Seafari 25 performance - Page 5

BigLew · #41 02-21-2010, 04:18 PM

Quote:

I sense a bit of Pavlov's dog out there. Keep the napkin handy!

Just trying to throw fuel on the fire

Under WHO'S tail??? We haven't been graced with any recent postings on "I Think I Need a Shrink!"

eggsuckindog · #42 02-22-2010, 10:20 AM

Those numbers sound really good for a boat that size and deadrise. Nice to have another SeaCraft on the WC too, you will like that boat in the gulf. There was one years ago in St Pete that a diver friend used to go on, twin inline 6's and he said loaded it needed a bit more, but he also said it would eat the gulf chop. Maybe will come down for the offshore race, forget exactly when it is.

cdavisdb · #43 02-22-2010, 09:19 PM

I'm looking for a rough day when I can find out what it will do.

Ok guys, pics are up under Seacraft Photos, enjoy.

eggsuckindog · #44 02-23-2010, 01:04 AM

LIke I said, sounds like you have the power to push it and from what I've heard you will be impressed. It is narrow for a boat that long but I have to believe its got to a bunch better than the Formula at rest.

Blue_Heron · #45 02-23-2010, 09:51 PM

Connor,
What's the HP rating on that 5.7 GSI?
Dave

cdavisdb · #46 02-24-2010, 12:15 AM

280 shaft HP is what the book says for a 5.7 GSI

Blue_Heron · #47 02-24-2010, 07:33 AM

Thanks. I'm thinking about power options for mine. Your performance at 280 HP gives me a reference point.

cdavisdb · #48 05-24-2011, 09:42 PM

Did an economy run today, 22 miles, F3 stainless props, flat calm, 3300 rpm, 2 adults and full fuel, 2.9 nautical mpg. I am a happy camper. That compares with 2.6 kmpg with aluminum D2s and similar conditions. My old Seabird, shorter, lighter, with the same size engine, did not do this well.

Octane rating apparently makes a huge difference in fuel economy in this engine. The knock sensor enriches the mixture if the engine starts to knock due to low octane fuel. My original fuel test was with mostly fuel from the last owner, who put high octane alcohol fuel in it. I had been putting 90 octane no alcohol gas in. The engine needs 93. Lower octane fuel gave me 2.3 kmpg with the stainless props and somewhere around 2 or less with Bahamian fuel, who knows what octane. Today's run was make with octane booster raising the octane to about 92.

Anybody else have similar results with low octane fuel? Whats the best way to raise 90 octane no alcohol fuel to 93 octane?

Bushwacker · #49 05-25-2011, 12:20 AM

Quote:

. . . Anybody else have similar results with low octane fuel? Whats the best way to raise 90 octane no alcohol fuel to 93 octane?

Good info Connor! Hard to find 93 octane non-ethanol gas these days however! I would expect a richer mixture to hurt mileage. I've heard similar stories about better mpg when towing with premium, and I use premium in my truck when towing for that reason. One guy I know towed a ~30' camper with a V-8 Explorer, all the way from S. Fla. to Canada and back. Burned regular going one way and premium on the way back, and said he definitely got better mileage with premium.

Some octane boosters contain ethanol, so I'd stay away anything like that. I recently had to tow my boat about 30 miles and had about 1/2 tank of 87 octane regular in the truck. Didn't want to fill it up with premium just for that short a trip, so I got a quart of some stuff called "Turbo 108" at Pep Boys. It didn't contain any alcohol but it didn't say how much it would raise octane. Recommended dose was 1 oz/gal, so I added enough to treat 1/2 tank and it seemed to work, as it didn't knock at all in OD, which it normally will with 87 octane when towing. I'm guessing it must have bumped the octane to at least 90-91. It was $8.47 to treat 32 gal, which works out to a little over $.26/gal. Bought some 93 octane premium for the car tonight at local Hess station that was $.25/gal more than regular, so doesn't sound like it's any worse of a rip-off than the gas stations IF it gives a comparable octane boost. Of course there's always AV gas at 100 octane if you want to spend over $5/gal!

Islandtrader · #50 05-25-2011, 09:04 AM

Quote:

Did an economy run today, 22 miles, F3 stainless props, flat calm, 3300 rpm, 2 adults and full fuel, 2.9 nautical mpg.

Nice information,

Just guessing here, but your burn rate per gallon is approx. 7.5 to 8 gph?

If that is true, it seems all 350 cid no matter what they are in @ cruise the burn approx. 8.

Soooooooooo we'll see what the stroker does in the next week or so.