93 Octane?

[tranzformer]

Originally Posted by carbonBLUE

i dont need to, its common sense, if my 2zz-ge has a 11.5:1 compression ratio and someone has tried 87 and had detonation problems, why would a 12.5:1 compression handle 87 any better... or if the car manual says USE PREMIUM, and says it on the gas lid, in the car, why would you use anything different, stop being cheap, treat the car right and give it 91-93 octane

I'm not the one that said I would run regular. I'm just stating that Scion said you could with a decrease in performance. Not sure why you are having an issue with this? It is common sense as you said because the engine can decrease/increase timing as needed.

[carbonBLUE]

Originally Posted by tranzformer

I'm not the one that said I would run regular. I'm just stating that Scion said you could with a decrease in performance. Not sure why you are having an issue with this? It is common sense as you said because the engine can decrease/increase timing as needed.

i was just stating a point and i know you've been here a while and prob know more about the 86 than i do, i was just stating a fact so others could read and i was in no way directing it at you

i know the engine can advance and retard timing, but its not worth risking reliability, the only time i would run 87 or 89 is if i had no other choice... as in im out of gas and the gas station im at ran out of premium...

[deesu]

I don't understand why people argue about which octane to use. Use what the car manual states. If you really want to save money then buy a different car.

[Ranatsu]

Originally Posted by deesu

I don't understand why people argue about which octane to use. Use what the car manual states. If you really want to save money then buy a different car.

or walk

[tranzformer]

Originally Posted by carbonBLUE

i know the engine can advance and retard timing, but its not worth risking reliability, the only time i would run 87 or 89 is if i had no other choice... as in im out of gas and the gas station im at ran out of premium...

I completely agree 100%. If I get the car I would run premium 100% of the time. But it isn't like the people are asking to run diesel in it.

As has been disused in many many many many other threads, running premium (whatever it is in your area) will run you about an extra $100-150 a year vs. regular. Cut back on Starbucks and you won't even notice the difference.

[tranzformer]

Originally Posted by Ranatsu

or walk

Or ride a bicycle.

[carbonBLUE]

Originally Posted by tranzformer

Or ride a bicycle.

[brufleth]

Might be worth it for some people to go read about what octane rating really means.

http://en.wikipedia.org/wiki/Octane_rating#Principles

It doesn't mean the fuel has more energy when it has higher octane. It means the fuel is less likely to self ignite. It is when the fuel ignites when it shouldn't that is known as engine knock. Cars have knock sensors these days and will try to reduce engine knock but it really isn't good to put anything less than the min specified octane rating in a car.

You can end up tripping a rev mode that will kill performance and fuel consumption can go up. It just isn't a good thing to do.

[borge12]

I don't understand the argument "If you aren't going to do X, then you can't afford this car."

I'm not trying to brag, but I could pay cash for this car. And, if it doesn't cause damage to the engine, I will occasionally run 87 through it. Maybe I'm just that cheap, but I know if I'm going to spend the day cruising at 70mph, I would prefer to save the $1.75.

[Draco-REX]

Personally I think 1.50 per tank of gas is cheap protection for my engine. *shrug*

The cost of premium is pocket change. The cost of an engine is not. I just don't see why it's worth even the slightest risk. It just doesn't make sense in any way, shape, or form.

[serialk11r]

I believe it will be possible to run lower octane fuel by restricting the engine torque via reducing intake cam advance...assuming we can get into the software, it should be pretty easy to limit the torque and use lower octane fuel. Another idea I came up with is figuring out at what point of accelerator pedal travel does the engine start knocking at low rpm, and putting a physical gas pedal stop behind the gas lol.

You lose revs and possibly a large amount of torque, but if you're going to be burning a full tank going down the highway on a trip I don't see why not.

[Want.FR-S]

I think it is understood that with a high compression ratio and D4S, the Premium fuel is required in North America. That means the AKI 91-93 (with RON 95-97). A current D4 (IS250) owner said that it is possible to run regular (AKI 87) for temporary if necessary, but it will decrease performance and do not rev high on that.

So the 93 octane is AKI 93, not RON 93, I think.

[carbonBLUE]

Originally Posted by borge12

I don't understand the argument "If you aren't going to do X, then you can't afford this car."

I'm not trying to brag, but I could pay cash for this car. And, if it doesn't cause damage to the engine, I will occasionally run 87 through it. Maybe I'm just that cheap, but I know if I'm going to spend the day cruising at 70mph, I would prefer to save the $1.75.

being cheap and poor are two different things...
being ignorant and being stupid are also two different things...
you are 2 of the 4 choices...

just do what the manual says...

and with that $1.75 you should buy yourself a cookie

Originally Posted by serialk11r

Another idea I came up with is figuring out at what point of accelerator pedal travel does the engine start knocking at low rpm, and putting a physical gas pedal stop behind the gas lol.

lol...
now thats being smart and cheap at the same time....

[Dave-ROR]

Originally Posted by tranzformer

Actually that isn't necessarily true about the fuel economy. We will have to wait and see once we get it in our hands if someone will test several tanks of regular vs. premium.

While different engine, different car the 3.8 GC has no difference between regular and premium. Owners have been saying that for a long time. Doubt we will see much with the BRZ. Probably down on a few HP ~5 but that is about it.

It depends on the engine. I get 4-5mpg less in my car when I've tried 87. It was painfully noticable. It was also noticable that I had to drive the car a bit harder to drive like normal, so perhaps if you don't care and just cruise with the slowest acceleration rates possible then yes, it won't matter.

That's not how I drive though (I don't floor my cars on the street either, but I do load the engine a fair amount to accelerate).

And really, a couple hundred bucks a year.. I dunno, seems penny wise pound foolish to me.