What GAS grade ?

[m3f_04M3blur_1ceee0bbd5]

I just filled up and noticed the gas station I was at actually had 87, 89 & 93 (I still use 93).

[m3f_95RogueM3]

go get full fuel service done and get some 76 racing gas 103 octane and run that gas straight for a few days, your car will love you.. and u'll love the results..



OUr cars cant take advantage of anything more than 93. We arent boosting and dont experience detonation on 93 octane..so why pay more for race gas?



-Richard

[m3f_Wicked_M3]

wow, i feel bad for you guys on the west coast..no 93 octane? and those crazy gas prices..thats enough to keep me here in FL. =) im used to spending the extra $ for premium gas. i even ran 93 in my 5.0 (heads/intake/cam/rr and advanced timing) so it was $30/tank.



is the m3 tank 15 gallon also, or more?

[m3f_tschank]

it doesn't matter what kind of emergency it is, i would never consider putting in anything lower than 91, if its emergency, u call a tow truck and get your car towed, or whatever else u got to do, if you stranded, call a friend, and if u did get 89 or 87 octane gas when u were stranded u could have got at least 91.. no excuse..



Well, that's just silly. You would pay to have your car towed to a gas station that has 91 octane. I have on ocasssion had to put in 89, because when your out in some hick town they don't always have premium, so there's my excuse. A lower octane is not going to hurt the car unless you hear knock.



Normally I use 93, it is only about $1.70 more a tank.

[m3f_Extrav.Dre_53c7fb859e]

Some of you are way to anal about this whole issue. For the most part gasoline is gasoline. If you use your car as a daily and live where it doesnt get too hot.... you could use 87 from certain gas stations and never see a problem. I think in this case it is more important from where you are getting the gas. I'm not suggesting to do it, but if you ever need to because you have no choice, go for it. Your car won't hold any grudges, just don't expect to be driving on the track.



As for me, I always use 93, I guess I'm pretty lucky with it being 'only' $1.76/gallon. What I like about many of the gas stations here is that instead of going up 10 cents for the next grade up, it goes up by 7 cents.



But since the price difference between 87 and 89, and 89 and 93 is the same, it is actually cheaper to fill up 1/3 87 and 2/3 93 to get to 91. saves ya anoher 1.66 cents per gallon when the price difference is 10 cents per grade.

[m3f_imports4ever858]

hey u all use the cheap ass 87, i came from russia and my dad always put in 95 octane or higher in his beemer, i was really confused of why we have the best economy, but shitty ass gas, i wouldnt mind 93, but 91 is pushing it, besides if the manual calls for at least 91, the fuel door sais not to use anything lower, why would you want to? to save a dollar or 2.. i guess u right i am very anal about my car, i change all the fluids before on time and use top of the line stuff.. and i don't know why some of you say that race gas doesnt do nothing - it made my car run .5 second better time in 8th mile drag.. and the car feels faster and sounds better.. not trying to start an arguement just my opinion and no matter what anyone sais i'll be stubborn and stick to it..

[m3f_95RogueM3]

and i don't know why some of you say that race gas doesnt do nothing - it made my car run .5 second better time in 8th mile drag.. .



This is really a terrible assumtion to make: that you are so consistent with the same 60's and et's every trip down the track on numerous occassions in one night that you could tell the difference with a bit of race gas. I dont doubt you ran faster with the gas but i dont think it was because of it.



I agree with you about not putting in much lower than 93 and I never put 91 in my car, though I would put in 91 if i were on the west coast.



-RIchard

[m3f_Extrav.Dre_53c7fb859e]

the 95 rating is a different rating then the the rating here. I think 93 is actually higher then the 95.



I agree with 95 dinan.. a .5 difference in time is far within the error range between runs, unless you are a pro



91 is a recommended rating.. sort of like a "buy by this date" on food. The date always passes before the food actually goes bad (assuming you stored it in its recommended place), this is so they don't get any law suits. Same thing with the grade of gas, they dont want to get suid by someone that just happens to not get perfect preformance from not good enough gasoline. In this case it basically means that 89 was too low to always get best results.

[m3f_m3-dude]

What exactly would lower grade gas do to your engine?

[m3f_genner21_b0df9c1cac]

Comon guys..we are talking about $3 dollar difference in a tank on a car that new was more than $46 K. I live in Cali and feel ur pain but the difference we are talking about is really really not that much. Maybe don't drive ur car as hard and put 91 octane, that should save ya some money.

[m3f_04M3blur_1ceee0bbd5]

is the m3 tank 15 gallon also, or more?

I can't speak for the E36 M3, but the E46 M3's tank is 16.6 gallons (I just filled up and squeezed in 16.52 gallons, and I was really empty, so it must be pretty accuarate).

[m3f_04M3blur_1ceee0bbd5]

if the manual calls for at least 91, the fuel door sais not to use anything lower, why would you want to? to save a dollar or 2..

I agree, if the gas is available, it wouldn't make sense to use anything lower than 91. Now as mentioned, if 91 is not available, you gotta do what you gotta do.

[m3f_sameguy]

What exactly would lower grade gas do to your engine?



A lower grade gas will cause knock, detenation, etc. Your engine management system will (in an M3 anyway) retard your timing, to prevent the knock, and protect your engine. (I'm not sure if the system can completely stop knock though) Retarding your timing will lower the power output of your engine. Excessive knock can put great pressure on the valve train, crank and it's bearings, piston, conn rods, bearings etc. A little knock isn't going to kill you, but 30,000 miles of it is going to take it's toll on your engine. Think of it like smoking. A cigarette here and there isn't going to kill you, (but most of us would never smoke one) but a lifetime of smoking is.

[m3f_98technovlt]

Let's do a little math...Paying .30/gal more for 93 would cost maybe an additional $6.00/week (20 gal/wk) or $312/year. Most of us have spent well over $5000 in maximizing the performance of our M's. It would take ten years for the difference to equal the cost of "light" modification. Assuming that we mod to maximize performance or increase durability, why would we leave the additional performance and durability that 93 may help afford "on the table"?

[m3f_imports4ever858]

i run consistent times, times fluctuate within hundredth of a second, not tenth of a second, and half a second is a huge difference, about 2-3 car lengths.. i don't know if you drag race much, but the people that do will understand.. my car is auto so it's not like i can miss shift, and my reaction times are pretty consistent also.. i ran on 91 and ran a time, then after putting in 103 on the same track, same night, i ran .5 seconds better time. next time a few months later i came to the same track again, ran 91 and ran my exact previous time with out race gas.. you can even feel a difference with NOS race formula octane booster, and it only raises rating by 7 points, this was straight 103 race gas... someone here should give it a try and see, maybe they change their mind..