A friend who is a retired engineer who worked in the automotive industry for years says that premium fuel creates less heat in the combustion chamber vs a lower octane fuel. That said I run it when I know I will be doing Long climbs in the Mtns out west here. So it is possible it could keep engine slightly cooler? I am also a firm believer in non ethanol fuel and run that whenever possible. It may be even more beneficial than the premium
Experience with 2 tanks of premium
- Thread starter stiles_s
- Start date
97BlackAckCL
Elite Member
I've been running premium for 5 years and feel like the truck just drives better with it. Granted my ECU is now tuned to run on 93 and the power gain is extremely noticeable, but after a few tanks of 87 when I bought the truck I felt that the gas mileage and overall performance of the truck was always better on 93. To each their own
baldrik78
New member
This. My truck hunts between 4th/5th so much when I turn on cruise control that I just put it in 4th and leave it.
Grug556
New member
I understand the above, was referring to what you posted on its diminished power output in comparison with petrol. Ethanols calorific output as likely you are quite familiar with is quite low in relation to other such fuel alcohols.
I am not in favour with how its produced either, with wasteful corn and such. It being hygroscopic likely more an issue during storage and transport as most consumers tanks dont last to long. But it also means the likehood of you getting shit from the pumps with a high ratio blend is higher than just an unblended gas.
Oh I've been on the same journey and had the same reaction. A few notes -- again 100% agree this is not data. We're just guessing.
For me: my slow ass truck can now more easily make it over the hill to work (freeway) without any dramatic downshifting. I drive this route every day. Nothing else changed. why? who the hell knows.
I can guess:
- I have heard folks say these engines can ping at low RPM. When the knock sensors detect pre-detonation they retard timing. Retarding timing lowers power/torque. So, if this is simply avoiding the engine retarding timing at low RPMs then this makes sense. We're talking 2-3k rpm here. I wouldn't be surprised at all to see an improvement in low-RPM "tip-in" in this scenario. A dyno run which typically only runs 3+ KRPM isn't going to pick this up.
- Transmissions and downshifting have changed a bit in the last decade. Our throttle pedal is a torque request and this interacts w/the transmission in terms of whether the ECU thinks it can make good on the torque request in current gear. If not, downshift. This is why i've found that ecu tuning boosted engines with automatics (modern) plays hell on shift points and makes the transmissions feel much "lazier". Happier to write much more on this separately.
Anyhow. Hooray: my truck can make it over the "hill" to work without reminding me every single day how gutless it is. The only thing that changed was the fuel. BTW I started this before the weather changed here in Seattle, so -- no -- it isn't colder/denser air
Hmm, where can one get this tune? I am new owner of a 4 Runner and would sell my kidney for a good tune.
97BlackAckCL
Elite Member
Here's the one I got, highly recommend it
VR Tuned ECU Flash Tune Toyota 4Runner Dual VVT-I 270HP | VRT-TOY-4RN-270
I'm not sure why some folks are finding it so hard to believe the 4Runner produces more power with higher octane fuel. It's probably true for most modern engines with an ECU that can adjust timing. It's just the reverse of a Porsche/Ferrarri/Lambo/etc. reducing timing to protect itself if you feed it less than the high octane it's optimized for.
An insider leaked HP numbers for the 2.7 Ecoboost in the Bronco before official numbers were published. Ford only recommends 87 for that motor, but they do publish official output ratings for both 87 and 91 octane...with 91 octane producing an extra 15hp due to the ECU being able to advance timing with 91. What I find interesting...the insider leaked numbers actually showed a 30hp difference...the final official rating increased the 87 octane number while the 91 stayed the same.
So, there's definitely more to it than wishful thinking or placebo. Watch an episode of Engine Power this weekend and see what playing with just timing does to a carbureted engine.
