Hey Everybody, I am just wondering what octane I should be running in my 1996 Z28. It is pretty much stock, except CAI, Cat-Back Magna flow, Magna flow cats.

Thanks guys

 

the 4th gens call for premium stock mine still has the little sticker on the gas tank flap

 

GM recomends premium in the car but your computer will compensate for lower octane by retarding the timing as needed to prevent knocking and pinging. If you can still hear the pinging while under load then go up a grade.

Massey

 

Ok is their anything I should do before filling it up with premium, as the guy I bought the car off had only run 87 octane in it for like 5 years.

 

not really but if you want to use a quality fuel treatment when you fill up next I would recomend the Lucas Fuel Treatment. Your local autopart store should have some. The one shot bottles here are like $6 for 5 oz or you can get 33oz for $10. The 32oz is like 6 or 7 treatments for $4 more. I use it in all my cars and put about 6oz in when I change the oil and it keeps my fuel pump, and injectors in prime shape.

Massey

P.S. I run 87 in my 2000 Z28 with no issues.

 

ok, sorry for all the questions, but it won't hurt the car to run 87 your saying?

 

It won't hurt to run the car on 87 octane, but it will be down on power compared to the same car on 91-93 octane. As mentioned before, the PCM will retard the spark to prevent engine damage, but the power and economy will suffer.

 

you can always seafoam your engine, it will run much cleaner.....

 

Here we go again

what is the #1 question we see on automobile forums? Why it's "how do i get more performance for few dollars?"

Then, from time to time, we get the octane question and wanting to justify using 87 octane in a HIGH COMPRESSION engine.

First, I suggest that you do research on what the purpse of octane is and also, do you see the little + and - symbols next to the 87, 89 and 91 or 93? That means that the octane rating could actually be as LOW as 85 and for premium, as HIGH as 95 but 93 can never be lower than 91. So, run with the worst case scenario and assume that you are getting 85 octane when you use the CHEAP STUFF. That is a low abaility to avoid detonation and the timing of the car would need to be significantly retarded. Retarding timing reduces POWER.

Now let's do the math

Assumptions- 12,000 miles per year
premium cost 20 cents more per gallon than the cheap stuff

20 mpg mixed driving

600 gallons per year used

multiply by the 20 cents per gallon uplift for premium fuel = $120 per year

divide that by 52 weeks = $2.31 more per week if you use premium fuel

So, you have to ask yourself. Am I really asking about this to save $2.31 per week when the benefits are obvious to using higher octane fuel on the LT1. That's the cost of 1 large coffee at Dunkin Donuts. Make 1 cup per week at home.

Let's go back to the most common question asked about increasing performance for minimal $$$

So, when you put it on paper, you tend to feel a wee bit silly actually asking the question.

 

t. i. g., you missed one thing. An engine with it's ignition retarded (because of too low octane in this case) can actually get worse gas mileage due to it's poorer performance.
So, actual cost differences between low and high grade would be less of a spread.