STP Gas Treatment in my car everytime with regular gas, is that just as good as putting premium in?

Question

My mechanic told me that putting in STP gas treatment everytime I fill up with regular is just as good as putting premium in. Since my '05 Subaru WRX Wagon(turbo) calls for premium, he says this is a great way to save money on gas since all gas is the same before it gets to the pumps; each gas station just adds additives to regular gas to boost octane and make "plus" and "premium". Anyone heard if this is safe/legit?

Answer 1

If you want the maximum horsepower from your car, then you should burn premium gas. It has a higher octane rating which means you're getting more energy from the same amount of fuel. The octane is determined at the refinery, not at the pump. The STP fuel additive is no more than ethyl alcohol which helps keep your fuel system clean, not increase octane. Sorry, but your mechanic is full of sh*t.

Answer 2

Everything he told you is absolutely false and a quick call to STP's customer service department will confirm that.

Answer 3

Man, that's some dumb advice given.

That 1 point of octane added per fulltank of gas that booster is added to is really .1 (yes, 1/10th of a point) of octane.

So, your full tank of 87 octane becomes 87.1 octane....not exactly premium on the octane scale if you ask me.

But, you go ahead and buy 60 bottles at $5 per bottle to get that jump from 87 to 93 octane...and find a new mechanic as well!

P.S.  Refineries add those additives.  The cashier at the gas station has other things to do and isn't HAZMAT certified, anyway!

Answer 4

wrong. if car needs premium gas, put that gas in .stp is a gas treament not a booster. if want to low grade gas you must use a gas booster.. by the timr you pay for it it is cheaper to buy the gas..

Answer 5

Your mechanic is dead wrong. Occasional use of an octane booster is OK, especially when premium is not available.

Premium gasoline is different from the time it is made at the refinery. It has been blended completely differently than regular. No gas station is going to add anything to the gas in their tanks without going to jail.

The drawback to any of these additive ingredients is the diminishing effect they have on higher-octane fuels. Adding the same booster to 87-octane pump gas will yield a lot more octane gain than adding a bottle to 91-octane premium gas. Excessive concentrations of these additives also damage emissions-control hardware, such as spark plugs, injectors, oxygen sensors and catalytic converters. This is why most off-the-shelf boosters have an emissions-legal street formulation and an off-road formulation that exceeds the government-regulated concentration of MMT or ferosene.For the power-hungry, there really is no point in testing 87-octane gas and street-legal octane boosters. That's why we performed our tests with a base sample of 91-octane premium gasoline taken from a local SoCal station. By law this gasoline must have an octane rating of at least 91 octane. Octane boosters were obtained at local auto parts stores while 99%-pure gasoline-grade toluene was sourced from the laboratory of Rockett Brand Racing Fuel.

Answer 6

they also have octane booster..its on the same shelf..I use the 104+ about every three tanks..as long as your car in running smooth, you are ok..with the low octane..sometimes,  put in the 87, at a half tank i add the 93 to fill back up..

Answer 7

SUBARU TELLS YOU PREMIUM --USE PREMIUM... ALL THE ADDITIVES YOU'RE USING WILL ROT OUT THE FUEL LINES AND WONT CREATE ANY MORE POWER ANYWAY.  USE THE PREMIUM... THATS WHAT THEY RUN BEST ON... I HAVE 2 OF THEM .. 1 IN A BUGGY MAKING OVER 400 HP....  

Answer 8

I'm not sure about STP, but you can always just buy octane booster. Something that says "Octane booster" on the bottle