Fuel Octane?

[Ludigdrums]

What Octane rating should C3 Vettes use? I've been using premium, but I'm not sure if I'm supposed to!?

Thanks!

- Jeremy

 

[82ColEd]

Jeremy,
i have been using 93 here in the US, though i used to use 98 in Germany. It actually is rated for 87 (as per the Stats in the CAC History).. Never tried that!! As far as i was told, it depends on your cars TDC and other settings. Mine had been adjusted when it was imported and it seems to run fine.. Later

 

[Vettehead Mikey]

It won't hurt to use premium fuel, but if your engine was designed to run on regular, then you're just wasting money for nothing.

What does your owners manual say?

 

[Ludigdrums]

Thanks for all the replies so far!

I have an 81, but the owners manual for an 82. All it says is to use at least 87. And I also thought that compression ratio had a lot to do with what octane of fuel to use. And on an 81, I think it was pretty low like 8.2:1. I agree with the statement that if a car is made to run on a certain octane, then it's a waste to put anything more in.

- Jeremy

 

[DDLS3]

Jeremy,

You are correct, your 81 has an 8.2:1 compression and will run very well on 87 octane. I've run 89 and 93 in mine and really see no noticible difference in power or fuel economy.

 

[Jacko]

Regular 87 octane actually runs better for low compression motors.
It actually ignites faster and easier.
High octane fuel is made to be lazy, it is slow burning.
Just a big waste of money to use it unless you need it.

 

[Jacko]

Also, on another note....it is a good idea to keep your tank as full as possible. It prevents condensation inside it. Condensation creates rust.
Rust inside a tank can get to your carb, then you have a problem.

 

[Stallion]

I think us L48s are better off running plus (89) becuase we don't really have a high pressure and there is no need for the higher octane. We aren't going to detonate on 89 and probably not 87 either. But the premium does have detergents in them which do give a little cleaning.

 

[Dave L.]

87 octane for my 81

I use Texaco 87 and have no pinging,car runs great. I've run 89 and also have noticed no difference.

Dave

 

[Vettehead Mikey]

I think us L48s are better off running plus (89) becuase we don't really have a high pressure and there is no need for the higher octane. We aren't going to detonate on 89 and probably not 87 either. But the premium does have detergents in them which do give a little cleaning.

That's an urban legend propagated by the marketing people. There's just as much 'detergents' in regular gas as there is in super.

 

[MaineShark]

Some companies do add additional detergents to their premium fuels.

But... the detergents in "fuel injector cleaner" are much better. Use a bottle of that every third or fourth fill-up, and you'll have better results than relying on the detergents in the gasoline.

Joe

 

[Vettehead Mikey]

You're right. Mobil claims to add more detergent to their super than their other grades. I couldn't find any Canadian makers that make the same claim.

Question is why do they put more detergent? Do cars that run on regular need less? Do cars that run on super need more? Why?

Nice marketing job on their web site, but falls short of givng a technical explanation. On the other hand, here is something from Shell Canada that dispells the myth about octane

http://www.shell.ca/code/motoring/encyclopedia/gasolines/octane.html

Surprised that they would publish this and lose out on sales of super gas.

 

[SurfnSun]

I ran 87 in my 75 L48 and never had any problems.