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1. Probably not. The plugs were not tight enough to not eventually come loose, with devastating consequences. But probably not loose enough to cause compression leak and lean conditions, which is what destroys the plugs when they do become too loose.
2. If you mean a NA engine, usually none. Colder plugs are less prone to detonation. If you were running lower octane fuel, or had higher cylinder pressures due to boost, colder plug is a benefit. If you are stock motor, running proper fuel, and your ecu isn't pulling ignition advance due to knock sensor hits, a colder plug won't do anything.
That is assuming the stock plugs specified for the motor, and the octane specified, indeed result in ECU not having to pull ignition on a regular basis. Maybe there is something I don't know, and this scenario is something that happens with our cars, so colder plugs would indeed help. Curious to know since this isn't something I've heard about before.
Believe me when I tell you that felt a significant difference in engine response, rev-ability and power throughout the rev range when I swapped from my nearly new PFR7-11S to Iridium BKR8EIX which weren't even new but less than a year old. Now the differences I mentioned weren't off the charts of course as the engine performed very well with its stock plugs but any keen owner/driver will experience such differences in their cars. In the land which I live we don't get high octane fuel at the pumps unfortunately. The most we get is 95 octane which I believe is equivalent to US 91 RON...? US guys get 93 RON there which I wish I got here... (I'm not an expert on the octane vs RON ratings so feel free to expand on this if I mixed anything up).
Another thing to note is that I am 5751 ft above sea level which sucks because I know my lady will perform even better at sea level!
Pump or posted octane (PON) in North America is (R+M)/2 which is about 4 to 6 octane numbers lower than RON. Call that an average of 5. Recommend octane here is 91 PON which corresponds to 96 and 93 PON octane to 98. 93 octane is far from universally sold here. California seems to max out at 91 and I only found 91 in Illinois and Wisconsin when fueling there. Hardly a massive sample.
Octane is a measure of pre-detonation prevention, not power. At higher altitudes the thinner air takes care of this so a higher octane is unnecessary. Rule of thumb is 3%/1000' power loss/gain. At 6000 feet your engine has only about 82% of the power it would have at sea level. Using 93 (or 98 RON) octane ain't gonna help 'cuz all it does is suppress pre-detonation which isn't going to occur using 95 RON. Fuel in the mountain states in North America is commonly a couple of octane numbers lower at 85 and 86 for regular vs the usual 87 octane elsewhere. 85 regular, 87 mid-grade, 91 premium -- probably similar to where you are.
If your ECU is tune-able you can get some more power out of 98 RON than 95 but that takes some effort. The OE ECU can only do so much.
Honda states fuel octane less than 87 can result in engine damage. Less than. Can, not will. Too far off the main roads I've had anxious moments trying to find even 91.
Pump or posted octane (PON) in North America is (R+M)/2 which is about 4 to 6 octane numbers lower than RON. Call that an average of 5. Recommend octane here is 91 PON which corresponds to 96 and 93 PON octane to 98. 93 octane is far from universally sold here. California seems to max out at 91 and I only found 91 in Illinois and Wisconsin when fueling there. Hardly a massive sample.
Octane is a measure of pre-detonation prevention, not power. At higher altitudes the thinner air takes care of this so a higher octane is unnecessary. Rule of thumb is 3%/1000' power loss/gain. At 6000 feet your engine has only about 82% of the power it would have at sea level. Using 93 (or 98 RON) octane ain't gonna help 'cuz all it does is suppress pre-detonation which isn't going to occur using 95 RON. Fuel in the mountain states in North America is commonly a couple of octane numbers lower at 85 and 86 for regular vs the usual 87 octane elsewhere. 85 regular, 87 mid-grade, 91 premium -- probably similar to where you are.
If your ECU is tune-able you can get some more power out of 98 RON than 95 but that takes some effort. The OE ECU can only do so much.
Honda states fuel octane less than 87 can result in engine damage. Less than. Can, not will. Too far off the main roads I've had anxious moments trying to find even 91.
