Is 91 octane really over kill on a 3rd gen?

[JtuckerSvces]

That 4Runner always ran premium. Plugs seems to last longer and look better when they were swapped out.

Right on with my feelings on it, but also i don't know that you do actually see gains or loss in MPG as I don't usually watch that since I drive around with the peddle on the floor unless @70-80 then I cruise.

I can say my parents are firm believers of premium and have been since 1988 in my papaws new 87 S10 blazer and moms silver FWD Charger (probably why I use it). As of recent a 2005 Buick terezza with 160k original miles on the original plugs was traded in running as it was the day it was bought new in 2004 so I believe proof is in the pudding.

It's like oil. You COULD run it for 7500 miles just fine and you could maybe get 300k miles on the motor, but why when you can spend a little extra money and change it every 3500 miles and get 400-500k miles on same said engine. :yield:

 

[jeremyc74]

It kills me that so many people are sold on this idea that higher octane = better gas. It's marketing nonsense.

A higher octane rating means the fuel is HARDER to ignite. Nothing more. The additive packages used in fuels these days are so tightly regulated by the EPA for emissions purposes that there's no way a consumer can tell the difference from one brand to the next.

And to the people saying it makes the plugs last longer....BS!! :toilet:

The original plugs in my truck had 200k miles on them when I pulled them, and were working fine up until about the last 3k. There's absolutely no way you could put enough miles on a vehicle to make the determination that the fuel had an impact on the plug life.

 

[AntleredRuin]

If it is truly BETTER for your engine to go with 91/93, then do it. (so NOT our 4runners) If you are looking to save money by getting better MPGs, it's not worth it.
Maybe Houston is just weird, but most of the gas stations I see have very significant differences in pricing between 87 and 91/93. Honestly sometimes close to a dollar per gallon difference. So you gain 1 or 2 MPGs highway, but potentially pay $15+ more per fill up? Do the math. That's not cheaper.

Kinda like the people who buy an electric car purely for the cheaper 'gas', but pay more on their car note per month than they would have on gas for a standard car...

I don't understand this either in all the supercharger threads around here.
"I got a supercharger, and ONLY lost 1 MPG!"
Well that's neat, but now you HAVE to use premium fuel, which means your gas budget is going to take a much bigger hit than you've anticipated...

 

[MAD 69]

No need for 91 octane - I use a bottle of Lucas Fuel additive at each fill up and avg about 2mpg better using the Lucas as opposed to not using it, great stuff.

 

[mtbtim]

You know, I've never bought into the need to run higher octane fuels. I've always just ran 87 in the vehicles I've owned and they seem to perform just fine but I'm not supercharged.

Interesting comments so far though.

 

[JayRolla]

Ive ran 85-87 octane on all my N/A cars and have never noticed a different in fuel economy or power. Like stated you need the octane rated for your vehicle and nothing more. High altitude can get away with running lower octane. i have noticed a slight ping uphill in he wifes 5.4L Triton when running 85.

Now if you have a supercharger/turbo/nitrous/high compression in your 4runner than yes high octane is needed.

 

[T5RUNNER]

No need for 91 octane - I use a bottle of Lucas Fuel additive at each fill up and avg about 2mpg better using the Lucas as opposed to not using it, great stuff.

Sorry but this is not true. There is no physical way for it to be true, and if it was it would be added to all gasoline. The mpg gain is in your mind, but the money you spend on the snake oil is real. Please don't state opinion as if it is fact. Others who don't know better might read this thread and believe you.

 

[MAD 69]

Sorry but it is true %100 I have a scan gauge OBII sensor n my truck to prove it. But I guess since you have been a member here for a few months you have all the answers?

 

[jkoni426]

Guarantee the RSX S requires premium, the 4Runner does not. So yeah it's a waste of money if you're not supercharged.

 

[LittleCaesar]

So the octane rating on the pump is actually an anti-knock number correct? Calling it (the highest number posted at the station) premium, super, the GOAT, etc is just purely marketing then I take it.

 

[nevada]

So I've read a few threads and posts that 91 octane isn't required on the 3rd gen. I have a 02 and I've been running it with 91 octane since I got it. And honestly I've ran all my previous cars with 91 octane. Specially my 04 RSX type S that I've had brand new. Mainly I run it because I heard it's the best gas for your engine, and I've never had any issues with my RSX

So is it true that it could be overkill to run such rich fuel?? I know you're suppose to run 91 on a super charger engine but mine is completely stock at the moment

Anyone care to elaborate if it's true?

My 91 octane babies :boink:

running higher octane than is required is a waste. nothing about overkill. its not BETTER. in fact, if you really wanted to get down to it, its worse. its harder to ignite.

what does your owners manual say?

 

[ChildrenOfBodom]

I have to run high octane fuel as every one of my vehicles is boosted. I solely use Shell V Power or Chevron Supreme. I'm not entirely sure of the exact differences, but boost is where the fuels show their weaknesses, there is a noticeable power decrease with some other "premium" fuels (arco, costco) at higher boost pressures @ 10+ PSI. Can't speak for regular as I don't run it.

It is frequently said that higher octane fuels contain more detergents, which I suppose falls under marketing. Not sure how much of that is true or not, these fuels claim to cause less carbon build up (or even clean it up) due to the detergents.

 

[runandcycle]

Based on current evidence, a 3rd gen 4runner will be super reliable and last a long time with all grades of gas. Buy what you like and what is available.

