Longevity of A Vehicle...

[B3sat16v]

Again, do your research.

Any old OBDII ECU will spark retard.

You think that link you posted is reference? Wow.

Try something reputable, like: http://papers.sae.org/2006-01-0607/

Look at that, maps are still involved. Now try using an iota of common sense here B3sat16v. (1) I know it's difficult, especially since you have no credentials to post, or even a reputable reference.

Here's how it works. (2)An ECU has a map that is optimized for a certain octane of fuel. If it detects knock, it switches to a map for a lower octane of fuel. Even the old ECU in my 1998 car does that. Calling it "adaptive" is just marketing hype.

1-Yeah, because you work designing these ECUs? Again prove to me that you do R&D or even work near these developers and come back to me.

2-So you are basically agreeing with me? But in the sense that the ECU will do it backwards ei: from 93 to 87, but then you believe it cannot do it from 87 to 93? This is where what I have been saying fall into. It will advance the timing until a knock is detected.

[B3sat16v]

It's funny how when you say I'm right, you still try to say I don't have a clue, yet you've explained absolutely nothing. You don't exhibit any technical knowledge, common sense or even the ability to post a reputable reference. You even ridicule someone else for not posting their credentials, yet you won't even do the same.

You know how I know you are not an Engineer? Because you wont research and come to your own conclusion.

[leaftye]

1-Yeah, because you work designing these ECUs? Again prove to me that you do R&D or even work near these developers and come back to me.

Do you?

2-So you are basically agreeing with me? But in the sense that the ECU will do it backwards ei: from 93 to 87, but then you believe it cannot do it from 87 to 93? This is where what I have been saying fall into. It will advance the timing until a knock is detected.

But it still has maps. If there's no map for 100 octane, it's not going to keep advancing until it gets knock with it. Without that, there's nothing new. If it would, then adaptive knock control would be more than a buzz word.

[leaftye]

You know how I know you are not an Engineer? Because you wont research and come to your own conclusion.

Yet you posted the link you did. If you were a real engineer, you'd post something reputable. Something technical. That would be incredibly easy to find because you actually work with it.

[1.8Tquattro]

B3sat16v what do you do for a living?

[leaftye]

B3sat16v what do you do for a living?

Would you believe B3sat16v anyway? His best reference so far is a link to a Mustang site. This person claims to be an expert, yet posts nonsense and a meaningless reference.

[CannuckCorradoVR6T]

If Im not mistaken, B3 is an engineer.

Anyhow, I think that looking at these ecu programs as different maps is a little odd. I think it is more like a different range of the same map. Therefore, if the car has enough range to accommodate spark knock from different grades of gasoline (forget E85 for the time being), and run normally and efficiently withing those ranges, using premium on a vehicle is recommended to run on lower octane can yield some improvements in performance.

Also, no car is designed to knock. car with knock sensors are designed to adapt to different knock situations. The ecu will attempt to maintain the most efficient range of timing advance for the situation (load, temp, octane etc.) which in many situations is just below the knock threshold.

Old cars are designed to stay well below the knock threshold, and will probably not benefit much from an increase in octane without the user making changes to the timing.

[leaftye]

If Im not mistaken, B3 is an engineer.

There are many kinds of engineers that bring nothing to this conversation, so even if B3 is an engineer, that must be why he won't admit it, much less the type. Even so, we have no reason to believe him.

[CannuckCorradoVR6T]

Along these lines, my QX4 will loudly complain if I do not use high octane fuel on hot days. It appears to me that it does not have enough timing adjustment to eliminate knock in some situations. The Corrado on the other hand, has never audibly knocked even when presented with boost, though I have observed the computer recording knock vents in vag com, and pulling timing as a result before the knock becomes damaging. Amazing to me considering the Corrado is 8 years older.

[JLJetta]

Watch out I want to inflate my Internet ego. Listen here, what is your background again, do you mind sharing it with us?

Well cr@p.

I wanted to dust off my old books on design constraints for the SSME HP fuel turbopumps and have a technical discussion on graduate level engine studies. To my knowledge, they never did solve the issue of in-flight restart. That was a major reason for the rebirth of the J-2X program.


But alas, you have chosen to take your marbles and go play elsewhere.

[JLJetta]

There are many kinds of engineers that bring nothing to this conversation, so even if B3 is an engineer, that must be why he won't admit it, much less the type. Even so, we have no reason to believe him.

[turbo_nine]

ECU allowances aside

Practically all these damn cars have ECUs, so why on earth would we leave that aside?

[tasty danish]

You can only advance timing so much until you hit MBT. You will not increase power beyond that. If you hit MBT without knock, higher octane is not doing you any favors. I have no idea WTF point B3 is trying to make. I just hope the rest of us understand that running higher octane than what your engine can tune for will cause a loss of power but is not dangerous.

[CannuckCorradoVR6T]

You can only advance timing so much until you hit MBT. You will not increase power beyond that. If you hit MBT without knock, higher octane is not doing you any favors. I have no idea WTF point B3 is trying to make. I just hope the rest of us understand that running higher octane than what your engine can tune for will cause a loss of power but is not dangerous.