An insider leaked HP numbers for the 2.7 Ecoboost in the Bronco before official numbers were published. Ford only recommends 87 for that motor, but they do publish official output ratings for both 87 and 91 octane...with 91 octane producing an extra 15hp due to the ECU being able to advance timing with 91. What I find interesting...the insider leaked numbers actually showed a 30hp difference...the final official rating increased the 87 octane number while the 91 stayed the same.
So, there's definitely more to it than wishful thinking or placebo. Watch an episode of Engine Power this weekend and see what playing with just timing does to a carbureted engine.
blksubykid
Member
Jeez and I thought I was bad with 13.5
I recently got tuned and I am curious to see how my butt dyno and mpg change with octane.
Thank you for the info. This is great.
Wanted to share a few more thoughts here after a good, long drive today. This was a fairly rare opportunity for me to get the 4runner out for a long freeway drive. This is a route I know well. Driven it >100 times (back and forth to parent's house). About 200mi round trip. Mostly freeway. Some hills; some traffic.
After today's run, i'm becoming more convinced that our 4runners do have more low-end power on premium. On regular mine is a total dog at 2k RPM on the freeway. Can't deal with a wind gust without downshifting. Today I was running at 70-80mph; flat, hills, accelerating (slowly) on hills, all without downshifting (with premium). Has really changed the drivability of the truck. It's gone from a huge irritant to something that is "still slow, but livable". The powerband that matters in this case is 1.5k - 3k RPM. I'm nearly certain our truck pulls a lot of timing on Regular when you lean into the throttle at these RPMs. Less ping == more timing advance == more power. I could care less about the power at the upper rev ranges. It's plenty but it's a painful sound that I don't want to hear too often
YMMV. Unscientific. Etc. I'm not motivated to spend more money on gas here, but this has turned out to be a significant game changer for me.
After today's run, i'm becoming more convinced that our 4runners do have more low-end power on premium. On regular mine is a total dog at 2k RPM on the freeway. Can't deal with a wind gust without downshifting. Today I was running at 70-80mph; flat, hills, accelerating (slowly) on hills, all without downshifting (with premium). Has really changed the drivability of the truck. It's gone from a huge irritant to something that is "still slow, but livable". The powerband that matters in this case is 1.5k - 3k RPM. I'm nearly certain our truck pulls a lot of timing on Regular when you lean into the throttle at these RPMs. Less ping == more timing advance == more power. I could care less about the power at the upper rev ranges. It's plenty but it's a painful sound that I don't want to hear too often
YMMV. Unscientific. Etc. I'm not motivated to spend more money on gas here, but this has turned out to be a significant game changer for me.
Charles Bronson
Member
Late turbo tuning strategy is VASTLY different from naturally aspirated motor tuning strategy and power left on the table. With a turbo motor, it is extremely easy to manipulate power/torque, largely through wastegate tuning (i.e., boost production). It's why turbos are so fantastic at altitude. ECUs in most turbo motors these days calculate engine load vs boost being delivered. At altitude, there is less oxygen in the air so when the ECU sees that there is less load vs boost, it increases boost to compensate and meet power targets. With that tuning strategy, a 500hp motor makes nearly all it's 500hp at 5000' elevation vs a naturally aspirated motor that is down about 10%+ of it's power and with no way to correct for it. Load based tuning is also why turbo motors enjoy higher octane fuels and generate wildly different power numbers between using 87, 91, 93, and ethanol fuels.
It is nearly impossible to "add" power to most any naturally aspirated motor by simply giving it more octane than what it was designed to run on. There's just nothing really to take advantage of.
Also, naturally aspirated motors tend not to generate high load at low and mid rpms unlike a turbo motor can that go into very high load at low rpms if driver mashes the gas, thus basically creating a massive amount boost (and torque) because the engine load pushes the turbo into overdrive (i.e., overboost). Naturally aspirated motors can't do this. They might ping and knock around a bit, but that's it. Most naturally aspirated that require higher octane fuels tend to be motors designed to live in the high rpms and have higher compression ratios. 4.0 V6 in the 4Runner is NOT that type of motor LOL
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