300 verados - 87 vs 93 octane

[glen e]

This is not to be the end all test… as the motors still only have 12 hours on them… and the 89 test was in 1 -2 foot chop in the ocean, and the 93 was in the flat ICW. I drained the tank down to 15 gals this week with all the fuel level alarms going off..my wife going nuts..(LOL), then I had Fuel Tech visit my house and fill me with 125 gallons of 93 (at $3.10, gotta love that)….. Ran a hour last night to get a good flow of 93 thru the motor.

Went out today, with the essentially the same climatic conditions as when Joey and I went out for the 87 test… and did this…Virtually no diff as far as I can tell….

[blueh20pc]

Higher octane gave you better GPH burn..

SO, the computer was making the same power burning less fuel, if you get what I'm saying.

Basically, the comp was ramping the timing because it could.

Probably be better when they get a few more hours on them.

[glen e]

Originally Posted by blueh20pc

Higher octane gave you better GPH burn..

SO, the computer was making the same power burning less fuel, if you get what I'm saying.

Basically, the comp was ramping the timing because it could.

Probably be better when they get a few more hours on them.

true..but unless they break in and become diff...I'm a low cruise kinda guy.... (I'm old) so I'll probably migrate back to 87.....

[blueh20pc]

Glen,

I'd bet you final numbers would loosen up, and you'd see 62 WOT, and burning 19 GPH at 4k Cruise once they loosen up, burning 93.

Depends on how tight Merc has the tolerances with rings.

Nice to see the motors are making just about the same power with regular gasoline. Seems like that was always a gripe with some owners.

[Hot Rod]

Do you think you have dispelled the idea that the motors are making less HP with 87 octane? There is an efficiency curve to consider I think. Whether it's 580 HP or 600 HP it's still a LOT and it's obviously more than enough for the boat.

[glen e]

i think so...i have talked to merc about it and they say it does not surprise them as some climte conditions trigger a slight decrease but most of the time not....so we'll continue to see how it goes...I know the engines were run on 87 to start as my old engines used 87 and we have those numbers when we bolted the new ones up....

[Kern O]

Glen: I notice you are running the Tempests on the boat. Have you tried either the Inertias or the Rev 4's?

[glen e]

Originally Posted by Kern O

Glen: I notice you are running the Tempests on the boat. Have you tried either the Inertias or the Rev 4's?

everything but the enertias - and I know they won't work...

[Bullshipper]

Amazing.

Questions
Do the guages read gph flows in 1/10's or just round off?Is there a chance that currents could have affected this?
Will the engines run hotter with the timing advanced for the slower burning lower octane?

This is so close it almost suggests that the vendor could be watering down his 93 with 87, is he a Mexican by any chance?

Where the heck did my jokester icon go?

[glen e]

no idea ship..that's why I'll filll up a few other places in the next few fillups with 93...temps never moved....gph does show in 10'ths

2 other peole have reported no diff either on the switch so.....