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Discussion Starter #1
The 5.7 liter Tundra is rated at 381 HP and 401 ft-lbs of torque with 87 octane (Regular). What is it's output with Supreme gas? Anyone know?

Only reason I ask is I know the 4.0 liter in my Tacoma is rated at 236/266 with REgular and 239/278 with Supreme. Both are relatively high compression engines that can take advantage
of it.
 

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Somebody in another thread - I think the "bigger gas tank" one - was saying that their mileage was a good deal better when running 91 octane rather than 87.

Not sure what kind of HP gain you can expect, but getting better mileage / longer range would be a performance gain.
 

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I get worse mileage with super, but by the seat of pants better acceleration. Every once in awhile I run a tank of super through it for the feel good factor. Although, my buddy at work had a check engine light for cat sufficiency come on, ran a tank of super through it and the light cleared... He does admit to normally putting the cheapest stuff he find in it on a regular basis... So who knows... I usually put regular 87 "top tier" fuels in. (Shell, Chevron, Amoco, and Marathon).

I was going to do some gtech dyno runs on regular and than super, but my truck has been acting up the last few months... I can't get intended acceleration all of the time - so I doubt that it would be of any scientific value to do it until Toyota figure out my problem.

Granted most of my driving is city. Although I also noticed the fuel mileage difference between regular and super on my 2005 Yukon Denali XL. (Better MPG with regular) Not knocking the guy that says it is the opposite, just posting my results.
 

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You won't notice the slightest bit of difference in daily driving. For mountain towing with heavy loads, it might be considered 'safer' to run 91 octane fuel just to combat the higher combustion chamber temps under sustained load.
 

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Discussion Starter #5
Well the thing I can't understand is why are none of you guys testing this? I know for a fact that there are few threads, one of which is quite long on tacomaworld where I frequent at times, where several people have tested the mileage difference with Supreme and found it to be worth the increased price of fuel versus the return on mileage alone. When you combine it with the fact that the engine seems to run quieter, and pull harder and have an easier time, it makes supreme gas more then worth it on the 4.0 V6 at least. The 5.7 Tundra has even more technoology than the 4.0 V6 (Dual Variable Valve timing and a few other goodies versus single variable valve timing on the 4.0) so I would think it might see even more gains on Supreme gas.

Keep in mind when I say "difference," I mean guys actually ran SEVERAL tanks of gas on each grade to let the computer adjust. The computer doesn't automatically advance or retard it's ignition timing automatically for each new tank of gas, it takes a few to readjust to higher octane gas. For example, one guy reported he ran 5 tanks of 87, 5 tanks of 89, and 5 tanks of 92, and he reported 15.1, 15.5 and 16.6 average MPG respectively doing mainly city driving in his Tacoma Double Cab (doing the same routes, driving speeds, etc.).

I'm just surprised no one has dyno'd it or at least done some more analysis on this engine. IF you have a high compression engine that can benefit from Supreme, why not. Also, the 5.7 being a larger engine will see larger gains. If I am seeing 3 HP and 12 foot pounds of torque, it'd probably be 5-8 HP and 20 foot pounds-ish with this engine.
 

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It's called premium right? Not supreme? Also if the manual tells me to run 87 octane then that's what I'll run. You wouldn't even feel such a small increase in HP. If you were testing this and you wanted to see better fuel economy it would be easy to accidently manipulate the numbers with slight driving differences. I'm sure though if enough people read this you'll find someone who has tested this. Why don't you test it since you're so caught up in this one MPG and three HP increase.
 

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I ran several tanks of 93* and didn't see any benefit,improvement or justification
to continue the added expense
 

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Let me see if I understand this Thread...If I use higher Octane I will get More Power and Better Mileage, so if I drive over to my local airport and fill up with 100 Octane Avgas I should get a real racing machine that will go forever!

This octane debate comes up on the Forum about every six months and if you had searched you could have read countless pages of octane banter. Anything over the recommended 87 Octane is just a plain waste of money. if you want to use 91 Octane you should have bought a Ford!
 

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Wow, tough sub.
Yup! They can be. But they don't mean any harm! They are just, um, 'direct'.

This one has come up several times. The general consensus through experience is that Premium is for higher performance engines with higher compression and is more resistant to pre-ignition. Not to mention that countless articles have been written which state the same. The gains, if any, are not worth the cost.

With changes of around 1 mpg, seriously, I can get that by playing different music on my stereo. Without a CONTROLLED test, where the driver had no idea what fuel was in the vehicle, and driving an identical course, in identical weather, identical humidity, identical weight, etc its just not scientific enough to be accurate.

BUT, that does not mean you are wrong, or that you can't post your findings/ other info you may have found on Taco World (or whatever its called!). It's all what forums are for.
 

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Yup! They can be. But they don't mean any harm! They are just, um, 'direct'.

This one has come up several times. The general consensus through experience is that Premium is for higher performance engines with higher compression and is more resistant to pre-ignition. Not to mention that countless articles have been written which state the same. The gains, if any, are not worth the cost.

