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Discussion Starter #1
Chevrolet recommends 91+ octane for the SS. A lower octane works fine just there is "a noticable loss in power that the driver can feel" if you use anything lower. Has anyone used high and low octane? Is there anything noticable?
 

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it will mt noticable because you essentially detuning the engine. High octane higher boost capabilities 91-94 octane is more then enough anything lower will carbon up everything no good there no one wants sticky valves.
 

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I remember reading in some SS documentation that lower octane fuel was fine, but it would not provide max performance if used.
 

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Lower octane gas will inhibit more knock, or detonation, which on any motor is bad but especially on boosted motors because of the heat from the compressed air. When knock is present the PCM will retard timing to try and stop it, but sometimes it can only prevent so much, and next thing you know you've got a hole in your piston.
Run lower octane at your own risk while the car is stock, but after any mods are done I would not recommend it, especially anything that would increase boost.
 

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When I bought my SS, I went with the dealer to top it off before I left the lot, and he gets out and opens the gas cap and says, "Hmmm, seems like it doesn't need premium." I thought ok whatever, and we went on our way. Turns out that he was just being cheap. Anyways, I filled up with 91 this morning (1/2 tank). Can't say I have noticed any diff., but I am still breaking it in, so who knows.
 

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it wont be something super noticable it will be minor and if you cut the fuel now your talkin 87 octance mixed wityh 91 so u have like 89.5 octane or so . . . the car is not gunna get a hole in a piston for using lower octane now get it running over 12psi yes higher octane is a reqirement but u can always cut 87 with some c12 or cut it with some mr1 i run c12 in my quad cut with sunoco 94 but once you go to race fuel theres no going back.
 

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Discussion Starter #8
Man damn I didn't know lower octane could be so dangerous to an engine like this. Thanks people I really appreciate it! I've been using 89 octane since I got it and its just about got 1200 miles on it now. On my next fill up I'll be using 93 octane. My engine should be just fine though right?
 

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dervin3 said:
Man damn I didn't know lower octane could be so dangerous to an engine like this. Thanks people I really appreciate it! I've been using 89 octane since I got it and its just about got 1200 miles on it now. On my next fill up I'll be using 93 octane. My engine should be just fine though right?
It's not dangerous. Not for a stock engine. You could very easily put regular 87 octane in your car, and you'll lose a bit of performance, but it won't hurt anything at all. It's not 'dangerous'.

Don't get me wrong. I'd still use 91 as is recommended. If you wanted lower performance to save on gas, then you should've just bought a 2.2L to begin with. :)

I'm just saying if you get really stuck sometime and need to fill up, 87 octane isn't going to hurt it at all. There's no need to be worried about using it.
 

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Discussion Starter #10
Oh ok, I want all the power this baby can offer and I'll be putting 93 octane in it from now on. Oh yeah today I changed the oil and it took a little over 6 damn quarts to fill this thing up! I had no idea a 2.0 L could possibly use anything more than 5!
 

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It takes about three tanks for the computer to set it self.Believe me my redline runs better on 91 or higher octane.
 

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Discussion Starter #12
Is the milage also better on higher octane?
 

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yea i put 7 quarts of oil in my ss, when i changed it
 

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Use low octane if you really need gas, but dont make a habit of buying it at regular intervals. 87/89 octane + boost + high ambient temps = knock from overly high intake/combustion temps. Will a problem show right away? No, probably not. Will damage occur over time from not using the right fuel? Probably. Could this damage cause a potentially fatal engine failure? More than likely yes.

If you want proof of what KR can do to a motor, go to clubgp.com and search for topics regarding excess knock retard and damaged pistons. Theres only so much your PCM can do to prevent engine failure. The rest is in your hands.
 

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Discussion Starter #16
Yeah mine took a tick over 6 quarts. Does anyone know if higher octane gets better milage on this car?
 

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I would think you would get better mileage, since the fuel thats being introduced to the chamber is being more efficiently and completely burned, requiring less throttle for the same amount of power as 89 or 87 would make at a given throttle percentage. If youre really worried about mileage though, buy a Cobalt LS :p
 

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MY GTP 8 U said:
Use low octane if you really need gas, but dont make a habit of buying it at regular intervals. 87/89 octane + boost + high ambient temps = knock from overly high intake/combustion temps. Will a problem show right away? No, probably not. Will damage occur over time from not using the right fuel? Probably. Could this damage cause a potentially fatal engine failure? More than likely yes.

If you want proof of what KR can do to a motor, go to clubgp.com and search for topics regarding excess knock retard and damaged pistons. Theres only so much your PCM can do to prevent engine failure. The rest is in your hands.

I would also read post #5 by MY GTP 8 U and this one and listen to him.

If I had a supercharger in my car I wouldn't put anything other then 91,92,93,94 depending on what I could get at the local gas station.

I known a car with a turbo and always put 93 or higher in it ;)
 

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Discussion Starter #20
No the milage doesn't bother me, I just hadn't had a car with this much power before and was unsure whether 93 was required or what cause I seen recommendations of 87 and 91+. Milage isn't important but hey if its better than its all good :D
 
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