rjcardinal

How do you determine the cruise speed for an EFI boat?

On my carb engined boats I would cruise just before the back barrels would open. This gave me great fuel milage. I even would adjust the carb so they would open slightly later so I could maintain a faster cruise. My last boat I could run 3000rpm at 48mph before the carb kicked in.

For those out there with a stepped hull 27 502 EFI at what rpm and speed do you cruise?

Is this information listed on the test report? I did not recieve one from the previous owner.

Im just trying to run the boat in its sweet spot but with the efi system the power band seems perfectly linear. One speed feels as good as any other. My carb boats would purr like a kitten before the 4 barrel opened then scream like a demon once the hammer was down.

Ron

Von Bongo

This is with a 496 but you won't be much different. My 454 EFI runs nice at about 2900 and 3200-3300 thats a detents on the Zero Efforts. Runs about 26 and 34mph on gps at those RPMs turning a 24 Mach 1 prop.


RPM MPH Knots Total GPH MPG NMPG Range NM Range dBa
1000 6.2 5.4 2.6 2.38 2.07 131 114 76
1500 8.4 7.3 4.5 1.86 1.61 102 89 76
2000 9.2 8.0 7.8 1.17 1.02 64 56 78
2500 12.5 10.9 13.3 0.94 0.82 52 45 82
3000 35.8 31.1 12.5 2.87 2.50 158 137 83
3500 43.6 37.9 17.5 2.50 2.17 137 119 88
4000 51.1 44.4 23.0 2.22 1.93 122 106 89
4500 58.5 40.8 31.5 1.85 1.61 102 88 89
5000 62.6 54.4 33.6 1.86 1.62 102 89 94


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




Time To Plane: 6.1 sec.
0 to 30: 9.9 sec.
Test Power : 1x425-hp MerCruiser 496 MAG HO sterndrive
Transmission: Bravo One
Ratio: 1.5:1
Props: 26
Load: 2 persons, full fuel, no water, min. gear
Climate: 70 deg., 60% humid.; wind: 5 knots; seas: flat

RUNNIN A FEVER

I have a 2000 stepped 27 w/ 502 efi and find cruising at 3100, 3200 with the drive at 3 and tabs at 3 to be very comfortable and speeds are in the low 40's. I have a 23 pitch Mercury Revolution 4 blade. If I run in the 4000 range I tend to go thru much more fuel.

BAJA WILL

I am running a 500efi, and I cruise in the 3300rpm area. Not sure on the speed that is? also with tabs about 2.5-3 and drive around 3. Provides a fun speed, and comfortable. Girls can sit on sun deck and not bounce around. I don't worry about fuel consumption, I just figure on gassing up every day about $90. I am spinning 26 Hydro rh.

Will

rjcardinal

Do you guys use the tabs all the time?

I have only been using them to get on plane or when the water gets choppy. I havent been using them untill the boat starts bouncing around or when comming on to or off of plane.

Doesnt dragging the tabs create more drag and slow you down while cruising?

New to tabs also,

Ron

Von Bongo

I only use them coming on to plane, then all the way up, unless it's rough or I feel I need to slow the boat a little, like with running with someone and the throttle detents are too much or too little.

Otherwise it's with the drive and I run about 3.5 for best cruise speed and 6.5 for WFO on the drive. If you have a GPS it's real easy to find the sweet spots

29Fever

I don't use the tabs while cruising either. Only to get on plane and when it's rough.
Every once in a while late at night just to keep it on plane at slower speeds to watch for barge traffic.

envision

When not moving, my 29 lists to port, while running it still lists to port. I have to have the port tab lower than the starboard all the time although the difference ranges from 1/2 to 1 full number. I checked to see that both read the same when parallell to the bottom.

I am going to add a second battery to the starboard side to see if that makes a difference.

I thought they all did that.

Jana

Envision - could be the battery. Mine's in the center and my 29 doesn't list at all. I only use the tabs for getting on plane or if it's rough.

29Fever

Envision,

Is your water tank full?. I too only have a single battery and I don't list at all. I assume you've tried to stow more gear on the starboard side? What year is yours?