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what octane to use

5.2K views 68 replies 22 participants last post by  JonV  
#1 ·
hi guys this is my first post in here, and this is the first saab i own. ok i heard and read that i should use premium octane(91) is this really necessary, does it only affect performance or does it damage anything else mechanical.

i was thinking of at least using 89 octane. any info would be apreciated.

by the way i have a 2004 saab 93 linear 2.0t
 
#6 · (Edited)
And Page 240 of the trusty manual says: (my Italics)


Fuel tank capacity ___________________ 16.3 U.S. gal. (62 l)
For optimum performance
Saab recommends:
2.0t (175 hp) ______________________ Unleaded 90 AON
2.0 Turbo (210 hp) _________________ Unleaded 93 AON

but it says on Page 128,

All Saab gasoline engines can be driven on
gasoline with an octane rating between
AON 87–93.
The engine management system monitors
the combustion and automatically adapts to
the fuel used.
Always use the correct grade of fuel:
unleaded AON 87–93.
 
#7 ·
The manual (US) says that 90 is recommended. The octane system is different in Spain and Europe. Why not use 90 octane?

89 octane is very close. So is 91 octane. If you want precision, try mixing gas. Octane ratings can be mixed and the value is linear. In other words, mixing half and half 93 and 87 is 90 octane. Mixing 60% 92 and 87 is 90. 91 is so close to 90 that mixing may not be worth the trouble. If you do then 75% 91 and 25% 87.

First guess how much gas you need. If you need 10 gallons (slightly less than 1/2 a tank, each 1/4 of a tank is 4 gallons), then add 4 gallons of 87 and the rest 92.

You will find that in most parts of the US (I don't know about Canada), 89 octane is more expensive then if you make 89 by mixing 92 or 93 with 87. 89 octane is mixed at the pump so you are making the exact same product.
 
#8 · (Edited)
If your just go hither and dither 87 will work fine (which would be 90/91 RON across the pond). IMO you will only notice a difference in performance if you are hauling a load or looking for quicker response and power at highway speeds. Lots of guys run on regular.

Edit: realistically it only costs a couple of bucks a week to go up to just mid grade from regular.
 
#9 ·
;)
Finch 93 said:
The manual (US) says that 90 is recommended. The octane system is different in Spain and Europe. Why not use 90 octane?

89 octane is very close. So is 91 octane. If you want precision, try mixing gas. Octane ratings can be mixed and the value is linear. In other words, mixing half and half 93 and 87 is 90 octane. Mixing 60% 92 and 87 is 90. 91 is so close to 90 that mixing may not be worth the trouble. If you do then 75% 91 and 25% 87.

First guess how much gas you need. If you need 10 gallons (slightly less than 1/2 a tank, each 1/4 of a tank is 4 gallons), then add 4 gallons of 87 and the rest 92.

You will find that in most parts of the US (I don't know about Canada), 89 octane is more expensive then if you make 89 by mixing 92 or 93 with 87. 89 octane is mixed at the pump so you are making the exact same product.
I've been mixing the grades for several months now. Around here, most of the stations have 87,89, and 93. I was using straight 93 until the price to refuel topped $50 which was causing me to re-swipe my debit card to finish filling the tank. I figured if I've got to deal with swiping it twice, I may as well mix 93 and 87 and save a couple of bucks in the process. My 2006 calls for 90 octane, so I just put in a liitle bit more than half the number of gallons of 93 that I think it will take to refuel, then top if off with 87. I'd rather be on the plus side of 90 than below it. The winding roads that I take on my commute allow me to "mix it thoroughly";)
 
#10 ·
i'm not exactly a penny pinche nor am i needless spender, but in the warmer months (late march -> sept) i always use 93. the extra few bucks per fill up for cleaner fuel is worth it.

do i notice a big difference? only when the car idles, and sometimes on the highway. i feel like the response is better and it has a slight edge. i use 87 when it's cold out and when driving fast isn't exactly.. applicable.

keep in mind it takes 2-3 weeks for the ECU to adjust to fuel before you see a difference in performance and mileage. i was getting 2-3 more mpg on 93 than 87.
 
#11 ·
cadcamjim said:
;)
I've been mixing the grades for several months now. Around here, most of the stations have 87,89, and 93. I was using straight 93 until the price to refuel topped $50 which was causing me to re-swipe my debit card to finish filling the tank. I figured if I've got to deal with swiping it twice, I may as well mix 93 and 87 and save a couple of bucks in the process. My 2006 calls for 90 octane, so I just put in a liitle bit more than half the number of gallons of 93 that I think it will take to refuel, then top if off with 87. I'd rather be on the plus side of 90 than below it. The winding roads that I take on my commute allow me to "mix it thoroughly";)
I'm not sure I get that logic, assuming you have 2 gallons in the tank, if you get 7 gallons of 93 at 3.00 a gallon thats 21 bucks, if you get the other 7 of 87 at 2.80 thats 19.60....you've saved a dollar and forty cents...why bother. just run on 87 if you can't afford 93, or skip a morning coffee stop on the way to work
 
#13 ·
Ive always gone with the highest grade possible, especially since tuning with the BSR PPC. Now I def make sure i get 93. I dont want to take the chance of knocking etc... 93 is for me usually $.30-.40 more than 87, so after a fill up, its a maximum of $5.00 difference. Times are tough, but Id rather look out for my expensive investment.
 
