I use 89 only in hot, dry weather, otherwise it's 87
My new regimen is 91 only on hot 100+ degree days and 89 otherwise.
I use 89 only in hot, dry weather, otherwise it's 87
My new regimen is 91 only on hot 100+ degree days and 89 otherwise.
I'd love to see you dyno it and see if there is a difference. Near the end of a 91 tank on a hot day, dyno it, and then next fill-up, get 87, and near the end of the tank on a day with similar temps, dyno that.
They shouldn't charge you more than about $25-80 per 3 pulls. That will save you money over the life of the vehicle if they can show you that the 87 isn't "costing you" anything.
Also bro...science!
Do it for the rest of us.
I switched from 87 to 89 octane (91 for 100+ degree temps) NOT for HP or TQ or MPG gains. Lets get that out of the way.
I switched as to minimize the amount of instances where detonation occurs. Detonation will always occur and there's no way to avoid it. A higher octane minimizes detonation which is especially important considering the skyactiv engine is extremely high compression. Although Mazda has gone to great lengths as to minimize knock, it cannot eliminate it. No engine can. What helps a lot is the 4-2-1 header which allows us to use 87 safely within spec. The 2016+ Miatas do not have room for said 4-2-1 headers and they require the use of 91 octane. So I'm merely helping the ECU out here. Plus the whole skyactiv pulling timing during extreme heat thing I mean you have to give credit to Mazda for keeping us safe from detonation but I want nowhere near the edge the Skyactiv detonation protection zone. I want to be well within it.
I guess my question then for everyone is:
Does the Skyactiv ecu eliminate knock 100%?
Does higher octane help minimize knock for engines in general?
What does knock (detonation) do for a car under load (especially is high heat conditions)?
the new miata recommends 91 octane, not requires it... it is because it has more aggressive ignition timing and cam timings (the cams are different than all the other 2.0l SkyActivs)
Your MPGs might improve slightly with high octane gas, but what's more important is less fuel dilution of your motor oil... this is a known phenomenon with the SkyActiv engine... it's been tested over and over with proven results... you use cheap regular gas in it, the oil gets quite a bit of gas in it... use high octane? hardly any
Under WOT, up a hill, towing a trailer, yeah, you could probably trim more than 8bhp off the output. B ut really...why don't you just use a little less gas pedal, or not stress about it and let it pull the power? who cares?
You would be surprised to see how many Toyota Prius's try to race me up the I-8 from Arizona heading into California. Up the mountains. I need as much power from my 2.0 155hp engine while running AC. Go easy on the gas? Those Prius owners make it tough LOL!!!!
Okay jokes aside. Am I wasting a few bucks getting higher octane fuel even though I'm in the safe zone using 87? Likely so in most cases. Is there a placebo effect which makes me feel good about my Mazda which in turn improves my well being, my vertical jump, my confidence? Is it worth it for me? Heck yeah!!!
(in a corny douche guy hitting on chicks in a club voice) I like using 89 even though the manual states 87, because I like living on the edge baby.
...what's more important is less fuel dilution of your motor oil... this is a known phenomenon with the SkyActiv engine... it's been tested over and over with proven results... you use cheap regular gas in it, the oil gets quite a bit of gas in it... use high octane? hardly any
I'd love to see you dyno it and see if there is a difference. Near the end of a 91 tank on a hot day, dyno it, and then next fill-up, get 87, and near the end of the tank on a day with similar temps, dyno that.
They shouldn't charge you more than about $25-80 per 3 pulls. That will save you money over the life of the vehicle if they can show you that the 87 isn't "costing you" anything.
Also bro...science!
Do it for the rest of us.
Here is the DYNO results in this PDF. Test resulted in 3.5 hp GAIN between the 87 and 91 octane on the Mazda Skyactiv 2.0l motor...
or a difference of 2.36%..
(birthday)
Apply the same 2.36% increase to 184 hp, and you get 188 hp... it is there for you if you want it...http://publicaffairsresources.aaa.biz/wp-content/uploads/2016/08/Premium-Fuel-REPORT-FINAL3.pdf
I'll keep the extra $5/tank, thanks, lol!
Thanks for finding this AAA Premium Fuel Research report. I guess this conclusion from the report should summarize it all:Here is the DYNO results in this PDF. Test resulted in 3.5 hp GAIN between the 87 and 91 octane on the Mazda Skyactiv 2.0l motor...
or a difference of 2.36%..
(birthday)
Apply the same 2.36% increase to 184 hp, and you get 188 hp... it is there for you if you want it...http://publicaffairsresources.aaa.biz/wp-content/uploads/2016/08/Premium-Fuel-REPORT-FINAL3.pdf
Inquiry #1: Does an engine designed to operate on Regular gasoline produce more horsepower when operated on Premium?
⋯
4.2 Findings: Maximum Horsepower
The vehicles tested did not produce more horsepower when using Premium gasoline. While some differences were recorded when comparing Regular to Premium fuels, they are very small, and are within the expected differences in run-to-run variation for maximum horsepower testing. The data collected does not support any conclusion that Premium fuel allows a vehicle designed for Regular to produce more maximum horsepower.
You are very welcome! I figured you would enjoy all the hard scientific data too!(usa)
Here we don't have a $5 difference in CA, usually only $.20-25cents diff so with a 13 gallon fill up here it is only about $2.80-$3.25 diff in a tank of 87 vs 91
I'll keep my 93 here in high temp, high density altitude San Antonio.. even before I was 93 tuned.
Snip...
Your MPGs might improve slightly with high octane gas, but what's more important is less fuel dilution of your motor oil... this is a known phenomenon with the SkyActiv engine... it's been tested over and over with proven results... you use cheap regular gas in it, the oil gets quite a bit of gas in it... use high octane? hardly any
Non US 2.0 models get 163 HP running 91 octane. I wonder if Canada and Mexico gets the lower compression models like here in the US?
On another note as Unobtanium pointed out...87 gas may really measure 85-86 depending on the station and pump? If true a case could be made that getting 89 would provide a safe buffer in that it may measure anywhere from 87-89.
I'd be interested in reading more about this too. What's the cause? I'm familiar with the cause of oil dilution in diesel engines using bio-diesel but this is the first I've heard of it in gasoline engines caused by using different octanes.