Detlef
Enthusiast
I am going to a dyno day soon and was wondering if adding 104 octane booster with the fill up before the dyno run would show better numbers? I also live at 5000 feet if that matters to this question. Thanks.
Octane booster and dyno run question?
- Thread starter Detlef
- Start date
Do not add octane booster unless you are running more compression, boost, or nos. You will actually lose HP on a car that doesn't need the extra octane.
YOu could do a test. GO to the dyno and add the octane booster before the first dyno run. It will not have enough time to go through the system until probably the 3rd pull. After the first pull let the car idle for 5 minutes and then cool down. Then make your 2nd and 3rd dyno runs and see if you see any power loss.
YOu could do a test. GO to the dyno and add the octane booster before the first dyno run. It will not have enough time to go through the system until probably the 3rd pull. After the first pull let the car idle for 5 minutes and then cool down. Then make your 2nd and 3rd dyno runs and see if you see any power loss.
joe117
Enthusiast
Some cars might gain from higher octane fuel. The way this would happen would be for the car's computer to advance the timing to take advantage of the higher octane fuel's resistance to knock.
The Viper has no knock sensor and so I don't believe there will be any way for the Viper computer to know that it has higher octane fuel.
The other question is do they give higher octane?
I'm not really sure that any car will gain anything measurable from the "octane in a can" products. Seems like I remember seeing a test of some of those products. They were measuring the octane improvement and I don't think the products did very much to improve good quality gas.
The Viper has no knock sensor and so I don't believe there will be any way for the Viper computer to know that it has higher octane fuel.
The other question is do they give higher octane?
I'm not really sure that any car will gain anything measurable from the "octane in a can" products. Seems like I remember seeing a test of some of those products. They were measuring the octane improvement and I don't think the products did very much to improve good quality gas.
You're right that a lot of them don't do much (one gimmick is that many of them claim to raise octane so many "points," and what they mean is tenths, i.e., 5 points is from 93 to 93.5), but there are some that seem to work pretty well. The widely available NOS race and offroad booster has MMT in it and is good for 2-4 octane numbers (not points), depending on what it's blended with and how much. And from exploring some other boards for FI cars the the product of choice the last couple of years seems to be Torco Race Fuel concentrate, a can of which supposedly will take 10 gallons of 93 to 100-104.
CROM
Viper Owner
Formula #1 - Toluene
R+M/2.........114
Cost...........$6.00/gal
Mixtures with 92 Octane Premium
10%...........94.2 Octane
20%...........96.4 Octane
30%...........98.6 Octane
Notes: Common ingredient in Octane Boosters in a can. 12-16 ounces will only raise octane 2-3 *points*, i.e. from 92 to 92.3. Often costs $3-5 for 12-16 ounces, when it can be purchased for less than $6/gal at chemical supply houses or paint stores.
Formula #2 - Xylene
R+M/2.........117
Cost...........$8.00/gal
Mixtures with 92 Octane Premium
10%...........94.5 Octane
20%...........97.0 Octane
30%...........99.5 Octane
Notes: Similar to Toluene. 12-16 ounces will only raise octane 2-3 *points*, i.e. from 92 to 92.3. Usually mixed with Toluene and advertised as *race formula*.
If you want to boost your octane get 4 gallons of Toluene or Xylene and then fill up with 12 gallons of gas (pumping the gas in after you added the go juice will help mix it up.)
Toluene can be purchased by the gallon at Sherwin Williams or any other paint supply shop. Xylene can be had at any hardware store (Home Depot, Lowes). I am not sure on the whole safety aspect of using this combination. I do know that individuals using Xylene drop in about .5oz of Marvel Mystery Oil per gallon of Xylene used.
Raising the octane in the viper wont do anything most likely. The pro's can chime in, but I don't think the ECU will raise timing with the presence of a higher octane fuel. Many cars computers (like the Turbo Supra's) will increase timing with higher octane fuel. I put a gallon of Toluene in my supercharged Integra one time at the track, was able to run very advanced timing and picked up half a second in the quarter mile.
CREDITS: http://www.vtr.org/maintain/gasoline-octane.html
R+M/2.........114
Cost...........$6.00/gal
Mixtures with 92 Octane Premium
10%...........94.2 Octane
20%...........96.4 Octane
30%...........98.6 Octane
Notes: Common ingredient in Octane Boosters in a can. 12-16 ounces will only raise octane 2-3 *points*, i.e. from 92 to 92.3. Often costs $3-5 for 12-16 ounces, when it can be purchased for less than $6/gal at chemical supply houses or paint stores.
Formula #2 - Xylene
R+M/2.........117
Cost...........$8.00/gal
Mixtures with 92 Octane Premium
10%...........94.5 Octane
20%...........97.0 Octane
30%...........99.5 Octane
Notes: Similar to Toluene. 12-16 ounces will only raise octane 2-3 *points*, i.e. from 92 to 92.3. Usually mixed with Toluene and advertised as *race formula*.
