YotaCurly

Ok guys I be ran two tanks of 93 octane in my 3vze I've noticed more power better throttle response and the truck just runs better overall my dad says he doesn't think it's good to keep running in my engine but I've read up and it says its for engines with high compression in which my engine has been rebuilt bored 40 over and has compression of 175per cylinder I'm just wondering if this is high enough for this fuel as the truck runs better and will it hurt my engine ? Thanks guys

arlindsay1992

iTrader: (8)

The octane rating doesn't give you any more power necessarily. Some stations have less ethanol in the higher octane fuels or less extra filler stuff. That is the only benefit that high octane fuel has to a motor with a modest compression ratio. The reason high compression motors need the higher octane fuel is to prevent predetonation, or the fuel igniting early from the heat created in compressing the fuel mixture. That would be very bad for your engine. Using high octane gas in a modest compression engine is pretty much a waste of money. The doesn't really tell as much as the compression ratio. Our engines run something between 9 and 10 to 1 compression ratios. It isn't until you get above 10:1 that I would worry.

MudHippy

Toyota's EFI systems with ESA(Electronic Spark Advance) take advantage of the additional anti-knocking performance and higher combustion temperatures of high(er than 87) octane fuels by using feedback from the knock sensor. With ESA the ECU constantly applies as much ignition timing advance as is possible without creating knocking/pinging. Thereby more power and fuel efficency can be achieved using higher(than 87) octane fuel. Because, using a fuel with a higher(than 87) octane rating = more resistance to knocking/pinging and higher combustion temperatures + more ignition timing advance = more HP/torque and fuel efficiency.

Meaning, Toyota's EFI engines with ESA(Electronic Spark Advance) are designed to run on fuel with octane grades 87 and higher. Using fuel with octane grades higher than 87 yields relative increases in engine performance based on how much higher the octane grade(than 87). This is a proven fact, as Toyota states it clearly in their advertisements and technical literature.

From the 88 4WD Truck sales brochure.


From page 8 of this technical document.

YotaCurly

Wow guys I didn't expect that thorough of and explanation but it's great info and I appreciate it my main thing like I say is I don't wanna hurt a new engine but 93 seems to run better just can anyone verify I will not hurt my engine because I have not read anything about this messing up a engine thanks guys I want as many replays as possible

arlindsay1992

iTrader: (8)

You learn something new everyday. I didn't know that about these trucks.

TNRabbit

I've been using 93 octane for 5 years now. I consistently get better mileage (1-2 mpg) with it & it just seems to run better/have more power.

Avoiding gasoline with ethanol helps even more (if you have that option---no can do in Southern MD).

YotaCurly

Thanks guys I'm gonna continue running this fuel then just wanted to clear it up a lil guys thanks for all the input!!

pwd

Thanks for the info and more importantly... the proof.

For the record I recently put 89 Octane instead of my usual 87 in my worn out 3.0L and I seemed gotten slightly better fuel efficiency. I am going to try 91 octane next time just for fun.

Chip N Sawbones

Is this also true with the 22re? I noticed the brochure was from the V6.

MudHippy

AFAIK, it's not only true for the 22R-E , it's true for ANY engine that uses a knock sensor.

lobukbuild

its not just the octane. i agree with all that has been said but what most of you are expieriencing is that higher octane fuels are a higher quality fuel as well (different fact other than a higher octane level). fuel is a mysterious thing, higher compression ratios (not compression psi ) demand higher octane to prevent detonation, among other things. using higher octane in a lower ratio motor will not harm it but is considered unnessesary and a waste. however the fuels of a higher oct rating are of better quality as well and offer up some improvements in performance. there is some argument as to the better throttle response being a direct link to the octane level and could be true, but all your improvements are mainly due to the higher quality. as i mention improvements and performance i am refering to everything in general , like better mileage, smoothness, response, the feel of power ,etc. now if your were to put this same motor on a dyno you would be shocked to see how little this improvement really is but driving it seems like a big differences. basically if you can afford high test go for it ,and enjoy it , with no worries.

MudHippy

Define "higher quality", and EXACTLY how that has anything to do with it. since that's the only mystery I see here thus far. The rest is just about as straight-forward as it could possibly be.

One more thing, I have seen dyno results(watch a lot of that Hot Rod TV if you catch my drift). And all the engines I've seen tested, regardless of compression ratio, make more power on fuel grades higher than 87. Some don't make max power on 93 octane. Some want a little higher octane than that, some want a little lower octane than that. Ever wonder why you can't find fuel rated below 87 octane? Because anything LESS won't even work!!!

