M8 Engine Temp
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From: poway
Yup,, I do suspect that engine temp and oil temps are that far off on the air/oil cooled models. At least for me.. I bought one of those mechanical gauges and get about 250F for an average.. (no fan cooler) They should be close as oil passages are probably seeing more heat than the engine temp sensor. I suspect the head temp is about 270 there as some of the logs I've collected show them getting close to that number.. I still need to collect a longer period of time or at least collect data after the motor is completely warmed up.
For me the oil temps on the average between 230 and 270F once warm. Still need to compare to monitor engine temps tho.
For me the oil temps on the average between 230 and 270F once warm. Still need to compare to monitor engine temps tho.
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I certainly never stated anything about "safe" temps. Please feel free to use my own words... not yours if you're commenting on my posts. Clearly the engine designers determined that spark advance needed to be removed due to Head temps being higher than optimum. The higher the head temps above 329 degrees, the more the engine designers calculated the need to remove more spark advance from the combustion process. And obviously, there is a point at which the head temps are no longer "safe" for proper engine operation. I assume since the tuning maps do not go above 450 degrees, that head temps above that level would be considered no longer "safe" for a 2017 water-cooler Milwaukee 8 engine.
Last edited by Heatwave; May 5, 2017 at 05:23 PM.
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OK here are your words and the idea you are trying to get to is those temperature are too hot or not safe.
Your assumption and conclusions are incorrect. Combustion is what controls where and when Spark Controls need to be modified not that it is too hot. What the tables are an attempt to do is control when the peak cylinder pressure occurs and keep it as close as possible to its desired engine position. As the fuel mixture hits hot surfaces it wants to ignite and those things must be accounted for. Much the same as Air temperature rises and falls it effects the combustion process the same way.
If and when the HD engine gets too hot the ECM will switch in to protection mode and many things will begin happening to try to cool the engine.
I certainly never stated anything about "safe" temps. Please feel free to use my own words... not yours if you're commenting on my posts. Clearly the engine designers determined that spark advance needed to be removed due to Head temps being higher than optimum. The higher the head temps above 329 degrees, the more the engine designers calculated the need to remove more spark advance from the combustion process. And obviously, there is a point at which the head temps are no longer "safe" for proper engine operation. I assume since the tuning maps do not go above 450 degrees, that head temps above that level would be considered no longer "safe" for a 2017 water-cooler Milwaukee 8 engine.
If and when the HD engine gets too hot the ECM will switch in to protection mode and many things will begin happening to try to cool the engine.
Member
Joined: Jul 2009
Posts: 4,310
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OK here are your words and the idea you are trying to get to is those temperature are too hot or not safe.
Your assumption and conclusions are incorrect. Combustion is what controls where and when Spark Controls need to be modified not that it is too hot. What the tables are an attempt to do is control when the peak cylinder pressure occurs and keep it as close as possible to its desired engine position. As the fuel mixture hits hot surfaces it wants to ignite and those things must be accounted for. Much the same as Air temperature rises and falls it effects the combustion process the same way.
If and when the HD engine gets too hot the ECM will switch in to protection mode and many things will begin happening to try to cool the engine.
Your assumption and conclusions are incorrect. Combustion is what controls where and when Spark Controls need to be modified not that it is too hot. What the tables are an attempt to do is control when the peak cylinder pressure occurs and keep it as close as possible to its desired engine position. As the fuel mixture hits hot surfaces it wants to ignite and those things must be accounted for. Much the same as Air temperature rises and falls it effects the combustion process the same way.
If and when the HD engine gets too hot the ECM will switch in to protection mode and many things will begin happening to try to cool the engine.
As the engine designers remove spark advance due to head temps, the rider will experience reduced engine power. I monitor engine, head and coolant temps to better understand when I will also be experiencing reduced engine power as the ECU map removes spark advance to compensate for higher Head temps.
So to help you out, try substituting "too hot" for "reduced engine power". From my perspective, that's the only reason to monitor engine, head and coolant temps on an otherwise healthy engine. By understanding whether the engine is "too hot" a rider can better anticipate what level of performance to expect from an air cooled engine. The difference in power when the bike is running head temps lower than 270 is dramatically stronger than the performance of a bike running head temps above 340 degrees. Those are real conclusions based on riding experience while monitoring temps.
Its a safe assumption that most professional tuners would avoid tuning a 2017 twin-cooled HD bike on a dyno while its head temp was over 340 degrees for this very reason.
Last edited by Heatwave; May 5, 2017 at 07:16 PM.
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I've made accurate assumptions and correct conclusions, unfortunately you're making different assumptions and conclusions than I am. "Too hot" from my perspective is understanding when a bike's engine will have reduced performance, not whether its running at safe operating temps as you appear fixated on.
As the engine designers remove spark advance due to head temps, the rider will experience reduced engine power. I monitor engine, head and coolant temps to better understand when I will also be experiencing reduced engine power as the ECU map removes spark advance to compensate for higher Head temps.
