Extension Box Opinions
 

I'm considering adding an extension box. I saw that B-Stubb put one on and seemed to like it. I'd like to get some additional comments on it and whether it's currently worth the trouble. The boat is a notch transom boat, I'll be using it in the Pacific ocean and lets assume current max speed between 65 - 70 mph.

What do you guys think?

I had thought about an ext box on it as well. I think Bruce Seroff??? had one as well. Don't remember the results or if he did multiple changes at the same time. I think the 11* transom angle comes into play. Also, for reference, Cattitude's 28 has an ITS with no notch.

Yah, I'm curious to see if people think it makes a difference and if so whether it's worth it. I'd also like to hear what people think of Stellings vs. Imco.

I want to say that Bruce kept breaking drives when he had his on. But I guess that could be caused by other things, too :drink:

I had a stellings box on my 1993 race 28 pantera worked good,was tough on drives no rubber coupler,i would prefer using imco box,still uses merc coupler and also uses nice torsional input shaft,a lot easier on drives,you will need atransom wedge made,my motor was mounted foward on driveshaft so i did not use wedge

My Konrad has an 8" box and the boat responded awesome with it. It gets on plane very well and runs excellent with the box.

I also had them make an 11 degree to 13 degree angle adapter plate though!

Interesting, it doesn't look like B-Stubb used a wedge spacer with his new Imco box. Could this have to do with motor placement differences between a notched boat and standard?

MDG, is this what you're talking about when you say the motor is mounted forward on the driveshaft?

I like mine, but have nothing to compare it to.....

Yes...I had one and it didnt work for me. I kept breaking the vertical shaft in my drives, and took me out of many races. I took it off and the boat ran better and no broken drives. If Im not mistaken, i think it has something to do with the angle of the Pantera transom vs. the angle of the box. the money and labor to switch, is not worth the minimal (if any) improvement in performance. The boat already runs and feels like most 30-32s. Spend your money elsewhere.

Transom angle on the 28' is 11 and most boxes are built for a 13 degree transom angle. I have never seen big performance gains with them.

JO

Hey guys I appreciate the input. I expected a few more guys to step in with comments but I think I got the guys who know what's what! Sounds like the x-box just got moved down the list of stuff I want to do! Thanks!

If you get an adapter plate it will be fine.

Kirk, I definately appreciate the input from all you guys and will do the plate. The box isn't off the table just moved down the list (after the interior and motor most likely). There so many ideas... I just have to prioritize!

I Have Two Imco Boxes For Sale If Anyone Is Interrested

Did you guys use an extension box when you ran your Pantera?

I like mine and would not go back I can get on plane in any water and it handeld much better 90 mph is a walk in the park now old days it was a little nervous.

How many inches back is yours B stubb?

Question. Brian and Kirk both made comments about imrpoved planing with the box. Do any of you guys have trouble getting on plane? My boat jumps right up on plane, quick and easy every time. Just curious.

don't have a box, and mine comes on plan OK
I would like to hear more about the high speed stability.
earlier in this post it was stated that imco uses the merc rubber coupler.
Is this the only box that uses a rubber coupler? (that seems weird)

Yes my boat has trouble getting on plane with high x the box improved it tremendously mine is netural and 12 inch imco the stability is huge ive been meaning to get over to joe and let him drive but hasnt happended yet

Right on. Thanks Brian!

Seems like the notch boats and the non-notch boats may behave more differently than it appeared at first.