#15 ·
I will never run 87 in my Saab, my CRV, past civics, and a few other cars all ran fine on it and i would never go over 90 in them but with the Saab i use 90 if i plan on doing alot of regular drviving and 93 if im doing highway or some back country fun driving. Ive noticed that my gas mileage will occasionally hit 30 on the highway with some nice 93 in it, but if i use any lower i have trouble geting to 26 MPG on the highway. Ive checked the cost and because i do so much driving here is the difference 87-90 $11.61 a month 90-03 $9.45 a month overall from 87-93 its about $20 give or take, that $20 a month helps my engine run better and gives me a slight bit more performance that i can easily see.
 
#16 ·
JonV said:
I'm not sure I get that logic, assuming you have 2 gallons in the tank, if you get 7 gallons of 93 at 3.00 a gallon thats 21 bucks, if you get the other 7 of 87 at 2.80 thats 19.60....you've saved a dollar and forty cents...why bother. just run on 87 if you can't afford 93, or skip a morning coffee stop on the way to work
Jon, I agree that it is not worth the bother just for the cost savings. I started doing this only because I was aggravated about having to wait for what seems like forever for the pump to reset and then re-swipe my debit card when it hit $50. When I use my card at other stations, this $50 limit does not necessarily apply, however, this is the only self-serve station that I pass on my daily commute that has competitive gas prices. I just figured that if I've got to pump twice why not save a buck in the process. Now that prices have fallen, I can go back to running straight 93 as it doesn't take $50 to fill it. And for the record, I grind and brew my own coffee.:cheesy:
 
#18 ·
JonV said:
i grind and brew with a french press ;)
...do you by chance mix caffienated and decaf?:lol:

I'll admit to mixing gas, mostly because 93 is 30 cents more per gallon than 87 (89 is 10 cents more) in this neck of the woods.

With the current pricing in my area (87 = $2.75, 89 = $2.85, 93 = $3.05), I'd spend 5 cents more per gallon but get 1 more point octane by mixing half'n'half 87 & 93 as opposed to using straight 89. However, I'd save 15 cents per gallon (but lose 3 octane points) over going straight 93.

I'd have to determine if any gains in mpg and performance are worth it or not. As winter approaches I doubt it, so maybe it'll be straight 89 for a while!
 
#19 ·
At a maximum, you save maybe $4.80 by using 87 vs. 93. Now on higher octane gasoline you get better MPG, Better performance, and Cleaner burning gas. So why not just spend the extra $4.00 and do your car a favor. Now if you drive granny style all of the time then 87 will be completely fine for your engine. But, you will still get better mpg with a higher octane fuel. Besides, whether you use 87 or 93 your engine management software is very intelligent and will adjust accordingly, just don't expect to get optimum performance out of your engine with lower octane rated gas.

(Sometimes I feel like a hand full of certain topics always come back up, i.e. what octane should I use? :D:D:D:D )
 
#21 ·
I mainly put 94 just, rarely 93...never went with 89 or 87 even though i dont think 87 or 89 would hurt the car
 
#23 ·
JonV said:
Can't get 94 around here or many places now, Sunoco has phased out there's in many areas....I understand it was to expensive to Crack....low profit.
yeah sunoco is the gas station i go to..theres not too many places around here either...lucky this one is 1 min away from my house so it serves well :]..i hope they wont stop selling it!!!
 
#24 ·
ok, sure i am kind of worry about gas prices, but like one thread said gas is a bit cheap now, if it is performance all i have to worry about i can do with 89 octane. but if knocking or something else would be the problem i'd rather use 91.


ONE MORE THING i notice my steerring wheel vibrate when i hit 110-120 k/h i read that it could be just wheels need to be balance. and i also notice a bit of a hesitation when i am stop and i hit the gas. it is like a bit of a shake coming from the front, feels like the wheels.
 
#26 ·
alexdrops said:
yeah sunoco is the gas station i go to..theres not too many places around here either...lucky this one is 1 min away from my house so it serves well :]..i hope they wont stop selling it!!!
Get it while you can, II drove through 9 eastern states this summer and didn't see alot, if any. You won't notice a difference at all using 91/93. We are not driving The Ring here.