Engine size selection 3500-I need help

[Huddo007]

Could I please get some feed back on engine selection for the 3500, I am in the process of find "the right one" and just don't know what engine combo I'm sold on, yes it's my choice but if you are out there and have the 6.3 or the 7.3 can you give me something to work with, lastly could you give me some idea on your fuel burn........please

Much appreciated

get me on the water

[pascavone]

I guess your talking 35'-0".

So twins, 5.0, 6.2, or 7.4 -v-8 MPI (mulit-port fuel injection)

If you look at the cruzing speed (26mph) or WOT (wide open throdle) 34mph, all those engine will do about the same, but its getting to that speed and the amount of people you have on board that's the problem.

Gettiing on plane, at 14 mph is about 14 GPH (Gallon per hour) each engine, WOT -22GPH.

So, more engine, more weight, a case of dimissing returns.

If you plan on 15 party girls and want to move out, go with the 7.4's or the 8.1's, but those are pre 2001 engines.

If only 8 party girls and 2 nerds, then the 6.2's which are post 2003 engines.

If you and your wife and 0 party girls then the 5.0's will be fine. ( zero party girls, what the point of having a boat?)

Ither way you will be spending 40 GPH x $4.69 gallon = $187.00/hr. if your running WOT to a party cove.

[Huddo007]

Pascavone, thanks some data!, I missed out on a 6.2, looking at a 7.4 and so hard to find fuel burn data - thanks and unfortunately being in Australia It's $5.10 x 40 $204 ouch, but why own a boat if you like economy, or just get there slower, hell you have 15 party girls, drop the anchor and open the bar...it's cheaper :-) thanks

[seapuppy]

welcome to the zoo.....



SP

[MCM]

Absolutely hilarious! Classic response (pascavone).

Question though, how to do count it if your wife is the party girl?

[MCM]

I don't vouch for the accuracy, and I know that there are multiple variables (weight, tide, conditions, planing resistance, salinity, whale farts, and butterflies flapping their wings in South America...), but here is what found in a boating magazine a couple years ago:

Engine size GPH (Cruise) GPH (Avg.)
3.0L 4Cyl 3.5 2.3
4.3L V6 5.5 3.6
5.0L V8 8.5 5.6
5.7L V8 10 6.6
8.1L V8 14.3 9.4

[Huddo007]

You guys are the best, thanks heaps I got the 7.4's, it was the number of party girls maths that sold me

[shrew]

I have yet to meet anyone who says "Ya, the boat is great, but I wish it had just a BIT less power". I find that the manufacturer's don't offer engine size options, they're offering "Cost Packages". The largest engine package offered is typically the one that is sized right for the boat. In order to generate sales, they simply knock some cash off the bottom line but tweaking the engine package. Boats delievered with the smallest engine package available are sometimes on the anemic side. Just my .02

[dronthelake]

I have a 3700 SCR with twin 7.4 v-drives. At 24,000 pounds loaded I cannot stay on plane below 25 mph. At that speed I am burning at least 32 gph. My typically cruise at 1200 rpm (+- 8 mph) and burn +- 6.4 gph

[ss3964spd]

Wow David, I thought those big beasts got on plane at a much lower speed. Does your 3700 have trim tabs?

Dan

[GlennW]

Another option would have been the 383 stroker. We just did a refit on a single 5.0 220hp and swapped it with a custum build 383 with 435 HP.
The extra 215 hp and aluminum upgrades not only raised speed but it also lowered cruise rpms which helped lower fuel consupmtion.
With this set up we were also able to shave about 150lbs off the engine swap.
This is based off my experience and our work.
If I get to the point of needing repower I will go this route with twins.

[dronthelake]

yes, she has plenty of tabs. Below 25 she starts to sink and is basically a displacement hull. She may look like she is up on plane but the reality is she is pushing one hell of a wake. Even on plane we create way too much wake for the lake. I try to stay below 16 mph so not to tear up the water too bad. I don;t mind going slow as we are never in a hurry.

[Huddo007]

Again thanks everyone, I really appreciate the feedback, I am very happy to let you all know I have now successfully negotiated a purchase of the 2002 3500 src with 7.4's and can't wait till it turns up

[Island Time]

I have a similar experience. I have a 3500 with 8.1s. Without using tabs, it will not stay on plane below 3200rpm or around 21 knots. Interested in whether the smaller (lighter) engine packages do better.