OEM Dual FAs better than 2 single OEM FAs

[SkiDaddy]

Has anyone done any testing to see if the OEM dual carb FA as comes on SJs from '96 up flows better than 2 individual '95 & earlier FAs? What about water ingestion?

I would think by looking at them the dual carb FA would be better on both counts; more vertical volume directly above the carbs and a less turbulent directional change of the air, and an inlet further forward in the hull. Any other opinions?

Granted the 2 single FAs look better and make carb access easier.

 

[michaelart]

the two singles IMO provide more direct access to air for each carb as opposed to a single point of entry which may reduce the amount of air the rear carb has access to.......whether this is true or not.....I do not know....

 

[michaelart]

and possibly less likely to ingest water....I'd like to know how much "area" is open on the two singles vs. the one piece set up.......

 

[Watty]

the two singles IMO provide more direct access to air for each carb as opposed to a single point of entry which may reduce the amount of air the rear carb has access to.......whether this is true or not.....I do not know....

I reckon you're right here but unless you are using high end carbs (46mm+ Full specs or Novi's) I don't think it would really matter that much.

Changes definately need to be made to popoff when going back to the stock dual f/a though.

 

[Sanford]

What I've found on my aftermarket hood (Wam), using the dual OEM setup puts the mouth of the intake right next to one of the (2) 3" hood snorkel. Performance wise this is great but any water that gets flushed down the hood can make it into the air intake next to it...especially if on the power (suction).

The nice thing about the single F/A is the opening is sheltered above the head so its far less likely water can get it.

I will soon be experimenting with a remote breather system (hose) that grabs air from in front of the gas tank. This is the furthest point away from any water.

 

[SkiDaddy]

the two singles IMO provide more direct access to air for each carb as opposed to a single point of entry which may reduce the amount of air the rear carb has access to.......whether this is true or not.....I do not know....

The dual FA has a much larger opening, & remember only one cylinder at a time is pulling in air.

BTW this is on a 790cc big bore w/44mm carbs.urr:

 

[SkiDaddy]

What I've found on my aftermarket hood (Wam), using the dual OEM setup puts the mouth of the intake right next to one of the (2) 3" hood snorkel. Performance wise this is great but any water that gets flushed down the hood can make it into the air intake next to it...especially if on the power (suction).

The nice thing about the single F/A is the opening is sheltered above the head so its far less likely water can get it.

I will soon be experimenting with a remote breather system (hose) that grabs air from in front of the gas tank. This is the furthest point away from any water.

I'm running a stock hood w/front holes plugged & an X-Metal pole w/dual breather tubes, so very little water should come out of the front hood tube.:biggrin:

 

[Sanford]

I'm running a stock hood w/front holes plugged & an X-Metal pole w/dual breather tubes, so very little water should come out of the front hood tube.:biggrin:

With the motor and big carbs you got, do you really think the two small 1.5" hoses will provide enough air? Especially if you're worried about "flow"

 

[SkiDaddy]

The rear holes in the hood are still open (w/no grommets).

The ski runs really strong & revs out well to 6950 RPM w/a moderately steep prop....

 

[SkiDaddy]

BTW ya coming to the ride Sunday Sanford? I still haven't met ya..

 

[Sanford]

BTW ya coming to the ride Sunday Sanford? I still haven't met ya..

Depends on several factors...even though its only 3-4hrs aways, its not as simple as just drive & ride.

 

[waxhead]

the twin pulls from the centre of the hull
if your ski is rolling around the water will go to the outside
anywater spalshing of your head will bounce into the stock single fa

 

[SkiDaddy]

Good point Wax. :biggthumpup:

 

[sjetrider]

and possibly less likely to ingest water....I'd like to know how much "area" is open on the two singles vs. the one piece set up.......

UM, only one carb breaths at a time pro, so more direct? Thats the carbs job to direct the air, all it needs is area to draw from and the newer OEM has more area. This doent mean the more area is needed, I think both will flow enough.

 

[michaelart]

True.......I was just thinking that because the opening is directly in front of the first carb therefore first carb has first dibs on fresh air coming in....and air has to travel a longer distance to get to the rear carb even though they only pull one at a time....I guess I am just thinking symmetry....