What Type Of Fuel Are 2004 Miata Ls (non-turbo) Owners Using?

M

maddog333

Member
:
Mazda Miata LS
Miata forum members,

I'm in the process of buying my first Mazda. I'm purchasing a 2004 MX-5 Mazda Miata LS (non-MazdaSpeed) and would like to know what type of fuel other forum members are using. The on-line owner's manual suggests 91 octane, but says you can use 87-90 with a slight performance hit. I was just curious, since gas is so high anymore. I'll be looking forward to your replies.

PMAD
 
look at it this way. the difference in gas price from 87 to 89/91 is usually another $0.10 cents, at most, an additional cost of $0.15, but, this is abnormally high. For comparison purposes, gas prices in my area are $2.30 for 87 and $2.60ish for 93.

Assuming the maita has a 14 gallon gas tank, and you average 14,000 miles per year, lets do the finances and lastly, assume the miati gets 28miles per gallon.

14,000 miles / 28 mpg = 500 total gallons per year (on average)

$500 gallons per year * $2.40 (gas price of 87 in my area) = $1,200

$500 gallons per year * $2.50 (price of 91, larger than norm spread) = $1,250

$500 gallons per year * $2.65 (price of 93, larger spread than norm) = $1,325

Therefore, does an additional 50 bucks per year actually make that much of a difference in the long run. I mean the car itself is thousands of dollars. You could even treat your car at 93 octange, and only spend an additional $125 bucks.

Understand this is all on average calculations and the 28mpg guess on the miata. I would say, since you can afford the car, at least put in 91. Also, why scarfrice performance, when you paid a premium for the extra horsepower. Just buy a cheaper car and put in the 87 octange, and its the same damn thing.

Hope this analysis is helpful.
 
I've had my 2001 Miata for 3.5 years and have never put anything other than premium (91-92) gas in the tank. I bought the car for performance, and I'm not going to take a performance hit to save a few bucks. And I definitely don't want the engine pinging, even the small amount needed to trigger the knock sensor.

With gas prices as high as they are, the extra cost of premium makes even less of a difference. 20 cents at $2.20/gallon is about 9%. 20 cents at $1.50/gallon is about 13%. The only case in which it would make more difference is if money is so tight for you that you can't afford to buy gas if it goes over a certain price. That's an unlikely scenario for someone who owns a 2004 Miata ;)

Having said that, my "new" 1999 Miata drinks nothing but 87 octane, because that's what it was designed for.
 
Last edited:
I put 89 in my 99, for 2001+ cars you should use 91. The performance hit that he manual talks about is the knock sensor retarding the timing so you don't blow holes in your pistons. It's always amazing how people are willing to spend $25k+ on an impractical toy car, but then will skimp on the $100 per year to get gas that the car requires to run properly.
 
KpaBap said:
I put 89 in my 99, for 2001+ cars you should use 91. The performance hit that he manual talks about is the knock sensor retarding the timing so you don't blow holes in your pistons. It's always amazing how people are willing to spend $25k+ on an impractical toy car, but then will skimp on the $100 per year to get gas that the car requires to run properly.
Click to expand...
Well said. OTOH, my car is very picky and pings on regular octane. I know it being a 99 means it should do fine on the regular, but it doesn't. (dunno)

but high octane is definately a requirement for the 01+ and I'd recommend it. :)
 
Diane,

It could be for a lot of reasons, the first thing to look at would be the spark plugs and replace them if needed (or if it's been 15-20k miles since last replacement), the stock spark plug wires are also pretty crappy and are good for about 20-30k miles. Carbon buildup inside the combustion chamber can also be a reason for pinging. Also, are you at stock timing or have you advanced it at all?

The other day I sprayed some throttle body cleaner around the throttle body, then I unplugged the 2-3 hoses that hook up to the intake manifold and sprayed a fair amount of cleaner in there (manifold) also. I let it sit for about 5 minutes and started the car (after a bit of cranking), the car will run very crappy for 20 seconds or so but it will be back to normal after that. I ran the car for about 5 minutes and then sprayed some more cleaner in the manifold and throttle body. I can't honestly say it made a huge difference but the car does seem to run a lot smoother now.

