RiceBurnerZ07

Hey guys,

Cold weather is here, and my father and I have been going back and forth on types of gas to run in the 1991 L98 6SPD with 100k on the clock, whenever I fill the car I put in the 93 octane prem. gas... When he fills it, he puts in the lowest level of gas (85ish?).... So what do you guys run, and is there any difference in performance between the 3, low grade, mid grade, or high grade gases? I know that $$ is a difference...

Thanks

CalvinMD

for me its high test all the time....I've seen the effects of detonation first hand and it isnt worth blowing up a good motor to me for the few extra dollars at fill up time

grantar2

The manufacture says 91 or higher. Chevy will tell you this isn't like todays computer that will compensate and just reduce your power. Eventually low test will hurt your engine. Nothing against your dad, but if you can't feed your car quality 91, you shouldn't own it. If .25 cents per gallon matters a C4 is to expensive for you to operate.

Geardo

I run 87 oct in my 87 L98, and never hear pinging in any condition

ddahlgren

It depends on how you drive it. The more power you demand with your right foot the more you need the good stuff. It also matters where you live or drive the car the higher you go up in altitude the less octane you need. It does matter to some degree how the octane number was reached. It is R+M/2 but they seldom publish the research octane and motor octane numbers so there are a dozen different fuels with the same number. If I lived at 4500 feet altitude I would put 89 in and never think about it at sea level the factory did not just dream up the 91 requirement.
Dave

lt4obsesses

Stay with a 91+ octane. In terms of money, I found that I get better mileage, driving normally, on the higher octane. So the price difference is almost, not quite, but almost a wash. But do the math, if the pemium is .30 higher and your tank holds 20 gal, you pay an extra $6 for a tank? Just skip the Starbucks that day and you're even.

Muffin

Do yourself a favor, run two tanks of 89, keep detailed records of mileage and your assessment of performance, then do the same thing with 91. Compare the two records and pick the gas that is best for you. Why the test, no two drivers are alike, what is good for you may not be so good for someone else. Note I did not include 87, I don't think either you or your car will like it.

stevie1dr

I found I got better mileage with the 93 octane gas in a rather round about way. Last week I needed some extra fuel for the Vette and was filling a 5 gallon gas can with 93 octane. Rather than stop the pump and re-enter my credit card to change to 87 octane for my 1990 Toyota 1.6 liter wagon, I just filled the Toyota with the 93 octane, since it only took 10 gallons anyhow and the extra 20 cents or so a gallon wasn't gonna put me in the poor house.
Anyway, when I checked my mileage at the next fill up, I improved my gas mileage by over 3 miles per gallon, going from 29 to 32 mpg. in the Toyota.
Now I think I'll try it with the 91 octane to see if it gains as much mileage as well.

CorvetteMike2024

Its only 20 cents a gallon more than the low test. So an extra 4 bucks. My car pings under accelaration with the cheap stuff.

anciano

.

OTOH, mileage on my 1500 Goldwing motorcycle DROPPED on the occasions when I experimented with octane higher than the recommended 87. Other owners reported a similar result.

Under normal operating conditions you can't go wrong following the "official" recommendations.

RiceBurnerZ07

Money really isn't a issue, its just that he rather go the cheap way and I'd rather give the car what it requires... thanks! I know I can feel a difference when using high test, and since it is cold here the car runs really rough with low test after sitting in a cold barn. High Test it is!

JackDidley

When my car was stock, it would ping like crazy on 87. Only tried it one time. Not stock any more, niether is the fuel I use.

BobMachus

91 or 93 here. As mentioned by several folks above my car gets better mileage with the high octane fuel. In fact the mileage improvement outweighs the at-the-pump savings. That made the choice easy for me.

kenmohr

I have to go in this column. 7% more for 93 and a 10% increase in milage. Plus the engine ran better.

CalvinMD

Once my 383 is done hi-octane will be mandatory!! I have a Sunoco station in town that still pumps 94 octane...yahoo!!!!

sfc rick

I ran 93 or so, then when my girlfriend got the car she runs 87 and it really runs like crap. 93+ is whats good anything less is horrible.

GKK

My 1991 C4 Corvette owners manual says, "Premium fuel is Recommended but, Regular fuel can be used with reduced engine performance."

PLRX

I did a search on this and over 500 threads popped out. This topic has been discussed here since day one.

http://forums.corvetteforum.com/c4-t...nd-of-gas.html

http://forums.corvetteforum.com/c4-t...-pump-gas.html

http://forums.corvetteforum.com/c4-t...ge-of-gas.html

http://forums.corvetteforum.com/c4-t...93-octane.html

http://forums.corvetteforum.com/c4-t...-question.html

Click on Advanced Search on the Tool bar and type Octane

lt4obsesses

It's okay, the horse doesn't feel it anymore

GKK

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