Air Scoops On Backwards?

[go chiefs]

a friend of mine had a dooley scoop on his nordic, always started the day with it facing forward but eventually spun itself around backwards, he got tired of fighting it so he left it backwards, no difference in sound or performance that we could notice, and didn't have to mf it anymore because he accepted that it wanted to face backward

[Sleeper CP]

Hey GUGS,
We are on the same page. Yes, the only way to find out is to do dynamic testing. Run it on your boat and see what happens. Some engines will like it other won't. I'm still surprised that the front carb on a tunnel ram can actually get enough air with the scoop on backwards, I guess that venturi effect is bigger than I thought.
Sleeper CP
P.S. Edit
GuGS you mentioned one thing that does suck on a jet boat. At some point you hit the wall (ie) H.P vs Drag equation and it takes a bunch of H.P. to see any change in speed. Once we got the open bow CP to run over 100, it would run 102-103 with the 250 hp shot or 300 hp shot of Nos. The extra 50 didn't help. Who knows what dynamics we were up againt: aero,hydro or pump efficiency.
The new combo I'm hitting the river with this year should be far more efficient. I'm hoping to get the stationwagon real close to 100 with out the Nos.

[patrolman808]

There was a thread on this a while back.
It was also said that running it backwards is like a cowl (sp) induction hood. It accually sucks air better.
Cowl induction works because air pressure builds up at the base of the windshield. On an open boat, there's nothing behind the scoop to cause the pressure to build. There would be a slight vacuum if anything.

[jetovatorjeff]

i quiets things down quite a bit running them backwards, looks lame though.

[Sleeper CP]

Cowl induction works because air pressure builds up at the base of the windshield. On an open boat, there's nothing behind the scoop to cause the pressure to build. There would be a slight vacuum if anything.
Patrolman,
I don't think there is a vacuum, I know of to many boats that either run the same or even run faster. My CP open bow has a 800+ HP 565" BBF in it with a single Dominator Carb. Off the nitrous it would run the same with the scoop forward or backward.I don't think there was vacuum because the engine pulled the same; it wasn't being starved for air. Now that was some years ago when we were pulling an American Turbine A3 at 5,250 rpm's and running 92-93 mph.
I just re-read your statement:There would be a slight vacuum if anything. Yes created by the venturi of the scoops trailing edge. If that's what you mean we are on the same page, I think?
Just for kicks I'll try it this summer with the new combo and see what happens. But ,ultimatley I'll run the scoop forward, because it looks better that way.

[raped southwind]

Ive agree with the statement that every motor is going to be diferent so either way may work better for you but to my testing there is something called good air and bad air ..and found that running backwards gets me the best air... just my 2 since

[patrolman808]

I just re-read your statement:There would be a slight vacuum if anything. Yes created by the venturi of the scoops trailing edge. If that's what you mean we are on the same page, I think?
Yea, that's what I was saying. Kinda like when you are driving a car/truck, there is a slight vacuum (or negative pressure) immediately behind the vehicle. I run mine foward for more of a 'ram air' function and it just looks better IMO.

[squirt'nmyload]

i ran mine backwards today and didn't notice any difference

[pw_Tony]

It just looks to gay backwards....

[W.O.T]

It just looks to gay backwards....
i agree even if it made my boat slightly faster it looks like crap backwards