Thread: Increasing Top Speed Ultra 250
06-15-2009, 04:22 PM #1
Increasing Top Speed Ultra 250
I just have a question regarding increasing top speed on an Ultra 250x. I have an 07' that I just bought with 25 hours. The ski was meticously maintained, as it will continue to be. The only thing the ski has is a Riva ride plate, 1 degree pump wedge, bolt holes siliconed, and a BOV block off. (I was also given the 2 degree pump wedge with the ski, is it worth putting on over the 1 degree wedge?) The first time I took the ski out, it ran 68.3 (93 octane) on gps with 1/2 tank of fuel. I took the ski out yesterday and with a 1/2 tank it ran 68.4. (with 87 octane fuel) It was approximately 95 degrees ouside and humid here right outside of New Orleans. I did a little research and saw where guys were doing the timing mod. If in fact these skis can operate safely with an additional 6 degrees of timing, I figured the ski would make more power by utilizing a lower octane fuel with stock timing than it would with 93 octane. What is my next step for bolt ons to get a higher top speed. Will aftermarket sponsons help? If so, what kind is suggested with proven success? Or any other simple mods for that matter. I drag race a turbo charged Suzuki Hayabusa, so the ski just somewhat of a relaxed hobby for me. I would like it to be faster, but on the same token reliable and something that doesn't cost me a whole lot. Thanks in advance for any input or suggestions.
06-15-2009, 05:17 PM #2
Welcome. Good to have you here! Turbo drag racer huh? Its only a hobby for you now, it will get addicting!
So many variables. The short is. For flat water. Riva plate is good. Get some chop and it sucks. 1* wedge is fine too. 2* will give you a bit more speed, but again hit chop and forget about hookup. The beauty of this ski is its hookup ability! NOT its flat water speed. You will get beat by Sea Doo's and Yamaha's…On the flat…Throw in some chop, and it’s a different game!
Add the timing, you will get more bottom end punch. Lots of little other mods to do, search the database. Pump, prop, pump tunnel, intake mods. Oil level, IC cleaning…Plate alignment. Free mods is what they call them.
Other speed adders are the Pulley Kits. LOTS of info on that as well.
Get one of them turbos fitted to your ultra! Like this one!
06-15-2009, 05:35 PM #3
Thanks for your fast response. What sparked this post was a race with an RXP-X yesterday. lol From a dead stop, he jumped me by a ski and basically we held there. This was calm flat water. We went from about a 40mph hit and we basically stayed side by side. I won't be riding in much rough water....very rarely if any. Most riding here is in flat river water. I assumed the RXP-X was going to beat me as a result of its size and slightly bit more (or claimed) horsepower, but it was surprisingly by less than what I thought. We were both roughly the same weight, 170ish. Thanks again, and I'll do some research here.
06-15-2009, 06:21 PM #4
- Join Date
- May 2007
- Orange County, CA
06-15-2009, 06:34 PM #5
Get rid of your 2nd waterbox with ebay stainless U-pipe it will give you a little more low end.
06-15-2009, 06:57 PM #6
fresh air mods. Get the R&D flat filter. 2* since your on flat water.
Pulley kit would suit you well I bet!
check clearences on pump/impeller.
06-15-2009, 08:04 PM #7
Thanks for the heads up. I'm not by any means trying to skimp on fuel as a result of cost, I just figured running 87 octane would yield more hp with stock timing. When guys are running the 6 degree timing mod, are they still running pump gas? In general, you could say that the most power you can get from any engine as far as ignition timing goes is that timing is just shy of causing abnormal combustion or pre ignition, detonation or knock. I would think if the motor was safe with 6 additional degrees of timing and still running pump gas, it would be safe to run the 87 octane. Considering it only gained a tenth of a mile an hour, if in fact that was the real reason, its not worth the chance of damaging the motor to me. Thanks again for the heads up. I'm all ears for any suggestions or input, especially considering this whole jet ski thing is new to me. I don't mind alot of trial and error with my bike because thats all part of it. I'm just trying not, which is already hard to do, to get to involved in effort of not getting beat by any farely stock ski. Thanks again guys for the input.
06-15-2009, 08:16 PM #8
Thanks....I know, I have a bad habit of "not leaving sh*t alone" I can see how this can become addicting. I guess its a good and a bad thing. The competitive nature comes out in everything, even things that "supposed" to be relaxing. Does 68.4mph on gps sound right for the mods done? Again, its a 1* pump wedge, BOV block off, Riva ride plate, siliconed bolt holes, and on flat water in 95 degree humid heat. I was wondering if any particular sponsons or intake grate bolted on gives any more mph in flat water also. I did some searching, without much luck though. Also I see the 2* pump wedge suggested, Off hand, do you know the "expected" gain in flat water over the 1* ? Thanks again for your time and input.
06-16-2009, 12:00 AM #9
I'm also considering pulling off my stock intake grate and removing the center bar. Will this help top speed, and is it worth the time? I've done some searches, but haven't found anything concrete. Thanks.
06-16-2009, 12:52 AM #10
I am sure with your racing experience you will help us a lot.
In general intake grates will slow u down.They are meant to improve handling as they get more water to the pump in rough conditions.
Removing the central bar may give u something but i dont recomend it.
The speeds u see i consider them ok.
Your competitive nature will lead you to a pulley/ECU combo where u can easy see 8200rpm+.
Removing the waterbox will help a lot but it will be loud for cruising.
If you wanna be "king of the lake" go turbo.
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