High Octane?

I was wondering that if I started running the highest octane pump gas I can get my hands on, if it would help my engine preformance-wise? The Rallitek intake seems to allow a whole lot more air into the engine, so I thought that maybe running better gas would even it out a little bit. I don't run nitrous, and I've basically rulled that out. Doesn't seem worth it to me, so that's not a problem here.

Somewhat it can, but not a whole lot.

The octane rating does not change or help the A/F ratio. Since your BD is MAF based, if the intake gulps more air, the MAF will calibrate accordingly with the ECU to mix the fuel and air to the right ratio. If the car feels fine your okay. What you could do reset the ECU so the computer starts out on a fresh page and then you drive the car in various engine speeds and the ECU will learn to the conditions.

-paK +2

For my 98 Legacy L (2.2 SOHC engine) I tried this.

With regular gas my car ran normally with good gas milage. With supreme gas I got less gas milage (about 50-100km less), but the engine sounded better.

Your best bet is to go with what your manual says.

To reset the ECU start the car and let it idle till it is warm or at normal running temp. Shut it off and pull the fuse to your ECU and leave it out for a few minutes. Plug it back in, start the car, and let it idle for a few minutes. Be sure to never rev the engine while doing this. If you don't rev it, when your ecu reprograms itself it will give you the best fuel economey. If you intend to run a higher octane gas be sure to run all the pump gas out of your car, then fill up with the high octane and reprogram your ecu. All a higher octane gas will do is burn hotter and more efficient offering better detonation and better performance. If you plan to run just 93 or so pump gas it won't do that much of a difference. If you plan to run 110 or above you should notice it. You can get higher octane gas like turbo blue from most any performance parts store (and i dont mean advanced or pep boys!!). What you can also do is check around local gas stations and performance parts stores for octane boost. Its a fuel additive that boosts your octane. Its not as effective as running turbo blue but it will get it done easier and much less expensive. For turbo blue be looking to pay upwards of $3 a gal.

9civicsi1: Your advice for resetting the ECU is completely opposite the subaru community.

The method is to have the vehicle cold, reset, then let it idle with all accessories off and not touching the throttle until the cooling fans activate. This lets the vehicle warm and cold idle among other things.