[Barry]

Hi,
Are there any other z275 (or similar) owners out there with a Volvo 7.4Gi and Duo-Prop drive?

I would enjoy comparing set-up and performance configurations.

My boat is a 2001 Z275 with 7.4Gi and DP with an F5 prop set, it tops out at 45mph

Regards,
barry

[theeasynine]

My Z240 has the 7.4 Mercruiser and Bravo III and it tops out at 60. I would think yours should be a little faster than that.

[rajjneef]

Patrick is that on GPS? I think your speedo is telling you a fib.

[theeasynine]

Originally Posted by rajjneef

Patrick is that on GPS? I think your speedo is telling you a fib.

Could be. Guess it'll have to wait til next summer to find out.

[z275st]

Hi Barry,
I have a 2001 z275 also. It has a 496HO (425hp) bravo1 drive. Last time I had it out I did a speed run and ran 53mph GPS. I had a full tank (125g) and about 1300lb of people on board ( a large chunk was the in-laws ).
I was running my Rev-4 21" prop. I would think you could do 48-52 if it is proped right. The duo-prop will cause a little more drag and reduce your top end, especially if it has 5 blades but you will have better hole shot.
Hope this helps.

[Barry]

John,
Thanks for that.
I agree with your estimate, 50mph should be possible.

I might try the next prop set up to see what happens.

Barry

[mis4tun81]

I have a 2001 Z275 with the 7.4l Merc. Bravo 3. and came with 26p props, pretty close to your volvo setup.

In perfect conditions lightly loaded and 1/4 tank, I come close to 50 (GPS). But low on max RPM....4200 ish.

I bought a set of 24p props, and they are a wash at best, and more often slower than the 26p, just at a higher RPM.

The local prop shop suggests I pull a small amount of pitch out of the 26's but I really like the performance across the entire range, so I'm not sure what I will do.

Do you know what pitch the F5 setup is? and what RPM are you at, at 45 MPH? And what is the max RPM for your engine?

[Barry]

Many thanks for your reply, I hope that you are enjoying your 275 as much as I am!

Alas Volvo dont give the prop pitch for the F5 (or any other Duo-prop).

At 45mph I am at 4600 rpm which is the max for the engine. The range for WOT is 4200 - 4600.

Your experience is interesting, I think that if I was to try a higher pitch prop such as an F6 or F7 then I might get more top end but with slightly lower RPM as in your case.
The engine seems to have plenty of torque.

As a matter of interest doue your boat lean slightly to port when traveling at speed?

[mikeyt]

The most efficient point of engine performance & prop is right at the max of the recommended range so it sounds like you are getting everything out of your set-up. Anything lower means it's lugging a bit and anything higher means she's spinning too fast. In both cases it means using a bit more fuel overall.

[Reed Hatch]

I have a Z252, 7.4 fuel injected, duel 24 props, tops out just over 50 at 5500 ft