Would it hurt to use 89 octane gas over 87? It would only cost $1.60 more. Would it hurt engine components? I want to try it out for a tank or two just to see if anything good happens.

Thanks

 

If you have dual tanks, you could put two different types of gas in each tank and see what the differences are. Otherwise try one tank at a time.

I am assuming you now use 87 octane. Going higher will not hurt other than a slight possible loss in gas mileage, kind of depends on your engine. Usually the bigger problem is going to lower octane from high.

The general rule of thumb is listen to your engine and see how it feels. If you hear knocking you should move up. If the engine runs fine with no knock, you can move down one step as an experiment.

I have done this since at least the 80s. Some cars I have owned recommended 91 or higher, but when I went one grade lower it usually worked fine and sometimes there was an increase in mileage, maybe. In summer the engine will require higher octane, in winter or wet weather you can use lower octane.

Your engine will tell you what it likes, assuming you have a good ear for these kinds of things.

Moving up will not hurt other than your wallet.

Good Luck,

Jim Henderson

 

Yeah you shouldnt see a problem. I run 93 octane through my beast. It loves it and still get about 7-9 Mpg. Nothing wrong in using better gas

 

The higher octane gasoline leaves more deposits in the combustion chambers.
I believe that Ford has a statement to this effect in their owner's manuals.

 

Contrary to popular myth higher octane will not gain you more hp, in fact the opposite is true it will actually reduce hp of your engine. I know some will claim that they feel increased performance, well it's all phsycological and not really there. Others will chime in that high hp race engines run much higher octane, well thats true they do, but not because it gains them any hp, but rather to keep the engine from detonating itself into pieces, you want to run the lowest octane you can without causing any detonation or having to back the timing off to run it (backing the timing off will cost you hp) now this is one place that running higher octane will gain you hp and thats with computer controlled engines, the ECM will monitor the engine for detonation and if it occurs will back the timing off reducing hp but thats an exception not a rule.
Now I run 112 octane fuel in my 900hp big block but I run 13.4:1 compression, the first year I ran 110 octane and upon disassembly found some minor signs of detonation (I had cap walk on 2 main caps) so I bumped up to the 112 to take care of it, and this allowed me to run it a little leaner gaining a couple ponies, but probably just enough to make up for what I lost with the higher octane fuel.
Will running 89 hurt the engine? no but it won't gain you anything and if your engine runs decent on 87 why pay for the higher priced fuel?

Edit to add: here is a decent article on using higher octane fuels for increased performance, it's dealing with motorcycles but the basics of internal combustion gasoline engines is the same no matter the application.
http://www.motorcycle.com/mo/mcnuts/rt-fuel1.html

 

If your engine knocks, the computer MIGHT(yours is kind of old so it may not do this) retard the timing a bit and you will lose horsepower with lower octane fuels. High octane is usually only an advantage if your engine computer and engine are designed to take advantage of the more advanced timing and cylinder pressures possible with high octane fuels.

MOST cars are designed to run on 87. Very few need 91+. You are not giving your engine a "treat" with higher octane, unless the engine knocks at low octane.

High octane really just gives you more room to advance the timing. High octane burns slower so equal things to equal, the engine will make a little less power and get less mileage with higher octane fuels. The tradeoff is when knocking begins you lose the advantages of low octane and then high octane is required.

Like I said before, listen to your engine it will tell you. A gentle occasional ping is OK and "the sound of economy". A knock for extended periods will damage the engine in the long run and decrease performance/mileage in the short. Detonation will destroy your engine quickly. Ping, knock, detonation are varying degrees of the same thing and move from OK to bad. A ping kind of sounds like a tick or a ping. A knock sounds more rattle like and is louder. Detonation is fairly obvious, kind of sounds like a bang from your engine.

Good Luck,

Jim Henderson

 

also be prepared to change your fuel filter, most midgrade gas has ethanol in it and if you dont normally run ethanol it will flush out more crud from your gas tank and into your fuel filter clogging it up

 

if memory serves me rite the highr octane the slower the burn and the lower the octane the faster it burns thats why a high comp engine dosnt detonate with 110 feul.but as the hair greys so do's the memory lol