Dave_in_TX Posted April 4, 2016 Share Posted April 4, 2016 I recently read somewhere that the liquid cooled boxers do not have a knock sensor. Anyone have any reliable info on this? It seems strange to me that with the higher compression ratio that there wouldn't be one. Link to comment
dirtrider Posted April 4, 2016 Share Posted April 4, 2016 Afternoon Dave I will have to look into that. I don't see a knock sensor or sensors listed but that doesn't mean that BMW isn't using a different technology for spark knock control (like a high frequency across the spark plug gap). Link to comment
dirtrider Posted April 4, 2016 Share Posted April 4, 2016 Afternoon Dave The quote below is from an early release BMW info letter-- It looks like no knock control on the WC engines (at least at time of the below letter) Link to comment
realshelby Posted April 4, 2016 Share Posted April 4, 2016 I recently read somewhere that the liquid cooled boxers do not have a knock sensor. Anyone have any reliable info on this? It seems strange to me that with the higher compression ratio that there wouldn't be one. Higher compression ratio no longer means detonation without the best fuel octanes and timing considerations. In the good ole days 12.5 to 1 compression would have demanded race quality fuel for no detonation and optimum power levels. Todays engineering produces compact combustion chambers that allow smooth, even flame propagation once the fuel/air charge is ignited. Aluminum heads are also part of that, as well as coatings on combustion chambers and pistons on some engines. Amazing world we are living in now, truly the good ole days as far as vehicles of all kinds go. Link to comment
Ride200mi Posted April 20, 2016 Share Posted April 20, 2016 So has anyone had issues with knocking? Mine sounds like it has a little knocking at slower speeds just as I let out the clutch. Sometimes as I open the throttle wide open at freeway speeds too... But not that much. Maybe I just can't hear it with higher wind noise..... Link to comment
Ponch Posted April 22, 2016 Share Posted April 22, 2016 Afternoon Dave The quote below is from an early release BMW info letter-- It looks like no knock control on the WC engines (at least at time of the below letter) 95 RON=91 AKI Link to comment
John Posted April 26, 2016 Share Posted April 26, 2016 Interesting. In AU we use RON ratings. I was told to run the bike on 95 (which I do) and the manual supports. The service manager at the dealer said that if I can't get 95, run it on 91 and not 98 (the next higher rating). His justification was that they have had several bikes back which were running rough on the 98, in particular poor idle and surging (ala the old R1100's). I was skeptical, but a week or so ago I was away on a trip where I could only get 91 or 98. So I filled with 91. What I did notice was that for normal riding I noticed no difference in performance. However, when giving the bike a hard run through the twisties (on Dynamic) it felt like it was in Rain mode. Significantly down on power. So it's clear to me there's some kind of intervention to deal with lower octane fuel, because when I refuelled with 95 it was back to its old self. Link to comment
realshelby Posted April 26, 2016 Share Posted April 26, 2016 There should be no discernable difference in performance between your 95 and 91 RON fuel. Only a dyno test would show any difference. Technically the 91 could in fact produce slightly more torque, everything else being equal. More likely the fuel you bought was either blended with ethanol ( don't know if y'all have that down there?) or for some reason below the standard of the 95 RON fuel. As for the 98 RON causing issues it would have to be run all the time to do anything. We did see owners running our "premium" grade gasolines in Ford Explorers back in the late 90's and early 00's and that cause a LOT of carbon build up. But that was the worst case scenario. Surging with the higher octane fuel makes no sense, but I am not there to see it.... Link to comment
Ride200mi Posted July 19, 2016 Share Posted July 19, 2016 So there is no knock sensor....... But mine knocks...... Sometimes ALOT....... On my last outing to CO and UT, I was using CONOCO gas as this was the most prominent name brand around. I'm going out on a rant here, so bear with me..... This brand of gas (premium 91) really sucks. Now I understand that most, if not all, are independently owned, but this gas, w/up to 10% ethanol, was not what I wanted to hear from the engine. Nothing but PINGING!!!! No load, 1/2 load, full load..... The only time it wasn't pinging was at idle. So after the 2nd day, I stopped off at a auto parts store and bought some Lucas octane booster (up to 104). Well this did the trick. No more pinging. A little better low end throttle response, cold started a little easier but thats about it. I'm not sure if it might have been because of the ethanol or...??? I then found a Chevron (w/still the 10% ethanol), but was still adding in the booster. So even back home in AZ, I still have a bit of a ping going on (always seem to have this sense new really) but now will be using a booster. I just cringe thinking I will alway have to have some kind of additive to the gas to make it sound like I'm not going to blow it up........ Link to comment
realshelby Posted July 19, 2016 Share Posted July 19, 2016 While you seem to be pleased with the results of your additive, there is more going on here. It is not likely your bike is pinging with no load. That is some other noise. If this was true detonation at all times the engine is under any load, you would have damaged the engine by now. My RT makes a noise that sounds a lot like detonation. Especially noticed when making a short local trip without ear plugs. But it is not detonation. I ran it low on gas and put a gallon or so of unleaded race fuel in it. Same exact noise, and that was 104 octane fuel. Link to comment
Ride200mi Posted July 19, 2016 Share Posted July 19, 2016 I tend to agree with you, however when the engine quiets down because of the additive, well from my past experience I think it is from bad gas octane. This bike has always had a noise of pinging and the dealer also told me that it shouldn't be detonation. But I have filmed w/sound and presented it to the dealer, they too feel it might be a detonation coming from the head. Can they do anything about it? They can not because BMW said it is not from pre-ignition. I said that this needs to noted on my service record incase the engine decides to launch. They agreed..... Link to comment
realshelby Posted July 19, 2016 Share Posted July 19, 2016 Pre-ignition is not detonation. Pre-ignition is when the fuel/air charge is ignited by something other than the spark plug arc. Detonation is the uncontrolled explosion of the fuel/air charge AFTER it has been ignited. You could have pre-ignition under light loads. But that problem is very uncommon in todays engines. Link to comment
Ride200mi Posted July 19, 2016 Share Posted July 19, 2016 Realshebly, my point of the response was this...... My experience with a brand of fuel was not what was expected. And while you seem to think that these bike should or will not "ping" is up for debate somewhere else. I have a noticeable "noise" coming from the bikes engine when a lower grade octane is used. Noted by when I added the octane booster the "pinging" disappeared. Now call it what you want. Some gas stations aren't dispensing correct grade fuel. And although I may not be experiencing "pre-ignition or detonation", the engine was "pinging" before I added the octane booster and then stopped COMPLETELY after the additive was used. And if you think pre-ignition is uncommon in today engines, well that your opinion...... And just to clarify..... My description of "no load" can be one of a very "slight load"..... Flat road with just keeping current speed.... If that makes sense. Link to comment
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