Three words:
acceleration fuel enrichment
Future is THIN
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acceleration fuel enrichment
Which is why every UOA on this board with a 20wt is excellent and why Japan now has 0w-20's listed in some manuals. If you believe that oil analysis portrays engine wear, then you have to like 5w-20's because they have shown nothing but outstanding results.
Judging by how hard it is to get BITOG people to convert and we have the factual data, I can understand their plan of America first, rest of the world later. Nothing worse than putting some "white elephant" quarts of oil on the shelf to sit for years. Just finding 5W20 in America can currently be a chore, then you have to deal the auto store clerk asking "are you sure you want to use this?"
BTW - I will admit that the first time I used 5W20 in my Ford 4.6 I was babying the gas and waiting for the motor to do something different.
Call it human nature, we don't like change
PS - the only thing it did different so far was to reward me with some better gas mileage
Call it human nature, we don't like change
PS - the only thing it did different so far was to reward me with some better gas mileage
Perhaps I don't know what you mean. Are you suggesting that if I must hold my throttle open at 15% to hold 75mph on the freeway, and that if I accelerate by holding my throttle open at 15% until I reach 75mph, that the computer (or carburetor) will richen the fuel mixture simply because some sensor input determines that I am accelerating? I do not believe this is the case, nor would I be willing to accept that premise without supporting documentation. In the case of a carburetor, I feel unlikely to accept it at all. The only time the vehicles I own richen the mixture is when the throttle is opened more than somewhere in the 75-90% range, which is also where they go open-loop. This is on my cars; I realize that many brand-new cars no longer go open-loop, so I wonder whether there is any enrichment on them at any time(?).
Would you clarify, please?
Hmmm...this just gave me an idea for a pre-school age children's book. Got to get to them at a young age or else they turn into thick head curmudgeons.quote:
Originally posted by nickmckinney:
BTW - I will admit that the first time I used 5W20 in my Ford 4.6 I was babying the gas and waiting for the motor to do something different.
Call it human nature, we don't like change
PS - the only thing it did different so far was to reward me with some better gas mileage
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Hmmm..maybe you could incorporate "Newspeak". Oils would either be "Thin" (a good thing) ..or "Unthin" (a not so good thing).
"Do you know Johnny used an unthin oil in his car?"
"No, I didn't ...do "they" know??
"
"Do you know Johnny used an unthin oil in his car?"
"No, I didn't ...do "they" know??
I already use a lot of thin oil: 10w30! It is pretty thin next to 20w50, right?
"Which is why every UOA on this board with a 20wt is excellent and why Japan now has 0w-20's listed in some manuals. If you believe that oil analysis portrays engine wear, then you have to like 5w-20's because they have shown nothing but outstanding results."
So far I conclude that vehicles in the US are exposed to less stress and that's why 5W20 works just fine. If it's better than heavier oils for wear protection why isn't it used more often among club racers ? In motorcycles ? In diesels ? In Ford vehicles outside of the US ?
I did run across a comment that I haven't been able to verify, that 20W were offered in Europe in the 70s (?) as an attempt to increase fuel mileage, and there were so many problems that it's not been popular since. In addition the extended oil change intervals in other parts of the world often end up needing heavier oils.
So far I conclude that vehicles in the US are exposed to less stress and that's why 5W20 works just fine. If it's better than heavier oils for wear protection why isn't it used more often among club racers ? In motorcycles ? In diesels ? In Ford vehicles outside of the US ?
I did run across a comment that I haven't been able to verify, that 20W were offered in Europe in the 70s (?) as an attempt to increase fuel mileage, and there were so many problems that it's not been popular since. In addition the extended oil change intervals in other parts of the world often end up needing heavier oils.
I don't disagree entirely. For cars that spec 20wts, they are fine.
Cars in the US are every bit as stressed. One super highway, in which not all drive that fast, doesn't mean all their cars are more stressed.
As far as club racers go, your starting to see more and more from what I've been reading about. Modern 20wt oils I would think would be superior to 1970's oils. Their will always be cases where thicker oils are called for. It also depends on the engine design as well.
Your also seeing NASCAR qualifty with Mobil 1 0w-5 oil and run 0w30 the entire race. Royal Purple and Redline also have many low viscosity oils. Yeah they rebuild engines, but the technology has allowed this type of viscosity to be used in cases where 20w-50 was the norm.
Cars in the US are every bit as stressed. One super highway, in which not all drive that fast, doesn't mean all their cars are more stressed.
As far as club racers go, your starting to see more and more from what I've been reading about. Modern 20wt oils I would think would be superior to 1970's oils. Their will always be cases where thicker oils are called for. It also depends on the engine design as well.
