91 Octane?
 

What do you guys use? 87, 89, 93? That's what I have available to me in my area, it says on the cap (91 Octane). Gas is getting kind of expensive here in Maine, and I've been running Premium. I mean... 1.9L, 138HP normally aspirated engine seems like it would only need regular? I know its cleaner burning (Premium) but besides that...?

89 or 91 normally, in florida you can find, 87,88,89,91 and 93 grades(All 5 at some 7-11s now in Orlando)

93 on a tank with injector cleaner.

My gas cap on my 96 says 89 octane.
I recall my 98 also said 89 octane.
I don't think it burns any better with 91 octane.
If anything, you are just wasting money.

so i could probably get away using middle of the road 89 octane from like shell or mobil?

Nothing to get away with. That is what the engine calls for unless you have chipped it.
Anything more you are just wasting money. I have found I got lower gas mileage with higher octane. I also used high octane at the track because I was under the theory that the engine would run a little cooler withunburned fuel. Now that I am chipped it is a moot point. I run 93 all the time. $$

I just run 89 and have no problems. I also get around 26-31 mpg depending on how I drive.

I run 89 too and averaged like 31.3 mpg on a trip this weekend.

93 all the way, best stuff for my bimmer, i love my car too much to feed her bad gas. this relates to just like u humans, u all wouldnt wanna eat bad food right? u all wanna eat good tasting food, so same goes for ur bimmer too feed her good food. yeah i know im goin crazy.

i put in premium around town, because i do a lot of short jaunts. highway, i throw in 89, and generally don't see a difference in mileage unrelated to ambient conditions (wind, air temp, traffic). if there is one, it's negligible.

You want to give it the best? Use gas from high volume stations and stick to the name brands. Don't fill up when the station is getting a delivery. Don't let the tank go below 1/4. It is not that 93 is any better than 89. It is just a different formulation. Unless you need a higher octane due to pinging you are only kidding yourself. That's my story and I'm sticking to it.:2gun:

My 1998 gas cap says 89 octane and that's what I use. If you're worried about doing damage, the knock sensors won't let that happen. Regardless, that's what the engine is designed for and even with an automatic in our ti and its 4.44 final drive, I never get less than 27 mpg on a tank incuding in-town shopping and school commutes with the OBC showing an average speed of around 30mph. On a recent back country-road trip in traffic averaging about 60mph, computer showed fuel economy of 38.8 which was later verified by gas pump quantity and odometer reading. About the same observed mileage one of the major car mags got in testing a Prius Hybrid in real-world driving. Including about 200 miles on I-95, my average on that trip was 35 mpg. I can drive to DC and back (over 200 miles) and still do my normal commute and kid shuffling for a week on the same tank.

That's what I've been told as well. My mother works for a company (used to be Lubrizol, now purchased by Enraf) that builds and sells petroleum equipment to control and administer additives, mix, etc... Many of the sales reps also recommend the same precautions, and as they sale to the refineries have their own preferences and ideas on which ones produce a better product or have a better additive mix.

I just bought my 2nd TI and the prior owner was using 91 or better, so I thought what the heck...I'll do the same and see what happens.

After running through my current tank of 93, I think I'm going to switch back to 89, which is what I used in my prior TI and check for a difference as well. I tried 91 and 93 in my prior TI and I "thought" the engine actually ran better on 89, so we'll see if my newest TI shows any notable difference.

If you mix 89 and 93 you get 91

In the UK we get 95ron regular & 97ron super unleaded in most places. I've tried both but didn't notice much,if any difference,so run on the 95 most of the time.

My local Tesco's just put 99 octane super in so I ran my tank dry & filled up with that. I can definately feel an increase in power/acceleration,although not massive.

Was watching some motoring prog. on cable the other day (cant remember which one) & they were testing different fuels using a dyno with three different cars.There was a crappy little econo-hatch which gave exactly the same bhp on all the fuels, a Golf GTI which had a few horse gain on super & an Impreza STI which showed a 24bhp gain at the wheels + increase in torque on the higher octane gas. Not really that surprising when you consider that that Japanese home market get 100ron fuel everywhere.

Why not below 1/4 Steve?