Changing Type of Spark Plug Lower Engine Temp?

[KRAM36]

Originally Posted by Quadcammer

uh no. The type of plug is not changing the timing of the spark. Whatever you're quoting is marketing wank. Not to mention, a modern fuel injected car like the 986 very accurately controls the a/f ratio, so this WIDE RANGE would be between about 12.8 and 14.7, which pretty much any plain jane copper plug can ignite all day for 40k miles, especially at our given compression ratio.

Lets start with how are you measuring these temperatures so accurately?

Oh yes the spark can happen faster and with more intensity depending on the what the spark plug is made out of. Have you never watched any videos of different spark plugs sparking? I thought this was pretty common knowledge for gear heads. Go watch some videos on the 4 prong type plugs, they seems to have some latency in their sparking action to them.

If you read my first post, you would know how the measurement was done. By the gauge in the cluster. Now if I had know this was going to happen, I would have logged the temps with my Durametric, it just turned out to be a unexpected surprise.

[maytag]

Originally Posted by KRAM36

Oh yes the spark can happen faster and with more intensity depending on the what the spark plug is made out of. Have you never watched any videos of different spark plugs sparking? I thought this was pretty common knowledge for gear heads. Go watch some videos on the 4 prong type plugs, they seems to have some latency in their sparking action to them.

How old are you?
Waaaay bank in the old days, when we used to have to tune ignition curves with weights and springs, it was important to monitor your flame front; ie, get it moving faster. We'd also maximize the quench area for this very same reason. This was particularly important when cylinder pressures were very high (boosted) or when RPM's were very high (10k rpm and up). So yes, in those days, knowing your spark plugs really well was vital. But only in those very extreme situations.

With today's adaptable/ learning ECU's controlling spark and fuel, based on actual readings from sensors means that you can pretty much slap any old plug in there and you'll see negligible differences, other than longevity of the plug itself. (Again, until you start taking about the extremes)

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[KRAM36]

Originally Posted by thstone

Ok, here's twelve to get us started...

Air temp
Humidity
Pressure
Percentage of cloud cover
Throttle position over the past 5-30 minutes
Load over the past 5-30 mins
Length of time at idle over the past 5-30 mins
Length of time at various speeds over the past 5-30 mins
Fans cycling on or off
Inaccuracy of the temp sending unit
Inaccuracy/inconsistency of visually sighting the temp gauge
Amount of other traffic

My Boxster is my daily driver and it's the only vehicle I have owned since 2013. I know this car like the back of my hand. I can feel when something is out of order. That being said, as noted the previous temp was between 185° to 186° (these temps are under normal driver conditions. Spirited driving would raise the temp more or sitting still for a long period the temp would go up), even in the Winter time and it's been this way as long as I have owned this car. I have experienced every variation you noted in the last week, except for the temp gauge inaccuracy other then Porsche's calibration, which I understand the gauge always reads lower then the actual temp and I don't have inaccuracy/inconsistency of visually sighting the temp gauge needle with over 6 years of ownership with the car being my DD and the only vehicle I have owned in over 6 years. The only thing different in the last week than previous weeks is the change of spark plugs and we are now in warmer weather.

It's been a week now since the plugs have been changed. I have done city driving short runs, highway driving for over an hour. I have experienced every situation in the last week, air temp changes, was very humid yesterday as it rained and went to 71° with Sunshine. Actually turned on the home A/C unit because of it. I have the four stalk column with the OBC turned on, so I can see the outside temps. I've always been puzzled why this car would still run as warm in the Winter time as it does.

Originally Posted by maytag

How old are you?
Waaaay bank in the old days, when we used to have to tune ignition curves with weights and springs, it was important to monitor your flame front; ie, get it moving faster. We'd also maximize the quench area for this very same reason. This was particularly important when cylinder pressures were very high (boosted) or when RPM's were very high (10k rpm and up). So yes, in those days, knowing your spark plugs really well was vital. But only in those very extreme situations.

With today's adaptable/ learning ECU's controlling spark and fuel, based on actual readings from sensors means that you can pretty much slap any old plug in there and you'll see negligible differences, other than longevity of the plug itself. (Again, until you start taking about the extremes)

I'm 51 and I have owned a very wide range of vehicles, all of them except one were fuel injected. I understand the ECU can advance and retard timing and adjust the fuel flow, however, the ECU can not control how quick the spark plug will fire over another plug, electricity follows the path of least resistance, the ECU can not control that and the intensity of spark you will get out of the spark plug do to the materials the spark plug is made out of and can not be changed by the ECU. No, even with today's computer controlled cars, you can't just stick any old spark plug into the engine and expect the engine to operate exactly the same. That's a very stupid statement.

