What gas do ya use???

[MinnowGT]

Union 76 - 87 octane.

only gas company in cali that I have seen that doesn't
use the stupid mtbe.

I've gained back 1-2 mpg when using them over anybody
else's stupid mtbe enriched gas.

 

[seatown.P5]

Chevron regular unleaded. After years of having to use premium for my (turbo) SAAB, it sure feels good to pay less at the pump!

 

[dukerjames]

dunno what kind of gas dealer put in the tank the first time, been using 87 since i bought the car, not a single problem.

 

[YlowP5]

Union 76 - 89 octane... it just makes me feel better. But if it's not doing anything for me, I may switch back to 87. PatrickP5, thanks for the engineering info... this makes me feel better about going back to 87 (I'll save myself some $... gas prices in the Silicon Valley are ridiculous!).

 

[sundevilMP5]

Okay, guys. Let me tell you this from the perspective of a guy who has a B.S. in Mechanical Engineering and an M.S. in Aerospace Engineering and has taken classes on this very thing:

Higher octane gas *only* helps you if you have a high-compression engine (or maybe if you have a truck pulling a lot of weight up a big mountain). Higher octane gas merely has more heavy, long-chain hydrocarbons in it, which makes it harder to ignite. What this does for you is prevent the fuel/air mixture from prematurely igniting from the compression stroke of the piston (this is what is called knocking). If you do not have a high-compression engine, you do not have a need for high octane gas, since 87 (or maybe 89 in some applications) is not going to pre-maturely ignite in our stock/nearly stock protege engines. Octane rating is *not* in any way a rating of how "clean" the gas is - only how "heavy" it is.


Patrick

you know that is the first "technical/scientific" explanation i've ever heard about gas on this board...thumbs up to patrick

 

[Esteban Toledo]

Actually, even for the p5 89 is recommended in the manual (read!)although it can run 87 just fine!!!!.

Please list a page number. Because on page 4-2, it recommends 87 OR above.

 

[blynzoo]

Please list a page number. Because on page 4-2, it recommends 87 OR above.

kay. I will head home tonight and try to find it. Look at the ASE stamp that they have in the manual. That may say 89. I remember sitting in my car reading the manual when I first bought it (my favorite part of a new car) and being suprised by the variance.


89 will do one thing. Octane makes the fuel less combustion-prone (to prevent knock). However this can, to a point, also even out the burn upon ignition.

Again, stick with 87, you're fine. However I do notice on my frequent road trips to DC from Indy that the car runs smoother on 89.

And hooray for chevron gas.

 

[jewelz007]

Again, stick with 87, you're fine. However I do notice on my frequent road trips to DC from Indy that the car runs smoother on 89.

And hooray for chevron gas.

I was using 89 for a little while.. more for a change - give it a little pick me up.. I did notice that on long trips..it took longer for me to have to fill it again.. I'm assuming thats because it burns slower?? 87 most of the time.. the best way to CLEAN the tank, would just be to get some fuel injection fluid.. thats the only sure way -- higher octane gas aint gonna do crap!

 

[tonkabui]

87 chevron for daily driving and either 89 or 92 chevron for long distance driving back to california. i get about another 3-5 mpg with the higher octane on the freeway. in the city, i noticed no difference.

 

[Rider69]

kay. I will head home tonight and try to find it. Look at the ASE stamp that they have in the manual. That may say 89. I remember sitting in my car reading the manual when I first bought it (my favorite part of a new car) and being suprised by the variance.

Here is from the manual:

Vehicle damage and drivability problems resulting from the use of the following may not be covered by the Mazda warranty.
Gasohol containing more than 10% ethanol.
Gasoline or gasohol containing methanol.
Leaded fuel or leaded gasohol.
Fuel Requirements
Fuel Octane Rating* (Anti-knock index)
Regular unleaded fuel 87 [ (R+M)/2 method] or above (91 RON or above)
USE ONLY UNLEADED FUEL.
Your vehicle can only use oxygenated fuels containing no more than 10% ethanol by volume. Damage to your vehicle may occur when ethanol exceeds this recommendation, or if the gasoline contains any methanol. Stop using gasohol of any kind if your vehicle engine is performing poorly.
Never add fuel system additives. Never add cleaning agents other than those specified by Mazda. Other cleaning agents and additives may damage the system. Consult an Authorized Mazda Dealer.

 

[PatrickP5]

I did notice that on long trips..it took longer for me to have to fill it again.. I'm assuming thats because it burns slower??

This is not because of the gas you're using - it's because you're not accelerating as much and you're not starting the car as much - hence the difference between city and highway mileage. The killers for gas mileage are acceleration and start-up. Long trips have less of both of these than an equivalent distance sum of short trips.


Patrick

 

[|Thrax|]

There is NO POINT whatsoever in using anything other that 87 gas in your P5, UNLESS you have a turbo. None. There is no benefit at all. If it makes you feel better to waste your money, go nuts, but you aren't getting anything from it.

Correct! Your car is acually slower because you don't have enough compression to require high octane.

 

[slenser]

THANK YOU!!!

Hopefully, this thread has shed some light on this very subject. I get so frustrated at people's opinions on octane. I've given the explanation to others before (not in as great detail of course) and pretty much get nowhere.

I've seen dyno results of changing octane. If you don't have advanced timing, high compression, or some sort of power adder, high octane is a waste of money.

My conclusion...

If you want to waste your money, go ahead, but I'm making more ponies and saving Benjamins!

Sam

 

[ESJ]

There is NO POINT whatsoever in using anything other that 87 gas in your P5, UNLESS you have a turbo. None. There is no benefit at all. If it makes you feel better to waste your money, go nuts, but you aren't getting anything from it.

thats not true

i saw a test in a mag that dynoed acouple of cars on 89 and then the same cars on 94, they got an average of 5 more horses out of the higher octane gas

 

[savaho]

im using 87 diluted with some water to keep the tank looking full. works great! less fill-ups. simply put, if the manufacturer doesn't insist on premium gas, don't waste your money. give it 2 yrs or so and you won't give a rats ass about sticking with premium gas...hehe it's like a phase people go through with their new toy. been there, done that. as for the diluting part, i was merely being sarcastic.

 

[falkofire]

94 octane or higher only...Ive acctually left places if they only have 91..Im still trying to find a place that sells higher octane around here

 

[PatrickP5]

thats not true

i saw a test in a mag that dynoed acouple of cars on 89 and then the same cars on 94, they got an average of 5 more horses out of the higher octane gas

What cars were they and what kind of engine / compression ratio did they have? With out this information, what you just said is irrelevant.


Patrick

 

[mazdadan]

In my '01 ES, I have been running the cheapest 87 octane gas in town since day one. Never had any issues and get over 30mpg on long trips.

 

[TURBO3WAGON]

10000,
jk

93+ Only!!

 

[uclap5]

exxon - 87. cheapest near me... which is $1.80, which is good since it was up to $2.15 at the cheapest a few months ago.