I agree. I suspect every passenger car and truck sold in NA is capable of knocking in certain situations before reaching its optimal timing though. Just a hunch.

[tasty danish]

I agree. I suspect every passenger car and truck sold in NA is capable of knocking in certain situations before reaching its optimal timing though. Just a hunch.

Forced induction, sure. N/A, I have my doubts.

[CannuckCorradoVR6T]

True. If the vehicle doesn't have any knock sensors, chances are, you won't be getting any more bang for the buck by using premium. All others are a coding crap shoot IMO.

[zhenya00]

Just as an interesting aside, my 190 was designed pre-knock sensors. Instead, MB used something else pretty interesting. On some models, they included a rotary knob in the engine bay that when turned to different positions, changed resistance, which effectively told the very simple ecu to choose a different timing map.

On others, like mine, it is a simple plug and play resistor. In the 80's it was assumed by MB either that premium fuel was not widely available in the US, it was of lesser quality, or that owners would not want to use it, so the car was equipped with a resistor that chose a map with 6 degrees of retard. A popular 'mod', since there are no chip upgrades for this generation of vehicle, is to unplug that resistor entirely which equates to infinite resistance and (there is some debate on this in the MB forums) causes the computer to choose a map with no retard, boosting performance a bit (at the cost of requiring premium). The idea with the dial was that, depending on what gas was locally available, you could manually adjust the amount of spark advance.

[tasty danish]

Just as an interesting aside, my 190 was designed pre-knock sensors. Instead, MB used something else pretty interesting. On some models, they included a rotary knob in the engine bay that when turned to different positions, changed resistance, which effectively told the very simple ecu to choose a different timing map.

On others, like mine, it is a simple plug and play resistor. In the 80's it was assumed by MB either that premium fuel was not widely available in the US, it was of lesser quality, or that owners would not want to use it, so the car was equipped with a resistor that chose a map with 6 degrees of retard. A popular 'mod', since there are no chip upgrades for this generation of vehicle, is to unplug that resistor entirely which equates to infinite resistance and (there is some debate on this in the MB forums) causes the computer to choose a map with no retard, boosting performance a bit (at the cost of requiring premium). The idea with the dial was that, depending on what gas was locally available, you could manually adjust the amount of spark advance.

That actually is really neat! Thanks for sharing.

[B3sat16v]

There are many kinds of engineers that bring nothing to this conversation, so even if B3 is an engineer, that must be why he won't admit it, much less the type. Even so, we have no reason to believe him.

Is that why your post count is twice of mine? Because all you do is talk hot air.

Sorry I was busy developing modern ECUs at work.

[B3sat16v]

Actually, that is one my dream jobs..... I love trains.

[tasty danish]

Is that why your post count is twice of mine? Because all you do is talk hot air.

Sorry I was busy developing modern ECUs at work.

Hot air... sounds familiar. So do you fly Romeos or build computers?

[B3sat16v]

Hot air... sounds familiar. So do you fly Romeos or build computers?

I do many things in life!

[turbo_nine]

Just as an interesting aside, my 190 was designed pre-knock sensors.

It wasn't, actually. W201 came out in 1982, same year that Saab added a knock sensor-driven boost control system to Saab turbos.

The BOSCH knock sensor that the APC system relied on probably existed for a short time prior to that as well.

[compy222]

I agree. I suspect every passenger car and truck sold in NA is capable of knocking in certain situations before reaching its optimal timing though. Just a hunch.

i would safely assume that it probably depends exclusively on the engine and its relative compression ratios, factory ecu tuning, and ambient air conditions. You could probably run an NB Miata on diesel given how low their compression is and how overbuilt the motor is.

[xmaciek82x]

Well I'm not going to try a start any arguments with some of the smarter guys here. I am not way an expert on engines, and ecu tuning. I know some, but definitely not as much as the few that are arguing.

Anyways, my old car was tuned for 93. It had 2 main maps High Octane and Low Octane. While driving around in a Closed Loop, obviously the oxygen sensor would try and keep my AFR ratio as close to stoich as possible and ignore my Fuel maps. And my EGR Advanced Timing map would add to my existing Timing Tables. This all happens during Closed Loop with MY old car. So if I went with a higher octane and still wanted to stay in closed loop (Load under 100 for the most part) then I would not see any hp gain but maybe slightly better mpg.

Now with Open Loop is a different story. All oxygen sensors are not used and my High Octane and Low Octane maps are in full effect. If the car runs and does not knock, whatever my High Octane table said, the injectors try to match it and my timing is whatever my timing table says it needs to be. If we hit knock, then ECU pulled 1 degree of timing per 3 knocks. Also my ECU had logic where the engine sees knock constantly then it used low octane fuel and low timing tables at ALL times. If this happens, something is wrong.

