How important is it to use Premium gas when it is suggested?

Question

I bought a 2004 Monte Carlo SS Supercharged car new in 2004. The owner's manual suggests running only PREMIUM grade gas in it. I have run mid grade since day one. Is there really any difference in performance? I have never had any problems with the engine and have never heard and "knocks" as the manual says you might hear if running less than PREMIUM grade fuel. Thank you for all your answers.

Answer 1

Not a huge deal on conventional engines, but you have a supercharged engine, even with retarded timing the cylinder pressures under full power might be too high and you will get preignition. Basically the fuel ignites too soon and is working against the piston as the piston is traveling up, eventually this can break a rod or cause other damage. The engine designers and engineers who tested this engine came up with the fuel requirement they did not make it up for no reason.

Answer 2

It makes a difference in some cars, not in others -- I have a 91 toyota 4runner and i get WAY better mileage with midgrade gas. I used to drive an '86 toyota pickup and when i used anything other than the highest grade it glugged. My husband and I did some experimenting and found that our mileage on all our vehicles increased with mid grade gas, but not a significant diff between mid and premium, that was just tracking our mileage over the summer (we have a '99 camry and '01 tundra, just as an fyi, don't know if it matters)

One thing to note though, every time we've used chevron gas we've actually gotten worse miles per gallon, I had heard that some places put the same gas in all the pumps anyway, but that's just my personal experience.

if there's no issue with knocking, i'd just track your mileage a bit and see if there's a difference there.

Answer 3

If the manufacturer recommends premium gas, that's what you should always use. Since you've never used it, I guess you can continue with the mid grade. However, don't ever buy anything less than the mid grade. The type of gasoline you use really does affect the performance of the engine, but since you don't have anything to compare it with, you are happy with the way your engine runs. If you ever put cheap gas in it, I bet you will not be happy.

Answer 4

My opinion is that you should use premium or mid grade gasoline. You can also use fuel additives once a month with a mid grade which can be a few cents cheaper per gallon than paying for premium. The reason being that it does help keep higher performance engine components running smoothly. Never use regular grade gas. I have done this and can tell a HUGE difference with the first tankful.

Answer 5

Very important, listen to the manual. Premium gas keeps the engine from knocking, like it says. If you want to know why, look up octane ratings. It has to do with the chemical composition of the fuel and how much compression the engine is making. Trust me: look it up on google.

Answer 6

Well you should use what ever it calls for with the way there making cars theses days you never know, ya know. but really the premium gas gives you a lil more mileage than the cheaper ones and is less harsh on your engine . to eachs own good luck!

Answer 7

most cars now days will run on a lower octane fuel,you just have to go down one stage at a time,and try that ,your car may run well on a lower grade,as far as hurting anything it wont,but it may cause a loss of power and gas mileage,you can try going down to a lower grade though,that's the only way you,ll ever know if it will run on it or not,but it wont destroy the engine or anything like that,good luck with it.

Answer 8

I agree with some of these that the computer will adjust timing and probably boost per your fuel...But if u didnt want to put premium in a car u should have bought a N/A vehichle...Just my .02$

Answer 9

In some cars it does not seem to matter at all.... especially newer cars... My car however wil sputter and run like complete S*** if I run less than 93 octane in it... Typical for my Beretta tho.... those cars HATE cheap s*** gas. If your car runs good on Mid Grade then I say keep using it... won't hurt anything...

Answer 10

Using premium gas on occasion will help to keep your gas lines running more smoothly.and usually prevents knocks and other symptoms associated with cheap gas.