If you haven't done this in a while, it might be worthwhile but probably won't solve your pinging. ITB cleaner cost me $2.99 at Autozone.

Anyway, California 87 gasoline is crap and I can definitely feel a power difference between 87 and 89. I actually get better gas mileage with 89.
 
Last edited:
Good advice.

I usually replace the spark plugs every 10K (yes I am THAT anal), but I am due for plug wires, I KNOW. The original owner (who had the car before me) replaced the plug wires once that I know of, but I bought the car at 65K and it now has 96K+. :eek:

I have also done the intake cleaning (for the EGR port) and cleaned the throttlebody while I was at it (which was relatively clean).

The big thing is that I do not know if the timing is advanced. When the owner advertised the car to our local autocross list, he didn't say anything about it. i asked him and he said he hadn't, but then I remember him saying something about it being advanced a few years ago. :confused:

I also rmember someone saying that advancing the timing will throw you out of stock class (still don't know if that is true), so maybe that's why he denied it later. ???
 
If you're worried about timing then you can always go get a timing light from Autozone/Kragen's/Pep Boys/Whatever, check out your timing and return it later.
You need to short some pins on the diagnostic module (driver side, near the fender) in order to get the actual base timing.

Check this out:

http://www.miata.net/garage/ignition.html
 
Oh yah, I have the manual that was comprised of the Garage Tech articles from miata.net. MUCH needed and the most valuable tool I own. I would have been at a loss without it on the water pump change. :)

But the car runs fine. Good and strong as always, so i am not concerned with the timing.

The new accessory belts, however, seem to need the old second adjustment. ;)
 
Getting back to my gas inquiry, I'll stick with high octane. The trouble is everyone around me carries 87, 89, and 93, not 91. The only gas station that has 91 is probably Sunoco. I'm guessing my engine will like it if I fill it with 93 (even though the owner's manual suggests 91). My wallet won't like it, but I guess that's the price you pay for fun. Hopefully, better gas mileage (I'm guessing at least 25-26 mpg) will help offset the higher gas cost for my 2004 Mazda (non-turbo) 6-speed Miata.

PMAD
 
I'm running regular in my 04 Miata LS 6-speed and I haven't had any problems. There's no pinging with regular either. www.mazdausa.com states recommended fuel is 91 octane and the minimum fuel requirement is 87 octane. If your not suppose to use 87 octane then why would Mazda say that 87 octane is the minimum fuel to use? The website doesn't say 91 is the only fuel to use. I know with my 03 Sentra SE-R the owner's manual states that fuel with 87 octane and greater is to be used. It would be different if it said Premuim only, I had an 01 Eclipse GT that required Premuim fuel only.

http://www.mazdausa.com/MusaWeb/displayPage.action?pageParameter=modelsSpecsSpecs&vehicleCode=MIA
 
Last edited:
Mikeyb,

Thanks for the reply. It seems that this forum leans toward using the premium fuel for this car, but it sounds like 87 has been working out okay with you. I also had an Eclipse Spyder (2001) which required premium, but only got about 22-23 mpg (also back when gas was not so expensive). What has been your gas mileage so far with this 2004 Miata? If I can get at least 25.5 mpg average (I do more stop and go than highway driving), I'll at least break even (using 93 octane) compared to my Subaru Forester getting 22.7 mpg, using 87 octane. I just wish more gas stations around Cincinnati had 91 octane instead of 89 or 93. I wish that I could feel comfortable with 89 to save a few bucks (keeping 2 new vehicles - 2003 Forester and 2004 Mazda Miata is stretching my budget to the max for a couple years).

PMAD
 
Please log in or register to reply here.

Similar threads

R
Seeking Guidance on Purchase of a Used 2016 Mazda6
Replies
2
Views
1K
potownrob
P
GTXT23
    • Like
Turbo "Truths / Myths" dispelled
Replies
15
Views
2K
Odrapnew
O
C
Turbo, Fuel Octane and Altitude
2
Replies
24
Views
6K
jadmt
jadmt

Latest posts

Back