08-29-2011, 05:55 PM #1
- Join Date
- Aug 2011
Single Bar or Double Bar intake grate
First off, hello to everyone and thanks for letting me join such a great site!
Reason I'm posting is that after about an hour of searching I can understand that
- 800 intake grate is only made in double bar form
- 800 intake grate performs best up top but cavitates out of the hole compared to the double bar intake grate
I am wondering how do the single and double bar 1200 grates match up. Found some info but it wasn't consistent like the 800/1200 comparisons.
08-29-2011, 06:00 PM #2
08-29-2011, 06:03 PM #3
The single bar holeshots & hooks up better than the 1200. Not sure how top speeds compare...never tested it back to back.
08-29-2011, 06:06 PM #4
08-30-2011, 02:42 AM #5
So excuse the newb question, but is this the leading cause as to why my GPR with an 800 R&D grate cavitates out of the hole and through the lower mid-range if I simply go WOT with it from a dead stop? Holeshot isn't a major concern to me, but it is something I've noticed at the start of my speed runs. Feathering the throttle works fine for it, but I've never ridden with a different grate on...
08-30-2011, 03:12 AM #6
- Join Date
- Jan 2006
- Texas City, Texas
Your boat goes through 2 phases. At hole shot, the impeller literally sucks water into the intake, and it cannot enter fast enough, so the impeller cavitates. For a good hole shot, you would need an intake grate that maximizes water flow as it enters the intake.
As the boat moves forward, water is literally driven or forced into the intake. For a good top speed, you would want an intake that limits or restricts the amount of water that enters the intake tunnel.
The single bar intake that allows for maximum water flow for hole shot would work against you at top speed, and the 800 intake that minimizes water flow would be great for top speed, but would work against you during the hole shot.
What we all need is an intake that allows for maximum water flow at hole shot and at the same time diverts or otherwise restricts water flow into the intake tunnel when we go from midrange to top speed. It is a very difficult design that so far no one has been able to accomplish with any overwhelming success.
Think about it: there are many 20 foot bass boats with 200hp engines easily doing well into the 80's, yet there are many waverunners 10-11 feet long with a lot less weight and with just as much if not more horsepower struggleing between 80 and 90mph. All that water entering into the intake cannot be processed and so people encounter what is commonly called the "buck". If you minimize the flow of water into the intake, than the boat should go faster. However, when intakes and shoes are modified to do this, the boat begins to cavitate at hole shot.
08-30-2011, 07:45 AM #7
im looking for an 800 grate so I can put it together with my 84mm nozzle and see how it feels out of the hole.
a 1200 grate with an 84mm nozzle is very sluggish down low. Or on the same thought, what about an 800 grate with a more aggressive prop pitch - like a 15 instead of a 14.
anyone tried this?
08-30-2011, 12:52 PM #8
08-30-2011, 02:36 PM #9
09-01-2011, 06:35 AM #10
welcome to the forum Pedro
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