PC Motor noise


T

Troy

New member
I am wanting to know about motor noise in the PC line. I typically am in the Drivers Seat and do not get the opportunity to hear the hum of the engines in the back of the cockpit. Is anyone else getting complaints from their passengers about the motors being too loud?

Gabby Girl was asking about Ideas for sound proofing in another thread. I wanted to see if this was a common problem or just with that boat it is a 37 PC with 496 Ho's.
 
When I first got my 41 it was louder than what I expected. However there is a difference between listening to it start up and running on plane. The exhaust exits underwater at the stern and we have no trouble holding conversation in the cockpit area. I have grown to enjoy the rumble at start up as I know it will not interfere with the enjoyment once we leave the marina. The 41 is quieter than the 34 we had but shouldn't an inboard be quieter since you have mufflers than an I/O with pipes which just dump into the outdrive?

Is there a way to add insulation in the engine compartment? Say along the sides or the back against the transom? The cockpit floor/engine hatches are well insulated as it is unless you add another layer over what is there, but don't you also have to worry about containing all that heat in a reduced volume area?
 
Our 37 is my first experience with v drives. I figured it would be very quite. I was very surprised at the vibration and rumble first time we fired it up. Not so much it creates any problems. Matter a fact I have grown to like the rumble. Once we get moving I don’t notice any engine noise or vibrations.

We recently had the boat out of the water. I was inspecting it and noticed under the rear platform there is a large opening / cavity in the center underneath. Further investigation I learned that it's where the engines exhaust. They actually exhaust inside the opening. I don't know if it is below or above the water line when the boat is in the water. I assume below water line?

To me that seems to explain some if not all the rumble.

i would insert a pic if i new how. It looks like i need the pic hosted somewhere?
 
THERE IS DEFINITELY A BIG DIFFERENCE BETWEEN I/O'S AND VEE-DRIVES, DUE TO THE EXHAUST EXITING OUT THE CENTER OF THE PROPS VS. UNDER THE BOAT OR OUT THE BACK.
I COULD BE WRONG, BUT GABBY GIRL IS TALKING ABOUT ENGINE NOISE UNDER THE LID. I BELIEVE HE HAS 496 H/O OUTDRIVES.
 
Thats right Gary, Gabby Girl was talking about a BIII package. I can't say that I have had a customer complain about noise on a stern Drive PC. Maybe one with 6.2's and that just because the 6.2 is a noisy motor. I wonder if this was their first boat?
 
I would say our 37 pc is a lot louder than our 322 monterey with out drives. 5.7 vs 8.1 and volvo vs merc b111. I do miss the quiet but i like the 37 a lot better.
A Note though, Monterey had the cockpit down vers. the Formula.
 
This kind of stuff is very important things to post, If Formula really monitors this sight Like I think they do theses kind of issues can be resolved in future models. Thanks Randy
 
Before buying my 37PC with 496HO BIII's I drove inboard version, hopped off and drove I/O version back-to-back. Yes, I/O version is noisier (louder) but the I/O offers better cruise speed, top end and fuel economy. I was coming from a 31PC with 454 and BIII's but did feel like the 496HO's were louder. I was scared my wife would think it was to loud so I brought her for a ride, of course only on the I/O version. She said "no, it's not to loud" and she spends all of our cruising time laid out on the sunpad over the engine compartment so if she's fine, I'm fine. After 3 years I'm thrilled with the HO/BIII choice. I do wish it was just a little quieter, but the performance is amazing. I cruise around 37mph at 3900rpm all day long and have topped out at 47.2mph with 6 people on board, a weeks worth of clothes and food, half tank of fuel and bottom paint. That's within 1 mph of factory test data which are performed in far more desirable load conditions. Formula makes incredible boats.
 
Yes I would agree with the performance.
I have the mags and I am about 3 mph slower for the same RPMs.
The only way i would give up this boat is for a bigger one.
;D
 
Castines,
My 37PC is a 2005. Those performance numbers are straight off GPS with nothing done to boat, engines, etc. Stock Bravo IIIX drives with factory 24 pitch props, Chesapeake Bay. I am however planning to try a set of Mercury XR props (4/3 blade) 22 pitch this spring since Mercury propeller division thinks I will see even better performance numbers. I'll post when I have the results.
John
 
I have the XR props on my 34PC. I talk about it on the forum quite a bit and performance at cruise has increased about 3 mph and I went down about 3 gph.

My 34PC had 24P stock props. I had these XR props from when I had my 31PC that had stock 28P. So i was told to go one pitch down to make up for the extra blade, thus I got 27P XR 4/3 props. they worked great on the 31.

When I got the 34 it had stock 24P. So i gave them a try, was a little worried about going up in pitch by 3! (actually 4).

Well i am glad i did it. takes about 1 more second to get on plane but i can cruise at 3000 rpm at alomst 33 mph. before I could not even stay on plane. 3600 r's is almost 40mph. Top speed it 51-52, half tank no bimini. Only get to about 4200 rrr's.

When I cruise with my club, I sit back at 3000 rpm and about 25 GPH and still slowly walk away while the rest are pushing 3600 to 3800 rpm to maintain 26Kts or 30MPH. Formula makes a great hull and power package. No doubt :D
 
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