87 octane vs. 93 octane

[rebeltaz83]

read on here when i joined most everybody runs 87, i also ran 87...... one day a month ago i decided to fill up with 93, seems yamaha calls for a min. of 91...... not sure about anybody else, but i bet i gained atleast 5 horse by switching to higher octane.... the throttle response, and the acceleration is night and day between 87, and 93 octane..... i felt the vboost with 87, but now i really feel the vboost....... not sure why, bone stock motor, just a stage 1, and a k&n with the y removed, and super trapp slip ons. i also noticed it runs alot cooler down the road, used to run just above half way on the temp gauge, and now it runs under half way, heats up in traffic like before, but it doesn't get near as warm as it did with 87. anybody else experience this?? my max is a 97, 15,000 miles. i'm gonna keep running 93....... one downfall my clutch is staring to slip, lol...... time for an upgrade, along with a updated segment, and a shift shaft seal, and a rotella diesel oil change, with a napa gold filter.... black oil filter matches the rest of the engine, lol.

 

[davesax36]

You're not burning all your gas...

Posted with my thumbs.

 

[Traumahawk]

You're not burning all your gas...

Posted with my thumbs.

+1...thats probably the reason why its running cooler.

"Your Yamaha engine has been designed to use regular unleaded gasoline with a pump octane number ([R+M]/2) of 86 or higher or research octane number of 91 or higher. If knocking or pinging occurs, use a different brand of gasoline or premium unleaded fuel. Unleaded fuel will give you longer spark life and reduced maintenance cost. If unleaded gasoline is not available, then regular leaded gasoline can be used.

http://www.vmaxoutlaw.com/tech/octane.htm

You probably saw the RON number of 91.

 

[Matt427sohc]

The reason why you bike runs cooler is due the ethenal (the moonshine) the govnerment forces us to run. The by product of burning (the moonshine) is water which cools the motor. The carbs get white residue inside the carb which eventually you have to clean out (use fuel stabilizer) helps. Example E 85 (octane rating at 108 or so) but put this in your bike and your carbs are toast. The fuel that was ran in the 60's is the best for your bike hands down. EPA is a joke saying that fuel harm the planet. Fuel was completely consumed ( our fuel today with the moonshine in it does not burn completely).

 

[ImCannibal]

I used to run 93 in mine until I read a writeup on here and realized that may have been why I was getting backfire and bad fuel economy (68 miles from full to reserve), when I switched to 87 ethanol free I saw improved fuel economy and a better feel in my power.

 

[rebeltaz83]

all i have around here is 10% ethanol, in 87, 89, or 93...... i can get non ethanol gas, at one station, but it's near $5 a gallon..... with only a range of 100 miles, and this station is 20 miles from where i live, i wouldn't be able to ride. it was the ron i saw on the underside of the faux tank cover....... but this thing is night and day between the two...... it's like getting kicked by a horse when the vboost kicks in with 93, i knew vboost was working with 87, but it didn't feel like like it does now..... about fell off lol. i could get some 110 octane (cam 2) racing fuel without ethanol.... i ran that in my old 68 plymouth..... ran it in my 87 dakota and burned off the o2 sensor. i'm not putting that in my max though.

 

[rebeltaz83]

I used to run 93 in mine until I read a writeup on here and realized that may have been why I was getting backfire and bad fuel economy (68 miles from full to reserve), when I switched to 87 ethanol free I saw improved fuel economy and a better feel in my power.

i'm the opposite, i got better mileage with 93, this is my 4 th tank, and i only put 3 gallons at the 98th mile on my trip..... i get close to 100 i fill up, i put it on reserve once at 125 miles, lol.... and i don't baby this thing....... maybe i should shut up and just ride this thing, it seems to be a good thing, lol.

 

[rebeltaz83]

The reason why you bike runs cooler is due the ethenal (the moonshine) the govnerment forces us to run. The by product of burning (the moonshine) is water which cools the motor. The carbs get white residue inside the carb which eventually you have to clean out (use fuel stabilizer) helps. Example E 85 (octane rating at 108 or so) but put this in your bike and your carbs are toast. The fuel that was ran in the 60's is the best for your bike hands down. EPA is a joke saying that fuel harm the planet. Fuel was completely consumed ( our fuel today with the moonshine in it does not burn completely).

i had the bike for about 14 months, and i've dumped 1/3 can of sea foam every fill up. i keep more in stock than the parts stores, lol. just seems weird the 87 i been running has ethanol as well as the 93. 10% for us here in upstate ny. only one station i know of about 20 miles from where i live has non ethanol for about $5 a gallon.

