XB2002 Bassracer/Optimax

[jimmyb]

i was just doing some math...

if you are turning a 28... you will be all over the rev limit at low 80's with a stock (1.75 gearcase). You really need to think about a 1.62 ratio if you really want to make it go fast with a stock 3L opti.

what kind of noseconed gearcase are you running on it?

 

[bassracer]

I had a Bob's big foot put on with the Allison setting - the tip of the point of the cone is 3/8 in below propshaft centreline - maybe I shouln't have had that done. I have tried to measure it myself and it looks more like 1/2 below but it is had to see the propshaft centreline thur the gearcase; may be 3/8. I told them to do it as per current thinking on the xb2002. With neutral trim or in slightly I can do 75 but bump her out even a bit and she just loves to fly and would gain a lot but she gets real snakey. So far I have endured 5 violent side to side and up and down splishy splashes but no hooks yet. I don't know if I should raise her anymore - I could put the nosecone even with the pad putting the propshaft 3/8 above but God knows what would happen?

 

[ally2dextreme]

batt

i woud move bat under passenger riding compartment under lid it fits nice and moves 70lbs forward also is there someones gearcase you could try to make sure yours is ok

 

[John Richied]

The first thing I would do if I were you is jack the motor up so the propshaft is even with the pad or even a tad higher…

With your propshaft height set 3/8” below the pad and your Bob’s nosecone mounted 3/8” below the propshaft you are dragging the nosecone through/under the water and this maybe why the boat wont’ handle…

Then getcha a Lightning ET or Chopper II and let it eat!

 

[bassracer]

Well now - an idea that may work - thanks John. Can you provide some experience on this one - is the Allison mod to cone meant to raise propshaft to even with pad??? As such the tip of cone will be 3/8 inch below. I had wondered about drag given the tip of cone below gearcase centreline and forcing water more up over the top of case but that would get more water on the top blades. Can someone speak from experience on the Allison cone mod????

 

[Jimxb02]

There are two reasons for the 3/8" downward slope to the gear case point. First, it gives the case more surface area on which the case can "ride" to provide more tail lift at high motor settings ( less gear case drag ). Second, better water pressure at high motor settings.

I thought I read above that the OptiMax still had stock mounts. Change these to solid mounts or at least the bottoms to solids. This will give you better control.

Jim

 

[Jimxb02]

I should have been more clear in the above post. I run my Bob's modified CLE case 1" above the pad. If I run it even with the pad or 1/4" below I loose 6 MPH by my GPS. This on a XB 2002 with 13 1/2" setback.

Jim

 

[bassracer]

Did you ever run it set as mine is and experience very poor handling?? And it is a heavy motor so do you think 6 in setback is good.

 

[Jimxb02]

I never had a handling problem set up like yours, even with the pad. However, when I tried it 1" or lower below the pad I did have a handling problem, both accelerating and backing down from top speed.

My motor weighs about 410 pounds ; ProMax power head on a XR6 lower half and stock XR6 cowling. My computor (CDI modified EFI) is in the starboard rear compartment connected by a Brucato 6' (foot) extention cable.

Don't foget to change those stock mounts. Bringing the motor closer to the transon will help to balance the boat. That Optimax weight hanging off the back is a significant element in setting up your boat to be predictable and stable.

Jim

 

[bassracer]

I set the height last night - centreline of prop shaft is even with the pad (bottom of very rear edge of pad) . Nose cone point is 3/8 in below pad. Will try to test today. I leveled the pad and shaft and put a 4 ft level, level on the ground and measured using that setup. I can't see how that wouldn't be accurate.

 

[Jimxb02]

That is a good point to start from. That measurement method you used works. After you run at this height, I would raise the motor 1/4" to see if there is improvement.

Jim

 

[bassracer]

Tested on Saturday - so many boats on lake I could only go 60 mph. With wife and a lot of stuff in boat and troller on - 60 mph at 3500 rpm. Is that what it should be at that rpm - boat feels a lot faster. Left trim neutral. Would you say 90+ at WOT?? Handling is completely different and i'll have to relearn how to drive it. Water pressure is 20 lb. Holeshot good with the trophy.

 

[jimmyb]

hmmm... what pitch prop are you running??? 28???

something is up if you are running 60 mph @ 3500 rpms with a 28 and 1.75 gearcase... with zero slip, you should only be running 53 mph

 

[bassracer]

Nope - these are GPS readings - I am running 53 at 3500 rpms and then I accelerate to 60 and once she gets cruising at 58-60 the rpms are back to 3500-3700.