STP Octane Booster for Gasoline Fuel Additive, 5.25 oz, Fuel Additive That Raises Octane Levels and Cleans the Fuel Intake System to Restore Lost Power and Acceleration, Help Improve MPG

Do not buy this if you are thinking it will improve your vehicle's performance in some way. I made that mistake of ignorance myself when first grabbing a bottle off the gas station shelf. It likely won't hurt your engine to use one bottle per 15 gallons (they say up to 20), but it's just not what most people think it is/does. **edit*- this DID cause transmission damage, knocks, and pings on my naturally aspirated system. I mistakenly thought that my variable octane (87-93) engine and drive train could handle this change in octane. This was my mistake, I was wrong, and this shouldn't be used on a naturally aspirated engine unless the gas has been sitting for ~6 months and has gone stale. Check with your dealer about your specific vehicle make & model.*Octane boosters raise the octane level of your fuel, making it MORE difficult for gasoline to combust under pressure. They get a bad rap as they're sold as performance enhancers, or speed boosters. High-revving, high psi turbo/supercharged engines can benefit from this as it leads to increased efficiency of combustion. High-octane fuel requiring performance cars that only have access to 87 octane gas stations, or fuel that's been sitting around a few months or more can benefit from this too. You can do some research yourself, but if your vehicle does not specifically recommend using an octane booster or a fuel with octane higher than 91 or 93, then it's likely not for you. Maybe if you only have access to low octane gas, but this is an expensive way to boost it by only a little. You're way better off using 93, or 91 octane as your car will take. Using with regular gas if your car takes regular 87 octane gas will do nothing.I use it in a naturally aspirated 3.8L V6 with 104k miles and it was what was causing me knocks around 3rd gear.Typically a fuel system cleaner (and this part is important!) which SPECIFICALLY lists the detergent levels, not just the name of the chemical the detergent used, is a better bet for increasing performance, but still only by a few hp in the best of scenarios on the oldest of cars in the worst of shape over a long time after a lot of uses, and typically is only around up to 0.5hp. This one doesn't even list the detergent I don't think, just that it has 'jet fuel' whatever tf that actually is. It's not fuel for a jet, that's for sure (kerosine is what jet fuel actually is).There are way way better options for boosting performance, and I'm not sure how this would handle in a system that can't take varying levels of octane. Snake oil for many, but it does have it's uses and works for some very specific cases and again, it does not make sense to me yet why. I have some unknown issue, in a 3-year-old car with a ton of miles for the years, which can take variable octane fuels. I likely have some hairline crack in my fuel system somewhere leaking vapor or letting moisture in. **edit*- it was this octane booster which was contributing to my tranmission knocking issue. After stopping use and going down in fuel grade for a month, it's running like new again.*

Great additive to vehicle.

seemed to work. used monthly to hopefully keep fuel system clean, was a subscribe and save item until substantial price increase then dropped item. if price drops to where it was I would resubscribe

Using in a 16 year old Lexus and has improved MPG and lost power.Only using every 3rd fill up with REG gasoline 87.Recommended for all V6 engines as also tried in a Ford, Dodge and other Lexus models.

i put this in my fuel cell to help with fuel storage

First and foremost, your engine needs a knock sensor to get any benefit from this. If it's not a performance car, it's probably tuned for 87 and may run worse if you add this. If you don't know whether it has a knock sensor, Google it.I added it to a tank of 91 octane gas, and my engine immediately responded with more torque. It was noticable. Not like adding a supercharger, but you can tell it's pushing a few more pound-feet of torque.I suppose this could boost mileage, but it just makes it so much fun to floor the accelerator...I will say that if I go on the freeway and reset the counter, and there's not much traffic, it'll read 35MPG with the air conditioning on all the way until I exit, even if that's 50 miles later. This is in a heavy Acura TL-S with a 3.5L V6. That might be two or three higher than usual. As for city driving, it's worse because, again, it just invites me to accelerate more quickly. Someone with a gentler touch might get better city mileage than me. Hard to say. I make mostly short trips on surface streets, so my mileage is going to be awful most of the time.

This is a great octane booster and it was able to keep my car running great but once they got ridiculous and made it so you couldn't buy single bottles or even buy six bottles you have to buy 12 bottles or more so I switched to a different company that completely destroyed my vehicle this is a great octane booster what worth well worth the money it's just that it's upsetting that you can't get it in smaller package deals

Be careful of this one. Make sure you notice the ounces! You can buy the larger one at Meijer usually for a small difference and get a lot more. It looks like its a deal if you buy this until it's delivered and now you see the quantity is so much smaller than what you may be use to purchasing.