Imco SC lower, Sportmaster or nose cone on XR
 

Ok I have some big slip numbers on the top end I am trying to finesse away. The last 400 rpms. does not result in any additional speed. I am running 18% slip at WOT. I have Imco SCX Extreme drives with Bravo XR lowers with Imco shafts. I believe I am getting blow out. I have also added a 1" spacer, which has helped the boat ride better and has improved my slip. So the question is what is my best option?

What props are you running?

32 Bravo 4 blades

Are the props out of the box? Labbed?
If your running under 90 i would play with props first.

Well over 90, not sure how much truth there is to it but I've heard anything over a 28 bravo prop is very inefficient, and slip is always high. Maybe a labbed Maximus?

If I remember correctly, there was + 1 MPH with the Imco lower verses the Bravo 1 lower at the same X. The XR lower was also slightly less than the Imco lower due to the longer skeg. Our testing was done in the 100 MPH range.

I have standard bravo lowers with cones, and I just bought some sportmaster lowers. The sportmasters are noticeably skinnier at the bullet. So I would assume they would have a better slip? Also I have heard the imco lowers are even skinnier?
But seeing as you have that big heavy boat I'd try taking the spacer back out and putting some 5 blades on

I would have the props labbed by someone who knows their business. In stock form, they are set up for good overall performance on a wide range of boats. Now it's time to fine tune them for your aplication.


Darrell.

The props have been labbed by Brett at BBlades for this boat, he added a little cup to give a little bow lift. I talked with Tres Martin and he told me to add the spacer ( big improvement) I should also say that I added offshore pick ups which increased the slip and I lost 3-4 mph but gained most of it back when I added the spacers. Maybe I should try 11/2 spacers. Thanks for everyone's input. I am determined to get it dialed in. The boat pulls like a freight train to upper 80's then slowly gets to 93 with fuel and 4 people.

you wont believe the less slip running a 5 blade,i went this last week running bravo 1 30p to maximus 30p,went from 23% to 12% picked up 4 mph with 400 less rpm.still dialing in and don't lab till your there.5 blade herrings next,good luck