My car ran great with the Bosch plugs and the car still runs great with the NGK plugs. The one thing I am seeing is the temp difference, while not huge, it's a pleasant surprise to see the lower temp. I watch my car like a hawk and I notice everything, even a slight change in the temp gauge needle position.

[maytag]

Originally Posted by KRAM36

I'm 51 and I have owned a very wide range of vehicles, all of them except one were fuel injected. I understand the ECU can advance and retard timing and adjust the fuel flow, however, the ECU can not control how quick the spark plug will fire over another plug, electricity follows the path of least resistance, the ECU can not control that and the intensity of spark you will get out of the spark plug do to the materials the spark plug is made out of and can not be changed by the ECU. No, even with today's computer controlled cars, you can't just stick any old spark plug into the engine and expect the engine to operate exactly the same. That's a very stupid statement.

Hey there, friend: you can call me stupid all ya like.... but YOU are the one making a fool of yourself here.

The ecu doesn't HAVE to control "the intensity", as you call it. All the ecu has to do is measure (with the o2 sensor) how close to stoichiometry the burn is, and then adjust from there, as necessary.

You're sure arguing a lot, for a guy who doesn't understand the subject matter.

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[Quadcammer]

Cool, no biggie.

Now as to your coolant temps, i cant offer any explanation why plugs would cause this temp decrease.

[KRAM36]

Originally Posted by Quadcammer

Cool, no biggie.

Now as to your coolant temps, i cant offer any explanation why plugs would cause this temp decrease.

I'm still thinking the NGK plugs are sparking at a more optimal time with a higher intensity spark. Which gives a more complete burn and allows the combustion to escape through the exhaust valve at the right time.

The Bosch plugs seem to have a bit of latency in their sparking. With the engine rpm at 3,000 just a tiny bit of latency could throw off the combustion cycle. The ECU it telling the spark plug to spark at a certain time and if there is a tiny lag in that spark time, less burn would occur before the exhaust valve opens, trapping some of the yet combusted fuel in the cylinder. Not a whole lot, but enough to make the engine run just a bit warmer.

The car does feel like the engine is running smoother....call it placebo, but as I have said this is my DD, it's the only vehicle I have owned since 2013. So I believe I can tell the difference.

[maytag]

Originally Posted by KRAM36

I'm still thinking the NGK plugs are sparking at a more optimal time with a higher intensity spark. Which gives a more complete burn and allows the combustion to escape through the exhaust valve at the right time.

The Bosch plugs seem to have a bit of latency in their sparking. With the engine rpm at 3,000 just a tiny bit of latency could throw off the combustion cycle. The ECU it telling the spark plug to spark at a certain time and if there is a tiny lag in that spark time, less burn would occur before the exhaust valve opens, trapping some of the yet combusted fuel in the cylinder. Not a whole lot, but enough to make the engine run just a bit warmer.

The car does feel like the engine is running smoother....call it placebo, but as I have said this is my DD, it's the only vehicle I have owned since 2013. So I believe I can tell the difference.

honestly.....
re-read your post. I defy you to do so with a straight face. This is one of the most bizarre, misguided ideas I've seen on this particular forum.

I'm somewhat confused by some of your terminology, so I'd need to clarify your meaning, before I begin to tear it apart.
For instance:
"....less burn would occur before the exhaust valve opens, trapping some of the yet combusted fuel in the cylinder."
by this, do you mean "...yet TO BE combusted..."? Is that what you're talking about? And if yes, then how, in the name of Pete, does it get "trapped in the cylinder" when the exhaust valve is open? And, HOW, also in Pete's name, does UNSPENT FUEL IN THE CYLINDER cause more heat? And if I've got ya wrong, and you mean SPENT fuel (we call that exhaust around these parts), same questions apply.

How about we set that aside for a moment. Let's try this one:
"...The Bosch plugs seem to have a bit of latency in their sparking." According to WHO? Do you have the spark-curves for the two plugs, to compare? Or are you suggesting that, because this is your DD, you can FEEL the "latency" in a park plug? Because you're basing your entire hypothesis (I use that term loosely) on this one factor. So there really should be something behind it given how vehemently you've defended it.

But really, this one just takes the cake, for me: "... are sparking at a more optimal time with a higher intensity spark. Which gives a more complete burn and allows the combustion to escape through the exhaust valve at the right time."

this is just.... i dunno.... um.... garbage?
Are you suggesting that the "timing" or "intensity" of the spark has anything whatsoever to do with when the exhaust valve opens, in relation to the exhaust stroke of the piston? Because if you're NOT suggesting that, then this statement is just plain fanciful misunderstanding of the basics of 4-stroke engines. And if you ARE suggesting that, well then, that's ALSO just fanciful misunderstanding of the basics of 4-stroke engines.

Now, it's possible that what you MEANT to say, is that a more complete burn would allow more...... nope.... see? I can't even think of what you could've meant that would be any less ludicrous than what you wrote.