I have a 2.4L engine and i just recently found out that the engine is recommended to run on 91 octane. I was just wondering if i switch to 91 from now on will it help my engine? i have 50,000km currently on my car.

 

I switched from 87 to 93 and I didn't gain anything. Lost mileage. I'm switching back to 87. If ur not having any issues using 87 then ur fine

 

go 91 or 93 imo. car felt better and got better mileage with it

 

Oh shut up Abraham jk

 

that stuffs condifential wtf! cant be saying my name everywhere

 

Omg

 

More octane, more resistance to detonation. More resistance to detonation, more timing advanced by ecu. More timing advance , more power and better mpg. Run 91+!

 

My mpg went down

And I don't think it will make a big difference in power on a n/a cobalt.

 

Big no, noticeable yes. If you have a car that will adjust timing automatically to take advantage of higher octane, an octane it was designed to run on, there were other outside influences that made your mpg go down when you switched.

 

Well I'm switching back to 87. It ran great and got better mileage. I got like 26mpg city on 87 and now it's at 21mpg on 93.

 

According to your sig, you have a tune. Your results are null, tune changes everything. Could be tuned for the lower octane for all we know

 

No I was specifically got retuned for 93 gas

 

May want to have that tune redone, lol

 

That's what I plan on doing. Cuz now my car is running bad

 

91 octane, there is a reason it costs more, because its better, realistically I can't believe this is a question, and even more so I can't believe people would say no

 

I get 26mpg City on 93 on my LSJ.

 

This

 

my dads solstice has the 2.4 and anything less than 91 gets 100% miserable gas mileage... like a 30% hit... and it drives like hell...

 

I data logged with hpt a while back to see what the difference would be for higher and lower octanes. Your pcm will pull timing all day if you run 87. I was getting bumped down to the low octane table a lot. Any medium to high loads and the pcm picked up kr every time. That was half a tank of 87. Then I topped it off with 93 and got ZERO KR. And that was obviously not even full on 93. Anyone who thinks their car runs better on 87 is a tool bag.

FWIW the low octane table is about 10 degrees of timing loss in some areas and more than 5 at wot...so yes it does make a noticeable difference.

Its going to take a couple fill ups before the octane is all the way up to what you want it at as well since the couple gallons of 87 you have left will bump the octane down a bit so that could be part of the reason its hard to tell on the first fill up.

 

93 ftw!

 

I will start running 91 now, should i disconnect my battery to let the computer adjust for 91?

 

No. The computer will not sense any further kr and will start using the high octane table automatically.

 

That

 

The only reason I want to switch back to 87 is because my mpg went down a lot. And my car is messing up. Ever since I got tuned for 93 the car runs bad now.

 

How many tanks of 93 did you go through?