Do most fuel additives really boost the octane number of the gas ? Most claim that but how true is it ? For example adding 1 bottle of additive in 15 gallons of fuel , how much the octane number will increase ? are they really worth the money or just use isoprpyl alcihol or nitromethane ?
Fuel additives octane boosting
- Thread starter scirocco16V
- Start date
- Status
Patman
Staff member
Road and Track did a test back in April 89 (I know, a LONG time ago!) and found that most of the products barely raised the octane at all.
Super 104+, which claims big numbers, only raised the octane by 2.2 points. So it turned 93 octane into 95.2 octane. They also found that if you doubled the dosage you didn't get double the kick, it only gave another 50% increase. So a double dose would only raise the octane by 3.3 points total (not 4.4)
A lot of these products will foul your plugs too (I found this with the use of 104+)
If you really need more octane, a lot of speed shops can locate race fuel for you. I know there is a race fuel place in my town which sells 98 octane, I used to run that stuff in my supercharged Mustang GT all the time.
Super 104+, which claims big numbers, only raised the octane by 2.2 points. So it turned 93 octane into 95.2 octane. They also found that if you doubled the dosage you didn't get double the kick, it only gave another 50% increase. So a double dose would only raise the octane by 3.3 points total (not 4.4)
A lot of these products will foul your plugs too (I found this with the use of 104+)
If you really need more octane, a lot of speed shops can locate race fuel for you. I know there is a race fuel place in my town which sells 98 octane, I used to run that stuff in my supercharged Mustang GT all the time.
The town next to me has racing fuel. It is a BP station and the pump has a 100 octane sticker on it and it is unleaded also. The kicker is the price. It is $3.87 a gallon. One thing though since the price of gas has gone up the price of the race gas has stayed the same.
When I run it in my 65 Impala SS it makes my exhaust smell like I'm at a prostock race.
Additives generally work on the law of diminishing returns, where you finally reach a point at which continuing to add gives next to nothing, as you've reached as far as you're going to get.
How effective they are is also determined by the make-up of the base fuel that you are trying to doctor.
As an example, with modern Aussie fuel, a couple boxes of napthalene flakes makes no difference at all. (used to work well with my old Torana back in the days of leaded fuel - helped you spot fuel leaks as well).
I'm leaning towards water injection as the most desirable street engine "octane on demand" solution.
Also, race gas requires a special licence down here, and will get you locked up if caught using it.
How effective they are is also determined by the make-up of the base fuel that you are trying to doctor.
As an example, with modern Aussie fuel, a couple boxes of napthalene flakes makes no difference at all. (used to work well with my old Torana back in the days of leaded fuel - helped you spot fuel leaks as well).
I'm leaning towards water injection as the most desirable street engine "octane on demand" solution.
Also, race gas requires a special licence down here, and will get you locked up if caught using it.
- Status
