Hi,

Just when I thought they were getting to a manageable level, gas prices are again on the rise and it hurts (in the area of my wallet) each time I have to make a pit stop.

For years I used Premium (hi-test) fuel (usually Arco) in my '83 Sport Coupe, 5-speed manual transmission, LG4 5-Liter V8, 305cid, and my engine ran smooth and trouble-free. A couple of years ago, again because of rising gas prices, I switched to the mid-grade (this time Chevron's "Plus") and again, no engine problems or loss of engine-power was noticed.

Now I'm contemplating going even lower in in octane to Chevron's Regular gas simply for the cost-savings.

I believe standard octane ratings are:

Regular unleaded is an 87 octane
Mid-level is 89 octane
Premium is 91 octane

Should I stick with the Mid-level (Chevron Plus) or could I go a step further and start using Regular without a noticeable change in engine performance?

Thanks!

 

Using 93 octane in a stock motor is wasting money. Just use 87. It'll be fine.

 

+1
Youd dont have the compression to warrant needing a higher octane gas, get good top tier stuff... I.E. Shell, Chevron, and so on, but you only need 87 octane in an LG4...

 

Thanks for the replies up to this point guys!

You have me wondering if I've thrown money down the drain with all the years I've used Premium and Mid-range (Chevron Plus) when I could have been using Regular.

At least you're telling me what I was hoping to hear.

Chevron has been my fuel of choice for about the last 10 years and I'll be sticking with them for Regular.

 

Higher octane gas is only needed to prevent detonation. It's not "better" like a lot of people think. A particular brand of gas will have the same additives wether its 87 or 93 octane. The higher octane just burns slower. I have to use to 93 in mine or it will detonate. Accidentally already figured this out once by mistake. If I could save money and use 87 I would love it, lol.

 

Ok, so the general consensus so far is using Regular should be of no concern with my engine.

My Camaro is on "E" right now and I'll be making a trip to my local Chevron station tomorrow (Friday) morning. I'm going to just put in $10 worth of Regular, ride around a bit, and see if I notice any immediate difference since I'll be running pretty much "straight" Regular and not a combination or a "cocktail" of Plus (Mid-grade) combined with Regular.

Thanks again!

 

Yeah, before 1985 the LG4 was a low compression motor (8.5:1). It was built to run on junk. Won't hurt it at all and I doubt you'll lose any performance.

In fact, you should check the base ignition timing on it (using factory spec procedure to do so). It's supposed to be set at 0* BTDC but many people advance it slightly for better performance and mileage.

My experience with LG4 motors (which is quite a bit) tells me you can EASILY bump it up to 4* BTDC, still run junk gas and never hear a knock or ping from it unless the chambers and piston faces are heavily carboned up from shot rings or valve guide seals.

And, as sometimes happens, say you check it and it's sitting retarded a few degrees even from the weak factory spec? Well then, my friend, you are in for a real treat when you move it up!

Timing tab is viewed by looking straight down behind the back of the water pump, by the way. Lots of people wonder where it is on those motors.

 

Thanks Damon for the additional confirmation.

Unfortunately (or fortunately as the case may be) I have a pretty good mechanic with his own repair business who's been doing my tune-ups and electrical for years now and I would just screw it up if I tried your suggestions, which sound quite logical. I'll just hope for the best using Regular and, worse comes to worse, I'll get his advice and mention your thoughts.

btw...I'm originally from North Philly, Huntington and Kensington El stop area. Yep, Kensington (and oh my, how it's changed since I grew up there many years ago).



GO PHILLIES!

 

not only do you not need anything better than 87 octane, but you are probably getting lower fuel economy by using it- so it's costing you money in more ways than just the price at the pump.

 

You should notice that the car revs more happily with the 87 octane gas. The higher octanes burn slower. Unless you are running high compression, stick with the regular unleaded.

 

You should have the option of bumping the timing just enough that you don't have pinging and running the higher octane fuel.Setting the base timing on my TBI to 4 degrees advanced made a "nice" improvement on throttle response.With out the bump its a dog off the line.For a mostly stock 5.0 it pulls pretty good so I'm willing to pay the extra for mid grade,try it and see if your willing to stay with the 89 for the benefits.

 

I used 87 and 91 o my '87 Iroc LG4 and I barely noticed any difference, mostly in the revs.

 

My tpi runs fine on fredy myer's regular, plus I can get it at 10 cents off!...sometimes...