Not to start a fight, but you are not entirely accurate here. While I agree that saving the extra 2 or 3 dollars just isn't worth running regular, the fact is that with today's engine management systems, you are NOT going to do damage to the engine by running lower octane gas than specified. This is because by federal law, all gasoline powered vehicles sold in the US MUST be able to run on regular gas (a product of the gas crisis back in the 70's), What WILL happen is that the ECU will pull back ignition timing (significantly in some instances) to compensate for the lack of detonation resistance.

Now as to what happened with your mother's lexus, detonation will rarely if ever cause a spun rod bearing. Spun bearings are a product of low oil levels, low oil pressure, and/or excessive amounts of high RPM operation. Detonation will melt pistons, crack ring lands, burn valves, even in very serious cases bend rods, but it will almost never (99.9999% of the time) cause a spun rod bearing unless the bearing was damaged by one of the other causes i listed. The dealership will use any and all excuses not to warranty an engine (I should know, I've worked as a tech for a Dodge dealership for coming up on 4 years now), so more likely than not your mom passively admitted to using 87 octane and they took that and ran with it.

In conclusion, while its highly unlikely that running 87 will damage the engine, the loss of power, probable loss of fuel economy (less efficient combustion), and possibility of warranty issues makes it not worth the money saved. There are probably a lot of other expenses elsewhere in your life that would be more cost-effective to cut back on than gas.

 

91+ Octane 24/7 don't care what anyone says with a S/C it's a must. For the winter yea you don't need the performance but it's more about taking care of your car, prolonging it's life.

 

now now, lets get back to the original question. I am also in Canada. Shell and Ultramar both had 93. Petro has 91 and everyone else somewhere in between. To we Canadians 43% of a liter of fuel is taxes. I can definetly sympathize with my Canadian brother. Do Not use anthing lower than 91 my friend, it's not worth the hassle.

 

Oh ya One this note can anyone reccommend an Octane buster available in Canada?

 

just some gee-whiz info....

Detonation, pinging or knocking are essentially the same.

Detonation, knock or ping is known as pre-ignition. This phenomenon occurs when the temperature in the cylinder's combustion chamber increases to a point where the air/fuel mixture pre-ignites; e.g. it "spontaneously combusts" prior to the spark plug igniting it as would occur under normal circumstances.

In a properly operating internal combustion engine, the air/fuel mixture in the chamber during the compression stroke will remain at an optimum temperature, ideally just on the verge of pre-ignition, until the spark plug ignites it forcing the piston back down to begin the power stroke. The flame front caused by the spark plug ignition should ideally be uniform across the entire combustion chamber so that the entire air/fuel mixture is completely ignited. Of course no engine produced is 100% efficient so there is always residual unburned air/fuel which creates the exhaust particulates & gasses known as emissions.

Improper ignition timing &/or air/fuel mixtures create pre-ignition & also hot spots within the combustion chamber wherein some portions of the mixture are ignited prior to others with or without the spark plug igniting it, resulting in multiple, irregular flame fronts occurring.

since the ideal 100% efficient engine doesn't exist in the real world (the ideal real world engine can maybe achieve 80% efficiency), there is always some irregular ignition & combustion occurring within a typical engine's combustion chamber. Proper tuning of the timing & air/fuel mixture minimizes the affects of this less than ideal operation, hence the current generation of computer controlled engine operating systems.

left unattended, improper ignition & combustion can cause very unpleasant consequences for the internal parts of an engine resulting in cataclysmic mechanical failures (Boom!). this is why you need to run GMs recommended premium octane fuel. 87, 89, or even 91 can and will pre-ignite. also, if you are running a different pulley, it is a good idea to have your car tuned to have your A/F ratio corrected to ensure you arent running lean (more air than fuel). i dont know much about the cobalts, but on most other modern engines the cars engine management computer will monitor and correct small irregularities in the A/F ratio, however theres nothing safer than getting a good dyno tune by a reputable shop. yes it costs money, but not as much as replacing an engine.

 

If your vehicle has the 2.0L L4 supercharged engine,use premium uleaded gasoline with a posted octane of 91 or higher for best performance. You may also use 87 octane or higher,but your vehicle's acceleration may be slightly reduced. If the octane is less than 87,you may get a heavy knocking noise when you drive. If this occurs, use a gasoline rated at 87 or higher as soon as possible,otherwise you may damage your engine.

Anyone else read this in our owner's manual, or was my book special ?

 

According to Kenne Bell, one point of octane is good to support one extra PSI of boost without pulling any timing.

And each degree of retarded timing being pulled by the PCM is 4 HP removed.

 

ur the man knight! everyone i hope ur reading his post cause hes right on the dime!

 

Dealerships for the most part don't know jack about what they sell. Our local dealership, where my dad is service manager, is a little better. He is top authority on Chevy and Nissan so he knows my car inside and out from GM training courses, but my salesman was very knowledgable too... It was refreshing after hearing so many people just ramble to try to get me in a car and get them some commission.

 

I used to live in Ohio ran 93 octane....now I live in AZ run 91

I ran my car at the track 1/4mile in both states now.
Car runs the same times in both states both trackes are around 1300ft.

All my times are 15.0xx @94-96mph

So no the car doesn't run better on 93 now if you were to run a 2.8 pully I/H/E the 93 may help a little to help not to knock.

 

I just got my car wednesday and i have nearly 600 miles on it already...today I decided to read my manual and i found out that i was supposed to be using premium...oops...have i screwed my car??

 

No, relax you have not screwed your car. Your engine will adjust the timing to compensate for the 87 octane. When you run premium it will again adjust itself.
The only way to really create "knock damage" would be prolonged use of lower than 87 octane fuel. I am not really sure where in North America , gas stations even sell lower than 87. Anyone out there want to help me out on that question ?

 

I'm getting the 2.4 ss and will be running which ever gets the best gas milage, as long as it doesnt ping... So i'm hopping it will go great with 87...
p.s. good thread!

 

use sunoco ultra 94, its the best!

 

My favorite part is the made up lexus story. Spun rod bearings are not a result of knock.

 

91 minimum for me 94 when available

 

I am about to run out the tank of crapola 87 octane the dealer put it. Hopefully 93 will make a difference in power.

 

i run 87 in my ss now all the time, prolly have 7k on it with 87 oct now. it doesnt knock, it is down on pwr some but not enough to care as i am cheap and baby the accelerator any how. i get 30-33 mpg, i have took off the bottom of the air box, put on a cheap high flow filter and remover the rear spoiler (dont laugh that was 2 mpg)