Is it safe for me to put 100 octaine in my stock wrx?
Will there be any change in performance?

 

A higher octane gasoline will not increase power output from your engine.

Unless your engine is knocking/pinging more than it should (slight knock under heavy load is normal), a higher octane gasoline won't make any improvements.

Running a higher octane gasoline than is necessary may actually cause a decrease in performance. Higher octane gasoline is more resistant to ignition under higher pressures. This is why high-compression engines require high octange gasoline. If they ran low octane gas, you would get detonation - the fuel would ignite before the spark plug fired. So running a higher octane gasoline in an engine that does not require it means that the fuel you put in is harder to burn and may not burn completely or will burn slower, delayed, etc.

 

You mean like the WRX?

To the original poster, you will definitely see an improvement if you move from 91 to 94 octane, but I have no idea how far up that will scale. You may need to look into an aftermarket engine management system to take advantage of 100 octane.

 

You use the cheapest gas you can without knocking. The WRX is designed for 91... 93, 100, 104... won't help you in the least bit unless your car is tuned for it. "Treating" your car to a tasty meal of overrated gas just empties your wallet.

http://science.howstuffworks.com/gasoline3.htm

My experience with motorcycles and tuning: race gas and high comp pistons... good stuff, but still... performance gains in the single digit percentile are not noticable by normal humans. Its just psychological. -anyone feel faster after a full tank of gas? I do (maybe I'm the only 1)... doesn't stand to reason with the extra weight, of course.

Any tuning shops wanna sponser a Pepsi challenge? Stock WRX vs. light tuned... see if anyone can tell the difference? Something like a 20 hp gain. (put a BOV on the stock 1 to confuse 'em)

 

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Yep...like the WRX at 8.0:1. G'job...give yourself a pat on the back, champ

 

Anytime, kid. Here I was, thinking forced induction might somehow factor into the picture...

 

No. 91 is required, and the WRX ECU will advance the timing based on the octane gas in use. 94 would be even better, but probably not worth the extra cost.

 

I thought everyone knew you get faster with a full tank of gas. If you wax your car you can create less drag and decreases turbo lag. Chrome makes any car faster too, but gold stuff will slow you down. Something to do with conductivity or something. Curb feelers on the WRX help distort airflow around the sides of the vehicle creating a low pressure area, thus making the car have a greater accelleration at higher speeds.