Opinion: 91 octane is superior. Especially if you have an MT

Were not talking about nutrition supplements here Sonny. Were talking gasoline octane.

 

Putting higher octane in your truck tuned for 87 will be less useful than GNC supplements, actually.

 

Theres no right or wrong answer here. I own a 16' MT Sport and have noticed a difference on 91. Is it enough to convince me to pay extra for as long as I own the truck? Probably not. 11.8/1 is a high compression engine. What I have noticed is the stock tune will PULL timing to prevent detonation much more frequently on 87 than 91. Around town on flat surfaces you won't notice, but pulling something up a steep grade you will.

 

Some of you might not remember but when the 2nd generation Tacomas first came out in 2005. Toyota recommended 91 octane in the 4.0 engine for the first couple years for best performance. In fact my 2007 Fj Cruiser had a label right inside the gas door that stated premium fuel only. They later backed off on that but nothing changed with the engine design.

This is what was stated by Toyota on the subject: 1GR-FE 4.0L V6 from a 2007 Toyota Tacoma. The 1GR-FE is the 4.0L version. Bore is 94 mm and stroke is 95 mm. Output is 236 hp (183 kW) at 5200 rpm with 266 lb-ft (382 Nm) of torque at 4000 rpm on 87 octane, and 239 hp at 5200 rpm with 278 lb-ft at 3700 rpm on 91 octane.

If premium fuel gives you 3 hp and 12ft lbs of torque more on a 10:1 compression engine how much do you think it gives you on a 11-8:1 high compression engine.

 

This thread:

 

I remember that it ran on premium back then, it was rated at 245HP and 282 for torque, I think I still have a magazine with a road test still laying around.

 

From one of OVtune's Blog posts

https://www.ovtuned.com/blogs/news/2gr-fks-toyota-tacoma-bringing-new-life-to-the-tacoma-platform

Running the new OEM tune did significantly reduce these anomalies, but Adding 91 octane reduced these anomalies even further in my experience.

I don't like having stupid dead spots rev range, and I don't like having to down shift to 3rd just to get up a Mountain. The new OEM tune and 91 octane has made it so I don't have to downshift to 3rd anymore. Further, I don't have anymore noticeable knocks, shutters or deadspots. Call me stupid. I really don't care. I like my improved driving experience.

 

I running 89. The reasoning being if 87 is short on octane the 89 will meet the minimum octane rating of 87. Think about it, do we always get what we pay for ?
Does octane have a variance ?
Using the 89 grade gives me peace of mind.

 

I’ve been running 86 in my brand new ‘19 since I bought the truck at the beginning of the year. It runs like a top. My buddy’s ‘16 on the other hand runs like shit. All those shifting and rough running issues? He has them, I don’t. He uses the same gas I do. It’s the tune not the octane

 

Easy bro! It’s Friday.

 

So, you're saying it is time for some well-aged E40?

 

I did a lot of testing of different octanes - and without a question my truck is more enjoyable to drive (even on stock tune) with 93 octane and for that reason, barring any major fuel $ increases, it is the only fuel that I'll pump into the truck. It costs me another $10 per tank or so... but for that $10, my truck vibrates less (steering/gas pedal) the HPFP is quieter, and I don't get the "slight miss" feeling under low load that I get with 87.

I also disagree that it takes FOREVER for the truck to adapt to new octane fuel. Y

es it does settle in more over time for sure, but there is an almost immediate advancement in ignition. These trucks are tuned for a -3 knock feedback value based on finely tuned knock sensors.... when it gets less than -3 there is at least some mild detection of knock (by -8 or so is when I can actually hear the "can of rattling bb's sound" indicative of knock) and the ECU will retard timing slightly until it achieves a -3 knock feedback value. when it's greater than -3 the ECU will advance the timing until it balances back to -3. If you ever watch on an OBD2 scanner / app you will see the knock feedback value and timing advance are always changing based on driving conditions (air/fuel, air density, temps, load, etc., all affect this). With this in mind, on my truck if I had 87 octane in the truck the knock correction learn value was generally in the 15-18 degree range, within a couple miles of a fresh fill-up on 93 octane, this value increased to 26-28 and this ignition advance can absolutely be felt in the low-end power on the truck (on my truck, at least).

 

Please tell me this is a friday post because holy shit.

Knock sensors only work in one direction. You have a timing map and you have a knock sensor. When the knock sensor detects spark knock, it retards the timing from the default setting on the map. There is nothing for it to detect if there is no spark knock and the truck runs at its default map. It doesn't play the "maybe I'll give it a little more" game until it detects knock, it's a static timing map based on engine inputs.

 

This is a true statement btw.

But only really shows on lap numbers during a race. I think it’s a hundredth of a second...

 

I agree that timing adjusts right away. I was talk about the ECU learning and reactions to driver inputs and would not say that a tank of fuel or so / a slew of stop/starts is forever?

Good stuff though.

 

It's because California uses ethanol year-round and ethanol supplemented fuel provides less economy (though it does improve NOx emissions by burning cooler). 2010ish they went to 10% almost state-wide.

 

Spot on. This truck will detonate on 87 in Stock form. It is consistently pulling timing. 91 Octane simply restores the power that you should have had all along.

 

This. Low octane gas has more energy than high octane.

 

If your truck is constantly detonating on it's specified fuel there is something seriously wrong with your truck. The timing map is set up for 87 because it lowers emissions. If you have spark knock so bad you have to go to 91 then you should be at the dealership.

 

First, 5w30 is crap, gotta use elf farts and Lima beans for oil.

Fuel, mix 2 parts dog piss, 9 parts Everclear, on a crushed Barbie doll head and the rest with ky jelly. Best fuel ever!