What gasoline to use for a speed3?

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khaydin

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MazdaSpeed3 GT Black Mica
The MazdaSpeed3 owners manual says to use 91 octane gasoline, is there any benefit to going to a higher octane such as 93?

Also, are some brands of gasoline better than others? I remember with my first car - a 1988 Chevy Nova - I bought Mobile gasoline once and the car started much quicker when filled with that gasoline. When I used Sunoco gas in the car for the next tank it took a lot longer to get the car to start. This was in cold weather, in warm weather there was no difference between the two gasoline brands.

I've also seen commercials on TV for Shell gasoline saying that their gas doesn't leave as much behind in your engine as other brands.

What does everyone use/prefer and why?
 
a friend of mines dad works in the shell development program or whatever its called. he said that when thier v-power formula was released, that his dad (even though he worked on the formula) said "we finally have something almost as good as techron." ever since i try to get chevron everytime i fill up. but shell is supposed to be damn good too.
 
I dated a girl in highschool who's dad owned an Exxon. He said Amoco gas was the best out there. I don't know how the Valero buy out affected that.
 
khaydin said:
The MazdaSpeed3 owners manual says to use 91 octane gasoline, is there any benefit to going to a higher octane such as 93?

Also, are some brands of gasoline better than others? I remember with my first car - a 1988 Chevy Nova - I bought Mobile gasoline once and the car started much quicker when filled with that gasoline. When I used Sunoco gas in the car for the next tank it took a lot longer to get the car to start. This was in cold weather, in warm weather there was no difference between the two gasoline brands.

I've also seen commercials on TV for Shell gasoline saying that their gas doesn't leave as much behind in your engine as other brands.

What does everyone use/prefer and why?
Click to expand...

Here's some info:
http://vettenet.org/octane.html
http://www.ftc.gov/bcp/conline/pubs/autos/octane.shtm

Basically all gasolines are the same, the only thing that changes are the additives they use.
 
I normally only fill up with Exxon/Mobil but if I'm in an area where the prices of the Exxon are retarded(like in Fayetteville atm, almost 0.10 higher a gallon) I'll fill up with Amoco. Oh...always 93 octane or higher for my car :D
 
I have a friend who works at a Chevron refinery. He says Techron is just an injector cleaner, and you would get the same effect as buying a bottle of the chevron brand cleaner at the parts shop and running it through every 6-8 tanks. Dont know how true that is, but I cant justify buying their gas at an average of 20 cents more per gallon than everyone else here in santa rosa.
 
lol my only choices here in the extreme northeast are mobil and irving... the ocasional getty or citgo but mostly irving (canadian) and mobil its pretty sad.
 
I dont have a brand preferance. Name brand 93 for me. The 93 will allow the comupter to hold a bit more timing back and have more detonation resistance compaired to 91 but were splitting hairs now. I have found that the no name gas stations often have 92 or 91 as premium which is fine as long as you know what your getting. As for not knowing if the MS3 has a fuel filter I will stick to the good stuff as to not fill my fuel system with crud.
 
Craighjr said:
I dont have a brand preferance. Name brand 93 for me. The 93 will allow the comupter to hold a bit more timing back and have more detonation resistance compaired to 91 but were splitting hairs now. I have found that the no name gas stations often have 92 or 91 as premium which is fine as long as you know what your getting. As for not knowing if the MS3 has a fuel filter I will stick to the good stuff as to not fill my fuel system with crud.
Click to expand...

You are right that 93 has more detonation resistance but IMHO I doubt the computer in the MS3 in its stock form is programmed to make use of 93 octane... my take is paying more for 93 vs 91 is throwing good money away...
 
over on our side of the pond they reccomend that you use super which is 99 ron it dont matter how its from as long its that octane
 
93 would offer some advantages when compared to 91.

I do occasionally get light detonation (along with slightly retarded ignition timing) with 91.
 
matsuda said:
93 would offer some advantages when compared to 91.

I do occasionally get light detonation (along with slightly retarded ignition timing) with 91.
Click to expand...

How do you know you are getting light detonation? for that matter retarded ignition timing with 91?
 
That's kind of weird......... my mazdaspeed6 manual says 93 octane (US) I would assume given the same engine that the mazdaspeed3 would recommend the same.

To me I use 93 octane in my car and wouldn't go lower unless I absolutely had to (like maybe a road trip and the gas stations only have 91 octane when I need to stop for gas)

Also I recall reading something once about how the higher octane gas "burns cleaner" and causes less build up of gunk in the car.... probably because of the additives, but you'll notice that the internals of a 93 octane car are cleaner/in better shape than a car that has used regular (83 octane) throughout it's life.
 
Koenig there was some info said that MAzda originally tuned the MS6 for 93 oct, but then later had an update as some poepl weren't able to buy 93 and running only 91 affected the performace. Do a search i think i read it here. i know i saw it one of the mags , because one of the big questions is why the MS3 has less oomph on paper?

As for Gas, just buy 93 or 91 what ever you can get in your area. Don;t waste money on 100 oct. higher octane won't help you if you can use it. IF YOU REALLY WANT TO KNOW IF THE GAS YOUR BUYING HAS ENOUGH OCTANE........... buy one can of torco race additive and see if you can HONESTLY feel a difference.

I know torco works, since the best boost i can muster on pump gas is about 18 psi on the SVO. on 2 cans of torco i have run up to 27psi of boost for a short duration and heard NO audiable knock. Also my car doens't have a knock sensor(disbaled it) so i listen VERY carefully to the engine under high load.
Anyways if you fell no change in performace with the torco , then what ever gas you are running is adequate. Torco is about 16.00 a qt and DO NOT confuse it with other "octane boosters". Long story short torco is not a octane booster, it slows the burn rate of 93 pump to make it EQUIVILANT to 104 octane, or what ever mix you run it at.
 
Last edited:
justa4banger said:
Koenig there was some info said that MAzda originally tuned the MS6 for 93 oct, but then later had an update as some poepl weren't able to buy 93 and running only 91 affected the performace. Do a search i think i read it here. i know i saw it one of the mags , because one of the big questions is why the MS3 has less oomph on paper?
Click to expand...

Yeah I know what you speak of, that resulted in the "re-flash" for the 2006 mazdaspeed6s cause of the 91 octane, and I think the 2007 speed6s are tuned for 91 because the 2006 MS6 is rated 274 but the 2007 MS6 is rated 270....

I always figured they tuned down the ms3 because it was FWD...... the speed6 is 274 hp, the speed3 is like 263, and the CX-7 is like 230 something right?

Kind of like GM........ the LS1 in a camaro/corvette/pontiac however it makes more HP in the corvette from factory than a camaro does, right?

I dunno, but I know what you mean about the power loss.

I've never seen higher than 93 octane at a gas station, I mean I know where to buy 100 and 110 octane race gas......but not from a "publicly" open gas station, lol
 
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