So I just realized the type of gas does matter

Page 2 - Seeking answers? Join the AnandTech community: where nearly half-a-million members share solutions and discuss the latest tech.

lurk3r

Senior member
Oct 26, 2007
981
0
0
So you put 89 is shitty import engines? That's win!

I was not actually saying all domestic engines were shitty, only that shitty domestic engines are the ones I've tried that do not notice a difference. (the sawed off V8 that became a V6 in the old trailblazers is a perfect example, most low compression V8's etc will not see any difference).
 

speedy2

Golden Member
Nov 30, 2008
1,294
0
71
Half the board here will claim otherwise, try it yourself, run at least a couple tanks of 89 and see if you get farther on it. I never run one of my cars on 87, 87 is for rentals and shitty domestic engines.

Import Fanboy right here. lol. Each engine has a specific amount of compression. Each grade of fuel fits that to prevent pre ignition. Whether it be a Veryon or a lawn mower. An engine that calls for 87 does not mean it's a crap engine.
 

thescreensavers

Diamond Member
Aug 3, 2005
9,916
2
81
Whats weird is Lexus requires Premium in all of its cars but the same engine in a toyota labeled car can run on regular. hmmm
 

Paperlantern

Platinum Member
Apr 26, 2003
2,239
6
81
Ugh, I wish that people would learn how this stuff works.

An engine that isn't designed to benefit from premium will get ZERO advantages from it.

Isnt that what i'm attempting to do... by asking the question, is learn how this works? Ass hole.

So would the consensus on my vehicle then be not to bother? just stating that "an engine that doesnt call for it wont benefit from it" doesnt tell me anything since, I dont know if mine would call for it or not, the car is 11 years old, it's not like i bought it from the dealer in 1999 brand new for $30,000 and the guy TOLD me what kind of gas to put in it. I'm just trying to find out from people who obviously know more than I do.

God, do you slam EVERYONE that asks you a question for not already knowing the answer?

EDIT: I googled a bit and found 5 separate pages that said 91 octane is recommended for the 1997 - 2001 V6 model Camry. Interesting.
 
Last edited:

KIAman

Diamond Member
Mar 7, 2001
3,342
23
81
The thing is most cars can run on 87 octane just without the advertise power rating. Some exceptions are forced induction and very high output engines.
 

jlee

Lifer
Sep 12, 2001
48,518
223
106
Isnt that what i'm attempting to do... by asking the question, is learn how this works? Ass hole.

So would the consensus on my vehicle then be not to bother? just stating that "an engine that doesnt call for it wont benefit from it" doesnt tell me anything since, I dont know if mine would call for it or not, the car is 11 years old, it's not like i bought it from the dealer in 1999 brand new for $30,000 and the guy TOLD me what kind of gas to put in it. I'm just trying to find out from people who obviously know more than I do.

God, do you slam EVERYONE that asks you a question for not already knowing the answer?

EDIT: I googled a bit and found 3 separate pages that said 91 octane is recommended for the 1997 - 2001 V6 model Camry. Interesting.

Do you have a sticker on the inside of your fuel door that indicates what you should be running? Some cars do.
 

MJinZ

Diamond Member
Nov 4, 2009
8,192
0
0
Whats weird is Lexus requires Premium in all of its cars but the same engine in a toyota labeled car can run on regular. hmmm

Same engines can be tuned differently. My 2GR-FE can run on anything from 87 to 93, and I can definitely feel a bit of a more kick in the higher octane and better fuel economy (not enough to offset the increased cost of the gas though).

The one in the Lexus ES is rated for a small boost in horsepower and is probably why it uses premium.
 

vshah

Lifer
Sep 20, 2003
19,003
24
81
i put 91 or 93, whatever is available. Maybe its placebo but i think i feel a difference with shell ultra
 

Malak

Lifer
Dec 4, 2004
14,696
2
0
My mom has been putting the 89 in her Lexus ES300 for a while now. Premium is getting too expensive here.

Where is "here" because premium is usually only a few cents more. I don't even know why there is an 89. Get crap or get premium.
 

LTC8K6

Lifer
Mar 10, 2004
28,520
1,576
126
Where is "here" because premium is usually only a few cents more. I don't even know why there is an 89. Get crap or get premium.

Premium is considerably more where I live, and my owner's manual says 89 octane is preferred for my engine.
 

Throckmorton

Lifer
Aug 23, 2007
16,829
3
0
You should use what is "recommended", not what is "required". If it says 91 is required and 93 is recommended, use the 93. The ECU won't have to retard timing and your gas mileage will be better
 

Throckmorton

Lifer
Aug 23, 2007
16,829
3
0
I use 93 octane in my old tech low compression Jeep 4.0L. Why? Because in some years, Cherokee owner manuals said to use high octane for severe use, hot weather, etc. The weather isn't especially hot here, but my Jeep does run hot and sometimes overheats.

I can notice a smoothness difference. I just hope the higher octane isn't burning incompletely and leaving carbon deposits.
 

Paperlantern

Platinum Member
Apr 26, 2003
2,239
6
81
Do you have a sticker on the inside of your fuel door that indicates what you should be running? Some cars do.

You know, I've never looked that close at the inside of the fuel door, i just unscrew the cap, put it in the little cradle in the fuel door and just turn around and grab the nozzle, i shall look when i get off work today to see. I want to say there isnt one, but i'm not 100%. i'm also going to look around at home for my owner's manual for my car, it might be in my glove box, but I dont think that is where it ended up after the accident and the car was an inch from being totaled.


