Your comparing an old school big block with a much newer more modern small block.

When I bought mine I found two test on the web, one with the 320hp small blocks and the other with the 496 375hp big blocks.

The big blocks had a higher cruise speed at less gph. Only at wot did the small blocks win out but at almost 5mph less

To me that said that the small blocks were having to work alot harder at cruise which probably meant a longer life span for the big blocks. Which was the deciding factor for me when I ordered my boat.

 

fuel burn

Do you have the numbers for the 496s? Would like to see. JIM

 

I can tell you my average fuel burn this summer with my 2007 33SS with twin 496 / 375 HP engines was just over 14 GPH.

I generally run between 35 and 45 MPH but did hit 60+ a few times this year. Several 50 MPH trips crossing the Chesapeake Bay.

Great boat! I don't think small blocks are correct power for this boat and I doubt it would save fuel.

Besides, if you need to consider how much fuel you're going to burn you're in the wrong boat or possibly the wrong hobby!

Sailboat people generally talk that way! :laugher:

 

330ss with 496s

lets see a 350ss gets 1.21 mpg@39mph with 496s but you get 39mph/14gph=2.78mpg It aint happening JIM see boat test http://www.boattest.com/boats/1649/test_results.aspx Test Power: 2 x 425-hp MerCruiser 496 Mag HO RPM MPH Knots Total GPH MPG NMPG Range NM Range dBa
850 4.1 3.6 3.4 1.22 1.06 193 168 67
1000 6.4 5.5 6.0 1.06 0.92 167 145 80
1500 8.3 7.2 9.2 0.91 0.79 143 124 73
2000 9.9 8.6 15.2 0.65 0.57 103 89 80
2500 23.2 20.1 22.1 1.05 0.91 165 144 81
3000 31.1 27.0 25.8 1.20 1.05 190 165 80
3500 38.9 33.8 32.1 1.21 1.06 191 166 81
4000 45.8 39.8 43.0 1.07 0.93 168 146 82
4500 52.5 45.7 62.3 0.84 0.73 133 116 85
4860 56.8 49.4 70.1 0.81 0.70 128 111 85

 

35SS weighs 2,520 more than a 33SS

 

28ss gets 1.88mpg@27.6mph@14.7gph

You get better mpg than a 28ss? Test Power: 2 x 300-hp MerCruiser 350 MAG Horizons Sterndrives RPM MPH Knots Total GPH MPG NMPG Range NM Range dBa
610 2.9 2.5 1.7 1.69 1.47 182 158 68
1000 6.5 5.6 3.2 2.02 1.76 218 190 70
1500 8.8 7.7 6.1 1.45 1.26 157 137 75
2000 10.0 8.7 9.5 1.05 0.91 113 99 76
2500 16.8 14.6 12.8 1.32 1.15 142 124 79
3000 27.6 24.0 14.7 1.88 1.63 203 176 80
3500 34.6 30.1 20.1 1.72 1.50 186 162 84
4000 41.1 35.7 27.1 1.52 1.32 164 142 86
4500 46.3 40.3 34.9 1.33 1.15 143 125 88
5000 50.3 43.7 39.9 1.26 1.10 136 118 90

Speeds measured with Stalker ProSports radar gun. Fuel consumption (gallons per hour) measured with Floscan digital fuel-flow meter on gas inboards, sterndrives, and outboards, TechMate electronic scan tool on gas EFI inboards, Caterpillar digital fuel-flow meter on diesel engines, or permanently installed fuel-monitoring equipment. Range is based on 90% of published fuel capacity. Sound levels determined using Radio Shack digital decibel meter on A scale. 68 dBa is the level of normal conversation.

Performance Chart

Test Conditions
Test Power: 2 x 300-hp MerCruiser 350 MAG Horizons Sterndrives Time To Plane 3.6 sec.
0 to 30 5.9 sec.
Test Power 2 x 300-hp MerCruiser 350 MAG Horizons Sterndrives
Transmission Bravo Three
Ratio 1.5:1
Props 22 cup
Load Load: 2 persons, Fuel: 3/4 full, Water: none, Gear: minimal
Climate Temp: 85 deg., Humid: 74.1%, Wind: 3 knots, Seas: 1-2 ft.

 

I can tell you my average fuel burn this summer with my 2007 33SS with twin 496 / 375 HP engines was just over 14 GPH.

This is 14GPH per engine, right? if so, looks like everyone's numbers agree.

If not, I'm getting a 330, because thats better economy then my 502/B1 in my 242.

 

330ss

28gph@39mph=1.39mpg yeah 28 gph would work if not I think everyone would want a 330ss with 496s JIM

 

242 with 502

Whats top speed of 24 with 502l, have picture?

 

Re: 242 with 502

Whats top speed of 24 with 502l, have picture?

mine tops out at 63.2 on GPS.

 

looks good

looks good nice shape,thats what my Fastech 271 did 63mph 502 b1 1:50 26 pitch bravo 1 prop, what year is it

 

Re: looks good

looks good nice shape,thats what my Fastech 271 did 63mph 502 b1 1:50 26 pitch bravo 1 prop, what year is it

That one is for sale some where. Did you just buy it or are you selling it.

 

This is 14GPH per engine, right? if so, looks like everyone's numbers agree.

If not, I'm getting a 330, because thats better economy then my 502/B1 in my 242.

Nope not each engine,I got just over 14 GPH for the season. I bought 470 gallons of gas this year and put 33 hours on the boat, you do the math.

