breakin period is done.

[jet set]

Took the boat out again today and finally hit the 10 hour mark. When it did, I stopped the boat and then full throttled her. All I can say is holy sh*t! Those twin 250s might as well be rockets. No tubing today, just running around having a blast driving. So glad I went ahead and got the 250s!

 

[Big Shasta]

BOOYA...Grip It and Rip It!!

And then smile all the way to the fuel dock.

 

[OrangeTJ]

Awesome! What was top speed?

 

[Pinhacker71]

Nice. I've got 8 hours on my dual 250s. Looking forward to hitting 10. Pretty darn fast right now.

 

[Speedling]

TOP SPEED?!

 

[Geiger41]

tango, oscar, papa.....sierra, papa, echo, echo, delta ???

 

[Speedling]

So I'm gonna say top speed isn't what it COULD be.
Top speed?
Is it on the limiter?
If it's not on the limiter, do a performance mod somehow, like filter or something.
If it's on the limiter, get some impellers tweaked by impros or something this winter and go a few mph faster.
Please, go faster than my 52. I really hope you're in the 60's.

 

[SCSTWG]

That is some HP on a 21' boat.

 

[jet set]

I hit 60, felt like it had plenty more, but I had wife and all the kids aboard had to slow it down. I'm more into quickness than topend speed. It feels li, e it wants to jump out of the water. I love the looks I get when I throttle down passing someone.

 

[Speedling]

The jump from 50 to 60 mph is pretty significant. Apparently 200 hp significant!!
That's pretty fun man. Get rid of the kids and wife, take anything you can off the boat, and go for a run. For my sake of course!

 

[Big Shasta]

Thanks...Thanks a lot...Now I want one. (Yeah, I have speed issues) Part of the reason I got rid of my motorcycles.

 

[Geiger41]

My 212X has twin 180's. Tops out at 56..........But twin 250's....I hope it gets at least 7075 with that kind of hp,

 

[Speedling]

The speed to horsepower ratio is exponential. To a lesser degree so is the weight as well. From 360 hp amd 56 mph to 500 hp and 64 (theoretical) is a 8 mph and 140 hp jump. Sounds about right. Gotta figure some of that hp is just pumping water through the cooling system as well.

 

[Speedling]

I could rephrase that...
if yamaha built a 60+ mph boat it would still reauire about 500 hp.

 

[Geiger41]

So you think 4 to 9 more mph would require an xtra 140 HP ???? Thats alot of cash I would assume just for the few mph you would gain...ALOT

 

[ScarabMike]

Pump design has alot to do with it. The Rotax 250HP engines need to spin a supercharger, and like @Speedling said, spin 2 pumps for cooling the exhaust, and engine. Im sure if you fit a better pitched impeller, you could get more speed.

My buddy gets 70mph at 8400 rpm in his SeaDoo GTR 215, but I can get 65mph on my Aquatrax at 6k rpm, and close to 70 at 6.4K.

 

[Speedling]

Yessir it is.
also, increasing pump diameter to 170 mm and horsepower just under or at 700hp to beinto the 72-75 mph range with light load.

 

[Speedling]

A single pump is more efficient than duals and will net more speed. The manufacturer has access to components to make a good dual boat. They aren't as efficient as a single but there are significant benefits to duals in a boat.
tweak what they give ya and don't try to reinvent the boat. Leave that to me. I have over 30 pages of condensed research and theory on it all. If I ever get to proving my theories/equations I will write a book.

It's the same with boats as it is with cars: if you have money you can go fast, otherwise stick with lights and speakers.

 

[Glassman]

A single pump is more efficient than duals and will net more speed. The manufacturer has access to components to make a good dual boat. They aren't as efficient as a single but there are significant benefits to duals in a boat.
tweak what they give ya and don't try to reinvent the boat. Leave that to me. I have over 30 pages of condensed research and theory on it all. If I ever get to proving my theories/equations I will write a book.

It's the same with boats as it is with cars: if you have money you can go fast, otherwise stick with lights and speakers.

Heck, I try and keep up with GAS.....but it's coming down. Yep, premium just dropped below the $4 mark this morning...