93 octane gas in stock wrx, is this ok?

[BPanda]

I thought our cars are tuned for 91 octane, but have a place with 93 that I like. I figured that having 89 or 87 would be bad, but 93 should be ok.

[Mike193]

93 is fine. Its all I've used in my car. I read somewhere the the reason our cars cant use 87 or 89 is because they have lower combustion rates, so if we used those the gas will ignite due to pressure before the sparkplug can light it, which then creates a misfire.

[RayfieldsWRX]

It's a "lowest common denominator" thing. A number of places in the US don't have higher than 91, so they tuned it for that. 93 won't hurt a thing.

[hindude]

BPanda, with all the other stuff you have planned for your WRX, why don't you bump the Cobb AP up in priority? I've read that a stage 1 flash will actually improve your fuel economy (apparently they run a little rich stock) along with your power and torque curves from stock. You can then flash it specifically to 93 octane too.

[BPanda]

I will eventually, I just don't want anything bad to happen to the engine and be screwed without a warranty. My clutch is already making this click sound when I push it down that's so annoying. 250 miles on it and I get my first problem, so I'm going to wait a little bit. I actually have my RA mudflaps and gauges just sitting around waiting for the temp to get lower. Hopefully the exhaust will be in soon so I can drown out that click sound.

[poly_poly-man]

93 is fine. Its all I've used in my car. I read somewhere the the reason our cars cant use 87 or 89 is because they have lower combustion rates, so if we used those the gas will ignite due to pressure before the sparkplug can light it, which then creates a misfire.

this is essentially it. The octane rating is a rating of how resistant that fuel is to premature combustion. The higher the better. Premature combustion is knock, which is terrible for your engine. If you use a lower octane fuel, the ECU's knock control strategy will pull enough timing to make it safe, but you'll lose a ton of power and efficiency.

Ideally, you'd tune for the highest octane fuel you can get, and always get that - that way, you'd be able to run better timing, potentially more boost, etc. The highest octane that subaru can guarantee the owners get is 91, so they tune for that. 93 is just extra good.

[hindude]

My clutch is already making this click sound when I push it down that's so annoying. 250 miles on it and I get my first problem, so I'm going to wait a little bit. Hopefully the exhaust will be in soon so I can drown out that click sound.

Yikes! Have you taken it to the dealer to have them look at that clicking? That's not cool at all for a new car to be having problems right away. I know you're all for drowning it out with the exhaust, but I'd still check to see if they can figure out what is wrong with it and fix it. I would expect it to be covered. Hope it's a quick fix and nothing serious.

[BPanda]

^^^^ Apparently it's "normal" and doesn't damage anything. I'm still going to bring it in sometime just to make sure because I don't need anything breaking on the car. After driving it all day today, it doesn't bother me nearly as much as it did the first time I was hearing it. If it gets any louder though I'm going to go crazy.

[Calvinball]

^^^^ Apparently it's "normal" and doesn't damage anything. I'm still going to bring it in sometime just to make sure because I don't need anything breaking on the car. After driving it all day today, it doesn't bother me nearly as much as it did the first time I was hearing it. If it gets any louder though I'm going to go crazy.

Well, this isn't the original thread you posted about it, but I did depress the clutch a few times yesterday once I finally got into my car. I think I may have heard something like this click you describe, but it was very faint and I couldn't even hear it when I was actually driving.

[BPanda]

Yeah, mine is a little bit louder. There are youtube videos of it sounding so ridiculously loud, louder than the turn signal, just hoping it never gets that bad.