What kind of changes can I expect in my car if I switch from 87 to 89 gas?

Question

Pro's/Con's? THanks for any help

Answer 1

Depends on the car. If your car NEEDS the extra octane, it will smooth out. If your car doesn't need the extra octane, you won't notice the difference anywhere except your wallet.

always use the lowest octane that doesn't make your car knock.

Answer 2

Nothing, if your car was designed to run on 87. There is no proof whatsoever that you will get any benefit from the 89, if you car was not designed from it. Infact, experts say you could get worse performance.
This is something that driver's will disagree on. Some people fully believe there are benefits (as you can see here) while others don't. But it is safe to say that experts say there is no benefit.
From MSN, 20 ways you waste money on your car:
Premium gas instead of regular. Buy the cheapest gasoline that doesn’t make your car engine knock. All octane does is prevent knock; a grade higher than the maker of your car recommends is not a “treat.”

About.com Chemistry:
The recommended gasoline for most cars is regular 87 octane. One common misconception is that higher octane gasoline contains more cleaning additives than lower octane gas. All octane grades of all brands of gasoline contain engine cleaning detergent additives to protect against engine deposit build-up. In fact, using a gasoline with too high of an octane rating may cause damage to the emissions system.
Higher octane gasoline did reduce engine knock in older engines that used carburetors to regulate the air/gas mix. Upping the octane was beneficial then, but engines and gasoline formulations changed.

There is no proof that provides any benefit, unless you count opinions as proof. But you could always try it yourself and see. Better off saving your money and keeping up with regular maintenance services that will actually help your car run better.

Answer 3

what kind of vehicle, and what is recommended (should be a tag somewhere on the vehicle). maybe nothing, might not be worth the extra expense.

i had a friend who had a newer car (a few years ago - maybe @ 1999 - 2001 or so), she was putting in mid-grad gas. well, she started having car problems and took it to the dealer a few times, when all was said and done, it turns out her vehicle did not like the higher octane gas! it was designed to run on regular, and using the higher octane gas was making it not run corretcly.

this is/was the 1st time i had ever heard of that, but with todays electronics, it can make cars finicky.

Answer 4

It's not necessary to constantly run a higher grade fuel to reap it's benefits. However it is noticeably different if you use a higher grade, putting in 89 or 93 on occasion (bi-monthly). This will help the engine run better in that it will to an extent "clean" the fuel line and the engine as a whole.

Answer 5

if the car requires 87 octane and you use 89 you are just wasting your money, you won't see any difference in performance.

Answer 6

Better MPG.
Better power.
Smoother idle.

ADDED:
I drive a 1991 Chevy truck with a stock 350 engine, throttle body injection.
I've tried lower octane gas in it, and I have noticed a difference in low end engine torque while getting on the freeway, and I don't have to push the gas pedal as far to maintain highway speeds.

11.5 MPG 91 octane.
9 MPG on 87.

I ALWAYS run 91 octane now.

The price difference at todays gas prices make up the difference in fuel economy.
Try it yourself!!

Answer 7

It will run cleaner but the cost isn't worth it everytime you change the oil dump a bottel of injector cleaner in with a full tank of gas

Answer 8

better idle, smother acceleration.
its not something you will notice that much, but your car will.

Answer 9

better performance over all