Mazda3 S performance with high octane gas

[solort]

I was wondering if running 93 Octane gas in a 2.3L Mazda3 S will give it more accelleration than 87 Octane by allowing the timing to advance? Anyone tried this on a dyno? And can you pull a fuse to reset the computer to adjust timing to the current fuel octane (Like I can with Dodge Neon DOHC)? Thanks

[robin2660]

I was wondering if running 93 Octane gas in a 2.3L Mazda3 S will give it more accelleration than 87 Octane by allowing the timing to advance? Anyone tried this on a dyno? And can you pull a fuse to reset the computer to adjust timing to the current fuel octane (Like I can with Dodge Neon DOHC)? Thanks

As I understand, higher-octane gas doesn't provide performance, but is required on higher-performance (higher-compression) engines to avoid detonation. Google "detonation".

[Raymo853]

If the DOHC Neon is designed to run 93 oct gas it will benefit. I assume at most the Neon was designed to run on 91 oct, so running 93 only benefits Exxon's profit margins. Since the 2.3 Mazda is designed to run on 87, running it on anything higher just wastes your money.

[krimsonviper]

If the DOHC Neon is designed to run 93 oct gas it will benefit. I assume at most the Neon was designed to run on 91 oct, so running 93 only benefits Exxon's profit margins. Since the 2.3 Mazda is designed to run on 87, running it on anything higher just wastes your money.

+1

[TheMAN]

I tried running a tank of 93 on mine once and it did nothing but smooth out how the engine ran... so it's a waste of money compared to my protege which did benefit from high octane

[Spdmnadam]

if you want to benefit from high octane goto m**************** and look for the MOnzta or Advance timing mod where you move the crank position sensor to change the ignition timing to benefit higher octane about 89 is good for 6hp not much diff between 89 and 93 gains

[krimsonviper]

if you want to benefit from high octane goto m**************** and look for the MOnzta or Advance timing mod where you move the crank position sensor to change the ignition timing to benefit higher octane about 89 is good for 6hp not much diff between 89 and 93 gains

OWNED! by the "we-dont-let-you-post-other-forums" rule

[Spdmnadam]

sorry im new to this forum but you can search it on a search engine

[derekMZ3]

i usually put in 89 or 91, after reading this i filled up with 87....it doesn't run as well. Right after i put it in it started making weird noises, those have gone away, but i still feel a SLIGHT acceleration decrease.

[Raymo853]

I suspect one thing that may be leading folks to believe paying for premium gas when not needed is getting a bad tank of regular. Now of course the distributers, refineries and dealers may be doing that on purpose. I do not think there is a state in the US that checks the octane ratings. They usually just check that the pumps put out gallon for charging you a gallon.

[krimsonviper]

if you car says to put a certain octane of gas then you use that octane of gas. now if you start advancing/retarding than you have to change the octane accordingly. especially if you slap on a turbo. now what might've happened in dereks case is that the car is used to the higher octane and needs to re-adjust to the lower octane. im not a specialist, just an educated guesser and i think that dereks car retarded its timing and now needs to advance it because of the octane change

[mazda32008]

ok while we are talking about octane...does the octane boost bottles work? i did the monstaz timing mod a week ago and thought about higher octane but never did it.

[derekMZ3]

thanks krimson, you're probably right

[krimsonviper]

derek-im just guessing so dont take my word for it lol

mazda32008-i wouldnt really trust those octane boosters. I know some companies boosters actually EAT the oxygen sensor causing problems, others only give you like +2 rating over whatever octane you put it. The stuff racers use is probably undiluted which gives them a better use. I think i've heard of some people who've used acetolyne(sp?) and get pretty good use out of those because it helps the gas "mist" better. SOMEONE CORRECT ME IF IM WRONG,PLEASE!

[derekMZ3]

well i think i'm just not going to run 87 anymore

[krimsonviper]

Personally i run 89 octane, its a step in the the middle where im not spending too much to try and keep my engine clean. After about a month or so i buy the lucas oil tune-up. its pretty freakin awesome. I really can tell the difference when its in there and when its not

[derekMZ3]

thanks, i'm going to try that out for a few months and see how i like it.

haha i'm at work right now and your sig made me laugh, i probably look funny....laughing at the computer screen.

