higher octane solves "this problem", whatever the cause of "this problem" actually is.Some of the turbos seem to be prone to it. I started using mid-grade almost immediately when I got mine and no problems. That's like saying 'I wear a garlic around my neck and so far have not been attacked by a werewolf.', but there is science to it - the higher octane will prevent knock up to a certain point depending on the octane and the engine, but in theory the 2.0L turbo should not knock on regular. That means something else must be happening to cause the anti-knock systems in the engine to be ineffective. Since it is not really known what that might be, I figure I will spend a little more on gasoline quality, which is apparently working. Pretty much the same with the synthetic oil - you don't have to use it but considering the power output of this small engine along with the fact that it has a sensitive turbine bearing, it seems like good insurance.
But as soon as combustion begins, the tip and electrode are exposed to a flame of around 1,000 degrees F, a swing of 1,040 degrees F almost instantly! The spark plug must hold up to this thermal shock over tens of thousands of miles of operation.
Spark plugs must also withstand the mechanical demands created by the pressure in the cylinder bore while maintaining a gas-tight seal. This requires strength, particularly of the ceramic, which is subjected to mechanical stress during installation as well as operation.
The same spark plug that gets hot in one engine can have a relatively low average temperature in another. When hot, the air/fuel ratio ignites on the glowing parts of the spark plug projecting into the combustion chamber, and when relatively cold, the insulator tip becomes so badly fouled by combustion deposits that misfiring occurs due to the formation of shunts (additional ground paths).
To ensure the plug doesn’t run too hot or cold in a given engine, plugs have different load capacities. The so-called heat range assigned to each spark plug characterizes these loading capacities, so the heat range is a yardstick for selecting the correct spark plug. There is no industry standard for heat range; it is determined by the spark plug manufacturer.
The Secret Life of Spark Plugs - Hot Rod NetworkThe supply of heat to the spark plug is dependent on the engine. Engines with a high specific output usually have higher combustion-chamber temperatures than those with a low specific power output. The heat-absorbing properties of the spark plug must match the engine type and application. Thus, the heat range is a characteristic of the thermal-loading capacity of the spark plug.
As already stated, each spark plug must remain within a specific temperature range during operation. To remain within that range, the spark plug for a hot-running engine must efficiently dissipate heat, while the plug for a cold-running engine must retain heat. Various design factors, with an emphasis on the configuration of the insulator nose, are used to adjust the heat range for specific engines and applications.
Most competition engine builders commonly choose a colder heat range plug to prevent possible engine damage.
http://www.enginelabs.com/engine-te...ark-plug-debate-separating-fact-from-opinion/(Left) There’s nothing wrong with a standard copper core spark plug, and some power-adder tuners prefer these plugs for helping tune. These plugs are inexpensive and should be considered a consumable. This is an Autolite race plug that is also configured with a side gap. (Right) This melted plug was destroyed when the nitrous system went lean. While it is a platinum plug – that had little to do with its failure. The plug melted because of excessive heat in the chamber. Likely the air-fuel ratio was excessively lean.
Plugs are still the honest witnesses of what’s going on in the combustion chamber, and as Don Ward, E3 Spark Plugs’ lead engineer, puts it, “It’s the only thing that’s in the combustion chamber that you can see; you can pull it right out and tell where it’s rich or lean, or when it doesn’t have enough—or too much—timing.” Don’s been sciencing out spark plugs in motorsports and street applications for the better part of 40 years, starting with Autolite
These days, you’re probably hearing about heat range when people are talking about bolt-on boost projects, but any time you increase cylinder pressure (through compression or boost), you need a colder plug, and it’s a measure of how much heat the insulator can absorb to maintain proper plug temperatures and prevent it from overheating to the point where pre-ignition occurs. “Heat range is determined by cylinder pressure or compression ratio of an engine. If you have an 8:1 motor, you probably want one of the hottest spark plugs out there, but if you have a motor with 16:1 compression, you’ll probably have the coldest spark plug.
Spark Plug Reading 101: Don?t Leave HP On The Table! - Hot Rod NetworkA broken tip can be a sign of knock, or in the worst case, physical contact with something in the motor (like a piston or large debris).
3. Heat – this is a very critical reading because it it the result of three factors. 1-fuel 2-timing 3-heat range of the plug. Excessive heat is recognizable by a glazing of the insulator and/or a discoloration of the ground wire and center wire. Other indicators of the amount of heat in the plug are the location of the heat color line on the shell threads and the ground wire. At the heat goes up. the color line will extend to more threads on the shell and move farther on the ground wire towards the shell.
For example, if there is a lot of heat in the plug at the point of best power for timing and fuel mixture, then you should try a cooler heat range plug. If you feel confident about the plug heat range and at the track the plug shows heat then consider fuel and timing.
https://www.vdlfuelsystems.com/anything-and-everything-you-want-to-know-about-spark-plugs/2. Choose as cold a plug as possible – this is a fairly new idea but is gaining a lot of popularity among the oval track and road racers. The approach here is to run a cold plug coupled with a lean mixture and sometimes an increase in timing. This choice eliminates the possibility of the plug limiting the air/fuel ratio and ignition timing by becoming a pre-ignition point thereby allowing the tuner the ability to find “best power” in both of these cases. Some reports are that fuel mixtures much leaner, and timing higher than previously thought possible have been run with success. This can be a benefit where fuel economy is an issue. Other benefits to the colder plug are that it is more sensitive to tuning changes as not so much of the fuel is burnt off by the insulator heat, also with the increase in compression ratios and subsequently cylinder pressures the colder plugs have provided some insurance against pre-ignition/denotation and are probably much more in-line with the proper heat range for the cylinder temps. In my opinion the only concern with this approach would be in the low RPM situation where there could be the possibility of misfires. However most of the racing done today is at a relatively high RPM and most racers could probably use a cooler plug with no ill effects and the possibility of some benefits, just be sure you have enough ignition.
no problems at all here since switching to 91+....30k km and counting after cracking two on 87 in the first 11k kmI know we went round and round over this issue on a previous thread. The situation remains the same. a few people are having the problem, and a much larger group of people have no issues at all with plugs cracking.
This in a lot of ways support that it is not fuel problems, but something else failing.
Has anyone running a higher octane in hopes of avoiding this had repeat cracked plugs?
https://www.carlemon.com/yes, you may have a Lemon, provided you’ve given the manufacturer an opportunity to repair the defect.