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I`m curious why some of the jet drag boats the two I`m curious about are in the 7`s go up & down alittle on the big end? I was just watching the latest race dvd & thought I would ask.
Is it because they are running out of (Gear / Impellar) & the nose is starting to fall, Or because they are going so fast it has something to do with getting the water into the intake? Thanks guys
 

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Jets

Hey tom Im thing there at their envelope. Like an airlpane elevator,Iits getting ready to lift off the surface at high speed. Great Question please all chine in with the 7 sec. boats!
 

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mine will run without hopping in flat water. when the wind comes up and the water gets choppy it will try to climb out of the water and unload the pump. the noise you hear from shore is the engine hitting the rev limiter.
 

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Unloading, nitrous turning off, wing providing more downforce at the end of the track. any number of things. A lot is happening with the fast jets at the big end usually.
 

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...... any number of things. A lot is happening with the fast jets at the big end usually.
At 144.9875 MPH, I can only imagine how much is going on....;) :)sphss A bunch of the jet guys are gettin it done for sure :)devil
 

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Discussion Starter #6
mine will run without hopping in flat water. when the wind comes up and the water gets choppy it will try to climb out of the water and unload the pump. the noise you hear from shore is the engine hitting the rev limiter.
Unloading, nitrous turning off, wing providing more downforce at the end of the track. any number of things. A lot is happening with the fast jets at the big end usually.
Thanks Mike & Widowmaker - I was meaning more like the hot tub / tom cat type boats..... Not slamming any hull type or builder cause I like all boats especially the cp`s are my favorite for jets.

Mike - I thought rev limiter`s could hyd. nos,boost type motors? I guess not though cause I`ve heard that noise when I`m watching you UBFJ & some other classes.


No doubt Dave the jets are hauling ass & from what I remember as a kid going to the track it didnt seem like the jets could mpher like the flats if so not the issue no more... I`m going to need some Alky & a bigger blower for next season, hence I`m getting tired of see the backs of you`re boats...:D

Craig - how fast you thinking your`s will run in september?
 

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Tom

I hope to see 100 or better! (But who knows) with aluminum kieth eckert (canfield) 320 heads, same cam 680 solid roller, 4 bolt block,13.5 srp pistons, H beam rods, forged steel 0/0 crank and the new to me Enderle injection bird catcher unit I got awhile back. Zig mag, 800 HP? We see soon.:D Hope all is well! If it happens then I will be looking for pop off or ratchet. After all this comes the 540 being assembled!
 

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Thanks Mike & Widowmaker - I was meaning more like the hot tub / tom cat type boats..... Not slamming any hull type or builder cause I like all boats especially the cp`s are my favorite for jets.
?
The Cp's have some handling issues when you start hauling ass like the 334 and 028 do. They have alot of lift built into the bottom and the relationship from the outer sponsons to the center sponson is very different, they bounce from one to the other, no drag but poor stability. Keep in mind these are tunnels, different from the other cp's which are gullwings like Patridge has.

You have very little connection with the water in a fast jetboat, prop boats have much more of a connection with the prop. We try to run them as loose as possible but still want to keep them hooked up and that is a very fine line. Some guys go for the best possible half track time then bounce and skip down the rest of the run, some like to keep them hooked up. I like 1 unload right in the lights, thats as loose as you can run it while staying hooked up. Lots of different ways to approach it
 
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