2.5 280 Capping Open Exhaust Mid-Section?

[Keith E.]

All,

I'm currently looking at a turnkey boat that has a 15" 2.5 280 with an open (and chopped) exhaust, like the one pictured. I'm curious as to what, if any, tuning issues would be encountered if the open exhaust was capped. Also, I'd be interested in any capping/blocking methods that could be used without damaging the structural integrity of the assembly.

ETA: Top pic is of the actual mid.


TIA,
Keith

[25two.stroke]

Leave it how it is

[KIRCHNER]

I fabricated a hinged, aluminum plate, counterweighted on the bottom, with peel n stick whl weights. a idle it ppens about 1/3 way, more rpms, it swings wide open. i tune it by adding +- weights. i used BMW weights, little neat cubes across the bottom, pre-finished. looks cool at idle, in reverse it closes. the door ma\\\\tches the snout shape. my 15 is a ridgebk, about 3.5''x3.5'' exit.

[Keith E.]

Leave it how it is

Thanks for checking in. I was hoping to be able to moderate the noise level a bit without compromising the mid. Have you seen bad results when this was attempted?

Thanks,
Keith

Keith

[Keith E.]

I fabricated a hinged, aluminum plate, counterweighted on the bottom, with peel n stick whl weights. a idle it ppens about 1/3 way, more rpms, it swings wide open. i tune it by adding +- weights. i used BMW weights, little neat cubes across the bottom, pre-finished. looks cool at idle, in reverse it closes. the door ma\\\\tches the snout shape. my 15 is a ridgebk, about 3.5''x3.5'' exit.

Thanks. Any pics would be greatly appreciated.

Thanks,
Keith

[derekfl]

Are you buying the boat for the motor or the hull? Cuz that motor will cop a major league attitude if you make it breathe out thru the prop. Either live with it or sell the motor and buy a couple-3 20 inch 200’s with the proceeds and go slower.

[KIRCHNER]

thanks. Any pics would be greatly appreciated.

Thanks,
keith

ill give it a try

[KIRCHNER]

Not true

[Baker343]

Have someone weld a plate back on to divert the noise back down as it came originally, will not hurt performance,

[LakeFever]

If your going to cap it make it removable. My 260 mid has a bolt in aluminum plate

[KIRCHNER]

My hinged exhaust wastegate is the bomb.if there was a market,i would patent it.. keith, i can send pick to your phone??

[Keith E.]

Are you buying the boat for the motor or the hull? Cuz that motor will cop a major league attitude if you make it breathe out thru the prop. Either live with it or sell the motor and buy a couple-3 20 inch 200’s with the proceeds and go slower.

Thanks for checking in. I was looking for the particular brand of boat and found one that had the 280.

I was told by a reliable source that redirecting the exhaust would not make that much of a difference in performance and would not cause a problem. I posted the questions here in order to get more opinions, options & ideas, all of which all are appreciated. My intentions are to consider them all and develop a better-informed plan of action.

Thanks,
Keith

[25two.stroke]

I would not cap it completely on a 280. I never have tried, but just considering the fact that from the 2.4 BP to the 260 and to the 280 all the "bass" mids came drilled for exhaust relief I would reasonably reckon that the motors neeed/benefit from it. I'm sure you could restrict it some, but I would not force it ALL out the prop. I do know from 3.0L motors that if you force it ALL out the prop you can have some horrible issues getting on plane with over-the-hub props. Youre blowing hella exhaust all around the prop during holeshot and it revs the motor too high and cavitates the prop so much you may not be able to even get on plane with a moderate load in a V bottom boat. If you are worried about noise get a 20" bass mid.

[Baker343]

My 20" smooth back is stock and the exhaust dumps down. If someone has shortened the snout, then you may have to leave it as is.

Attachment 522380

[tlwjkw]

you could plug it then drill tha 10 holes above tha cav plate makin' it equivalent ta tha hi perf "bass" can?.. might ask around about a trade with one of tha racers................... jus hate it when someone does that to a nice can.......... jus for a lake motor.