Now the motor oil you use will make a huge difference in gas mileage and engine life......:artist:

 

[Roc Doc]

Sorry but it is true %100 I have a scan gauge OBII sensor n my truck to prove it. But I guess since you have been a member here for a few months you have all the answers?

Real MPG testing is a highly detailed process in controlled conditions, and they use exhaust gas analysis to determine how much gas was consumed. So unless you're running the exact same route, in the exact same environmental conditions, with the exact same acceleration/decel methods, a 2mpg is going to be hard to quantify accurately. My truck gives between 17 and 19mpg (hand calculated), depending on speed. If I'm in traffic that only allows 60 or 65mph then I do better, on the open road running 80 it will give less. The aero load on a vehicle has much more to do with MPG than any other factor, want better mileage, slow down.

I like Lucas products, and I'm sure its' good at keeping the injectors clean, but in order for it to produce a MPG increase it would have to be a fuel, or increase octane allowing more ignition advance...but we've already established that this is not the case in these engines. Me, I use a bottle of Techron in the next to the last tank of gas before I change the oil.

 

[AntleredRuin]

I think it's mostly marketing, but then, you HAVE to call it something different to tell it apart.
There is the fact, though, that you can run 'premium' on a vehicle that does not REQUIRE premium, with no ill effects, but you can't run 'regular' on a vehicle that REQUIRES 'premium' and expect it to behave normally (power output, pinging, etc).
So in reality, premium is technically better than regular, even if its not used to its full extent.
A Corvette is technically 'faster' than a Civic, but if you never go over the speed limit, are you fully utilizing the Corvette's abilities?
I don't believe it keeps anything 'cleaner' though. I don't think that our 3rd gen engines are smart enough to advance their own timing depending on fuel octane either, but I could be wrong.

All the different octanes really are is a measurement of when the fuel combusts under pressure. Gasoline will explode by itself, no spark plug required, if enough pressure is applied. So to prevent engine damage, higher octane gasoline is used on high compression engine so it won't 'spontaneously combust' before the spark plugs fire. The explosion needs to be time with the pistons, valves, etc, or you run the risk of damaging your engine.

Look back to the 60s. Those big block high power engines had MASSIVE compression and advanced timing and required super high quality fuel to run properly, but when they lowered the compression and retarded the timing in the 70s for emissions purposes, the need for high quality fuel diminished.

We have lower compression engines (they weren't built for power) so premium is NOT required.

 

[PWD4R]

running higher octane than is required is a waste. nothing about overkill. its not BETTER. in fact, if you really wanted to get down to it, its worse. its harder to ignite.

what does your owners manual say?

Exactly. Thank you.


Sent from my iPhone using Tapatalk

 

[JayRolla]

I have to run high octane fuel as every one of my vehicles is boosted. I solely use Shell V Power or Chevron Supreme. I'm not entirely sure of the exact differences, but boost is where the fuels show their weaknesses, there is a noticeable power decrease with some other "premium" fuels (arco, costco) at higher boost pressures @ 10+ PSI. Can't speak for regular as I don't run it.

It is frequently said that higher octane fuels contain more detergents, which I suppose falls under marketing. Not sure how much of that is true or not, these fuels claim to cause less carbon build up (or even clean it up) due to the detergents.

I run e85 on all my previous boosted applications. Corn alcohol FTW! I was able to go from 18psi to 32psi just from swapping the fuel. NTM raising max timing from 16* to around 22-24* at max rpm.

The shell gas really sells the premium with that detergent talk. They only add it to the premium v-power.

 

[Roc Doc]

Look back to the 60s. Those big block high power engines had MASSIVE compression and advanced timing and required super high quality fuel to run properly, but when they lowered the compression and retarded the timing in the 70s for emissions purposes, the need for high quality fuel diminished.

We have lower compression engines (they weren't built for power) so premium is NOT required.

What's really amazing is the high boost, high specific output engines like in the GTR or Porsche Turbo, that are running relatively high CR, and really high combustion chamber PSI (under boost), and they run just fine on pump gas...even with that GD ethanol.

And it's not that the 5z will advance for premium, but it might under the right circumstances have to retard for 87 (or 85 like they have in some high altitude locations). Semantics, I know. :nod:

 

[4Runnin2000]

This seems like a "synthetic vs regular oil" argument. To each their own. I'm sure everyone has some kind of statistics as to why they are using what. Bottom line is if your rig is running great on 87 or 91 then don't change it. I ran 91 in my WRX because if I didn't, it ran like crap. I ran 91 in the 4runner for a little bit because it was detonating and having a turbo vehicle brainwashed me to do that. Turned out it was a bad MAF. Now I'm back to 87 with zero detonation and its running really smooth. No reason to go back to 91. I run 89 in my Subaru Legacy because it stops the little detonation I get in these hot summer days and my "butt dyno" says it runs better. Play with each one and see what You feel is better. Every car is different. Shoot, throw some race gas in there and hit the streets and take out some Honda civics.

 

[JayRolla]

What's really amazing is the high boost, high specific output engines like in the GTR or Porsche Turbo, that are running relatively high CR, and really high combustion chamber PSI (under boost), and they run just fine on pump gas...even with that GD ethanol.

And it's not that the 5z will advance for premium, but it might under the right circumstances have to retard for 87 (or 85 like they have in some high altitude locations). Semantics, I know. :nod:

The ethanol actually helps lower detonation. Its why e85 works so well and makes such good power.

The newer cars run a lot better because of all the tech, direct injection and really efficient turbo setups that dont produce much heat. I was never able to make more than 350whp on 91 octane. But ethanol never stops making power!