 

[Matt427sohc]

Look you blend the fuel 2 gallons 93 to 1 gallon 110. The reason you burn up the 02 is motor runs more efficient timing & fuel make the motor too lean because the 87 dakota computer set to run poor gas not good stuff. Your max will run better but don't run straight 110 octane your jet setting are not right to run really good gas. Look go to drag strip & go by the cars running in the pit the motors that run really good 110 octane and higher will be cleaner. Your old 68 was carbed just like you max. Just don't run pure due to the little motor not getting ready of the heat fast enough but your max will run better than it ever has. Don't run all the time either because if you go say 2 gallon 110 to one gallon 93 you bike will run hotter and if your cooling system is weak you will over heat your bike. Other than that you should be fine.

 

[Itgoes]

Look you blend the fuel 2 gallons 93 to 1 gallon 110. The reason you burn up the 02 is motor runs more efficient timing & fuel make the motor too lean because the 87 dakota computer set to run poor gas not good stuff. Your max will run better but don't run straight 110 octane your jet setting are not right to run really good gas. Look go to drag strip & go by the cars running in the pit the motors that run really good 110 octane and higher will be cleaner. Your old 68 was carbed just like you max. Just don't run pure due to the little motor not getting ready of the heat fast enough but your max will run better than it ever has. Don't run all the time either because if you go say 2 gallon 110 to one gallon 93 you bike will run hotter and if your cooling system is weak you will over heat your bike. Other than that you should be fine.

:ummm:

 

[davesax36]

Uhhhh.... no.

 

[srk468]

110 covered the O2 sensor with lead, that's all that happened. My bike runs best on 92 octane with the ethanol, I've tried them all at the track and on the street and I've gotten the best overall ridability with the 92 octane. I have made passes on 110 octane race gas and the results were identical to 92 octane so when people tell you that excessive octane will actually slow you down they are wrong except in extreme cases like running C16 in a 9:1 engine.

 

[wildweasel_pt]

I never understood why you have so low octane grade gas there. Here the regular is 95 octane and premium is 98 but we pay way more than $5 a gallon, closer to $8 a gallon

 

[Matt427sohc]

110 covered the O2 sensor with lead, that's all that happened. My bike runs best on 92 octane with the ethanol, I've tried them all at the track and on the street and I've gotten the best overall ridability with the 92 octane. I have made passes on 110 octane race gas and the results were identical to 92 octane so when people tell you that excessive octane will actually slow you down they are wrong except in extreme cases like running C16 in a 9:1 engine.

OK I don't what going on. Higher octane will always make more power. The problem most people have not tuning for said ocatne level. For exmaple take nitro running top fuel cars and bikes. Now dump that in a stock max. Bike will not run. Nitro makes the most power but motor has to be set up for the fuel. In your example of course your bike will run the same on 92 octane as 110 because your tune is for 92. The original question presented was 87 vs. 93. On stock vmax 87 works just fine. 92 or higher best results will be when you tune to run this fuel only. Just go to any dyno shop where anything making over 600 hp and they will ask you what fuel will you run. To make over 450 horse (600 was just a number I choose) on any car you will have to run at least 92 and 92 only. Same thing with vmax. Look motor just air pump air and fuel coming in and going out. Power adders so popular is due to additional air force while running lower octane fuel (motor more effiecent) but if you take the same motor and tune for higher octane motor will make more power period. Just looking at only one variable in today's world of crappy ethanol fuel (which I have to run the lowest for my bike 93 octane with ethanol) causes issues poor idle white residue in carbs which clog up jets (not jut the main jet). Nrote no discussion on E 85 fuel which is 85 percent (moonshine) and 15 percent gas. Try (don't ever) run that in your max. First alcohol dissolves rubber (which is the main reason why you don't run in your bike) but also you fuel mileage will drop.
Just ask anyone running E 85 in any vehicle.

