Subaru WRX Forums banner

1 - 3 of 3 Posts

·
Registered
Joined
·
339 Posts
Discussion Starter #1
I know the owner's manual says to use super unleaded... and I have been since I bought the car.

But I wonder... is the motor equipped with a knock sensor and enough intelligence to work okay on 87 instead of 91?

The main reason I ask is because one of the reasons I bought it is to go to/from Reno (from San Jose), which is about 250 miles each way. Since this is all highway cruising at 70-80 mph, it seems like a waste of money when out here, Super Unleaded is 30-40c/gal more.

Back when I had my 2002 Grand Cherokee, it had the "4.7L HO" motor which made 265 hp if you used Super Unleaded, but only made 235 hp if you used regluar. You could definitely tell the difference. But it was nice to have the option to run lower octane. 'Course back then, gas was around $2/gal.

Rob
 

·
Registered
Joined
·
1,643 Posts
your car will run like crap and the gas will not burn as well as premium

you will not save any money

use 91 octane or better
 

·
Registered
Joined
·
1,802 Posts
Can you run 87 in the tank... YES you can, baring an emergency, would I do it NO WAY IN HELL. If you do STAY OUT OF THE BOOST, which would be nearly impossible going up hwy 80 or 50 to Reno (I live in Fairfield ;D). Don't go WOT, your car will run, it will run like crap, although it should get a little better in the higher altitude.

Bottom line, even at the more extreme side of the spread (looking at $4.40 for 87oct & $4.80 for 91oct) $.40 difference and you are putting 15 gallons in the tank you are looking at 6 bucks difference. Actually, I have been finding that the spread from 87 to 91 has been around $.20 - $.30 per gallon. So 15 gallons at $.30 per gallon $4.50 and finally purchasing 15 gallons ad a $.20 spread you will save 3 bucks.

One last thing, running 87oct your mpg will go down some too, so you will use more gas...

*** EDIT: In an emergency I would run 87oct, knowing that, I would try to mix as much of the 91oct with the 87oct as possible, but still baby it for a few tanks of 91oct.
 
1 - 3 of 3 Posts
Top