So having said everything above in regards to open loop, I would not really see higher HP numbers when using higher octane when I was tuned for 93 since timing and AFR would stay the same. I would see higher HP number if I retuned my ECU for the higher octane since I would be able to advance my timing or when I tuned for e85, I was able to lean out and advance timing like no tomorrow and gain 50whp + but then you have MBT to worry about.

I'm only familiar with my car and my ecu. I have no idea what other car manufacturers do and program their ECU, but I would imagine their logic and technology changes all the time how timing and AFR is derived.

[tasty danish]

I do many things in life!

obviously trying to actually converse with you is an exercise in futility. As one who actually does fly for the navy, I highly doubt that you actually do both at work.

[DrFrisker]

LOL @ all the idiots, not sure if trolling or just stupid

[CannuckCorradoVR6T]

Is it safe to say most new cars could benefit, in performance or mileage, from higher than minimum octane fuel if programmed to take advantage?

because:

knock sensing adaptive ignition systems nearly across the board
relatively high compression engines nearly across the board

Whether its worthwhile is a whole other can of worms imo.

[B3sat16v]

obviously trying to actually converse with you is an exercise in futility. As one who actually does fly for the navy, I highly doubt that you actually do both at work.

Well, people sometimes need to relax. The problem is that people in here think they are automotive know it alls (Including myself and yes a lot of times I am wrong). People take things way too serious. If I belittled anyone I assure you it was not my intention. When I asked who here has taken or works designing modern ECU, it was in order to engage into a better conversation, but people automatically take that the wrong way. I just wanted to make sure the stuff being said was correct and backed up or correct by someone who actually works on the field.

I have taken higher level engine design courses and have participated in Formula SAE. I have a few pubs that I keep on my book shelf. My knowledge about these things sometimes can be wrong. Just like any of us can be wrong as we are not experts on the subject matter; however, I have had some introduction to a lot of these concepts.

I still stand by my original comment that modern engine controls can and will accommodate a the array of fuel available today (87 through 93). It is also easier for a manufacturer to simply recommend Regular vs Premium since the gas prices as pretty high these days and even luxury brands are now calling for 87. Also using 91 or 93 wont degrade engine performance, if the ECU cannot accommodate for it. It simply will burn it as if it was 87. If there is a loss it is minimal and not even noticed, because I certainly have never noticed it.

I am a car nut and I have turn wrenches for many years. I simply love all things mechanical, but I certainly do not know it all, even though sometimes I think I do and it is wrong to think so. Pure fact of the matter is, all of us have said something wrong in this thread. I certainly have, particularly with the 100 Octane comment early on.

Now let see if we can, with proper knowledge arrive at a reasonable conclusion.

B3ST16V

[BSD]

I still stand by my original comment that modern engine controls can and will accommodate a the array of fuel available today (87 through 93).

Why are you people having a hard time grasping this? Almost every modern ECU is adaptive now.

[B3sat16v]

Why are you people having a hard time grasping this? Almost every modern ECU is adaptive now.

I have not a clue! I think it is funny how then some people attack and then cannot answer what level of expertise they have in this field. I do not have a lot, but I certainly undertand code and how these control units work. Systems Controls was one of my favorite subjects back in the day. Still is, I just do not really work on it anymore.

[tasty danish]

Who ever disagreed with that?

[B3sat16v]

Who ever disagreed with that?

You well know several people were not capable of agreeing. Go back and read some of the posts. I have been saying the same thing since early in Page 2.

[1.8Tquattro]

Why are you people having a hard time grasping this? Almost every modern ECU is adaptive now.

I have not a clue! I think it is funny how then some people attack and then cannot answer what level of expertise they have in this field. I do not have a lot, but I certainly undertand code and how these control units work. Systems Controls was one of my favorite subjects back in the day. Still is, I just do not really work on it anymore.

Who ever disagreed with that?

You well know several people were not capable of agreeing. Go back and read some of the posts. I have been saying the same thing since early in Page 2.

No one here is disagreeing that modern ECU programming can run a car on different octane fuels.
What is being disputed is that it is a common practice for cars originally designed and tuned to run on 87 octane to significantly improve their performance if 93 octane is used.

B3sat16v would rather ask for qualifications and education background than provide proof that this is a common practice.

[B3sat16v]

No one here is disagreeing that modern ECU programming can run a car on different octane fuels.

What is being disputed is that it is a common practice for cars originally designed and tuned to run on 87 octane to significantly improve their performance if 93 octane is used.

B3sat16v would rather ask for qualifications and education background than provide proof that this is a common practice.

WOW!

And I asked for proof because some of you do not seem to know how modern systems and controls operate. It is better for a manufacturer to design an ECU that will run all Octanes available and then just recommend 87 (A lot of people like to run cheaper fuel), but also make it known that the car will perform better with Higher Octane. This covers a higher array of drivers. Electronics are cheap and fast today and it is easy to store more data in ECUs. Have any of you seen the CR on these new cars calling for 87 Octane? Some have it as high as 10.8:1.