Opinions on 7.4 DP power/drive combo in 22' V-hull

[bear_69cuda]

Good day,

I wanted to get some opinions and possible performance info with anyone who has similar power/drive options in their boats.

I'm lookin at a 22' deep V bowrider with 8.6 beam, ~ 4500 lbs wet and loaded.

Power/drive 7.4 Volvo Penta MPI with 310 hp, and Duo-Prop outdrive. The props are 24" P

I understand fuel economy isn't gonna be the greatest, but most of the time I like to cruise to a nice cove or bay, relax, fish, and read... Every once and awhile, I like to hammer down, cruising a few min at WOT.

In your opinion is this going to be a good power package?

Does anyone have a GPS speed at WOT?

I would imagine this combo should have a great hole-shot and midrange torque...

Thanks in advance!

 

[captkevin]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

That combination should make for a very nice combo. Should run mid to low 50's

 

[QC]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

Yes it will have great hole shot, good power and I actually think decent fuel economy as compared to other combos in the same size and weight class. What exact boat? Unless it is exactly the same, GPS speed from someone else could be very misleading although I agree with Kev's estimates. I will err toward low 50s with a load until we have more data on the boat itself. I have a 23 footer, deep V with 320 bhp (6.2) and a Bravo 1 and she runs 57 MPH flat out and a light load. Friend has a 22 footer, 320 bhp (5.7), DP and she runs 53 MPH with a light load.

Just a quick question. Yes the 7.4 MPI 310 will have great mid-range torque, but why do you care? The DP will give you the hole shot, so the biggest benefit of mid-range torque will be in in mid-speed acceleration, so let's say from 20 - 40 she might be a tick quicker than a 5.7 MPI 320, but only a tick. What else would it get you? Somewhat rhetorical, but I am always curious about the perception . . . Once you are on plane, you are on plane, and top speed is top speed (read horsepower).

 

[Bondo]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

Ayuh,... For more Info, 'n background....

 

[QC]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

Thanks Bondo ^^^^^ and Don is giving you good info over there Bear. It seems you have one perception issue, yes higher pitch props will increase speed, but you have to spin them so you need the horsepower to do it. The point being that if the boat runs 45 MPH (I think you'll be quicker as noted above) you can't simply add pitch to go faster unless she is seriously under propped now . . .

As to Don's DP comments as far as top speed. Note my buddy's boat's speed above and mine with a single prop drive. Definitely not the whole story as they are different boats, but same hp, same weight (both small blocks) and I am significantly faster considering we are talking mid 50s.

Still need the Boat info unless I missed it

 

[bear_69cuda]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

It's a Cobalt 226.

 

[bear_69cuda]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

Ayuh,... For more Info, 'n background....

Thanks Bond-o I started drifting off topic on the engine forum so I changed to general topics...

 

[QC]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

She'll run as Kev and I have suggested. low to mid 50s. Nice boat, but Cobalts are heavy so she's not gonna reach the high 50s unless very lightly loaded with no perople and no fuel. If I found a nice deal on a Cobalt that fit my needs, with a good power package (this is one) I'd jump on it with both feet hard

Edit: Found this: Cobalt 226 6.2 320 Bravo 3 she ran 54 and they are never as fast as these tests in real world use and this combo may be a tick faster as the engine is a few pounds lighter and 10 more ponies.

 

[642mx]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

The 7.4L MPI is a great motor that is darn near bullet-proof. I've got the Mercruiser version with a Bravo 1 drive in a 22 foot cuddy. Its not a very deep V nor is it heavy. And I'm flirting with 70.

 

[QC]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

MX, is yours the 7.4L 310 or the 454 Mag 385? HUGE difference.

 

[bear_69cuda]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

She'll run as Kev and I have suggested. low to mid 50s. Nice boat, but Cobalts are heavy so she's not gonna reach the high 50s unless very lightly loaded with no people and no fuel. If I found a nice deal on a Cobalt that fit my needs, with a good power package (this is one) I'd jump on it with both feet hard

Edit: Found this: Cobalt 226 6.2 320 Bravo 3 she ran 54 and they are never as fast as these tests in real world use and this combo may be a tick faster as the engine is a few pounds lighter and 10 more ponies.

