Home made air box/ intake modification custom ... 2013 SX240

[yam240sx]

Ok .. so I have decided to modify my air intake system , and im not talking about ordering the cookie cutter riva cones or pleniums filters / k/n or.... ribbon delete ( which i already have ) ... i have custom engineered 2 different designs that i have thought up and am about to embark on .. i cannot show pics because i have not done any work yet .. so try to bare with me as i explain : OPTION 1 relocate air boxes to sides and backward about 4 inches .. the port airbox will be totally relocated from directly under the engine lid to the side where throttle cable /body area ... , completely close off / silicone snorkle area on each box .. drill a 3' inch hold in the back of each airbox and connect a 3 inch section or elbow hose routed to where the flush ports are , there i will be removing and relocating the flush ports and drilling a 3' size hold for a vent ( there are some pretty vents caps on amazon , behind there will be a 3 inch hose going directly to back of air box creating a ram air pressurized air box ( now im no scientist but at 40+ mph at 3" diameter im sure we are almost at supercharger status !!! ... OPTION 2 ( non presureized less labor , less performance) drill x2 3 inch holes directly left and right of sight hole on engine compartment lid each hole will be capped off with a custom pretty vant cap .. behind will be copies of the factory fan blower elbows ( the black ones at the rear ) these will stay mounted tucked under behind the face of engine lid cover ... they will be facing startboard and port will be mounted at 45* directly forcing clean cold air AT not connected to each airbox ( no mods or removing of and air box) .. ... NOW do i opt for option #1 or # 2 .. taking a poll .....

thnx

 

[Ronnie]

I’m not an engineer but don’t think either option is going to result in any noticeable performed improvement. Although there is a lot of air flowing past exterior of the boat when it is underway not much of thIs air is being captured and pressurized in the back of the cockpit. Even with the center door and window open. To get a true ram air effect the vents need to be out in the open with no obstruction to the air flowing past the hull and instead of being capped with a vent they should be capped with scoops, IMHO.

on a semi related note, if you want to start a poll, you need to configure a post differently when you created it. this can be done by selecting the appropriate options as theOriginal post is created. Sorry but I don’t have enough experience in creating polls to type you through it.

 

[zipper]

Good luck with your design/build. Here is a member who did a lot of mods on a new boat. https://jetboaters.net/threads/results-of-latest-gmtech-mods-and-a-shark-on-the-boat.16388/ and https://jetboaters.net/threads/gmtech-custom-fishing-rod-holding-tubes.16169/page-2

 

[haknslash]

Good luck but not sure if you get noticeable gains. A member with an AR192 Mae his and had it go towards the back when the cutouts are under the seats for the most fresh air location and I want to say it had adverse effects.

 

[jmargo]

What are you trying to achieve ? I don't think there are gains to be made through the intake side that already have not been done through replacement filters such as the cone or RIVA drop in.

 

[212s]

I was looking at perhaps increasing air flow but after checking the size of the inlets and location, I changed my mind. I'm no expert, but I know from fluid dynamics 101 that the relatively low speeds of boats under 100mph ram air intake has little effect on naturally aspirated engines, especially without the Venturi principle used to design an increased air speed through a narrow opening to the intakes. Also any kind of opening that is 90 degrees to the air flow suffers from the Bernoulli principle which causes a drop in pressure - like air over the top wing of a plane which forces pressure to drop and allow air under to cause lift - that's how planes and birds can fly. Just cutting more holes in the wrong places can easily cause a drop in air pressure in the engine compartment which we don't want.

Designers put cars, boats, planes, etc. in water and wind tunnels so they can test configurations to ensure a good design. Since the intakes are located in a relatively normal pressure zone, and are twice the size of the throttle bodies, intake pressure will be more than enough for these small engines. If we had big V8 engines with blowers on them, the design would need to be completely different. So I wouldn't worry about it...just get out there and have fun.
??

 

[yam240sx]

the factory set up is bad for hot air .... cold air is more dense which = more power ... so if thats all your able to attain is cooler air intake temps and cooler engine temps i think its worth it ...

 

[Speedling]

I don't know about the newer motors but when i studied up on the mr-1 motor i noticed the intake volumes were quite large. The motor is from a motorcycle that has been bored and stroked. The motorcycle had ram air and i believe the motor would benefit from it. However as you suggested the low speeds in which we operate would dictate a large surface area for a scoop and besides that keeping water out of said scoop would be nearly impossible