Looper exhaust porting

[bigbluechevy454]

loud is good

[Captain75]

[QUOTE=Captain75;2579111]when I look at the lower unit it seems like the best way/place to drill is a couple of 10mm vertical holes like shown in the pic... Only concern is weather it will be to loud?Attachment 289846[/QUOTE
is this mod gonna be louder than a bobs? Like I stated before; I'm not looking for the extra sound, I'm looking for a mod that will help clear the leg fast from water when I floor it going from idle...

[NosBoss]

I can't tell you if it will be louder. What I can share is that the sound going out from the side is louder than the exhaust exiting the back (like a bobs snout) when sitting in the boat.

[BeefKid]

Really ain't no way around it I had a case with one 1" 1/2 hole and it was still loud and the way it is now with my sporty which is skinnier than the omc mid so had bout 3/8-1/2"opening at the bottom of the mid on each side of the case and it is still loud
This pic is with the Merc 3.0 case the sporty is the same



Here's the sporty


Here's an idea this was Saturday. .. don't mind the 4 stroking still tuning this motor yet that's at 6500
https://www.youtube.com/watch?v=ifE_...e_gdata_player

[Captain75]

If I would drill from underneath the cavplate at an upward angle, would that reduce the noise?
That would however force the motor to push the exhaust further down before exit...

[wanagofass]

I don't think that will help b/c the exhaust you're letting oout is still to close to the prop and will cause it to slip.

[baja200merk]

I dont know why but beefs with the OMC case drilled is louder then a buddys 260 with a 20" offshore mid with snout. First time we ran the sporty we thought it was quieter but it must have been the wind that day because its just as loud. Kinda wish it wasnt so loud but the relief helps holeshot too much to plug it up. With the 1.62 he can get on plane at 1/3-1/2 throttle.

any hole in the exhaust is gonna make it louder, if your worried about it start small and work your way up.

[Captain75]

I don't think that will help b/c the exhaust you're letting oout is still to close to the prop and will cause it to slip.

I've seen in one of your posts earlier that you like the bobs ex housing to cure bogging, what do you think about the noise level with the bobs? Have you drilled according to the bobs instructions or a few, but bigger holes?

[wanagofass]

I have a mid with a bobs snout and one with a homeade welded on snout but I haven't ran either of them yet. The homeade one actually looks better to me. It would probably be quieter with a snout and leaving the gear case open b/c some of the exhaust will be beloew the water but it's alot of work.

[Captain75]

I have a mid with a bobs snout and one with a homeade welded on snout but I haven't ran either of them yet. The homeade one actually looks better to me. It would probably be quieter with a snout and leaving the gear case open b/c some of the exhaust will be beloew the water but it's alot of work.

Ok, you mean stay away from cutting/drilling in the lower... What about holes throught the mid and can; many small or a few big ones?

[baja200merk]

You can drill the lower it will accomplish the same thing as the snout. The snout takes welding/putty body work, then finally paint. Then plan on the putty cracking and needing attention/ repaint every year due to the heat.

Drilling the lower takes about 10 mins. I have run them both and they are equally loud

[BeefKid]

Drilling holes in the mid weakins it and may cause it to crack. .. I've seen Merc mid with holes in the back break all the way around and loose everything from there down. ... drill in the lower if your gonna do anything... like I said either way it's gonna be noisier with the exhaust open but it does help

[wanagofass]

You can drill the lower it will accomplish the same thing as the snout. The snout takes welding/putty body work, then finally paint. Then plan on the putty cracking and needing attention/ repaint every year due to the heat.

Drilling the lower takes about 10 mins. I have run them both and they are equally loud

Seems like Iit might be quieter out of the mid but I've never tryed it, drilling the gearcase is way easier. I also blocked the exhaust out of the lower with a piece of 1/4" plate, it worked good until my first ported powerhead, the front half was stock and it hesitated bad until 3k, if I had a little exhaust in the lower I think it would have slipped the prop a little to get it out of the hole.

[Captain75]

Been away for a week snowboarding and skiing with kids ands mrs, now I'm back home working and trying to proceed with my motor hop-up. During the week in the mountains I thought alot and decided to go fingerporting... Here are some pictures descriebeing the hopeful progress;
First thing I did was marking the transferports on paper.

Next step was to by turning, make a steelpipe fit perfectly inside the cylinderbore...
Place the portmap on the steelpipe, and cut the boostportarea and the future fingerports...
Steelpipe with the portmap cutted and installed in the cylinderbore...
Start the tiny beltgrinder and grind following the slots...

I will post more pictures showing the result, hopefully tomorrow
I've read alot on the drystacking subject aswell, wouldn't covering of the holes on the picture below work as drystacking?

[Captain75]

Forgot one picture on the drystacking subject...here it comes!