Gas Type For Speedster 150 255 Supercharged

[alindley]

Hey, so I just noticed the other day that on my boat it tells me to put in regular octane. I've always been putting in premium since I got it because the old owner said to put premium in as well.

Was just wondering if anyone knows if it's bad to put premium in it? Or if it only needs regular?

 

[JPass]

Supercharged motors should be running premium.

 

[alindley]

Ok thanks.

I figured it was premium too, but my buddy saw that the boat says regular and said if it says to put in regular from OEM that I should only put in regular and that it could actually be worse off using premium.

 

[JPass]

The higher the octane number the greater the fuel's resistance to knocking or pinging during combustion. The higher the octane number, the more compression the fuel can withstand before detonating (igniting). Force fed engines (turbos, superchargers, etc.) can suffer from pre-ignition with lower octane fuels. This means the fuel ignites before the spark plug fires, causing and uneven flame front which can lead to major issues that can cause catastrophic damage to internal components (pistons, valves, heads, etc).

There's plenty of videos on YouTube if you wanted to see this explained in more detail.

 

[alindley]

Well thanks for the explanation!

 

[drjack]

High octane gas usually does not contain ethanol. And ethanol has the ability to absorb moisture, leading to corrosion of certain metals in your fuel system. If you chose to use lower octane fuels, you can search on Web sites for gas stations that provide ethanol free fuel for each grade.

 

[JPass]

High octane gas usually does not contain ethanol.

I'm fairly certain this is not accurate. Missouri and Montana are the only 2 states that have an exemption to adding ethanol to premium fuels by law.

If you want to avoid ethanol for sure, then you need to go with ethanol free labeled pumps when filling up.

https://www.bellperformance.com/blog/bid/110140/Does-premium-gas-have-ethanol-in-it

 

[drjack]

Then I guess it depends on what state or Country you buy at.

http://www.pure-gas.org/
This site shows many Canadian high test pumps and all grades of fuel in Alaska are ethanol free.
Is this a simple marketing scam? How can anyone prove that a fuel is ethanol free?

 

[JPass]

Then I guess it depends on what state or Country you buy at.

http://www.pure-gas.org/
This site shows many Canadian high test pumps and all grades of fuel in Alaska are ethanol free.
Is this a simple marketing scam? How can anyone prove that a fuel is ethanol free?

You're right about Alaska. http://peninsulaclarion.com/stories/041303/ala_041303alapm0020001.shtml

Most pumps also say "may contain ethanol". Key words being "May".

Ethanol free is available right down the road for about $0.70 more per gallon. I only use it when our boat is going to see for a few weeks, otherwise it's regular unleaded for us.

 

[roju6]

Supercharged motors should be running premium.

I have a 2010 230 Wake with the twin 255 hp supercharged engines, sticker flat out says use 87 octane fuel. Have run it with 87, 89, and 91 and no discernible difference between them. Wasted money to pay for premium at that point.

 

[JPass]

I have a 2010 230 Wake with the twin 255 hp supercharged engines, sticker flat out says use 87 octane fuel. Have run it with 87, 89, and 91 and no discernible difference between them. Wasted money to pay for premium at that point.

2012 service manual states minimum recommended octane is 87, optimum performance recommends 91. Anyone who understands how force fed motors work would not put 87 in their engines. Your computer will adjust timing as the knock sensor dictates to prevent detonation. It's worth the extra money to avoid the potential damages of detonation, but in the end, it's completely up to you what to put in it. If it were me, I'd always go premium on high compression, force fed motor.

We run 87 in our twin 155s, but they're not supercharged, so no issues.

 

[roju6]

I understand the mentality behind your statement, I wasn't planning on running 87 octane either until I saw the sticker. So I worked my way down from 91 octane, to trying 89 octane (had no knocking or pinging), then 87 octane and had the same results. Can't say there was any noticeable difference in performance either, so summed it up that it wasn't an issue.

Where you buy your fuel is probably of more consequence IMO. Up here in Canada, an 87 octane Coop fuel causes pinging on high performance motors (500+ hp cars), but an 87 Shell or Esso fuel doesn't. The octane ratings are a bit of a joke in that sense, over the years it became clear Shell/Esso have higher quality fuels than other retailers. The fuel I've bought for my boat has always been Shell, where 87/89 seems to be equivalent to others 91 octane.

Just my 2 cents, end of the day everyone will do what they want to of course.