 

[Biker Dash]

OK I don't what going on. Higher octane will always make more power. The problem most people have not tuning for said ocatne level. For exmaple take nitro running top fuel cars and bikes. Now dump that in a stock max. Bike will not run. Nitro makes the most power but motor has to be set up for the fuel. In your example of course your bike will run the same on 92 octane as 110 because your tune is for 92. The original question presented was 87 vs. 93. On stock vmax 87 works just fine. 92 or higher best results will be when you tune to run this fuel only. Just go to any dyno shop where anything making over 600 hp and they will ask you what fuel will you run. To make over 450 horse (600 was just a number I choose) on any car you will have to run at least 92 and 92 only. Same thing with vmax. Look motor just air pump air and fuel coming in and going out. Power adders so popular is due to additional air force while running lower octane fuel (motor more effiecent) but if you take the same motor and tune for higher octane motor will make more power period. Just looking at only one variable in today's world of crappy ethanol fuel (which I have to run the lowest for my bike 93 octane with ethanol) causes issues poor idle white residue in carbs which clog up jets (not jut the main jet). Nrote no discussion on E 85 fuel which is 85 percent (moonshine) and 15 percent gas. Try (don't ever) run that in your max. First alcohol dissolves rubber (which is the main reason why you don't run in your bike) but also you fuel mileage will drop.
Just ask anyone running E 85 in any vehicle.

Lets break this mess down a bit...

Higher octane will always make more power.

Higher octane allows you to run more ignition advance, more compression, and/or more radical cams without running into issues of pre-ignition or detonation. Higher octane in itself will not make more power.

For exmaple take nitro running top fuel cars and bikes. Now dump that in a stock max. Bike will not run.

This is an apples to giraffes comparison. Seriously, the fuels are no where close to being comparable.

Nitro makes the most power but motor has to be set up for the fuel.

Nitro makes so much power because the sheer volume of fuel needed for it to work. Do you know what the A/F is on a top fuel car? 2:1. And they have injectors that could double as a 2 1/2" firehose. BTW, the CR of one of them cars is generally 6:1 or so. They are just boosted as hell normally. As stated above; apples to porcupines. (or something equally ridiculous.)

To make over 450 horse (600 was just a number I choose) on any car you will have to run at least 92 and 92 only.

Okay... I call bullshit. Why do I do that? Cause a decent builder CAN make 450hp easily with 87 using the right engine. Displacement helps a lot. Do you even math? A stock Vmax (1st Gen) is rated at 140hp with a 73 cubic inch motor. Multiply that by five, you have the displacement of a 5.9 Magnum bored .030 over. now, what is 140 x 5? Comes out to 700. Granted, that is quite over-simplified, but, you can see that it should be relatively easy to make the 450hp from a Mopar A block running 87 octane. (or a 351 Windsor, or SBC, for that matter)

Lastly (cause I am bored with this debate already) you repeatedly stated about tuning an engine for the fuel. You do NOT tune an engine for the fuel, you tune an engine to make a specific power in a specific range, and use the needed fuel accordingly. And in all actuality, using the word "tune" is not really accurate, because when you get into changing things such as cams, pistons, crank, ect., this is building an engine, and not tuning.

 

[Rusty McNeil]

You cannot tune an N/A motor for higher octane other than playing with the timing advance or retard.

To do anymore than that you'd need to raise the compression to utilize the higher octane. That's not tuning that's engine building.

I'm not expressing an opinion on whether anyone's Vmax runs better or worse on any given octane. Mine when stock ran best, got better fuel mileage, and best 1/4 mile times on 87.....Anyone else's experiences are theirs and there are lots of variables to that.


But back to the actual science....


Engines make the most power when right on the edge of detonation.
That's not an opinion.

Edge of detonation for a given motor can be brought on by several things, usually a lean fuel mixture, high heat, or low octane fuel.
My bike, after I rejetted for Utah 10,000 ft , ran wildly better back here in Houston at 20ft.
Showinging that leaner is better, not because it's lean but because it brings the engine closer to burning ALL the fuel and closer to DET.

You see (or hear) the same thing when your two stroke yard tool begins running out of gas, it starts going lean and the rpms shoot up, without changing throttle input.

Running higher octane than you need is no different than running too rich a mixture, or lowering your compression, or over-cooling your motor.

And whoever said "higher octane ALWAYS makes more power" is ........

Well, never mind...

 

[jedi-]

Higher octane allows you to run more ignition advance, more compression, and/or more radical cams without running into issues of pre-ignition or detonation. Higher octane in itself will not make more power.

Exactly.

 

[johnblaid]

My bike ran best on mid grade gas. But when it hits the streets again it's going to have 150 jets in it per Sean and I have no idea what will work.

But reporting that mid grade rather than premium worked best for me with stock jets.

This is not a crack at the present administration, it's just a crack at the federal government in general. keep your F**ing hands off the F**iing gas because engines burn gasoline, not rubbing alcohol. Jeez. I've had more trouble with gas and booze separating.

 

[Itgoes]

Exactly.

Agree.....and specifically with a Gen 2, 89 makes more power than 92 or 93.

 

[wildweasel_pt]

Lets run diesel and see what happens... LOL