[mazdaspeed32007]

octabne boosters suuuuuuuck. they say you can gain like 10 points per bottle but they dont tell you each point is equal to like....1 octane point....lol. so to the 93 octane. putting higher octane will kill any spark knocks your motor would put out on 87. 93 will increase gas milage by a little bit because it burns slower and cleaner than 87. lastly in burning cleaner your not leaving so much gunk in your motor. i have a speed and it requires 93 because like stated above...the high compression. it take so much compression to detonate the gas. each gas takes a different amount of compression to detonate it. higher compression, higher octane. but if your motor doesnt need the high octane...the fumes will burn more complete than the lower octane fuel. There are also improved timing maps that can be used with higher octane fuels. Higher octane allows more aggressive ignition timing and allows more margin for a hot lean A/F mixture without detonation so you can gain more power. but only by maybe 3 hp that wouldnt even be amounted to shit at the wheels.

plus, at the difference from 3 a gallon to 330 a gallon....imo...not worth it with gas prices the way they are.

[mazdaspeed32007]

btw...krimsonviper...your sig is funny as hell

[robin2660]

octabne boosters suuuuuuuck ... 93 will increase gas milage by a little bit because it burns hotter ...

Hotter?

[mazda32008]

it doesn't burn hotter it burns slower.....i run 89 and i felt a difference the rpm band is smoother thats about it....but then again i did advance timing so prob that's why i felt a difference. depending on gas prices i run 87 reg most of the time still runs fine but like i said 89 it runs better, specially at low rpm's.

[cmedrive]

I'm pretty new to this forum but I've had my 3 (and been on other forums) for a year now. There really is no reason to run a higher octane than 87 (86 for us High Country folks) unless your motor is highly modified. And by highly modified I don't mean intake/header/exhaust. I mean standalone, internals, manifolds, turbo...etc. There have been exhaustive discussions on all of this and the fact of the matter is that gas is gonna burn just fine with our very smart computer. A higher octane is simply a waste of money.

[krimsonviper]

A higher octane is simply a waste of money.

aside from not leaving so many deposits

[mazdaspeed32007]

Hotter?

someone corrected me....i meant to say slower. i have no clue why i said hotter. (smash)

[RabidRich]

To continue this conversation...I recently purchased a new Mazda 3 GT (not the sport as being discussed)...sweet ride, loving it. However I just noticed in the user manual (after a few fills of course) that it recommends 91 octane, and 87 should only be used in an emergency. When i speak to the dealer, they laugh and say the 87 is fine. Any thoughts on this one

[krimsonviper]

if the manual says a higher octane, than you're suppose to use a higher octane. the dealer laughed because none of them know wtf they're doing.

*edit*however, since it isnt forced induction, its not like it will blow your motor immediately. it will cause pings, and the damage done might be minimal, but in the long run of keeping the car, it will damage it. if you're not wanting to deal out the extra dough for the highest octane available, just take one step down from it...also, where the hell are you guys getting this 93 octane, here in my area (vacaville-vallejo,ca) i can only find 91. is it the gas station or what? i use chevron or 76. i cant afford shell

[robin2660]

if the manual says a higher octane, than you're suppose to use a higher octane. the dealer laughed because none of them know wtf they're doing.

*edit*however, since it isnt forced induction, its not like it will blow your motor immediately. it will cause pings, and the damage done might be minimal, but in the long run of keeping the car, it will damage it. if you're not wanting to deal out the extra dough for the highest octane available, just take one step down from it...also, where the hell are you guys getting this 93 octane, here in my area (vacaville-vallejo,ca) i can only find 91. is it the gas station or what? i use chevron or 76. i cant afford shell

Chicagoland premium fuel is all 93 octane. It's either that or midgrade at 89.

[krimsonviper]

Chicagoland premium fuel is all 93 octane. It's either that or midgrade at 89.

wow, thats one helluva difference in octane grades

[mazdaspeed32007]

here in MA the shell down the street is 87 89 or 93. others like sunoco do 87 89 91 and 93. were running about 313 for 87 and about 335 for 93 give or take depending on what those money grubbing fucks have in mind. i always run 93 shell gas because 1...well its 93. and 2...they put in small amounts of fuel additives that keep your motor clean and prevent build up. ill "shell" out a little extra for shell. im sure itll make a decent difference in the long run.

[cmedrive]

I've been involved in these discussions numerous times and I think we all have our own opinion. I'm ok with using 86 (high altitude so the octane is low) in my car. There's nothing bad about using higher octance but I don't see the benefit for my car.

[mazdaspeed32007]

whatever.....im eco friendly. i burn nothing but pure ethanol. my car runs like shit though. cant figure it out. must be a lemon.