I can only tell you what my experience is with this boat. I'm not saying you wouldn't burn more if you run it differently than I run mine.

My days of going as fast as I can all the time and getting major air is behind me. I bought a 60MPH boat just in case I needed to pass a sailboat one day! :blush:

I will tell you my old Liberator with a single 460 Cobra burned 18 GPH on average. I did push that boat most of the time, I guess I am maturing! I'm convinced the technology changes in the last couple years made a huge reduction in fuel burn.

If I had an older 33SS with big blocks, I would guess the fuel burn numbers would be significantly greater.

 

fastech271 was sold

The fastech 271 was sold to a guy Ryan in Canada

 

Nope not each engine,I got just over 14 GPH for the season. I bought 470 gallons of gas this year and put 33 hours on the boat, you do the math.

Those appear to be incredible numbers. Your basically saying your burning only 7 gallons per hour per motor?

That would mean your boat, which probably weighs at least double mine, and has 14+ liters of power is more economic then my boat which weighs in at 2500 pounds max and has a 3.0 liter engine?

I burn 14-15 gallons per hour at cruising speed, and 30+ @ WOT.

 

Those appear to be incredible numbers. Your basically saying your burning only 7 gallons per hour per motor?

That would mean your boat, which probably weighs at least double mine, and has 14+ liters of power is more economic then my boat which weighs in at 2500 pounds max and has a 3.0 liter engine?

I burn 14-15 gallons per hour at cruising speed, and 30+ @ WOT.

I will admit I was very surprised with the fuel consumption myself. The engines in this boat are made to run on the gasoline we see at the marinas today, not 100% gasoline. I am running a Bravo 3 with Duo-Props behind each engine. That drive alone increases fuel efficiency by an amazing factor. All those fuel burn charts are accurate I'm sure. I find myself in a lot of 6MPH sections of water. When I do wind it up the RPMs rarely ever pass 4,000, most of my running is either just off idle or between 3 and 3,500 RPMs.

I suspect if I buried the sticks and blasted down the Chesapeake at 62 MPH all the time, I would be burning the kinds of numbers you all are saying, that's just not the way I travel.

My wife and I use this boat more like a car. We come home from work, walk out to the boat and go to dinner. Most of the places we go to take about 10 to 20 minutes to arrive.

We don't take off on the weekend and have the boat flying all day long. We know where we are going and we go.

I can tell you I'm not the only owner of a 2007 Formula 33SS that was pleasantly surprised by the economy, ride and craftsmanship that Formula produces.

The support after the sale from the dealer network and manufacturer is second to none.

If a dealer doesn't perform to the liking of Formula, he's gone. Full Tilt Marine in Maryland had the line for a number of years until a few weeks ago. Poof, they lost the franchise!

 

Re: looks good

looks good nice shape,thats what my Fastech 271 did 63mph 502 b1 1:50 26 pitch bravo 1 prop, what year is it

its a 1991... interior shot.

 

Nope not each engine,I got just over 14 GPH for the season. I bought 470 gallons of gas this year and put 33 hours on the boat, you do the math.

OK, guess I'm going to start shopping... I'd be plenty happy at 35-40MPH if I could be in the 2MPG range in a boat that big.

 

Ghart that is incredible, I will have to do a little more keeping track next summer and see where I come in.

I do know I can get about 3 mpg at 65-70mph.

 

That would mean your boat, which probably weighs at least double mine, and has 14+ liters of power is more economic then my boat which weighs in at 2500 pounds max and has a 3.0 liter engine?

I burn 14-15 gallons per hour at cruising speed, and 30+ @ WOT.

My new boat weighs in at 10,950 dry. My old Liberator was just under 6,000 pounds, it was a very heavy 26 foot boat.

The Libby would top out around 53MPH, depending on the prop I had on it.

The area of the Chesapeake Bay we traveled in the Libby is the same as with the Formula. The Libby did have thru hulls so I had a tendency to let it talk to me on occasion, the Formula is quiet.

We used that old boat much as we do this one, like a car to make a dinner run in the evening. The fuel burn in that old Liberator was significantly higher and required higher octane fuel than the Formula.

I am absolutely convinced the greatest change in fuel consumption comes from the changes in technology.

I would wager that if three like boats were going to the same place at the same speed, my 2007 33SS, a 2002 33SS and one from the '90s, you would see a significant difference in fuel burned on the same trip as the age of the boat was increased.

 

Hmmm.....you weigh 7500 pounds more then me, and have 11 more liters......

I still can't figure how you would burn so much less fuel then me.....maybe my numbers are off?

 

496

Those 496 drink 60-70 gph @ wot, you do not get 2-3 mpg , a 35ss gets 1.21mpg@39 mph its best mpg with the same 496s and bravo 3s

 

Hmmm.....you weigh 7500 pounds more then me, and have 11 more liters......

I still can't figure how you would burn so much less fuel then me.....maybe my numbers are off?

How old is your boat?

 

Re: 496

Those 496 drink 60-70 gph @ wot, you do not get 2-3 mpg , a 35ss gets 1.21mpg@39 mph its best mpg with the same 496s and bravo 3s

I think you are correct in your statement about WOT fuel burn, especially in older models. I don't run my boat at WOT for any more than a few seconds and can count on one hand the number of times I did that, so I really have no idea what the fuel burn would be.

The only thing I know about the 35SS, aside that I like it, is it weighs 2,500+ pounds more than my 33SS and is only 7 inches longer than my boat.

 

How old is your boat?

2002