when you come up with the right numbers let us know. We are waiting with baited breath. By the way, let us know who you work for so we can be sure to avoid buying anything that you "engineer". You'd be a lot farther ahead if you had taken the time to read my earlier posts, look at my point and say, "my bad, I used the wrong numbers". Instead you keep trying to make excuses. That sh!t won't carry you far in the working world.
for dragging this out, but you are an embarrassment to your "profession".
There it is, your own words. TWICE. 36% less gas to combust.
Huh? Changing your tune again? And what is that .00107? The increase in gas by volume is 1.16%. (which is equal to ~1.5oz gas per gallon)
Really, where?
So now it is a .107% LOSS. A percent loss from one volume will not equal a percent gain from another number due to the fact that you are taking PERCENTAGES of different starting amounts.
Oh, but you assume you know about all of us and take your little "I'm a PE, I know what I'm doing and you don't" stance? You are joke dude. You don't know squat about anyone on here in terms of what their aptitude is or whether any are PEs. You're living proof that having your engineering degree is worth a bucket of warm spit. You can't put together a word problem and solve it properly and you keep changing your tune (and still get the wrong numbers).
Ben Walker already came up with the same numbers I did. BTW, you still haven't come up with the actual % increase in oil volume by richening the mix to 32:1 ( hint, it isn't 36%), and you are still arguing the point. You have done more to discredit engineers in one thread than all of NASA in recent years.
That's right, start back-pedalling little boy. And when you come up with the right numbers let us know. We are waiting with baited breath. By the way, let us know who you work for so we can be sure to avoid buying anything that you "engineer". You'd be a lot farther ahead if you had taken the time to read my earlier posts, look at my point and say, "my bad, I used the wrong numbers". Instead you keep trying to make excuses. That sh!t won't carry you far in the working world.
I tend to agree with you in regards to what determines oil requirements. The problem is the materials used to produce todays saws have changed very little since the days when a 32:1 mix was standard. What I am getting at is the fact emmisions, specificly visable smoke(with the oem dino oil) plays a role in what ratio is speced by the OEM not whats best for the saw. A 50:1 ratio for a severe service use in a chainsaw is laughable as far as I am concerned. Especially when the saw is required to have a restrictive muffler and is run as lean as possible for emmisions purposes.
Please don't direct any more questions towards me regarding this issue. I have stated my point, I stand by my calculations (yes from 32:1 to 50:1 you gain 0.107% more gas) If you want to figure more out just plug numbers in the formulas I provided. The reason manufacturers don't tell you why they recommend a certain mixture is because they don't feel it is important for you to know. You are expected to understand that they, as the ones that made the saw, know what it should use. Lucky for us, 2 cycle oils are easier to understand then 4 cycle ones. As an example, Ford and Honda now recommend 5W20 in some engines but the only reason for this is so they get a small increase in MPG, making their company look better to the environmental organizations (don't run 5W20 in these cars, stick with 5W30). All we have to worry about with a 2 cycle is brand and mix, I say anything between 32:1 and 50:1 will be just fine. Well that’s it for me, I am tired and this subject is not worth any more of my time.
