# Gas octane level **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [May 21, 2009, 2:34am UTC](https://community.cartalk.com/t/gas-octane-level/30768 "2009-05-21T02:34:21Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![whatsupdoc](https://avatars.discourse-cdn.com/v4/letter/w/97f17d/32.png) [@whatsupdoc](https://community.cartalk.com/u/whatsupdoc)\ **Post date:** [May 21, 2009, 2:34am UTC](https://community.cartalk.com/t/gas-octane-level/30768/1 "2009-05-21T02:34:21Z")
I just bought a 2009 Toyota RAV4 V6 4x4 Base Model. The manual says it needs 87 octane gas. Is this true or can I use the less expensive 85 octane? ---
**Author:** ![waterboy](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/waterboy/32/764_2.png) [@waterboy](https://community.cartalk.com/u/waterboy)\ **Post date:** [May 21, 2009, 2:42am UTC](https://community.cartalk.com/t/gas-octane-level/30768/2 "2009-05-21T02:42:28Z")
Follow the manufacturers recommendation. ---
**Author:** ![Caddyman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/caddyman/32/23_2.png) [@Caddyman](https://community.cartalk.com/u/Caddyman)\ **Post date:** [May 21, 2009, 2:42am UTC](https://community.cartalk.com/t/gas-octane-level/30768/3 "2009-05-21T02:42:33Z")
You must live in a high altitude area where “regular” is 85 octane. Your car will run fine on it. In the rest of the country, “regular” is 87 octane…Engines require less octane at elevations over 5000 feet, so the oil companies reduce octane (but not price) in those areas… ---
**Author:** ![Docnick](https://avatars.discourse-cdn.com/v4/letter/d/ecae2f/32.png) [@Docnick](https://community.cartalk.com/u/Docnick)\ **Post date:** [May 21, 2009, 2:42am UTC](https://community.cartalk.com/t/gas-octane-level/30768/4 "2009-05-21T02:42:43Z")
For best performance use what the book calls for. If you wanted better mileage and lower gas costs, a Matrix 2 WD would have been a better choice. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [May 21, 2009, 2:43am UTC](https://community.cartalk.com/t/gas-octane-level/30768/5 "2009-05-21T02:43:18Z")
You must be in Denver? 85 is only available at higher altitudes, should be ok as long as you use it there. ---
**Author:** ![waterboy](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/waterboy/32/764_2.png) [@waterboy](https://community.cartalk.com/u/waterboy)\ **Post date:** [May 21, 2009, 2:44am UTC](https://community.cartalk.com/t/gas-octane-level/30768/6 "2009-05-21T02:44:39Z")
I have never seen 85, 87 89 and 91 are my only choices. What is up with that? ---
**Author:** ![BustedKnuckles](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bustedknuckles/32/25_2.png) [@BustedKnuckles](https://community.cartalk.com/u/BustedKnuckles)\ **Post date:** [May 21, 2009, 2:50am UTC](https://community.cartalk.com/t/gas-octane-level/30768/7 "2009-05-21T02:50:25Z")
You must live in a high altitude region. Even with that, I’d stick to the required octane rating. Damage to your new truck is not worth saving $2.50 a tankful. ---
**Author:** ![Caddyman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/caddyman/32/23_2.png) [@Caddyman](https://community.cartalk.com/u/Caddyman)\ **Post date:** [May 21, 2009, 2:53am UTC](https://community.cartalk.com/t/gas-octane-level/30768/8 "2009-05-21T02:53:58Z")
It doesn’t require 87 octane at high elevation…Why waste your money? ---
**Author:** ![Marnet](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/marnet/32/41_2.png) [@Marnet](https://community.cartalk.com/u/Marnet)\ **Post date:** [May 21, 2009, 5:09am UTC](https://community.cartalk.com/t/gas-octane-level/30768/9 "2009-05-21T05:09:40Z")
Why, may I please ask, do engines require less octane at over 5,000 feet elevation? I know the air is thinner at that height with less oxygen in the air, but how does that affect the octane needed? ---
**Author:** ![hellokit](https://avatars.discourse-cdn.com/v4/letter/h/6a8cbe/32.png) [@hellokit](https://community.cartalk.com/u/hellokit)\ **Post date:** [May 21, 2009, 9:21am UTC](https://community.cartalk.com/t/gas-octane-level/30768/10 "2009-05-21T09:21:25Z")
Less atmospheric pressure results in less combustion chamber filling which leads to lower combustion chamber pressures and temperatures (upon ignition) which results in less chance of pre-ignition (aka “knock”) which needs lower octane fuel to maintain. ---
