i used 89 for the first 4k miles after buying my 07 then switched to 87 and actually noticed higher gas mileage. As for pinging, as long as u let the car idle when u start it up and shut it off for about 30 seconds to a minute it should never ping or knock

 

Since i'm low in budget, i will start using 87 and i'll let you guys know if i see a difference after filling it 2-3 times. i drive Mazda 3 2.3L

 

Thx guys...good info! I think I might use 89 octane once in awhile but will stick with 87 octane since the engine is designed to use that grade of fuel! thx again

 

http://shellne.com/btrmiles.html

 

Worht a quick read, Guys. Nice hit UBM!!

 

I think adding Premium is just a waste of money. Everything I have ever heard is if the car is programmed to run on 87 your doing it no good adding 89 or higher gas. My VW jetta is suppose to run on 89 and when gas hit $2.00 I started using 87 with no noticable proformance change. If the car starts pinging then you need to up your octane. otherwise you are prob. doing more harm then good. At best your just wasting money.

SEE BELOW FOR THE REAL STORY.
For the complete story go to http://theserviceadvisor.com/octane.htm

WHAT IF I PREFER TO USE GASOLINE WITH HIGHER OCTANE RATINGS?
You can, but there are no real benefits, other than the gasoline manufacturers making more money off of you. When you use a fuel with a higher octane rating than your vehicle requires, you can send this unburned fuel into the emissions system. It can also collect in the catalytic converter. When you over stress any system, it can malfunction or not do what it was designed to do properly. In the early 90's, an early warning symptom was a rotten egg smell from the tailpipe. Easy fix, go back to using regular 87 octane gasoline. The rude odor usually disappears after several tanks of gasoline.
DOESN'T HIGHER OCTANE GASOLINE HAVE MORE CLEANING ADDITIVES THAT ARE GOOD FOR MY ENGINE?
No. Government regulations require that all gasoline contain basically the same amount of additives to clean the injectors and valves. The only differences are the type to help create the different octane ratings. All gasoline burns at the same rate, it is the additives that create the different octane ratings for the different types of engines.

 

Most of what he'ssaying here is exactly what I'd said in a previous post on page 1 of this thread. Though I did not know about the cleaner legislation before.

 

Government regulations (in the US) specify the minimum level of detergent additives.

A groupof auto manufacturers have formed a top tier detergent gasoline coalition. This group has formulated standards specifying a minimum effective level of detergent additives.

If you are interested inminimizing gunk and deposits(and if you are at this forum, chances are you ARE interested), the link belowis worth a look.

Clickaround within the top tier site, you'll find some interesting reading, as well as a current list of retailers who sell top tier gasoline.

http://www.toptiergas.com/index.html

 

Well, I'll be damned. In the manual it says to use 87 or higher octane in the 2.0 and 2.3. However, it says that the Mspeed, 2.3 Turbo requires the 91 octane.
I will dumb down to 87 for a while and see if my milage goes up. Can't get too dirty, after all it is a new car.

 

i wouldnt if i was you, the speed3 is designed to use 91 octane...anything less and ur asking for the engine to knock