If you want to boost your octane get 4 gallons of Toluene or Xylene and then fill up with 12 gallons of gas (pumping the gas in after you added the go juice will help mix it up.)
Toluene can be purchased by the gallon at Sherwin Williams or any other paint supply shop. Xylene can be had at any hardware store (Home Depot, Lowes). I am not sure on the whole safety aspect of using this combination. I do know that individuals using Xylene drop in about .5oz of Marvel Mystery Oil per gallon of Xylene used.
Raising the octane in the viper wont do anything most likely. The pro's can chime in, but I don't think the ECU will raise timing with the presence of a higher octane fuel. Many cars computers (like the Turbo Supra's) will increase timing with higher octane fuel. I put a gallon of Toluene in my supercharged Integra one time at the track, was able to run very advanced timing and picked up half a second in the quarter mile.
CREDITS: http://www.vtr.org/maintain/gasoline-octane.html
Warren S
Viper Owner
I thought I heard somewhere that as the elevation increases, the engines' need for octane decreases. Would higher octane help if Detlef is at 5,000 ft?
CROM
Viper Owner
I really don't think 1/4 or 1/2 a gallon will have any noticeable effect on octane levels or performance.
When I used it, carrying around the gallon jug was quite easy. I just used a simple funnel to pour it in. I had about 3 gallons of 93 in my tank at the time and actually noticed the difference my first run down the track.
When I used it, carrying around the gallon jug was quite easy. I just used a simple funnel to pour it in. I had about 3 gallons of 93 in my tank at the time and actually noticed the difference my first run down the track.
No, unless he has some method for advancing the spark (such as a Vec).
Any noticeable improvement with a Viper (no knock sensor or spark timing adjustment based on knock measurement) is probably due to the cooler engine temp during the first run than anything else.
The elevation effect mentioned is accurate. If you think in terms of pressure, at altitude you have a lower pressure available. The engine operates essentially like it has a higher intake restriction due to the lower pressure. The exhaust is also operating in a lower pressure, thus reducing some back-pressure, which helps offest some of the lost potential. The end effect is that peak cylinder pressures are lower, so the knock sensitivity is reduced.
Any noticeable improvement with a Viper (no knock sensor or spark timing adjustment based on knock measurement) is probably due to the cooler engine temp during the first run than anything else.
The elevation effect mentioned is accurate. If you think in terms of pressure, at altitude you have a lower pressure available. The engine operates essentially like it has a higher intake restriction due to the lower pressure. The exhaust is also operating in a lower pressure, thus reducing some back-pressure, which helps offest some of the lost potential. The end effect is that peak cylinder pressures are lower, so the knock sensitivity is reduced.
CROM
Viper Owner
Definitely. If the ECU won't advance the timing, then it's pointless.
My point was a 2% mixture won't get you anything even in a car that has timing adjustability via ECU, distributor, or controller.
My point was a 2% mixture won't get you anything even in a car that has timing adjustability via ECU, distributor, or controller.
GTSnake
Enthusiast
So with 100 octane versus 94 versus 93 how much more advance can one go in timing? Is there some type of formula or proportion of timing advance when the octane is raised?
I used toulene in my car when I go racing and I used to use it all the time when I had a 9lb without h20 injection. Works great and is easy to add and is cheap "high octane fuel"(55 gallon drum $150). You simply add it to your fuel and you can run more timing/boost/n20, etc. I usually only added 2-3 gallons of toulene to each fill up and it allowed probably 2-4 degrees of additional timing.
The statement about higher elevation needing less octane is correct. My static compression here was 125lbs and at sea level it was 155-160. That is part of the reason why we make less HP up here.
The statement about higher elevation needing less octane is correct. My static compression here was 125lbs and at sea level it was 155-160. That is part of the reason why we make less HP up here.
Tom, to my knowledge there is no formula for determining how much advance with aditional octane. It is very much engine specific. What you really want is to have enough knock resistance to advance the spark to MBT (most beneficial torque). Advancing spark beyond that will reduce power. Fuel air ratio is another knob to turn in this same regard. In the case of f/a you want to find the f/a that produces the highest power while monitoring various temperatures (exhaust port, catalyst inlet, etc). To do this right you would need to have a chassis dyno (not an inertial type) so you could adjust both control factors to find the best combination. Having a bolt on knock sensor could help as well to avoid getting into damaging knock (the ear is good but not perfect).
Overall that is a very in-depth and slow process. Much easier to err on the safe side with a pretested starting point (like with the Roe Vec) and make minor adjustments while driving or on a dynoject dyno.
Overall that is a very in-depth and slow process. Much easier to err on the safe side with a pretested starting point (like with the Roe Vec) and make minor adjustments while driving or on a dynoject dyno.
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