-- Chuck
Most informative, thanks I'd run the highest octane I could find (I believe this is Honda's recommendation in the manual "run the highest octane available" unless I saw that in another car's manual or somewhere on the Net) so if 96 or 98 were available here then I'd run 98 all the way unless it was ridiculously more expensive than 96.
Now on the topic of more power at altitude on higher octane - I ran Liqui Moly octane booster (called Benzin which is German for fuel) and on the dyno I gained 1.5 to 2kw more at the wheels (roughly 4-5 whp) at this current altitude so the ECU must have been happy with the higher octane offering more resistance to knock/pre ignition to advance timing that much more generating the higher HP...yes?
And on that note I noticed my daily Corolla feels sluggish if I run 93 but peps up a lot if I run 95.
Last edited by RolanTHUNDER; 05-16-2019 at 05:17 AM.
The ECUs in many cars/trucks can adapt to higher octanes and tweak the timing for more power and less fuel use. Not sure just how much more the S2000 ECU can do than the 4 or 5 horsepower you're getting with an octane booster.
Slightly off topic: The Ford 3.5L EcoBoost engine in my Expedition SUV drinks 87 pump octane every day. I forget the power it makes but it will make significantly more power using 91 or 93 octane. This is reputedly because it's secretly really a "premium fuel" engine that will run just fine on regular. I do run 93 on those occasional weekend I tow my travel trailer but even on 87 there are no towing issues.
The Ford owner's manual states:
Your vehicle is designed to operate on
regular unleaded gasoline with a minimum
pump (R+M)/2 octane rating of 87.
Some fuel stations, particularly those in
high altitude areas, offer fuels posted as
regular unleaded gasoline with an octane
rating below 87. We do not recommend
these fuels.
For best overall vehicle and engine
performance, premium fuel with an octane
rating of 91 or higher is recommended. The
performance gained by using premium fuel
is most noticeable in hot weather as well
as other conditions, for example when
towing a trailer. See Towing (page 202).
Don't know about Honda but but Ford does not like any manganese in octane boosters:
Do not use:
• Fuels containing metallic-based
additives, including manganese-based
compounds.
• Fuels containing the octane booster
additive, methylcyclopentadienyl
manganese tricarbonyl (MMT).
The use of fuels with metallic compounds
such as methylcyclopentadienyl
manganese tricarbonyl (commonly known
as MMT), which is a manganese-based
fuel additive, will impair engine
performance and affect the emission.
Colder plugs have more insulation around the center electrode, hotter plugs have less. The hotter the plug, the hotter it gets, this is good for burning off deposits, but can also cause pre-ignition of fuel. Colder plugs foul faster but resist pre-ignition. You have to find the right balance between the two.
The only way a colder plug will make more power is if the ecu is having this constantly pull ignition timing advance because of detonation. One fix for thatwouod higher octane fuel. Another would be colder plugs.
If your engine is not currently pulling timing, colder plug won't help you.
What reason would your engine be pulling timing if its stock and running factory recommended plugs? If it had alot of carbon buildup on the tops of the pistons is one reason. A better fix than colder plugs would be to remove such carbon.
That is what Seafoam i supposed to do. Its also possible to 'steam' clean the engine by very, very carefully injecting water into cylinders while engine its running. I've done this with success, based on view into cylinder through plug opening. Followed a diy I found on this forum.
Since then I've kept it clean by means of regular Italian Tuneups...
Rolan, what is the idea behind using one-step cooler NGK plugs? I'm currently running NGK Iridium IFR7G-11KS plugs.
Thanks!
The idea for me anyway is this: in technical terms we can say that the BKR8EIX is superior to the PFR7-11S. The colder plug contributes to cooler combustion chamber temps which would help the engine make a tad bit more power when the ECU realizes this change. The colder plugs weren't too pricey to begin with so I viewed it as a possible mod that would give some bang for buck and just because I love modding
When I swapped the plugs out for the colder plugs and felt the engine was quicker, I was sold. One of the reasons for this heightened response is the finer plug gap of the BKR8 (less than 1mm) compared to the PFR7 (1.1mm). I did not gap the Iridiums, I just installed them out the box as is.
Slowcrash mentioned some of the differences between hotter and colder plugs above.
05-15-2019, 11:06 PM