Your also seeing NASCAR qualifty with Mobil 1 0w-5 oil and run 0w30 the entire race. Royal Purple and Redline also have many low viscosity oils. Yeah they rebuild engines, but the technology has allowed this type of viscosity to be used in cases where 20w-50 was the norm.
Remember the old SL Mobil 1 specs for 10w30:quote:
Originally posted by TallPaul:
I already use a lot of thin oil: 10w30! It is pretty thin next to 20w50, right?
9.8 cSt @100C
61.3 cSt @40C
Heck, it was within a PH of a SAE 20 grade!
I was thinking more in the line of Dr. Seuss's "Cat in the Hat" books...with equivalent versions in Spanglish and Ebonics.quote:
Originally posted by Gary Allan:
Hmmm..maybe you could incorporate "Newspeak". Oils would either be "Thin" (a good thing) ..or "Unthin" (a not so good thing).
"Do you know Johnny used an unthin oil in his car?"
"No, I didn't ...do "they" know??"
That is correct.
Consider the following, found on page 162 of "Ford Fuel Injection and Electronic Engine Control" by Charles O. Probst, SAE:
"If you are driving for economy, you may wonder how far to push the accelerator to increase speed. Some energy conservationists advise drivers to operate the accelerator as if an egg were on the accelerator pedal. During an earlier fuel crisis, BMW ran tests showing that the egg-on-the-accelerator concept did not save fuel. Indeed with fuel injection, accelerating briskly to the desired speed is more economical because the acceleration enrichment time is shorter. I accelerate "briskly" at about 90%, "90kPa" on my manifold-pressure gauge. I want to avoid sending a Wide Open Throttle (WOT) signal to the computer because that changes all the rules of acceleration. I suspect the egg on the accelerator bit is a leftover from carburetor days, avoiding that extra squirt from the accelerator pump that carburetors needed to prevent engine stumble."
As far as open and closed loop:
The main difference between open and closed loop is that during closed loop operation, the computer is adjusting the air/fuel ratio based on output from the oxygen sensors. At the same time it is storing this information (GM called it "block learn", OBD-II calls it "fuel trim") in memory for use...
...when it is in open loop, and the oxygen sensors are not giving a reading (too cold, the computer has richened the mixture for WOT, etc..it is important to realize that the most commonly used oxygen sensor is a binary device that tells the computer nothing more than "RICH" or "LEAN". There are wideband sensors that can actually directly tell the computer what the a/f ratio is, but they are not very common and quite expensive).
Everything that happens in open loop depends on what happened in closed loop. That is how the system works. If the computer determines, during closed loop operation, that the engine is running lean compared to the factory programming, and it must add fuel to compensate for this lean condition, then it will continue to do so during open loop operation.
So I'm not quite sure what you mean by new cars never going in open-loop. Due to the limitations of the oxygen sensor, they must go into open loop when the mixture has been richened for wide-open-throttle acceleration.
I suppose that there are probably some primitive implementations of fuel-injection that do not operate as I have described with respect to open and closed loop.
"BTW, Ford did a tremendous amount of testing with 5w-20's. One of the cars was a V6 also."
Which I guess is why Ford doesn't seem to recommend 5W20 outside of the US. It doesn't seem to be avilable anymore, but I have downloaded owner's brochures from the Ford site for vehicles in other countries, and they didn't recommend 5W20.
Which I guess is why Ford doesn't seem to recommend 5W20 outside of the US. It doesn't seem to be avilable anymore, but I have downloaded owner's brochures from the Ford site for vehicles in other countries, and they didn't recommend 5W20.
Can you even get 5w-20 in other countries? Also how does the oil and gas in other countries compare to ours quality wise?
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I don't agree with everything you said there, brian. This is regarding my jeeps and is out of the DC FSM (paraphrased for length). This is a speed/density system.
In closed loop all the sensors are used. In open loop ..just one ..the MAP ..and that determines what the pre-mapped fuel curve in the PCM will generate for injector pulse width. The O2 sensor has no bearing on fuel adjustment in open loop ..but ISN'T ignored. The rich or lean conditions are recorded IN THIS MODE. These are the long term adaptives that compensate for fuel system decay (leaking or clogged injectors, lower psi from fuel pump, etc.) After so many open loop lean or rich events ..the PCM will either incriment or decriment the compensation factor. (+1, -1, +2, etc.). The only thing that it effects is the deviation (+ or -) from the premapped fuel curve in open loop.
In closed loop there is no need for any "adaptive" memory. The whole system is continually adjusting the injector pulse width. If it's lean ...the pulse width is broadened..if it's rich ..the pulse width is narrowed.
