I have a 2001 ES and I'm running 93 premium in my car. Is anyone else? I'm running 93 because my manual suggests it for better performance.
Let me explain.
For the first year or so I ran 87. That's what the dealer said to run and it works fine. But when I went to my owners manual (for something else I don't remember) it said all Pro engines: 1.6, 1.8, 2.0 will run on 87 octane. But THEN it says 2.0 Special Edition should run 91 or higher for best performance. Well, I assumed they meant the MP3 with its slight bhp bump.
A short time later when washing the car I noticed my vehicle info tag inside the passenger side door. Next to vehicle type it said:
ES 2.0 Special Edition

???? I was perplexed. I called the dealership- they knew nothing of this. I decided to give the premium a shot anyway. After the 2nd or 3rd tank of 93 I noticed a difference in the car. Before, when running with the AC on, the car was a DOG. Now the AC doesn't hamper the performance as much. With the AC off I noticed a big difference. The car is much easier to rev, and is no longer anemic at high rpms- is now completely rid off a 4500-5500 lull in the powerband.

Anyway, I wondered if anyone else had any experience with this.

 

UH... maybe you didn't read my post. I agree that the engine was designed to run on 87... says that in the book. BUT it does say it will run better on 91 or higher and I HAVE noticed a marked improvement in performance. That seems to be worth my 20 cents. BESIDES, my manual predated the mp3 by quite a while. I purchased my 2001 well before there were even rumors of a higher performance model.

My step-mothers Camry V6 was the same- ran on 87, but better with 91. My Old Quad-Four required 87, 91 improved performance for not and could even cause damage.

 

Try running the car on 94 and let us know. If you run anything that is purer, it will run better. Personally, my car runs fine on 87. Performance would be better with cams, exhaust, etc, etc, but that car wasn't designed for the masses, not to mention the car would be $40 grand: I can't afford that, nor will I pay the money for the gas, but hey "to each is own."

 

what a terrible post.

 

You'll have to dyno it to tell if it makes any difference (between 87 and 93.) Alternately, somebody who knows a lot about this particular engine might be able to tell you.

It all depends on how much timing advance the computer will allow. With a knock-sensing ignition, the ECU will keep advancing the ignition timing until it senses detonation(knock), the take it back a notch. If 87 will keep your timing advanced as far as the ECU will allow, anything higher is a waste. If 89, 91, 94, 98, etc. allow for more, then for the best performance you should use the lowest octane that will gicve you full ignition timing advance.

As I said, a dyno will tell you, or something that can read your ignition timing under load could also help you out.

 

Ok, then just figure out what it needs to not retard the timing at all, then go with that.

 

Well while you all are on the subject of gas I thought I would ask a question that no one can seem to figure out. My car along with many others in my family including my girlfriends 00 Esteem, all have light spark knock when we use 87 Octane (makes no different of the brand of gas used). I really don't understand what is going on. When we use 89 Octane there is no problem at all. Anther thing that is strange is that when I use 87 Octane when I am out of town ( like when I was at the beach 300 miles from home) I had NO spark knock at all. All of our owner manuals say use 87 or higher. What do you guys think is going on? Could it be that the gas in my area is CHEAP or has lower octane then 87? I have no clue. When it first started, I took my car to the dealership and they said there was no problem and all sensors were up to spec. If it matters at all, I do live in a high altitude area in Virginia.

Thanks

 

Now that some funny shiat mazdanewbie!

 

So if I ran 87 and had some knock, the ECU would decrease my advance and lower the max timing advance. On the next fill up I put in 93. . . the ECU still won't give me my timing back! I'd have to reset the ECU to get more timing advance. Should I install a quick disconnect and reset my ECU at every fill up?

 

I run 87 octane and have been since day 1. It's what the manual says to use and it works well.

I do run 89 in winter though as they really water down our gas up here in the cold months and I was getting a bit of knock under hard acceleration. 89 in winter seemed to cure that.

 

I think the point that seems to come through is that if you have engine knock, go up in octane; otherwise, stick with the inexpensive stuff. On most economy cars (sorry, but we are for the most part Mazda Protege owners), 87 octane is all that is needed, and the ECU is mapped for that.

If you own a high performance car designed for high octane, or one that is modded to change the timing, then you would get more power from the higher stuff. Otherwise, you are just making the oil companies richer. BTW, my understanding is that all grades now have a decent level of detergents and additives, so no need to upgrade for that.

Any petrochemical engineers out there want to add anything?

 

I thank you all for your input; but, I get the feeling like no one actually read my whole post. My engine runs FINE on 87. It runs BETTER on 93. The Manual SAYS it will run better on >91 and guess what... it does.
I've always loved this car but I'd be lying if I said I was always satisfied with the motor. Plenty of torque to tow the car around in the lower range, but push it above 4500- all bark and no bite. My other cars were not like this. My Q4 Grand Am was all horsepower- no torque ( fun to drive at the limit ). Both my Jettas responded when pushed hard ( not just the VR6 the 2.0L too ). And then there's my SHO... lets just say the Taurus is giggles all the way to red line.
But low and behold, after I switched to 93- HORSEPOWER. Now the car is very responsive at the limit and consequently (spelling?) funner to drive.
Also, NO ONE has mentioned anything about the fact that my car says its a Special Edition. Again my manual says:

All 1.6, 1.8, and 2.0 engines run 87 octane minimum.
Special Edition 2.0 performs best with 91 octane minimum.

So there...

 

Point 1 - I whole heartily disagreed, unless you can prove that they "water down our gas". Who is 'they' and where do 'they' do that? It's called illegal, besides the engine would be screwed....nuff said

 

You didn't read between the posts! LOL! Try running your car on 99 octane and then put another thread up. Try it. I am a smart-***

 

So has anybody other than this guy ever actually seen or heard of a special edition ES? What the hell is up with that. Anyway for the special edition to need the higher octane it would need a significantly different ECU, possibly higher compression, good stuff like that. Just buy what the frickin manual recommends! If it says the car will run better with 93 then buy the frickin 93. Don't come on here asking questions about whether to follow the factory manual or not.