With changes of around 1 mpg, seriously, I can get that by playing different music on my stereo. Without a CONTROLLED test, where the driver had no idea what fuel was in the vehicle, and driving an identical course, in identical weather, identical humidity, identical weight, etc its just not scientific enough to be accurate.

BUT, that does not mean you are wrong, or that you can't post your findings/ other info you may have found on Taco World (or whatever its called!). It's all what forums are for.
Well said, points sent
 

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Back in the 80's lived a while in a state with one of those pita emission test's, course my ragged out car didn't pass, was wondering what to do when someone at work said simple fix"go down to the dirt race track for your next fill up, load her up with the 100 octane race fuel, you'll pass the test", sure enough it worked and the car ran like it was on steroids. Never ran it till next emission test, then moved back to Louisiana where they got bigger fish to fry. I'd imagine the car got better gas mileage.
 

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You should see a big improvement from the reduced weight. Just think how much lighter your wallet will be.:eek:
 

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Doing Dyno test will tell the truth on any mod or improvements.

Problem is no two dyno tests are equal (even for the exact same car the same day)

so if you test a car using regular gas today ( 64F and 20% humidity) and test again next week using premium gas ( temp is now 68F with 40% humidity), you will likely have "gained " 10 HP. Now you are convinced that premium gains you 10 HP even though the test would have showed 10 HP using regular gas just the same.

I have checked my HP using my Scangauge and never got the same numbers (even the same day), The HP varies plus or minus 10 HP every time.
 

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Here's another thing to consider as far as seat of the pants feeling goes. A 3-10 hp gain in a 240 hp truck that weighs 4000 lbs is gonna be way more noticeable compared to a 3-10 hp gain in a truck that already puts out 381 hp and weighs well over 5000 lbs. 3-10 hp is not going to vastly improve gas mileage or performance in a 5000 lb truck. Will you feel it, maybe, but there's a good chance it could all be in your head.

Being tuned for 91 octane on the other hand is a different story.
 

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Just completed a 1400 mile trip, one way was loaded in the back (moving my son's bed, dresser, etc) and I tried 87 and 93 on the way up and back. I got the same results either way. The MPG gain for 93 is trivial, maybe 1 MPG but the difference in power is substantial. Going up the hills the truck would downshift two gears when I was using 87. I'd run the tank almost to the point I was getting scared and then fill up with 93. No more downshifting. And it ran quieter. So I ran 89 since, can't afford the 93 everytime and rreally don't need the power just putzing around town. But the 87 just makes the engine downshift everytime I go up any decent hill.
 

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Premium fuel does NOT equate to Premium performance. Premium fuel is made for higher compression, higher performance engines that operate at higher temperatures. It is needed to reduce pre-detonation, and knocking. In short, premium fuel requires a higher temperature to ignite. While many fungible premium blends may contain some beneficial additives, it is, unequivocally, a waste of money unless your engine requires it. If I had a dime for every person who thought premium fuel somehow gave them better performance....I'd be a rich man. Same goes for race gas (101+ octane)....pure garbage unless your motor requires it.
 

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Johnny are you talking to me? If so its not opinion, its fact. With 87 octane the rig downshifts because the gas doesn't have enough power to keep the truck moving at a constant speed. With 93 octane the truck doesn't downshift and I maintain a constant speed. Period. Fact, not opinion. And if 87 won car races you could bet your last dollar that's what they'd be using. And airplane fuel is 104 octane or better. It has more power per unit than lower octane.
 

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Johnny are you talking to me? If so its not opinion, its fact. With 87 octane the rig downshifts because the gas doesn't have enough power to keep the truck moving at a constant speed. With 93 octane the truck doesn't downshift and I maintain a constant speed. Period. Fact, not opinion. And if 87 won car races you could bet your last dollar that's what they'd be using. And airplane fuel is 104 octane or better. It has more power per unit than lower octane.
I agree with you on your experience with 93 Octane. I live in So Cal, our fuel additives are not the same as yours. Our highest here on pump is 91. So I've been using 91 Shell 99% of the time. Big difference in throttle response and tranny shift. Not much downshifting and you can really feel the pull.
My Tundra is an 07 RCSB. Tried 87, 89, 91, Shell, Mobil, Chevron, and Texaco. 91 Shell works great for my truck. 87 octane de-tunes the truck big time. Slow acceleration, frequent downshifting even when not loaded, sometimes delayed shifting. Before the 07 RCSB, I had an 06 RCLB V6 Tundra. Same experience. Almost got rear ended one time on my 06 V6 Tundra while I was passsing a slow big rig. The tranny did not downshift right away so the truck did not accelerate quick enough. I had to wave sorry to the driver behind me. After that, I drove the truck like crazy. Put it in low gear to use up all the 87 octane gas and then refilled it with 91. It brought the truck back to life. :becky:
 
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