**Author:** ![Marnet](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/marnet/32/41_2.png) [@Marnet](https://community.cartalk.com/u/Marnet)\ **Post date:** [May 21, 2009, 10:32am UTC](https://community.cartalk.com/t/gas-octane-level/30768/11 "2009-05-21T10:32:14Z")
Ahhh. Thank you. Learn something new every day! ---
**Author:** ![andrew\_j](https://avatars.discourse-cdn.com/v4/letter/a/91b2a8/32.png) [@andrew\_j](https://community.cartalk.com/u/andrew_j)\ **Post date:** [May 21, 2009, 12:06pm UTC](https://community.cartalk.com/t/gas-octane-level/30768/12 "2009-05-21T12:06:56Z")
Less power at higher elevation too unless you have a nice turbo engine to compensate. ---
**Author:** ![whatsupdoc](https://avatars.discourse-cdn.com/v4/letter/w/97f17d/32.png) [@whatsupdoc](https://community.cartalk.com/u/whatsupdoc)\ **Post date:** [May 21, 2009, 2:19pm UTC](https://community.cartalk.com/t/gas-octane-level/30768/13 "2009-05-21T14:19:33Z")
I do live in a high altitude area–Colorado. Thanks for that info. I didn’t realize that other areas don’t have 85 octane! ---
**Author:** ![MikeInNH](https://avatars.discourse-cdn.com/v4/letter/m/a587f6/32.png) [@MikeInNH](https://community.cartalk.com/u/MikeInNH)\ **Post date:** [May 21, 2009, 3:14pm UTC](https://community.cartalk.com/t/gas-octane-level/30768/14 "2009-05-21T15:14:29Z")
Caddyman has it correct. The 87 Octane is for MOST of us who live at or near sea level. The higher up you live the lower octane you can use. 85 Octane should be fine. ---
**Author:** ![FoDaddy](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/fodaddy/32/717_2.png) [@FoDaddy](https://community.cartalk.com/u/FoDaddy)\ **Post date:** [May 21, 2009, 4:21pm UTC](https://community.cartalk.com/t/gas-octane-level/30768/15 "2009-05-21T16:21:06Z")
Keeping the warranty valid comes to mind. If something went wrong with the engine and and the OP was using 85 octane. That would give Toyota enough of a reason to deny the claim. ---
**Author:** ![MikeInNH](https://avatars.discourse-cdn.com/v4/letter/m/a587f6/32.png) [@MikeInNH](https://community.cartalk.com/u/MikeInNH)\ **Post date:** [May 21, 2009, 4:36pm UTC](https://community.cartalk.com/t/gas-octane-level/30768/16 "2009-05-21T16:36:06Z")
> Keeping the warranty valid comes to mind. If something went wrong with the engine and and the OP was using 85 octane. That would give Toyota enough of a reason to deny the claim. I don’t think so…Never ever heard of ANY company denying any claim on any vehicle for using the wrong octane gas. ---
**Author:** ![FoDaddy](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/fodaddy/32/717_2.png) [@FoDaddy](https://community.cartalk.com/u/FoDaddy)\ **Post date:** [May 21, 2009, 5:28pm UTC](https://community.cartalk.com/t/gas-octane-level/30768/17 "2009-05-21T17:28:08Z")
I’m not saying it happens all the time. But I’m sure it could conceivably give Toyota a leg to stand on in denying warranty coverage. On page 178 of my owners manual it states "We do not recommend the use of gasolines labeled as “Regular” that are sold with octane ratings of 86 or lower in high altitude areas" [http://www.motorcraftservice.com/?link=002&urlfile=/pubs/content/~WO3MUS/~MUS~LEN/42/03musog5e.pdf](http://www.motorcraftservice.com/?link=002&urlfile=/pubs/content/~WO3MUS/~MUS~LEN/42/03musog5e.pdf) On page 8 here [http://www.motorcraftservice.com/pubs/content/~WO3MUS/~MUS~LEN/41/03frdwa5e.pdf](http://www.motorcraftservice.com/pubs/content/~WO3MUS/~MUS~LEN/41/03frdwa5e.pdf) It mentions that warranty coverage is not covered should the owner of car use “improper” fuel. Since the minimum recommended octane is 87. Using lesser octane could be construed as “improper fuel” Granted this is Ford info, but I’m sure all car companies have a similar policy. ---
**Author:** ![oblivion](https://avatars.discourse-cdn.com/v4/letter/o/3ab097/32.png) [@oblivion](https://community.cartalk.com/u/oblivion)\ **Post date:** [May 22, 2009, 1:27am UTC](https://community.cartalk.com/t/gas-octane-level/30768/18 "2009-05-22T01:27:14Z")
Try 85 octane and if you get your normal level of performance out of the car and no spark knock (rattling sound during acceleration), keep using it. If you get spark knock and/or reduced performance, you need higher octane that what you’re using. I would be utterly amazed if any Toyota dealership or representative had the know-how and/or ambition to actually test your gasoline and determine the octane rating in the event of a warranty claim. If it worries you, and you do have a failure, top off the tank with premium before taking it to the dealer or use one of the many octane boosters that come in a can.