what octane fuel does subaru suggest for 01 2.5 Rs'? i couldnt find it in my manual.

~SGD

87, 89 tops until you start to really tweak the motor. Cams, forced induction then you need 93 but until then, regular ol 87 is what the car was designed to run on.

nice!

~SGD

At the prices you canucks pay per liter... why put spend $$ on something that is 100% useless :lol:

thats why i was asking lol....gas sux up here.

thanks again dude, u saved me a crap load of cash.

~SGD

ack
87 in the winter/springs/fall 89 in the summer

I had been running 89 octane in my '00 RS, but with the engine warmed up, everytime I pulled away from idle there would be a single knock from the engine as it revved up. I've since switched to 93 and the knock is gone.

Just my experience.

P.S. Only mods are K&N filter and Stromung Exh.

sqrl b8

In my experience my car actually runs worse on premium. It might just be in my head, but I don't bother with it anymore.

squirrel-bait, where do you get your gas?

JC

JCs right, there is NO reason to up the octane unless you're having detonation (either due to a mechanical problem or you're tweaked the motor). Remember, octane is resistance to detonation... higher octane gas doesn't want to ignite. You must increase cylinder pressures or temperatures or you will not get complete combustion and the car will be down on power.

I tend to stick w/87 and on "special" occations go 89 or 91 or whatever.

I also frequent "good" petrol stations like BP, Shell or Mobil and try to stay away from smaller brands. I don't know if there's really a difference but in my mind there is... :huh:


-mykr.

Originally posted by JC

squirrel-bait, where do you get your gas?

JC

JC,
I usually get my gas from Mobil or Amoco. I used to use the cheap stuff (i.e. Speedway) years ago in other cars, until I found nasty deposits on my spark plugs.

Heck, I feel a bigger performance difference between rainy and sunny days than I ever did between octanes.
:lol:

sqrl b8

I know "brands" change depending on which area of the country you're from but I use Texaco exclusively here in North Texas, when I drive down to DFW I use Texaco or Chevron, when I'm up north (Ohio, NY, PA, IN) I try to use Sunoco exclusively. I have had mixed luck w/ BP (including a couple of really bad tanks) and I know they mess with their blends alot.

Originally posted by squirrel-bait
JC,
I usually get my gas from Mobil or Amoco. I used to use the cheap stuff (i.e. Speedway) years ago in other cars, until I found nasty deposits on my spark plugs.

Heck, I feel a bigger performance difference between rainy and sunny days than I ever did between octanes.
:lol:

sqrl b8

I stay away from Amoco. My car doesn't seem to respond well to it. I try to stick to Shell, Mobil, and the occasional Sunoco.

JC

this is what sparked my thread.

i know it's a honda board, but we still drive combustion engines :p

check it out.

http://www.hondalife.com/modules.php?name=Sections&op=viewarticle&artid=17

~SGD

So 87 is cool if you have no performance mods?
and then run 89 in the summer months?

Hahah I went to the mobil station this past weekend and I was trying to pump 87 in my car as I usually do. And I notice that the pump is going real real slow. The dude comes out and tells me that they are out of regular and he told me to put super in the tank because it would "clean" out my car and that would be great ofr the engine. I was like "Uhh..yeah ok bye" And I just went down the street to the exxon station and finished filling up.

Any truth to this? "If you put super in your tank it will clean your engine" Sound slike BS to me.

I used to put 87 in my 00' RS with no mods. Then for a while I switched to 93. Then when I decided to put 87 back in one time on a long freeway run the check engine light came on. I have since been putting in 93 and haven't had a problem since.

Does a car get "used" to having nice gas and develop problems when you use cheaper stuff?

Before anyone says it, my gas cap was indeed closed all the way and my 02 sensor has been replaced.

Do I have another problem maybe?

Well with the newer 00 and 01 RS the computers are designed to determine the octane of the fuel that is in it. The computer can then adapt to the higher octane and run more efficiantly. If you are in an older car I would say stick with what the manual says but if its newer it is worth the extra money to use 91 octane.

My friend has a dyno shop and he has run vehicles to determine if octane makes a differance in performance for a stock vehicle and it does. A newer vehicle will have about 1-2 more horses when a higher octane is run (but do not run more than 93 octane in a stock motor, your computer cant handle any more than that). On the other hand an older car ran 5-6 horses less with a higher octane than recommended.

The moral of the story, no one is going to agree, just use whatever you see fit.

To reiterate! The stock ECU sets an advance multiplier to the baseline timing curve over time... it is not a turn on the car and the ECU knows what fuel it has thing. The ECU does its warm up by advancing timing, this is true, but nowhere near enough to make use of 93 ocatane fuel. Over time, the timing and fuel curves are tweaked based on any knock incidents, but again, the timing is not adjusted enough to justify more than 87 ocatane on a healthy motor. If you experience knock, pinging, etc, then raising the octane will provide symptom relief but the underlying cause of the detonation will still be there and should be fixed.

Dramatically improving airflow, artificially adjusting the timing with an ECU/piggyback, forced induction? Then go with 93. OTherwise you'd be better off just sending me the extra money, I need it more than your motor does ;)

Originally posted by BOY
I know "brands" change depending on which area of the country you're from but I use Texaco exclusively here in North Texas, when I drive down to DFW I use Texaco or Chevron, when I'm up north (Ohio, NY, PA, IN) I try to use Sunoco exclusively. I have had mixed luck w/ BP (including a couple of really bad tanks) and I know they mess with their blends alot.

I went up to 89 for about 4 months and then decided that I really have an Outback motor, and I doubted that Subaru would recommend 89 for an Outback, so I'm back w/ 87.

~~Quentin

Thanks, BOY. ursine won't give up his high-octane dreams in N/A or this forum.

Yeah just use what you see fit, or do what the manufactuer recommends.