ezstriper

how do you figure that, air merly blowing by the side of the boat, with a 4" hose connection, vs the blowing helping draw that outside air in ? not talking about being hooked to engine, just bringing outside air in

Tinkerer

The point is that when the engine is running it is causing a high negative pressure inside the engine compartment at speeds above cruise. The exhaust fan is trying to push air out and by doing this causes a slight negative pressure inside the engine compartment thus drawing air in ANY opening. The problem is that the engine creates a much higher negative pressure than the fan can. SO - ANY opening including the one the fan is trying to push air out of are now flowing air inward not out. The fan is restricting that air from coming in. IF you have enough opening in the engine compartment this doesen't happen.

Tinkerer

To put it another way - If you had a twin engine Cat with 1000 HP per side that was capable of 150 MPH and you mounted a 50 HP outboard engine between the drives do you think the boat would go faster or slower?



The outboard engine would create far more drag than it could possible overcome with 50 HP of thrust.

getrdunn

iTrader: (7)

Just throw that heavy azz engine hatch in the lake and go grab a screen door at the hardware store and be done with it. Lol

endeavour32

iTrader: (4)

That would be too easy, and I like a challenge. I'm going to get the boat to run well with it on and have it be 100% functional.

SB

iTrader: (1)

I remember back in the Speedwake days, we had gone thru this with a ton of people, and many where able to raise their hatches (all different boats) up an inch or so and problem solved.

endeavour32

iTrader: (4)

I just don't understand how the manufactures didn't solve this issue out of the gate. Oh well, I'm about to head down to the boat, put on the new props, and inspect what I need to do to get the issue resolved. I'll report back later in the day. The best speed I've had so far was 80 mph with the hatch off and labbed Bravo 30p castings @ 4800. New props are BBlades Bravo 26p castings, I'd like to get these engines in the 55-5600 RPM range today.

SB

iTrader: (1)

NVH. Seal them better and less noise. + to some designers and customers, less venting looks better, fits better, etc,etc

+ Water intrusion (typical boater doesn't cover their boats like what we do and etc,etc.

+,not too many builders are Reggie Fountain's that are willing to make a boat faster at all costs (shorter than advertised boat, lighter lay ups, less sealant ((doh !)), and etc, etc.

People give too much credit to all OEM's - cars (especially), boats, and etc, etc. for believing they know more than 100% what they are doing. This is not always true !

I have heard this allmy life on cars/trucks and semi recently snowmobiles - why would the car manufacturer choke the air intake so much ? Reason, they have to , by law, as they have intake air noise regulations too ! Yup - believe it !

They have gotten extremely good, however, in the past decade with quiet intakes and exhaust that still make good power. In fact, with snowmobiles, the louder aftermarket systems make less power than the extremely quiet OE exhausts. Exhaust extremely critical on 2 strokes !

Starting from 18yrs old, I worked for, and helped with, a respected performance and circle track guy. Everytime my little brain came up with a way to make more performance, the glasses would get raised, the eye's would dilate, and I'd get the "If your idea/design is so much better, someone else would have invented it already."

After, believe it or not, 4-6 (maybe more?) things I designed and went to try on a car or circle track car, and got that unwise wisdom, 1-2yrs or more later I'd be thumbing thru NationalDragster or Circle Track mag or Stock Car Racing or even Hot Rod or Car Craft and bang ! There was the item and there it was being tested. No, no one copied my things, it was just evolution and someone else stumbled up on it.

My wise mentor, was not wise in this regard. I had to stop listening. Which I did, and didn't look back.

endeavour32

iTrader: (4)

Well I blew my port drive guys. So I am down. I need to try and find a new set of gears today, and hopefully I can have the boat back on the water next weekend. It never ends does it!

I will say this. The only real venting are the two vents that are right behind the windshield. The other vents for the blowers are a joke. Each only have 2 3" holes in them and the starboard side has blowers hooked to them so that size is really choked down. While the other vents are large and completely open on the back side, there is no way they are large enough.

getrdunn

iTrader: (7)

Sawzall