93 octane when the manual calls for 87?

[tahmad575]

Hello all,
I have a 05 Yamaha sx230, the manual calls for regular 87 gasoline however on the lake I keep my boat there is only 93 octane.
Would filling it up with 93 and using the ring free fuel treatment from yamalube be okay?
Or would it cause damage to the engines

Thanks

 

[marcham]

93 is fine.

 

[anmut]

93 is a waste of money, but it's fine.

 

[Looper7]

When I was at Norris Lake last month that's all they had at the marina and only .60 cents more then 87 pump prices my boat seemed to love it ran great I ran about 100 gallons through her.

 

[tahmad575]

Great thanks for the info, I don't really care about the price difference since driving the trailer up to the lake 1 hour each way required Abt $20 in gas and by doing that I only save about $5?
I was just concerned about the engine running on a higher octane,
Thanks!

 

[BrentEB]

From what I've read 87 octane burns hotter then 92-93 oct. The implication is that since these engines are run cooler (than automotive), higher octane gasoline will tend to form more carbon in the cylinders versus 87 oct. And like said - why waster the $

 

[eastcoaster]

The gas dock I use has only 93 octane. The primary reason being 93 is ethane free

 

[eastcoaster]

meant to say ethanol free

 

[Theryan]

If an engine calls for lower octane gas, running the occasional higher octane won't really do any damage. I wouldn't necessarily do it all of the time, but every so often shouldn't affect your engine at all.

As others have said, it's going to just be a waste of money for the most part.

 

[H20 skier]

Decided to do some "internet" research this article was a good read.

https://www.hemmings.com/stories/2014/04/11/tech-101-octane-the-facts-and-the-fiction-behind-those-higher-priced-fuels

i got this from it and a couple other ones but I am no expert.

to be "high" octane must be over 91 octane and is considered to be cleaner fuel "not cleaner burning" but less contaminents from the refineing process. so less gunk gets built up.

it also burns slower producing less knock/ping at higher RPM's and higher compression.

my point to this is the 1.8 supercharged motor in my 195 is 8.5 to 1 compression (from yamahas website)
the stock 1.8 motor is 11 to 1 so why does my require the higher octane? Im thinking it has something to do with the supercharging or helping the computer not to think so much as neither motor hits the RPM's the MR-1 does.
anyway the article is good informative read.

 

[anmut]

Decided to do some "internet" research this article was a good read.

https://www.hemmings.com/stories/2014/04/11/tech-101-octane-the-facts-and-the-fiction-behind-those-higher-priced-fuels

i got this from it and a couple other ones but I am no expert.

to be "high" octane must be over 91 octane and is considered to be cleaner fuel "not cleaner burning" but less contaminents from the refineing process. so less gunk gets built up.

it also burns slower producing less knock/ping at higher RPM's and higher compression.

my point to this is the 1.8 supercharged motor in my 195 is 8.5 to 1 compression (from yamahas website)
the stock 1.8 motor is 11 to 1 so why does my require the higher octane? Im thinking it has something to do with the supercharging or helping the computer not to think so much as neither motor hits the RPM's the MR-1 does.
anyway the article is good informative read.

As I understand, forced induction engines use higher octane because of the timing.

 

[H20 skier]

Thanks, I figured it had to do with the S/C

 

[Tobes]

As I understand, forced induction engines use higher octane because of the timing.

No, they use higher octane because it can handle the higher cylinder pressures and resist pre-detonation. Timing is retarded/advanced in modern engines by the computer to compensate for using the wrong octane. If you run a low octane on a 91+ motor (usually high performance N/A or FI engines), the computer will retard the timing to compensate and you will lose power.

Decided to do some "internet" research this article was a good read.

https://www.hemmings.com/stories/2014/04/11/tech-101-octane-the-facts-and-the-fiction-behind-those-higher-priced-fuels

i got this from it and a couple other ones but I am no expert.

to be "high" octane must be over 91 octane and is considered to be cleaner fuel "not cleaner burning" but less contaminents from the refineing process. so less gunk gets built up.

it also burns slower producing less knock/ping at higher RPM's and higher compression.

my point to this is the 1.8 supercharged motor in my 195 is 8.5 to 1 compression (from yamahas website)
the stock 1.8 motor is 11 to 1 so why does my require the higher octane? Im thinking it has something to do with the supercharging or helping the computer not to think so much as neither motor hits the RPM's the MR-1 does.
anyway the article is good informative read.

Compression on the motor is 8.5:1 but after supercharger, it goes up quite a bit. You have to build a FI engine with lower compression depending upon the amount of boost you are running and what the motor is designed for. 91 doesn't burn cleaner than 87, it just resists pre-ignition from compression/heat allowing for higher cylinder pressures.

From what I've read 87 octane burns hotter then 92-93 oct. The implication is that since these engines are run cooler (than automotive), higher octane gasoline will tend to form more carbon in the cylinders versus 87 oct. And like said - why waster the $

It doesn't burn hotter, technically, but more efficiently and completely.


Will it hurt to run 91/93 in a motor spec'ed for 87? No. If you can tune, you MIGHT get the slightest bit more performance by modifying the timing but its minimal at best and not worth it. You can hurt a motor spec'ed for 91/93 and running 87 (although most likely you won't hurt modern engines).

Altitude matters too. 91 octane @ 5000' is almost a waste unless tuned for even if the motor wants 91 (although I would still feed it 91 myself).

Run what the manufacturer calls for. Unless you are making large modifications, worrying about octane to get the best performance is a waste. You wont keep your 87 spec'ed engine cleaner or more efficient by running 91 and you can hurt your 91 spec'ed engine running 87.

 

[H20 skier]

Thanks Tobes! more great info.
I run premium all the time. Where i drop in the lake is pretty much where i enjoy so I dont mind the expensive stuff. I dont have go more than couple miles either way to find a cove and chill or do water sports.