[fennec2009]

It may just be in my head, but I have an '04 3i and I definitely noticed a difference in acceleration when I went from 87 to 93. I bought it used and the lady that had it before me used 87, and I didn't notice anything wrong. I tried Shell 93 in at the next fill up and it accelerated a lot faster. The ride also felt a tad smoother as well. I've gone back and forth between 89 and 93 (gas prices are killing me!!) and don't notice much difference between those, but I haven't ever put 87 in since I've gotten it. I know Shell 93 has something in it to remove buildup, that may have been why. The car had 80,000 miles on it and I doubt it ever saw anything else besides 87. I'm sticking with the 89 for now, occasionally 93 to clean everything out though.

[BoostThat3]

It may just be in my head, but I have an '04 3i and I definitely noticed a difference in acceleration when I went from 87 to 93. I bought it used and the lady that had it before me used 87, and I didn't notice anything wrong. I tried Shell 93 in at the next fill up and it accelerated a lot faster. The ride also felt a tad smoother as well. I've gone back and forth between 89 and 93 (gas prices are killing me!!) and don't notice much difference between those, but I haven't ever put 87 in since I've gotten it. I know Shell 93 has something in it to remove buildup, that may have been why. The car had 80,000 miles on it and I doubt it ever saw anything else besides 87. I'm sticking with the 89 for now, occasionally 93 to clean everything out though.

(boom06) Don't use Shell!!!

[staples187]

On my '06 Toyota Avalon the car is tuned for 91 octane. I can run 87 on it, but I lose 10% horsepower performance in doing so. The ECU learns what type of gas goes into the car by the type of combustion it makes. They were extremely smart when they came out with Dual VVT-i.

For a 4 cyl engine, if 87 is recommended, then that's what the car was tuned for. It would be a waste at that point to put in higher octane.

Basically keep it at the recommended level, spending more on gas will be a waste, and no it won't make the engine or the life expectancy last any longer.

[fennec2009]

(boom06) Don't use Shell!!!

Why not? It's the best thing around here, when all you have to choose from is BP, Shell, or Sunoco. I use Marathon on my way back from school sometimes, but not on a regular basis.

[mazdaspeed32007]

i use shell religiously. same with sunoco. one is rated the best to keep your engine the cleanest and the other is the official gas of nascar. those are two trophies ill side with.

[ehidle]

Let me speak with a little bit of authority on this. I design control systems for oil an gas refining platforms for a living, so I can tell you with confidence that you do not need to run premium fuel in an engine unless it is dictated by a high compression ratio or a radically advanced timing map. Doing so will not change the performance characteristics of the stock engine in any meaningful way.

The only things the octane number represents is the resistance to spontaneous detonation of the fuel mixture and the volatility of the fuel. As a gas is compressed, its temperature rises. A high compression motor increases the pressure significantly more than a lower compression motor, which causes the mixture to be raised to a higher temperature. All combustible mixtures will spontaneously combust (i.e. without a spark) at some temperature. Lower octane fuel has a lower temperature of spontaneous combustion than does high octane fuel.

So, if you have a high compression motor, it is possible to spontaneously detonate a mixture of 87 fuel before the spark plug fires. This detonation causes the "ping" sound that you may hear.

A quick note on ignition timing. One other property of higher octane fuel is that it burns more slowly than lower octane fuel, because it is not as volatile. This means that if you are going to advance your timing significantly from stock, a higher octane fuel may also be indicated to prevent the combustion cycle from ending before the piston reaches bottom. If this occurs, the combustion cycle ends and the temperature starts to fall, causing the pressure to fall, but the piston is still increasing the volume, so what happens is that you lose any pressure at all on the piston, and you do not get a complete power stroke.

But, the other note on timing is that regardless of when you detonate the fuel, the amount of energy is the same, so whether you spread your combustion cycle over a longer time is really irrelevant to the power output of the engine. If you plan to run extremely high RPM, it may be necessary to advance timing so the fuel has enough time to burn completely before the piston reaches bottom, but I can't imagine any other reason to advance the timing significantly.

Finally, a quick note on "octane boosters." All these things do is lower the volatility of the fuel by introducing ethanol. Ethanol has a very high equivalent octane number and, when mixed with fuel, will ever-so-slightly increase the detonation temperature. Usually, a 12oz bottle of "octane booster" will do more or less nothing for you in terms of ignition temp, and will actually decrease the amount of energy taken into the cylinder on the intake stroke, because ethanol has a much lower volume energy density than gasoline.

Hope this is helpful :)