Fuel for the Aurora

[ckpaas]

Does anyone know why they require premium fuel in this car? Is it an emissions issue or will regular damage the engine?

[Indy8]

It has 10:3.1 compression ratio which requires 91 octane rated fuel, or better to support it. It also has a knock sensor that will detect pre-detonation(pinging) and retard the timing to help stop it, resulting in less power. You will get all kinds of advice on this topic. Just suck it up and pay the diff in fuel price. Why would anyone take a chance on this? Give it what it was designed for. I didn't know until I got mine home either.

[dsatt12]

Yeah, that was a rude shock the first time that I went to put gas in. I live in Iowa where the state rather heavily subsidizes ethanol fuels. I go to a chain of gas stations where they have 90 octane ethanol blend for the same price as regular. I haven't had any troubles with respect to the engine/fuel systems in the last 70,000 miles. I do know my car doesn't run as well and the SES light comes on if I am forced to use 89 or worse though.

[bustedratchet]

I knew before buying mine "Premium only".On day last winter a guy at work told everybody they were selling premium for 99 cents up the road. I told him go top mine off. So the next day going up a hill I heard a little valve clangin'.So now on my car only goes to the 76 station !

[97 silverbullet]

I live in MD but I travel to illinois and iowa frequently I know what you mean about the ethanol, i love the stuff cause I get like 50 more miles per tank. I would continue using the ethanol it never hurt my car it made it run cleaner and better.

[Indy8]

Now a couple of Japanese makers are getting 260hp out of V6's on 87 octane. A little depressing, but that's what keeps us buying new cars.

[smokeyzx]

I read a review that when Olds changed the body style they also dropped the requirement for high octane. I bought an '01 over the weekend and put 87 in it, no warning lights yet. Unfortunately, the car did not come with an owners manual to see what is recomended.

[dsatt12]

Originally Posted by Indy8

Now a couple of Japanese makers are getting 260hp out of V6's on 87 octane. A little depressing, but that's what keeps us buying new cars.

For that matter Mazda gets 238 hp out of a 1.3 liter 2 rotor engine in the RX-8. I read they were doing 250hp easy but opted for a standard powertrain rather than a 210hp standard edition and a 250hp performance package. Of course maybe my Aurora makes me partial to extraordinary designs

[Indy8]

Yeah those Wankel motors can really wind-up! 10,000+ RPM redlines! Getting 30 pounds of steel rotating at that speed will probably make 50HP alone.

[RorthStar]

Ok, I have another question...In Colorado, fuel really sucks - Regular is at 85 octane. I've calculated that it would be cheaper to use octane booster here. Has anyone tried using octane booster with regular fuel? I know it sounds expensive, but it is cheaper here with the insane price of super here...Just wondering. Oh, also, has anyone tried using E-85 in these cars? That's relatively cheap here, and I know it meets the octane requirements of this car. I know it could damage certain rubber parts in a fuel system, but after a complete fuel system teardown and rebuild (later to find out, problem was NOT fuel delivery ), I didn't see any parts that would really be susceptible to the alcohol in ethanol. I've done a conversion before (to make a car e-85 compat.), and I didn't see any components in the car that really would be damageable. Strange, it's almost like gm designed the fuel system to last almost forever. Anyway....Hopefully we can find a cheaper solution to this - I have a few Cadillac buddies who would kiss me (hopefully not) if there was a slightly cheaper alternative to fuel. Oh, and btw...Mitsubishi just came out with a 4 cylinder with over 270 hp running on mid-grade - I hate this world...lol

[Indy8]

The formula used to calculate octane rating is adjusted for altitude. So "premium" in Colorado is sold as 89, right? It should satisfy the needs of the engine due to the air density factor. That's how they can get away with it. Less refining should equal lower price, but it doesn't. Imagine that! I would stay away from ethanol enhanced fuels unless you can afford to repair/replace the engine if it grenades.

[dsatt12]

Originally Posted by Indy8

...unless you can afford to repair/replace the engine if it grenades.

I felt a little faint just reading that sentence...

[ckpaas]

it's only 20 cents more per gal. and the car is a pleasure to drive so what the hell.. Might as well feed it what it was designed for like indy said.

[brin]

Have driven my '97 for 4 years and only use 87 octane gas. No problems, no knocking. Am only 1,000 ft. above sea level. Guess the 'puter is taking care of the timing.

[RoraStar96]

You are definitely not getting the most out of your engine. Hopefully its not causing any unseen damage.

The vehicle clearly indicated premium fuel only and with 10.3:1 compression, premium is required for optimal economy and performance.