Just got a 1987 GL Turbowagon and am wondering what would be the best grade of gas to run in it. Here in Colorado, we get the privilage (LOL) of using gas that is two percent lower in octane than the rest of the country. Hence, our regular is 85 octane, midgrade is 87 octane, and premium is 91 octane. Of course, there is no discount for getting the lower octane levels. Having no previous experience with turbo charged motors, I am confused as to what grade of gas I should be using. What do you guys run in yours?

 

Dog1

I run 93.. you will probably hear lots of debate about this one. Bottom line; in every turbo car I have had, the higher the octane, the better the car runs. and thats not just soobs..

excellent point caleb, in "every turbo car" max octane is key, but for those casually reading this, regular is the best for the N/A subies, unless ofcourse you are running higher compression.

 

The owners manual may have a reccomendation, just adjust it to your elevation and you should be good to go.

I use 91 for my 125 mile round trip commute everyday from Manitou to Denver. I have tried to go cheaper (87) but the car just doesn't seem to like it. I drive an '89 Turbo Touring Wagon.

 

Jay

Wherever you are, just use whatever is labeled "premium".

 

In Colorado, we have lower octane premium because there is less oxygen in the air to combust with the gas.

 

As you get closer to sea level, there is more oxygen available, hence the need for more "gas in your gas" to achieve the same results.

 

I drive a '92 Legacy Turbo Touring Wagon LE. I experimented a bit while I was in Alabama last year. Nope, at that altitude, 91 octane (their mid-grade) didn't cut it. Had to use 94 octane or my car would ping some under a load.

 

Emily

http://www.ccrengines.com

now for my .00002 cents of input

87 turbo wagon 220k+ miles on what seems the original motor

running 10-11 psi boost

i run what ever i can afford wich is usually 87 or so octane gas

almost no ping except when cold then its occasional under hard throttle

oh an no intercooler yer either

 

i also have my timing set back about 1-2 degrees before what the books say

and i drive 60+ miles every night to work

mix in a gallon or 2 of kerosene to a full tank to bump the octane. the kero around here is rated at 110 octane

Thanks for the info. I fiquered that I should run premium in it, but I just wanted to make sure. If nothing else, it will give me a source of gas to siphon out for my motorcycles if in need. Any hints or warnings from the guys in Colorado on tuning it up for high altitudes? Still trying to find a subaru wizard to help me plumb in the intercooler. Anyone know somebody around Colorado Springs who is good at this? I live up in Black Forest.

 

Dog1

No special tuning necessary for your car at high altitude. The MAF and computer handle it all automatically. Mine ran the same in CO at 11000 feet (berthoud pass) as it did in Seattle and Dallas.

Doesnt an intercooler allow you to use a little lower octane?

an intercooler cools off the hot compressed air (pre-TB) coming from the turbo, and helps reduce detonation. higher octane fuel needs higher temps to combust, so if youre running high boost, high octane will not detonate nearly as soon as low octane fuel will.

 

so in theory, you could run lower octane with an IC because the air temp isnt as high going into the combustion chambers. (but im still going to run 93 in my buggy when i get my IC, just so i can crank the boost even more )

 

feel free to correct me if im wrong!

I would stick with the premium gas that I could get at your gas station. I would especially do this now considering a post I read here that measured intake air temps (non-intercooled) and intercooled. Non-intercooled air temps was really high.

I log 175 miles a day in my ’87 RX (bone stock… for now), I’ve been running 87 octane with no real trouble. I have noticed some detonation as the boost just comes on, its seems more pronounced when the engine is cold. Now that the weather is getting warmer it seems to be a little worse and I may be getting some detonation at lower RPM full throttle. I think 87 is just a bit to low, I should try the mid grade and see if it makes a difference, I’d just run premium but money’s real tight right now (only working 32 hours a week) and the cost adds up.

 

I’d like to get an intercooler installed, it might bring down the temp enough to make 87 useable.

Gary