In closed loop all the sensors are used. In open loop ..just one ..the MAP ..and that determines what the pre-mapped fuel curve in the PCM will generate for injector pulse width. The O2 sensor has no bearing on fuel adjustment in open loop ..but ISN'T ignored. The rich or lean conditions are recorded IN THIS MODE. These are the long term adaptives that compensate for fuel system decay (leaking or clogged injectors, lower psi from fuel pump, etc.) After so many open loop lean or rich events ..the PCM will either incriment or decriment the compensation factor. (+1, -1, +2, etc.). The only thing that it effects is the deviation (+ or -) from the premapped fuel curve in open loop.
In closed loop there is no need for any "adaptive" memory. The whole system is continually adjusting the injector pulse width. If it's lean ...the pulse width is broadened..if it's rich ..the pulse width is narrowed.
Actually as heated UEGOs, faster processors, and better sensors are incorporated into more engine control systems, you'll see continuous closed loop operation within seconds after cold start on more and more vehicles. I believe the Prius already features this technology. (I can't mention some of the others I'm privy to.) Additionally, there are a whole host of other variables between different engine designs to make general predictions based on one engine test difficult at best. But seeing on how we debate viscosity, don't let me slow you down.
In point of fact, even the lowly Dodge Neons no longer enter open-loop (excepting possibly the first moments of startup; I do not know that for certain). They use a wideband O2 sensor and combine this with an ECU which constantly adjusts whatever it needs to in order to maintain specified output. Many, many boy racers have been disappointed to find this out AFTER they've spent hundreds or thousands of dollars on modifications that the computer nullifies.
Brian703, thanks for the quote. However, that quote, on its own, does nothing but use the term "fuel enrichment time." Can I get some numbers as to how much the mixture is enriched? How much acceleration does it take to enrich the mixture? 0.5g? 0.1? 1.0? What sensor(s) are used to determine that we're accelerating?
A couple very simple things appear to me to refute the idea that brisk acceleration is more fuel efficient:
1) How does NASCAR cap horsepower without directly capping horsepower? Restrictor plates. What is a throttle? A restrictor plate.
2) If the restrictor plate prevents the engine from making more than 30hp, then there's only so much fuel it can burn, even if running rich. So, if I never let my engine make more than 30 hp (by modulating the throttle, dropping rpms, or both), how will I burn MORE fuel than if I let it make 150hp part of the time and 30hp the rest of the time?
3)Many automakers, including SAAB & BMW (mentioned above), say to upshift early and open the throttle to achieve maximum fuel economy. This practice also achieves what I talk about; it does it by keeping the engine at an rpm where it simply can't make more than 30hp no matter what.
So, I call BS on the person who made the statement in the first place.
Brian703, thanks for the quote. However, that quote, on its own, does nothing but use the term "fuel enrichment time." Can I get some numbers as to how much the mixture is enriched? How much acceleration does it take to enrich the mixture? 0.5g? 0.1? 1.0? What sensor(s) are used to determine that we're accelerating?
A couple very simple things appear to me to refute the idea that brisk acceleration is more fuel efficient:
1) How does NASCAR cap horsepower without directly capping horsepower? Restrictor plates. What is a throttle? A restrictor plate.
2) If the restrictor plate prevents the engine from making more than 30hp, then there's only so much fuel it can burn, even if running rich. So, if I never let my engine make more than 30 hp (by modulating the throttle, dropping rpms, or both), how will I burn MORE fuel than if I let it make 150hp part of the time and 30hp the rest of the time?
3)Many automakers, including SAAB & BMW (mentioned above), say to upshift early and open the throttle to achieve maximum fuel economy. This practice also achieves what I talk about; it does it by keeping the engine at an rpm where it simply can't make more than 30hp no matter what.
So, I call BS on the person who made the statement in the first place.
My F150 (1995) owner's manual has ridiculously low shift points for upshifting. I have never followed them because it seems to me it would result in frequent lugging. In fact, I like to run closer to the torque peak so that I can accelerate quickly when needed.
An engine is the most fuel efficient when the throttle is wide open and the rpms are at the torque peak. I said "most fuel efficient," not "would burn the least fuel." In order for my truck to run efficiently at WOT and torque peak rpm it would need a serious load. So a compromise is needed on an unloaded vehicle. Apparently the open throttle is more important to economy than being at the torque peak; hence the low shift point recommendations.
It is in open loop that the adaptive memory is used, as I stated. The "adaptive" memory is built in closed loop.
[ September 02, 2005, 10:24 AM: Message edited by: brianl703 ]
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