Octane Boost Recommendations

[PAezb]

Ok, so I have a 05 OBW XT, which we all know requires premium fuel (Turbo = 91 Octane minimum). In the Twin Cities, 91/92 Octane typically runs around $0.15/0.20 more than 87 Octane - no biggie. However in my regular travels to northern MN I've frequently had to pay $0.40 to $0.50 per gallon more for 91, which 87 is already $.20 more than in the TC - biggie. So, I've begun my research into purchasing an Octane booster to add to 87 for cost savings when up north.

 

I was in Wally World checking out the Octane booster products which typically run $2 to $5 per bottle to treat a tank of gas (15 gallons). But most of the products do not state how much their product will raise the octane level.

 

Anyone with experience and product suggestions...?

[porcupine73]

Maybe some xylene and toluene. These are still more expensive than gasoline ($5-15 gallon depending on where you get it).

 

Most octane boosters don't boost the octane a whole lot. They will say 'boosts 5 points!'. Well that means increasing 89 octane to 89.5 octane when added to the stated amount of gasoline (i.e. maybe 10 gallons for a bottle).

 

These are (R+M)/2; other countries that boast about 'the lowest we get here is 95 octane' is typicall the research octane only, which isn't the same rating as the U.S. method of the average or research and motor octane.

[subaruplatt]

Read this.

http://www.elektro.com/~audi/audi/toluene.html

 

http://www.europeancarweb.com/tech/0503ec_octane_boosters_tested/index.html

[porcupine73]

If you have trouble finding toluene in your area, try Ace Hardware (sometimes it is listed as toluol and xylene as xylol). In my area anyway, home despot doesn't sell toluene because of its use in certain, erm, shall we say, cottage industries. Here's a pic from my home brew penetrating oil formula:

[aircraft engineer]

Hey Porc - so you get the pictured cans, get a 5 gallon can with a lid, mix 'em together and pour maybe a pint or so into a tank huh?

 

I would point out to you that the potential problem would be with those solvents and the "seals" in the fuel system.

 

Depending on what the seal material is, it could EASILY soften the seals or maybe even the o-rings.

 

The hydrocarbon "gasoline" - (even with MTBE or ethanol) doesn't quite behave the same as those solvents (acetone and toluene being the most "aggressive" to even synthetic rubber products) I don't think the cat would have a problem with it (fortunately)

 

The VM&P Naphtha is the same as 'Coleman lantern fuel" - otherwise known as "white gas"

 

ah... "penetrating oil. NOW it makes sense. You aren't BURNING it, you're spraying it.

[jamal]

certainly not worth the potential damage to your fuel system and I doubt you could save money anyhow.

 

Also those octane boosters in autozone don't do anything.

[porcupine73]

hehe, yes that's my penetrating oil mix. I haven't tried it yet but it does stink, and it ate out the plastic in my harbor freight diy spray can.

 

The only ones I've tried in teh gasoline are the toluene, xylene, and acetone. Toluene and xylene would worry me the least, since toluene is already a constituent of gasoline at up to about 35% v/v and xylene at up to about 15% by weight. I think both their (R+M)/2 octanes are above 100 but I'd have to check it somewhere.

[bulwnkl]

This isn't what you asked for, but I run 88 octane gasohol in my turbo Baja all the time (91 octane 'required'). So long as I'm just driving around there's no issue at all. To the point you asked about: Try HEET (alcohol) if you can find big enough containers on sale. That'll raise it as much as anything and be much, much less expensive. Still, I'd try it on 88 (probably 89 in your area?) and see how it runs. Just fine, I bet. Worst that'll happen is you don't get much power.

[porcupine73]

Heet or any drygas is typically either methanol (heet yellow botle) or isopropyl alcohol (heet red bottle).

 

I'm not 100% confident in these octanes, but here is roughly what I've found:

 

Noting of course toluene and xylene are already in gasoline potentially significant amounts:

 

Toluene/toluol (R+M)/2...114

Xylene/xylol (R+M)/2...117

Methyl-tertiary-butyl-ether (MTBE) (R+M)/2...118 [this is the stuff NY and others have outlawd because of ground water contamination issues, usuig ethanol instead now]

Methanol or Ethanol (R+M)/2...101

Isopropyl Alcohol and Tertiary Butyl Alcohol (R+M)/2...101

[Hester]

Just some supplemental, on topic reading:

 

http://www.elektro.com/~audi/audi/toluene.html

[Bluestone]

My gut feeling tells me that playing around with home brew recipes for upping the octane is just risking engine/fuel system damage and reduced engine life.