So to help you out, try substituting "too hot" for "reduced engine power". From my perspective, that's the only reason to monitor engine, head and coolant temps on an otherwise healthy engine. By understanding whether the engine is "too hot" a rider can better anticipate what level of performance to expect from an air cooled engine. The difference in power when the bike is running head temps lower than 270 is dramatically stronger than the performance of a bike running head temps above 340 degrees. Those are real conclusions based on riding experience while monitoring temps.
Its a safe assumption that most professional tuners would avoid tuning a 2017 twin-cooled HD bike on a dyno while its head temp was over 340 degrees for this very reason.
As the engine designers remove spark advance due to head temps, the rider will experience reduced engine power. I monitor engine, head and coolant temps to better understand when I will also be experiencing reduced engine power as the ECU map removes spark advance to compensate for higher Head temps.
So to help you out, try substituting "too hot" for "reduced engine power". From my perspective, that's the only reason to monitor engine, head and coolant temps on an otherwise healthy engine. By understanding whether the engine is "too hot" a rider can better anticipate what level of performance to expect from an air cooled engine. The difference in power when the bike is running head temps lower than 270 is dramatically stronger than the performance of a bike running head temps above 340 degrees. Those are real conclusions based on riding experience while monitoring temps.
Its a safe assumption that most professional tuners would avoid tuning a 2017 twin-cooled HD bike on a dyno while its head temp was over 340 degrees for this very reason.
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I am not making assumptions, I know why it's done. Again, I've not only tried to explain to you how it works, by why it is done. As far as it goes, I am one of those designers you seem to refer to and I am trying to teach you how and why it works the way it does. I spent over 10 years doing this very work for HD too. The tuner better damn well look at these adjustment and correct them as necessary for anything but a stock engine build, as that is what those values were done for. A performance engine typically will need different values than a stock engine and at different temperatures too. Just because timing changes does not mean power is reduced, nor does it mean (in your words) "what temp is too hot". As a matter of fact the reason for the timing changes is to keep power output the same, as much as possible. As the combustion process changes (due to temperature changes) the spark requirement changes to keep power output the same. Cylinder pressure changes as RPM and the temperature changes, timing is how you control where those pressures are. Your real conclusions based on your riding experience may well be wrong, if, the tuner did not correct for these very changes. These tables were developed on a known set of parts and as soon as you start changing any of them you need to correct this just the same as you would changing the VE tables or the lambda tables and any good tuner should already know this.
As an "expert" you know that to be a fact. Its why you'd never tune a bike on a dyno with head temps at 340+. Its also why my twin-turbo car and supercharged boat have intercoolers. In fact you'd either let the bike cool or direct more fans to reduce temps to improve performance while dyno-tuning. Not sure why you feel everything must be a "battle royale" but I'm afraid you're wrong with respect to my remarks on "heat". You're focused on the combustion cycle while my remarks were always focused on the riding experience. And "more heat" equals reduced performance after a certain point.
That point of meaningful power loss on a twin-cooled M8 is nearly the same time the designers withdraw spark advance from the tuning tables as a direct result of heat. You know it, I know it and anyone that understands combustion engines knows it. The heat-adjustment timing tables I shared are from HD developers.
Prove me wrong...do a dyno run with an M8 bike at normal operating temps say 250 degrees and then do a dyno run with temps well over 340. Use your own bike as i assume it has what you consider a perfect tune. I guarantee the dyno will show a measureable reduction in power comparing the 250 degree dyno to the 340 degree dyno run.
Last edited by Heatwave; May 5, 2017 at 10:30 PM.
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Seasoned HDF Member
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From: poway
snip
As an "expert" you know that to be a fact. Its why you'd never tune a bike on a dyno with head temps at 340+. Its also why my twin-turbo car and supercharged boat have intercoolers. In fact you'd either let the bike cool or direct more fans to reduce temps to improve performance while dyno-tuning. Not sure why you feel everything must be a "battle royale" but I'm afraid you're wrong with respect to my remarks on "heat". You're focused on the combustion cycle while my remarks were always focused on the riding experience. And "more heat" equals reduced performance after a certain point.
As an "expert" you know that to be a fact. Its why you'd never tune a bike on a dyno with head temps at 340+. Its also why my twin-turbo car and supercharged boat have intercoolers. In fact you'd either let the bike cool or direct more fans to reduce temps to improve performance while dyno-tuning. Not sure why you feel everything must be a "battle royale" but I'm afraid you're wrong with respect to my remarks on "heat". You're focused on the combustion cycle while my remarks were always focused on the riding experience. And "more heat" equals reduced performance after a certain point.
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Joined: Jan 2006
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From: Charleston, SC
1. Hot air is less dense and therefore contains less molecules of oxygen per unit volume. This means less air for the motor in a given stroke and therefore less power produced.
2. Hot air also causes a higher cylinder temperature and therefore can aid in pre-detonation of the combustion cycle causing what we call, detonation.