Originally Posted by LAKE EFFECT (Post 2980943)

If your spinning 30p Bravos @ 5400rpm on a 311, that calculates to 102mph with out any slip, and 79mph with 22% slip. If thats right I would have to guess you have some pretty big power, and too high of an X dimension.

I had 550/575hp in a 88 311 with deep TRS's, it ran 77/78mph on GPS with labbed 25p Mirages @ 5400/5500rpm with 10/11% slippage.

If all your data is accurate, you need to get your slippage in check. What drives are you running? Bravos? If so you can buy drive spacers to get the drives a little deeper without buying new props. The only other choice would be 5 blades, which shouldnt be necessary on a 311.

The 311 was designed for a 3 blade prop and a deep drive. Get the X dimension right and keep your 4blades and you should get some pretty good performance from that hull.

LE

Originally Posted by Formula88 (Post 2981061)

I'm running Bravo drives and prop shafts are 7" deep from the part of the hull directly in front of them. The props are also spinning out. Setting the drive parallel to the hull about 1/8" of the blade is breaking the surface. At full trim one blade is out of the water. The bravos on the boat are a standard length.

I will get in touch with Bret see what he recommends.

All the info is very helpful and really appreciated.
Thanks, Reese

Originally Posted by ThirdBird (Post 2982335)

Something still doesn't add up. You cannot be spinning 30" props on a 311 at 5400 rpm unless you've got like 700 horses per side. Are you absolutely sure your props are 30 pitch?

Originally Posted by ThirdBird (Post 2982335)

Something still doesn't add up. You cannot be spinning 30" props on a 311 at 5400 rpm unless you've got like 700 horses per side. Are you absolutely sure your props are 30 pitch?

Originally Posted by LAKE EFFECT (Post 2982497)

22% slippage on a straight hull with 4blades is alot. He might not want to share what kind of power he has for what ever reasons, but it wouldnt be un heard off to have a couple blower motors in a 311..

I hope he gets it hooked up and posts some speeds. I'm curious how fast a 311 can go. I was thinking of putting some big power in mine when I had it, but I stubbled on to a 353 instead.

LE

Originally Posted by LAKE EFFECT (Post 2982497)

22% slippage on a straight hull with 4blades is alot. He might not want to share what kind of power he has for what ever reasons, but it wouldnt be un heard off to have a couple blower motors in a 311..

I hope he gets it hooked up and posts some speeds. I'm curious how fast a 311 can go. I was thinking of putting some big power in mine when I had it, but I stubbled on to a 353 instead.

LE

Originally Posted by Formula88 (Post 2982552)

No blowers here just a pair of good running 283's. LOL ;)

http://i742.photobucket.com/albums/x...h_DSC02535.jpg

Originally Posted by LAKE EFFECT (Post 2982497)

22% slippage on a straight hull with 4blades is alot.