Thanks,With a extention box it really sets the prop way back there!!!!


Whats the week link in a #6 drive?


Rob

Below is a post that I made on another site last March after I got tired hearing internet experts post about how bad #6's are. I still believe that the poster just has a bad case of #6 envy!!

For what it's worth....Here you go:



( post 76 of 97)

quote:
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Originally posted by Speedwake
converting to dry sumps is good - that way you'll only lose about 75 to 100 hp in the drive train. the wet sumps were reported to gobble up as much as 150 !!

ps: engines looks great!!!
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Hey Jeff,
After your post, I really wanted to find out as much info as could about the #6 drives and how much HP is lost with them, so I called Mercury Racing and ended up getting a call back from the head engineer in charge of the #6 drives. His name is Tom Theison (pronounced Tyson). I'm not trying to get into a pissing match with you about this, but I thought that you might be interested in what he had to say.

They have done extensive testing and research on both drives and he told me that their data is that, at 6000 rpms, the dry sump drives eat up about 15 HP. The wet sump drives eat up about 45 HP. He said that at lower rpm's the figure is lower and the number increases with higher rpm's. There are variables to be considered, such as temperatures of the drive fluid that would of course change the figures. I think that a safe assumption (including transmissions) would be that a dry-sump eats up 35-50HP and a wet sump eats up 65-80 HP.

I apologize in advance for steering this thread in a different direction, but I will say that I would be very honored to own Kageman, or any other 41 Apache. In my book, the aren't nostalgic museum pieces yet!!!! they are what they are...bad-azz wave crushers!!!!!!

Your wallet

Pardon my ignorance, but what are the big hoses on the back of the outdrives sticking up?

Never mind, just went through the threads..............ventilation

I’m not an expert, learning the same as the rest of ya. Numbers sound real close to what I have been told over time as well.

Also been told that you lose 3 mph to 6 mph when you go to a #6 drive.

I think this is where a lot of people get discouraged and figure the #6 is robbing major Hp.
Was told the biggest difference is your pushing so much mass through the water in comparison to a bravo drive and that’s where Hydrodynamics start to play there role.

Hence also why a lot of people stay with bravo’s even though they break them, there top end mph is important to them. LOL

You can pick up a few mph with drysump and a swept back skeg. But also was told the swept back skeg doesn’t help till your near triple digits or exceeding.

Cougarman

If you measure the cross section of the bullet on a #6 and compare it to a Bravo, the Bravo has a wider foot print than a #6. The #6 is a lot longer but not sure that would slow a boat down. Hasn't seemed to hurt the numbers of my boat

The thing to do would be to compare the Super Vee, and Siper Cat Light Race Boats that swapped between Bravo's & #6's to see the difference in Speed.

Here's my .02 cents - 36' skater w/ 525's 8,250 lbs with bravos never tested for top speed but had the boat 124 mph with 4.4 % slip ( Never tried a bigger prop becuase this is a race boat and we never need to go faster at a typical track)

Switched to # 6's added 808 lbs ( including longer tail pipes) - moved engines forward 17" ran a big prop 124.3 mph 4.8% slip -

Bottom line we set the boat up for 118 mph - either bravo or # 6 will do that easily - however we did spend A LOT of time getting it dialed in, with props and drive heights - do not underestimate the change in CG

The question was how much Hp to turn a # 6 - @ 118 mph we burn 42 gph per engine with bravo OR # 6 drive- Hp = fuel

I would love to see some picts of you boat I cant seem to find any on the site