Yeah I ran across that in my googling, read the whole first part to get an idea of it, and it is interesting, I mean, i'm not going to lie, I was under the impression that i'm sure 90% of the population is, higher octane meant more POWER, but its not the case at all. This thread has been quite enlightening.
 

BurnItDwn

Lifer
Oct 10, 1999
26,355
1,867
126
My forester likes 87, I give it 87. (NA engine)

My previous car, Chrysler 300m Liked 89, but, could handle 87 just fine since the ECU was smart enough to play with the compression (never once had an issue with knocking). Mileage was the same with 87 and 89, but, 89 could accelerate ever so slightly better.

I miss the engine in that car, but, the last year I had it, it spent about 1/5 of the time in the shop, and it got crap milage (I averaged 19 in my mix of city/highway, I average 24-25 in the forester with the same mix)
 

AstroManLuca

Lifer
Jun 24, 2004
15,628
5
81
Is it true that if you always use a higher octane fuel, suddenly switching to lower octane can make it run rougher than if you always used a lower octane fuel? I've heard that but I don't know if it's true.
 

Pulsar

Diamond Member
Mar 3, 2003
5,224
306
126
This thread.... it's just FULL of fail.

93 must be better than 91 and 89! It's a higher number, so it has to be better for my vehicle!

Seriously?

If your car calls for 5W20, do you put in 10W40 because the higher number must be better?

If your car calls for a specific gap spark plug, do you knock it open wider because bigger must be better?

Seriously..... same sort of people who buy one product over another just because it costs 15% more.

Read your freaking manual people, and understand WHY they want you to use a specific octane.

Now I'm going to go put Antifreeze in my car. I think I'll put the concentrate in without adding water. After all.... it's concentrated, right? That's better!

Kudos to Paperlantern for actually learning the difference.
 
Last edited:

Pulsar

Diamond Member
Mar 3, 2003
5,224
306
126
Is it true that if you always use a higher octane fuel, suddenly switching to lower octane can make it run rougher than if you always used a lower octane fuel? I've heard that but I don't know if it's true.

Yes, because it takes time for the ECU to adjust to the fuel change.

Same way that if you're used to drinking Mountain Dew all the time, when you stop for a couple days you feel slow and tired. It takes you body time to recalibrate.
 

Throckmorton

Lifer
Aug 23, 2007
16,829
3
0
My forester likes 87, I give it 87. (NA engine)

My previous car, Chrysler 300m Liked 89, but, could handle 87 just fine since the ECU was smart enough to play with the compression (never once had an issue with knocking). Mileage was the same with 87 and 89, but, 89 could accelerate ever so slightly better.

I miss the engine in that car, but, the last year I had it, it spent about 1/5 of the time in the shop, and it got crap milage (I averaged 19 in my mix of city/highway, I average 24-25 in the forester with the same mix)

Compression doesn't change, ignition timing does. Normally the spark happens some time before the piston reaches the top of its stroke. If you put in lower octane than you need, the ECU makes the spark happen even sooner to preempt detonation. That wastes energy because the piston is fighting the burning fuel for longer
 

Throckmorton

Lifer
Aug 23, 2007
16,829
3
0
Yes, because it takes time for the ECU to adjust to the fuel change.

Same way that if you're used to drinking Mountain Dew all the time, when you stop for a couple days you feel slow and tired. It takes you body time to recalibrate.

That's only true if the vehicle is actually made for the higher octane and has to adjust ignition to compensate for you making the mistake of using lower octane.
 

jlee

Lifer
Sep 12, 2001
48,518
223
106
You know, I've never looked that close at the inside of the fuel door, i just unscrew the cap, put it in the little cradle in the fuel door and just turn around and grab the nozzle, i shall look when i get off work today to see. I want to say there isnt one, but i'm not 100%. i'm also going to look around at home for my owner's manual for my car, it might be in my glove box, but I dont think that is where it ended up after the accident and the car was an inch from being totaled.



Yeah I ran across that in my googling, read the whole first part to get an idea of it, and it is interesting, I mean, i'm not going to lie, I was under the impression that i'm sure 90% of the population is, higher octane meant more POWER, but its not the case at all. This thread has been quite enlightening.

Yep, it doesn't necessarily mean more power, but it can allow the engine to make more power (safely). I run 93 in both my cars - the MR2 can run on 91, but I'm running higher boost so I like the safety net. The Subaru has a tune specifically for 93- I can flash to a 91 tune, but I'll lose a few ponies. I like ponies too much to give them away. :D
 

Paperlantern

Platinum Member
Apr 26, 2003
2,239
6
81
Yep, it doesn't necessarily mean more power, but it can allow the engine to make more power (safely). I run 93 in both my cars - the MR2 can run on 91, but I'm running higher boost so I like the safety net. The Subaru has a tune specifically for 93- I can flash to a 91 tune, but I'll lose a few ponies. I like ponies too much to give them away. :D

Ponies I'm not even all that interested in... though in my googling i found my engine has 194 of them, which, is respectable I suppose, it's efficiency, if i can make my engine run better to increase fuel mileage I'll run a higher test in it. Making it feel snappier really wasn't my initial intent on getting involved in this thread, though if it's a side effect, and if what jlee says it true, and that's what happens, i wont complain.
 

punjabiplaya

Diamond Member
Nov 12, 2006
3,495
1
71
it's also about the ethanol content. 87 will probably have a higher percentage of ethanol than 91/93
 

AznAnarchy99

Lifer
Dec 6, 2004
14,695
117
106
They dont even sell 93 in my area. Goes from 87-89-91. I put in Costco gas anyways so its either 87 or 91.