Octane at altitude...

[samsonic]

What octane have some of the Colorado crowd used and did you have good, bad, or indifferent performance?

Sorry, this is a semi-specific outreach to my fellow 303ers...I'm into my 1st tank of gas after the dealership filled mine at purchase. The manual says to use 87 and as I understand it, in theory 85 at altitude should be the equivalent(?) I filled up at a Shell and they had the option of 87, so I went with it to be safe until I could get some input. I emailed the dealer to find out what they used as the car ran great, but have not heard back yet. Car is running great on 87, but if they used 85, I would obviously prefer to stay with the less expensive fuel.

Cheers!

 

[ChrisJ]

What octane have some of the Colorado crowd used and did you have good, bad, or indifferent performance?

Sorry, this is a semi-specific outreach to my fellow 303ers...I'm into my 1st tank of gas after the dealership filled mine at purchase. The manual says to use 87 and as I understand it, in theory 85 at altitude should be the equivalent(?) I filled up at a Shell and they had the option of 87, so I went with it to be safe until I could get some input. I emailed the dealer to find out what they used as the car ran great, but have not heard back yet. Car is running great on 87, but if they used 85, I would obviously prefer to stay with the less expensive fuel.

Cheers!

I don't have an answer, but I'm curious what altitude you are at? No specific reason just curiosity.

I didn't even know they had anything lower then 87 octane these days.

 

[Eric Smit]

in El Paso , 4200 feet, we have 86, 88, and 91. I never use less than 91, but I'm sure lots do.


-Eric Smit

 

[ThatTmoGuy]

I always get the highest rating I can every time.

 

[ChrisJ]

I go between 40 and 600 feet and I use 87. I was tempted to get 93 last time but there was no way I was paying $3.80 a gallon when I could get 87 for $3.40. I drive too many miles and use too little power.

 

[ThatTmoGuy]

ChrisJ have you ran full tank of 93 to compare to a full tank of 87?

 

[ChrisJ]

ChrisJ have you ran full tank of 93 to compare to a full tank of 87?

Never ran anything other than 87 in the Sonic. Why?

 

[ThatTmoGuy]

way better MPG's with the stronger stuff, WAY BETTER.

More than most of the members here will back this up as well, The MP$ with 91/93 is equal to or greater than 87. The best benefit is the extra kick in the pants since it's not learning down the fuel map using the knock sensor.

 

[ChrisJ]

way better MPG's with the stronger stuff, WAY BETTER.

More than most of the members here will back this up as well, The MP$ with 91/93 is equal to or greater than 87. The best benefit is the extra kick in the pants since it's not learning down the fuel map using the knock sensor.

I don't know, my typical is 42MPG I would be surprised if I could surpass that. I suppose I could try it though, what can it hurt.

 

[ThatTmoGuy]

it can hurt your feelings that you've been missing out on the extra oomph this whole time

 

[ChrisJ]

it can hurt your feeling that you've been missing out this whole time

Only 4600 miles on my 1.4T. My 1.8 had 11K on it, so if that was the same deal then yea it might hurt my feelings.

But at only 4600 miles, na I'll get over it.

 

[ThatTmoGuy]

BTW I'm sorry to hear about your old 1.8 but glad to hear you got the right motor this time

 

[SSpeckerwood]

I'm at 5,100' and I don't use anything but 91 octane. It's so much better. Heck, I even run 91 in my 83 Chevy with a 250ci I-6.
Ethanol is so bad and 91 seems to run better in everything I own.

 

[ChrisJ]

BTW I'm sorry to hear about your old 1.8 but glad to hear you got the right motor this time

Oh let there be no mistake, I wanted a 1.4. Sadly I was unprepared when I went to the dealer to trade in my 06 grandprix on a Sonic. When I said I wanted the 1.4 turbo with 6 spd manual I was told it wasn't going to be out for several months. I even confirmed that it was a stick not an auto and they said yes, its not out yet.

So I bought the 1.8 auto LT2 and then found out pretty fast that hey, for not being out yet a lot of people own them....... Obviously we didn't return to that dealer.

 

[dblackston]

I run 91 in the sonic with my tune and run 87 oct in our un-tuned Cruze. Our Cruze is picky about its fuel. If we run 85 it runs like crap and gas mileage sucks (25-29 mpg avg), if we run 91 it runs way smoother but gas mileage tends to be lower as well (30ish) (most likely due to our right foot when it runs smooth, not necessarily the octane.) So we now tend to run 87 which is best of both worlds. I can get 33-35 mpg consistently and the car still run smooth with some pep.

Sorry I don't know in the Sonic as all I have ran is 91 since I got it but would assume it would react in the same manner. The higher the grade the better, in my opinion.

 

[ThatTmoGuy]

Chevy knew these cars would sell better if they could run 85/87 that's why they made sure it would learn down the fuel through the knock sensor. In any Turbo application you will get a better bang with 91/93.

 

[samsonic]

Just heard back from dealership. They pumped 85 for first tank. I'm running around 38.5 mpg at the moment with 87. Now that I know 85 is safe to use, I will run the next tank in 85 and get a solid average on it (1st tank was all over the place for average due to me sticking my foot into the turbo non-stop and accidentally resetting the average midway through tank while I was playing with controls). Then a tank of 91 and some cost analysis to figure out which makes most sense opcorn:

Thanks for all the feedback!

Denver elevation = 5280' (Mile High City)

 

[brandon1239]

Just buy 91, the shell by my work on 120th and Claude has 91for like 3.40 and you'll notice a difference in smoothness and mpg

 

[sx sonic]

I feel like I'm the archangel on this subject. Never noticed a difference between 87 and 93 (min & max octane in illinois several hundred feet).

Best tank on either was within .5. ~49mpg hand calc. Worst on similar drive cycles was 37 mpg. If I wasn't objective I could say 93oct gets worse mpg because my worst tank has been on 93 and is over 2mpg worse, BUT that was due to the tune and my right foot making love haha.

Try running both like you plan and try to keep the drive cycles similar and see what happens

 

[Swordsmith]

I always run 105. I know, 23 mpg seems pretty bad, but you have to understand that's with my foot constantly in turbo, if I drove it like a grandma I could maybe get 28. Not sure I'd be getting the full benefit of 230hp if I did that though.

On the bright side, that means I'm getting 153mpg (of gasoline) compared to the mere 44 mpg (of gasoline) I was getting before. Look at me all green and ****. Oh wait, you can't because those are my taillights way up ahead of you and there's no hope of you catching me. But that's green exhaust you're breathing, I swear.