Too much octane?

[Polaris900RMK]

I am still leaning my turbo set up. I have a 2019 800 with about 200 miles on it. I have a Silber on it. Is it possible to put too much octane in my gas and cause it run worse?

I am running 5# and a few rides ago I mixed 110 fuel with 91 clear premium. I don’t have access to AV gas. I used about 1.5 gallons of 110 and the sled ran pretty crisp. Today I used about 2.5 gallons of 110. And the sled just wasn’t as crisp on the bottom end off the hit of the throttle. Nothing else changed. Weather and snow was about the same. My elevation is about 6,000 to 7,000 feet. I have a TRS clutch kit.

Is it possible that I have the mix too high causing it to run worse? Is that a thing or am I just crazy?

 

[NapaMatt]

Too much octane ... can be bad.

finding the right mix is key!

 

[Polaris900RMK]

What are the normal side effects of too much?

 

[tuneman]

Octane is a measure of how much effort it takes to get the gas to burn. The higher the number, the more resistant it is to burning, and thus the lower btu content. Low octane fuel likes to burn quite readily and puts out lots of btus.

When you compress gas, it heats up. If you compress low octane/highly volatile gas to a very high compression, you run the risk of pre-ignition(dieseling) or detonation. So you have to increase the octane to keep high performance/high compression cars, as well as turbo engines from detonating.

The downside to high octane fuel is the lower btu content. So it makes less power, compared to an equivalent amount of low octane fuel. Thus the reason why you don't use high octane fuel unless you need to.

In your case, running 6-7k elevation, with a TRS kit and 5# boot, you shouldn't need anything more than straight 91 pump gas. My sled is set up the same and all I use is 91. If you do get some detonation, then add race gas sparingly. The more you add, the less snappy it'll be.

 

[Polaris900RMK]

That was a really helpful reply and explained that really well to me. Thank you for that Sir. I really appreciate it!!!

 

[Polaris900RMK]

If anyone is interested.... I ran out all of the race gas and it’s just pump gas now. The sled is currently running better than it has since the turbo was put on. I might try a little bit of AV gas or just leave well enough alone.

 

[Snowman.PRO.]

16 axys silber here @ 7psi. I run about 15% av gas. I've never hit DET, riding 8500- 11k feet.

If you are riding similiar elevation that I am, I would try running just pump 91 with 5lbs. That's what I'd run if I was on 5lbs.

 

[Clarke673]

no such thing. Benifits are a plenty. downsides to not enough are WELLLLL known. lol Always better plaing it safe than sorry. The peace of mind is great too! Obviously you cant try and run 110 in a stocker and expect it to not run like a turd! the plugs help too! Brisk lr 12 zc .



imgoing to become a dealaer for them i reckon. Not to make money, but to supply my friends with the best! Ohh and turn the boost up way more

 

[Polaris900RMK]

Well I am gonna have to disagree with you. I have rode three times now on straight pump gas and it’s running better than ever. Ran like ass with the 110.

On another note, what is the benefit of those plugs?

 

[Clarke673]

Lol turn the boost up ehh. And idk? They don't fowl out! I can tell ya that much. Originally designed for leaded racing fuels. Makes a huge difference- to the point of and so I'm becoming a dealer in that I can afford to fix my fleet up with em, and the limited supply of parts I will stock for my friends will only consist of literslly the best available. Most my junk is old as f, they make a huge difference on the old irons like my srx mountain-mod. 97 670. Ect. Dont notice anything on my 11 sno pro sx 600 (blew it up plugs don't didn't care)

No electrode to drop and bang around.

Premium and I will out my word on it, for whatever it's worth... lol "but wait, there's more"

I don't do what I do nor ever will with aspirations of being rich. I am now! Lol won't be long and I know it! But, I do believe in integrity and it's something I will never EVER sacrifice, and that is being able to say whatever the f I want to about whatever it is I feel is needed. Wont see me sponsored ever for a lot of reason's and if you do? Well whoever that is will be BAaaullllsy #sponsured? Any old cats remember that from the Golden days of snowest?

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[xpturbo600]

The less octane you can get away with, the better. You figured that out via testing. Octane raises the energy required to burn the fuel. Higher dynamic compression requires more octane because it raises cylinder temps. Dynamic compression is best described as the operating compression created by adding air density via boost to increase from factory static compression.

The problem you described gets worse as boost goes up because dynamic compression increase with boost, but the sled operates on static compression off boost...making the sled lazy off boost if you have weak ignition.

You should be able to run 50:50 pump 110 mix with no problem using good NGK plugs spec'd for your sled. If you have an issue, check your spark plug gap. Set them to 17 to 18 thousandths. Most plugs have huge gaps out of the box. And, apply a little bit of dielectric grease to plug wire connections to ensure a good connection.

 

[Clarke673]

I agree with xp600 100% . I'm inebriated and this is Shawn off Facebook in Alaska right? If I have you mistaken I'm sorry (reread previous part of post)

I was at the bar making last rounds before putting myself in solitary for a "last push".

Check out the photos. I will pry only use snow west for the following week or so more or less as social media. To make a point amongst points and without getting too deep into talk. Consider this post a milestone. I do. Lol and I hate myself a lot so don't mistake hidden meaning. Subtext/context... lol wherever reality and the spirit world cross is where I'm at right now. Did the math. There is NO WAY to run pump gas and push the power I'm talking about when I say race gas turbo I 'f'n a.. mean like setting my bd ebc to 27 pounds over atmo instead of 17 and f'n letting it(gtx2867r) just EAT. HAVE a lot of miles doing that. More than most but less then a select few and this season into next fixing on not just "catching up".





"#onelove"

900, turn the boost way up -whole new map will be needed or it wont/shouldn't run right. Like... lol it should "thermal" after one good pull. Or? Your not racing a race sled. 1 min on and off wot should be getting hot. 2 min pull? If it's not hot why are you what are you? A member of team Yamaha? -deep jab especially if you really know, are/have been in the know.


*look at my profile pic for reference on or if "you should" listen to anything I ramble about.

Sure hope Cole willfords care package shows up tomorrow (12:05 makes it today) but worst case I will swap more parts and blow my 3" cat track into chunks first ride

☆Last words i will ramble before the unplug- by the great kid rock "it ain't brag'n if you back it up" ☆ and "you get what you put in and people get what they deserve" ,if you'll excuse me; I have some neighbors to impress and a month worth of work to do before-now tonight- ? p.s.p.s.p.s -pray for me and DAL3 dog- probably need it more than most really know

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[BrapBirk]

great article from cycle world in regards to why your sled runs better on pump gas. If you really wanna learn some stuff read all the articles by Kevin Cameron. He's been writing tech articles for longer than you have been alive.

Fuelish Myths

Our own Sherlock Holmes, Kevin Cameron solves the mystery of race gas versus pump gas, dispelling a few myths along the way.

www.cycleworld.com