Maybe it's ok with an older high mileage car if one is willing to to do one's own repairs or rebuilds that may be needed as a result.

But on, say, a 2005 OBW XT, don't look for trouble. So gas prices in certain neighborhoods are 50 cents more per gallon....just pay it. Engine damage resulting from fecking around with do-it-yourself chemistry can easily result in many thousands of $$$$$ in repairs. Is it worth the risk?

And proprietary octane boost additives from your local auto supply store are not cost effective and are, at best, only marginally effective.

We'll all be paying $5, $6, $7 a gallon for gas (and possibly even higher:eek:) in the next few years anyway, so just get used to it. The overall cost of driving and maintaining a car is high and getting higher all the time. That's just the way it is.

If ya don't want to assume the higher and higher costs of car ownership, then just don't own a car. Paying more and more for gas is just something ya need to accept. You've got a turbo engine in your Sube; ya have to pay a price for that. And Subies, being AWD vehicles, are not the most frugal on gas, anyway. Either "pay, or don't play", period.

That's my 2 cents.

[PAezb]

My gut feeling tells me that playing around with home brew recipes for upping the octane is just risking engine/fuel system damage and reduced engine life.

Maybe it's ok with an older high mileage car if one is willing to to do one's own repairs or rebuilds that may be needed as a result.

But on, say, a 2005 OBW XT, don't look for trouble. So gas prices in certain neighborhoods are 50 cents more per gallon....just pay it. Engine damage resulting from fecking around with do-it-yourself chemistry can easily result in many thousands of $$$$$ in repairs. Is it worth the risk?

And proprietary octane boost additives from your local auto supply store are not cost effective and are, at best, only marginally effective.

We'll all be paying $5, $6, $7 a gallon for gas (and possibly even higher:eek:) in the next few years anyway, so just get used to it. The overall cost of driving and maintaining a car is high and getting higher all the time. That's just the way it is.

If ya don't want to assume the higher and higher costs of car ownership, then just don't own a car. Paying more and more for gas is just something ya need to accept. You've got a turbo engine in your Sube; ya have to pay a price for that. And Subies, being AWD vehicles, are not the most frugal on gas, anyway. Either "pay, or don't play", period.

That's my 2 cents.

 

 

I agree totally with you're statements above - all considered when I purchased the Turbo, among many other factors. I'm just learning that the Octane boosters don't boost enough to even consider, let alone ramifications to the engine and fuel system.

So....

 

Anyone know of a low mileage mule for sale...

[bulwnkl]

///nevermind///

[PAezb]

This isn't what you asked for, but I run 88 octane gasohol in my turbo Baja all the time (91 octane 'required'). So long as I'm just driving around there's no issue at all. To the point you asked about: Try HEET (alcohol) if you can find big enough containers on sale. That'll raise it as much as anything and be much, much less expensive. Still, I'd try it on 88 (probably 89 in your area?) and see how it runs. Just fine, I bet. Worst that'll happen is you don't get much power.

 

I have put 89 once in a great while, and its seems to run fine with that (I don't/won't spool the Turbo up though). I thought products like HEET were hard on the CATs and such.

 

BTW I don't know if your last reply was because of my comment about the mule and your username - I just have to post...

 

http://ww2.glenbow.org/search/archivesPhotosResults.aspx?AC=GET_RECORD&XC=/search/archivesPhotosResults.aspx&BU=&TN=IMAGEBAN&SN=AUTO3351&SE=835&RN=0&MR=10&TR=0&TX=1000&ES=0&CS=0&XP=&RF=WebResults&EF=&DF=WebResultsDetails&RL=0&EL=0&DL=0&NP=255&ID=&MF=WPEngMsg.ini&MQ=&TI=0&DT=&ST=0&IR=11420&NR=0&NB=0&SV=0&BG=&FG=&QS=&OEX=ISO-8859-1&OEH=ISO-8859-1

 

There are moose in northern Minnesota as you know - could be a alternative...

[bulwnkl]

Nah, HEET's just alcohol (NOT drinkable for anyone out there with more dollars than sense).

 

That's a funny picture! My nevermind was just OT so I deleted it.

 

BTW, I can still run ~0.07 MPa boost (according to factory gauge; may or may not be close to accurate and equates to ~10 psi) on 88 octane w/o any issues at all. The ECU will just pull timing if it was to start to knock; don't worry too much about it.