Do yo need to use 93 octane gas in the WRX, or can u use anything u want? What about in the RS's? thanks

Originally posted by punisher
Do yo need to use 93 octane gas in the WRX, or can u use anything u want? What about in the RS's? thanks

I believe the WRX calls for 91 or higher.

minimum 91 octane for WRX, 93 would be better. don't know for the RS

for wrx, higher octane = mo' better

In the California bay area, most of the Shell and Chevrons have switched from 92 to 91 in the last two to three weeks. :( The WRX seems to run ok...

It could be worse, here in Fairbanks all that is available is the 90 and it generally runs 1.85-1.95 a gallon. Which is strange , because we have a refinery less than 20 miles away.......:confused:

What would happen if you used 87 octane gas? Would it just be a decrease in performance or something else?

Using 87 octane gasoline in the WRX could result in severe engine damage due to detonation. It would also be a violation of the warranty agreement resulting in denial of warranty claims.

The ECU is smart enough that it will probably attempt to retard ignition timing to stop the knock, but I have heard the stock knock sensor is not very sensitive.

I once accidentally put a tank of regular unleaded (85 here in Colorado) and immediately knew I had a problem. As soon as I stepped on the gas and got some pretty good boost I immediately heard the detonation and realized what I had done. I went straight to the auto parts store and got some octane boost which stopped the detonation. I really would recommend carrying a bottle of octane boost in your trunk just in case you need fuel and the appropriate octane is unavailable.

Punk

Turbocharging involves the compression of air to allow for more air per cylinder volume which in turn allows more gas to be mixed with it. This higher air fuel mixture gives more bang for the buck. However this type of compression within the cylinders requires gas that can handle it without premature detonation which in turn means higher octane. The manual does claim that regular gas ( octane of 87 or higher) can be used temporarily. Any octane less than 91 may cause premature detonation within the cylinders (engine knocking) and is not good for the car.

Does the knocking that occurs with low octane gas linger or does it end after 1 or 2 tankfulls of high octane? I ran 1 tank of 90 octane which I was happy to find with my fuel light on in the middle of rural Minnesota. Usually I run 92 or 93 and have 3800 miles. Normal, mainly highway driving. Now 1/2 through a tank of high octane and I hear the knock. May just be the ticking of this engine that I've heard people refer to as"normal". Maybe I baby this WRX too much. Rally inspired cars should be the opposite of delicate anyway.

Bob

I've been running Sunoco Ultra 94 ... cars runs great with it.. just filled up again yesterday and only $1.65/gallon .... oh yeah and thats FULL serve also!! gotta love jersey!

Lugnuts,

I would tend to doubt that running 90 octane 1 time would hurt the engine. I base this on the manual which states that regular gas can be used temporarily. I have had occasion in the past to use less than suggested octane with other cars without any permenant problems.

Originally posted by PunksWRX
As soon as I stepped on the gas and got some pretty good boost I immediately heard the detonation and realized what I had done. I went straight to the auto parts store and got some octane boost which stopped the detonation

Same thing happened to me! I did a posting on what I should do when the attendant put regular into my tank:
http://www.i-club.com/forums/showthread.php?threadid=80676&referrerid=5344
However, it seems to have run OT...:rolleyes:

>91