2000 450 EB with 3208TA?

LMBoat

LMBoat

Well-Known Member
Oct 4, 2006
757
Ft Lauderdale
Boat Info
1999 450 EB
Engines
Cummins 6CTA's
Hello All,

I'm looking at this boat with the 435 HP 3208TA's Cats. Any comments on these engines? or on the boat/engine combo?

Thanks!
 
Great engines, older design that Caterpillar stopped producing because they would not meet emission regulations. Still great engines, but a little smokey and not as efficient as other engine choices in the 450EB.

This is strictly a personal opinion, but I'm not much of a fan of the EB series. Others love the layout and space, but I hate not having a safe access down the side decks. For me it is a royal pain to have to unbutton all the bridge canvas to get access to the bow. You are in storm country so this will impact you........every time you get a storm and have to go to the boat several times a night to check and adjust lines for winds and a surge, you will be unsnapping/unzipping your bridge canvas in a strong wind just to access your bow cleats.

I delivered a 2003 450DB with 450 hp Cummins engines and the boat ran well, but I found engine access a challenge.
 
Every time I have been aboard one the engine access was pretty similar to a 460 DA, which isn't bad at all.
 
I remember Frank saying that the Cats had more torque and even if it had lower HP, you would not know the difference <I can't find that thread Frank>.

I'm looking at 2 boats <450EB> that have differenct engines, the Cat 435 HP 3208TA and the 450 HP Cummins 6CTA's. In looking at the specs for both engines, I've noticed these things:

This is Cat/Cummins

HP: 435/450
Shaft HP 422/430
Cylinders: V-8/IL6
Displacement: 10.4L/8.3
Max RPM: 2800/2600
Cruise RPM: 2500/2300
Torque at cruise: 923/1003. At 1600, 1800, 2000, 2200, and 2400 Cummins has more torque.
Fuel consumption at cruise: 20.7 gph/13.4 per engine

Searay shows a fuel burn for this boat with the Cummins at 33 GPH, but does not have a number for the Cats. They do list fuel burn at WOT at 48 for Cats, 47 for Cummins.

Cruise speed is listed at 28 MPH for both engines.

A few questions:

What do the Cats have 25% more displacement and produce less HP? Does this mean the engine is not working as hard and might last longer?

Why is fuel consumption so much more at cruise for the Cats?

I'm favoring the boat with the Cats, but am concerned that this may not be enough power, and the fuel burn.

Any/all comments are appreciated

Thanks!
 
The discussions we've had about torque were relative to slow speed or idle handling. Your comparisons are at mid throttle and cruise rpm settings.

My fuel burn tables are on my desk in Tennessee and I'm in Florida. I have the 3208 GPH for various rpm settings, but I won't be able to get it to you until I return..........and as long as its snowing and the temps are below freezing, I'm not going to Tennessee.

SOmething we didn't discuss is that the Cummins boat will be a higher demand boat because Cummins is viewed as the current engine choice. The 3208 is a great engine but it isn't produced any longer. Buyers who do not know the engines may shy away from the older design 3208 since Sea Ray opted for the 3126 then Cummins for the EB in later years. You might be able to get a better buy on the 3208 boat.

I don't understand your concern about fuel burn........you say Cat has 25% more displacement but burns the same amount of fuel at WOT, SR doesn't publish cruise speed fuel burns #'s but you want to know why Cats burn so much more at cruise. From your numbers, Cats have 25% more engine to feed yet they burn the same GPH at WOT.......looks like they are more efficient, not less.
 
Agreed on Cummins being more in demand.

I'll try again on my concerns for fuel usage <Fuel consumption at cruise: 20.7 gph/13.4 per engine>

Cat recommended cruise RPM 2500, speed 28 MPH, fuel burn at 2400 rpm <chart does not show 2500> 20.7 GPH per engine, 923 lb-ft torque

Cumming recommend cruise RPM 2300, speed 28 MPH, fuel burn at 2200 RPM <chart does not show 2300> 13.4 GPH per engine, 1003 lb-ft torque.

I'm interested in fuel burn at cruise speed because that's where I hope to have the thottles most of the time. i.e. headed out on a trip.

The numbers seem to suggest that the Cummins will use less fuel, but I can't believe the difference is so great. And again, Cat has more displacement, but less HP & torque.

I'm just trying to be sure I'm looking at the numbers the right way.
 
I have an 390 EC with the 3208s and I will list below a table of fuel usage. The fuel use in gallons per engine per hour for each rpm is from CAT published literature. This is for the 375hp engine and should be consistent across boat applications. You can find this on Boatdiesel.com. I simply then went real world and measured my mph per rpm step and computed mpg from that. The fuel burn per hour is consistent for the engine but mpg will vary with different boat hulls and weights and conditions.

Fuel burn rate
RPM * * GPH * * * * * *MPH * * *MPG
2000 * 6.5/13. * * *18.8. * *1.44
2100 * *7.8/15.6. * *20.5. * 1.31
2200 * *9.0/18. * * * 22.1. * 1.22
2300 * *10.5/21. * * 23.4. * 1.12
2400 * *12/24. * * * 24.9. * *1.04
2500 * *14/28. * * * 26.2. * *0.94
2600 * *16/32. * * * 27.4. * *0.86
2700 * *18.8/37.6. *28.8. * 0.76
2800 * *21/42 * * * *29.8. * 0.71

This table shows the fuel burn per engine at 2400 to be 12 gal/hr and 14 gal/hr at 2500 which is consistent with your above Cummins numbers.

As you can see, fuel use varies greatly with speed. The question is just how quickly do you really need to get there.

They are by the way phenomenal engines. Instant starting, very strong, just smoke more than the newer engines
 
Last edited:
In the table able the first number is single engine and 2nd is total fuel burn with two engines. The 390 with diesels get better fuel economy than my 300 gasser did.
As I remember, the 8mph is at about 900-1000 rpms and is above 2mpg
 
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