Bottom line...buy the cheapest fuel you can, and you'll be guaranteed to get the worst engine performance from it. And that don't have a damn thing to do with "quality".

brianh699

85 octane fuel is available here in Utah, the highest available at the pump here is 91 octane. I won't run 85 but I know people who do with no pinging or knocking. There engines probably look like crap inside though.

lobukbuild

a little confused. it has everything due to quality. not octane!!!!!!!!! octane MAY have an effect on throttle response but that it.

lobukbuild

sorry to be a what ever! ive built drag motors sense the 70s and will argue this till i die. quality fuel is what your seeing, not octane!!!!! OCTANE IS A REQUIREMENT OF COMPRESSION ratio no more no less!! some motors run better on low octane , look up the spects on an 80s olds cutlass, nuff said.!!! this is my thing dont second guess it! the throttle response is an un proven bonus that has not been exsplained or proven in my eyes yet.ive run 120 octane on dynos and thats at 800 - 1000+ hp at 8500 rpms with 16:1 compression RATIO not 170 psi compression even tho that is nice but whats the ratio tjhats what matters, please forgive me im an old school guy thats got a serious opinion on the subject and can get a little heated under the collar over it after dealing with it for 30 years.

lobukbuild

my apollogies , and showed a little attitude its a subject close and dear to me and i have maybe over stepped my relm.

Chip N Sawbones

I forget exactly why, but being at higher altitudes allows you to burn low octane fuel without predetonation. I ran 85 and 86 octane in my Camry in Colorado for years and never had a problem. The spark plugs were never fouled, so I guess the engine stayed clean enough inside.

Resto-noob

iTrader: (3)

No, you didn't get too heated.

Can you please tell me(I trust your opinion) if I should run 93 in my sleds, chainsaw, and bass boat? The boat is 4 stroke, the others aren't. I tend to run 93 in them since they don't go through as much gas per year-it costs me about 20 extra per year give or take.

Threadjack complete.

lobukbuild

deffinatly use the best gas you can justify paying for.they run cleaner, safer and will give you the added benifit of some performance mainly due to the cleaner, safer properties. 2 strokes seem to like it more. remember that octane is basically the burn rate of the fuel, higher octane the slower the burn.the slower burn=longer burn, longer burn=more efficient burn. the big problem lies in the fact in order to to be ignited propperly it needs to be compressed tighter into a smaller space. slower burning fulls need to have less contaminents and by product like fillers and additives. there is a point of over doing it and the gains will start reversing. although this is unlikely with any fuel that you could buy at the pump as the rating (even 93-94 octane) is on the lower side of the full specrum of fuels. ived used 101 octaine in a very mild rotax motor that ran so clean that it was hard to tell that the plugs were ever used by the end of the season.this alone would seem to give you the feeling of more power because its simply just running better and not getting fouled and dirty. back to pump fuels, average motors are between 8.5:1 and 9.5:1 compression ratio and the different levels of fuel at the pumps will cover these needs.the reson they dont have lower octane ratings is due to that there arent any motors with lower ratios.motors require a minimum octane rating based on their ratio in order to run with out detonation. you can run higher than the minimum requirement but not lower. the cause of detonation has alot of variables like heat,timing,altitude,etc. and can be another entire page on its own.basically higher oct fuels are of higher quality with less additives, octane does help performance to a small degree in the average motor but more gains are from the quality. this is not easy to explain without writing a book and including every possible variable. motors make power and performance and fuel is just a tuning device to allow that motor run at full potential just like setting propper timing and using the right size carb, etc. we are getting to deep for a subject this complicated. yes do use the best fuel you can buy , your motor will thank you, it will not harm your motors. octane does play a part in performance and gas mileage but is more due to the composition of the fuel its self. to much octane can/is be considered a waste.the biuld of the motor has the most effect on performance. lower octane fuels (-85) are available but not sold for use in automotive motors (white gas for a colman style camp stove will run a lawn mower with out knocking) the 101 rating that i used was bought from a local airfield (very strict quality standards set by the feds) and ran better times than a major name brand racing fuel at 105 rating

lobukbuild

my only piont was its not just the octane level that increases the over all performance. there is alot more to fuel than its burn rate. and that is all that octane determines.