20 HP / 14 lb-ft torque gain from 91 Octane gas on Tacoma Gas Engine 2.4 i-Force (dyno tested by Sti

1st tank I put in prem. 2nd I put in reg...I don't drive it like a racecar so I won't notice much power difference, especially with the MT. The MPGs were a bit better with premium. My 3rd gen had a premium tune so I'm used to the expense... For piece of mind, I'll be using premium for now on.

 

A snorkel. The issue is an electrical connector (Can't be moved) and the passenger side Hood Pad mount.

 

Don't the detonation sensor and ECU take care of pre-ignition and knock in modern vehicles?

 

Knock sensors sense knock when it’s happening, while higher octane fuels could prevent it before that point.

I’d get a lot of knock in my old 99 and my Hyundai. Just for a second and mostly at low speeds and high cylinder pressures. The engines did adjust, but I always wished it didn’t happen at all for the sake of longevity

 

My old Hilux 4 cyl manual was a gorgeous knock queen. Despite that she had a long beautiful life. Still regret that sale, but at the time I needed the cash badly.

I'm reading this thread predominantly from a cost/benefit eye. Around me it's 33% more to buy 91 octane right now. For maybe 10% HP gain, maybe 10% MPG improvement, and likely already infrequent knock & preignition due to ECU adjustments in normal daily use, I would be happy using premium under high load like when towing or consistent mountain use, but probably not otherwise. I do recall testing premium on my 2011 4.0L and got about 10% MPG improvement, at a time when premium fuel was only about 10-15% more expensive, so I did it frequently back then. But I can understand others' cost/benefit scales leaning more towards wanting the small performance gains in normal daily driving or the peace of mind having a little less knock/preignition in case it might eek out a few more miles of engine life a decade or two down the road. Reminds me of the judgments people make regarding frequency of oil change, an instance in which I'm actually on the more cautious side (oops, I just opened that pandora's box, sorry).

 

Oh yeah, I’m sure it’s fine. Everyone makes their own cost:benefit analysis.
For me, at 12k miles a year, assuming 1mpg difference, it’s ~$175 a year for a little more towing power and peace of mind. I’m fortunate enough to not notice that

 

I just spent two hours again on what should have been a 30-minute tops install. This air box does not fit the Trail Hunter. It contacts several interior areas.

 

Well. That sucks for you. I would offer to work with them on a modification or alteration to get it to fit. They might give you one for free for helping them out...

 

Most of my driving is freeway. I ran 87 for the first 2000 or so miles, and the tankful averages were right at 25mpg. I have since bumped it up to 93 (no 91 at my local station) and the tankful averages are now around 26.5mpg. I never romp on my vehicles so I can’t compare seat-of-the-pants befores to afters.

 

I don’t disagree with anything this video has to say about octane and turbo’d engines under max load. However, I really don’t understand why they would make essentially scientific assumptions about the 87 octane being the reason for the four initial runs. He said they had 1/8th tank and then drove it to the gas station to fill with high octane fuel. They burned off some of the 87 driving it and then diluted the added high octane with the remaining low octane. What’s left in the lines is being consumed on the drive back. I question how much 87 was even in the lines by the time they got it on the dyno.

For a scientific result you need to isolate the test runs. Dyno on a full fuel tank of 87 then drain the system. Fill with high octane, drive it for 50 miles to be sure any residual 87 is gone from the lines and then do the next high octane dyno.

*Edited to remove inaccurate information regarding return fuel line. The 4th gen has a returnees fuel system.

 

Kinda why I am running several tanks of 93 octane before I decide a long term direction.

 

Fuel system has been returnless since 3rd gen.

 

Good to know. Have you got a link to the regulated fuel pressure the fourth gen uses? I'd be interested in reading about that.

No return line changes nothing about the fact that they have no idea how much 87 was left in the fuel system, though.

 

I had the dealership fill it with Shell V-Power from new and that’s all it gets…… Ever.