Cool,

It's a low hour 2000 cream-puff one owner boat. I put money down on her today... All pendant on survey... I'm getting a great deal... I plan on keeping her forever... Or until all the worlds gas is gone

 

[bear_69cuda]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

MX, is yours the 7.4L 310 or the 454 Mag 385? HUGE difference.

Mag is 385...

 

[642mx]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

MX, is yours the 7.4L 310 or the 454 Mag 385? HUGE difference.

Its a 310 (for now ).

 

[Don S]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

I think you are going to be dissapointed when you find out your boat doesn't hit between 50 and 55 mph. The Bravo I and III drives being discussed, were designed for high speed use. The Volvo DP drives are designed for up to 50 mph speed. Occasionally a light, overpowed boat will go above 50 with a Volvo DP drive, but they were not designed for it.

 

[QC]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

I generally agree with that Don ^^^^ but I do have GPS experience in similar rides at 53 MPH with DPs. A 236 SSi Chap 5.7 320 and the other a 256 SSi Chap 8.1 375.

 

[Don S]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

I generally agree with that Don ^^^^ but I do have GPS experience in similar rides at 53 MPH with DPs. A 236 SSi Chap 5.7 320 and the other a 256 SSi Chap 8.1 375.

Neither of which is an EF model 7.4Gi (310 hp) Both of your examples have a top rpm of 5200, the 7.4 has a recommended top rpm of 4600.
I think Bear needs to go for a test ride with a GPS and see what speed/rpm it gets.

 

[bear_69cuda]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

Unfortunately the frozen lakes are keeping me from any GPS data.

I think if I can get ~50 mph out of this combo, and the low and mid-range torque is great, I'd be satisfied... I'd rather have a boat with a great hole-shot, nice smooth mid-range, and fair top end than a boat with only great top speed... A small part of me thinks I should look for a different boat with Bravo I or III drives... This boat is so flippin sweet though....

 

[superpop]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

The other question to ask is how often do you need to go 50+ MPH. That is really fast on a boat and the water needs to be fairly flat even with a big ol heavy Cobalt. I could prop my boat to get 50+ out of it but hole shot would suck and I could not use it very often because I rarely come across flat water. I have it propped to leap out of the water but max out at around 40 MPH. Any faster than that and the wife starts giving me the look, especially if it is not glass smooth. Just some more food for thought, hate to see you walk away from a nice boat because it is not fast enough 5% of the time.

 

[QC]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

Don would know, he has been around more Volvo powered stuff than the rest of us combined . . .

 

[dockwrecker]

Re: Opinions on 7.4 DP power/drive combo in 22' V-hull

Good day,

I wanted to get some opinions and possible performance info with anyone who has similar power/drive options in their boats.

I'm lookin at a 22' deep V bowrider with 8.6 beam, ~ 4500 lbs wet and loaded.

Power/drive 7.4 Volvo Penta MPI with 310 hp, and Duo-Prop outdrive. The props are 24" P

I understand fuel economy isn't gonna be the greatest, but most of the time I like to cruise to a nice cove or bay, relax, fish, and read... Every once and awhile, I like to hammer down, cruising a few min at WOT.

In your opinion is this going to be a good power package?

Does anyone have a GPS speed at WOT?

I would imagine this combo should have a great hole-shot and midrange torque...

Thanks in advance!

Good Lord boys. The OP clearly states he wants a quality boat with the occaisional 50+ mph romp. What he's looking at is plenty. The wife/dogs/cooler flying out the aft isn't what he's about in the first place or he'd be looking at mabe a Baha. Yep it will probably do 50+ or so, close enough. It's a Cobalt, not an offshore racer. And he'll be damn glad he bought it a few years from now having invested in a good quality boat that deilvers great performance and lasting quality. Yep he might lose a boat race or two, but he'll look good doing it. Enjoy your new boat!