Octane question....

[kirk98]

Ok, on chevy.com it says a Cobalt SS supercharged runs on 91+ octane. Every gas station where I live has a differnt premium octane. It goes from 91-94. By putting a different octane in everytime would it hurt the engine? Say I go from 91 to 94, then to 92 back to 94, ect ect. Does it hurt to mix the octanes? Or should I just make sure I always go to the same gas station and get the same thing everytime. Whatcha think? I'm still learning how engines work.

[ January 09, 2006, 01:35 AM: Message edited by: kirk98 ]

[camaro_speedemon]

I'd stick with the same octane every time, but I imagine mixing 91-94 wouldn't hurt, as long as you didn't put anything lower in.

[J. Henley 17]

It won't hurt... it will change the rating, though, as you mix. As long as you stay at 91 or higher, you'll be fine, though.

Some racers I've talked to mixed octanes... 93 with something really high, maybe 103 or 110 or something to get around a 97... I don't remember exactly the numbers, but I know they mixed to get a higher rating without having to spend all the money to run straight racing fuel.

[mwh27]

There was a pretty nasty thread about octane a while ago. Saying if it makes the car go faster. Wither way, read up on it.

http://en.wikipedia.org/wiki/Octane_rating

[camaro_speedemon]

Originally posted by mwh27:
There was a pretty nasty thread about octane a while ago. Saying if it makes the car go faster. Wither way, read up on it.

http://en.wikipedia.org/wiki/Octane_rating

If you're car doesn't have a fuel map to advancethe timing for higher octane, putting higher octane in WILL ABSOLUTELY NOT MAKE YOUR CAR GO FASTER.

The only reason you would get better performance with 93 from a car thats designed to run 87, is somethings wrong with the car and it's knocking.

For example, putting 87 in an LS1 will pull the timing killing performance. Putting 93 in won't pull the timing.

Putting 87 in a car designed for 93 will decrease performance. But putting 93 in a car designed for 87 won't do jack ****.

Now say, if you always use 7-11 87 gas, then put in mobil 93, you'll yea will probably get better performance. Not because of the 93 octane, but because the gas is a hell of alot better. The 7-11 gas isn't as clean so it causes the car to knock more and that makes the computer yank the timing. When you put the cleaner gas in, the engine doesn't knock and it won't pull the timing. You'd probably get the same results using mobile 87.

[cam98aro]

octane is based on compression.

if you have a low compression car, you put low octant in, if you have a high compression car, then you take high octane.

My camaro takes 115 octane, therefore it has high compression.

[camaro_speedemon]

Originally posted by victimizati0n:
octane is based on compression.

if you have a low compression car, you put low octant in, if you have a high compression car, then you take high octane.

My camaro takes 115 octane, therefore it has high compression.

Kinda. This is true for old school motors, but it's not really with new motors. Technology has advanced to allow for better airflow and such so you can run higher compression and low octane. For example, my old Matrix had a compression ratio of 10:1, but was designed to run on 87. An LS1 can run on 87 just fine without problems, albeit at reduced power, but still it won't damage the engine.

[Mighty Thor]

Just about all Force Induction car requires high octane. The higher octane the better.

[camaroman1181]

you use 115 octane1?!?!1 what all do you have done to your car?????

[J. Henley 17]

Seriously... you must have 13:1 and 20 psi on it or something...

Also, direct injection technology is allowing for higher compression and lower octane, meaning more efficient engines that can still run on pump gas.

[cam98aro]

Originally posted by camaroman1181:
you use 115 octane1?!?!1 what all do you have done to your car?????

im not sure, i bought it used.

there was i think... 115 octant in there when i bought it

[shenanigans]

*sigh*

you guess waste money on gas. I know my car is only a bolt on car.

But I ran 87 octane no issues, no knock, well teeny amount of knock but it shows up with 103 octane on the stock tune so its not octane related.

pulled my best times with 87. Only other times I ran high octane was when I added alot of timing, and leaned out the car a little just to be safe.

I know it sounds cool to be running "high octane" but its just wasting money. But I am sure people will tell me it feels better and only their car feels faster because of it. I bet the same people think their car feels much faster after they wash it too.

[HokieBird]

Originally posted by victimizati0n:
octane is based on compression.

if you have a low compression car, you put low octant in, if you have a high compression car, then you take high octane.

My camaro takes 115 octane, therefore it has high compression.

It sounded like you knew what you were talking about there for a second. If your car has high compression then you have to put in higher octane gas. You're therefore statement is backwards.

Do you have any clue what is done to your car? I seriously doubt you need to be running around on 115 octane.

[cam98aro]

Originally posted by HokieBird:
</font><blockquote>quote:</font><hr />Originally posted by victimizati0n:
octane is based on compression.

if you have a low compression car, you put low octant in, if you have a high compression car, then you take high octane.

My camaro takes 115 octane, therefore it has high compression.

It sounded like you knew what you were talking about there for a second. If your car has high compression then you have to put in higher octane gas. You're therefore statement is backwards.

Do you have any clue what is done to your car? I seriously doubt you need to be running around on 115 octane. </font>[/QUOTE]how is the statement backwards???

if a car takes 115 octane, then it has high compression.

edit*

I know the car has a new intake

[ January 11, 2006, 05:04 PM: Message edited by: victimizati0n ]

[camaro_speedemon]

Originally posted by victimizati0n:
</font><blockquote>quote:</font><hr />Originally posted by HokieBird:
</font><blockquote>quote:</font><hr />Originally posted by victimizati0n:
octane is based on compression.

if you have a low compression car, you put low octant in, if you have a high compression car, then you take high octane.

My camaro takes 115 octane, therefore it has high compression.

It sounded like you knew what you were talking about there for a second. If your car has high compression then you have to put in higher octane gas. You're therefore statement is backwards.

Do you have any clue what is done to your car? I seriously doubt you need to be running around on 115 octane. </font>[/QUOTE]how is the statement backwards???

if a car takes 115 octane, then it has high compression.

edit*

I know the car has a new intake </font>[/QUOTE]*sigh*

Just because a car needs high octane doesnt automatically mean it has high compression. What about all those supras and GNs and such that run on race gas. They all have low compression, but are running high boost. And if all you have is an intake on your car, and your using race gas, you're an idoit.