Thread: 2008 RXTX Top Speed Problem
08-11-2010, 08:12 AM #1
2008 RXTX Top Speed Problem
Have a top speed problem, here's the story:
My 08 RXTX ski has 144 hours (serviced each 50hrs, SC rebuild at 100hrs). From memory it use to do 8020-8060rpm (or thereabouts) and top speed (Garmin GPS) of 105-107kmh, and at times 109kmh (65.2-67.7mph), until more recent times when I noticed nothing more than 7500rpm or so and top speed 102-104kmh (63.4-64.6mph). Ski seemed to have lost all of its former mojo and just didn't have the X factor anymore.
So here's what I've done about it:
- Visited dealer for a slightly earlier than usual service and explained running lower rpm/top speed then usual and doesn't feel like an X anymore. Somewhere along the way decided I'd get an ECU reflash. Was advised should see 8200-8250rpm after it and definitely all around performance improvement, as would be expected. Was hoping I would see 110kmh (68.3mph) regularly.
- Pick up ski to find the following has been done: service, OPAS lifted, ECU reflash, new wear ring, and prop had some damage so was repaired by dealer on best endeavours basis.
- Hit the water, very excited, only to find running max 7750-7800rpm and 64.6mph. Feel like the ski is no different to pre service & ECU reflash.
- Return to dealer. Dealer investigates SC, slight slip and replaces new clutch washers. Further investigation finds main problem is intercooler severely blocked. Cleans out IC. Feels the blocked IC was definitely a major issue causing lack of boost and performance.
- Hit the water again, very excited again, and find my ski has its mojo back! Now running 8100rpm but no top speed improvement and still only 64.6mph. Ski SC is boosting and whizzing nicely, revs come up quickly and mid-range pull real good. Feels like it is back to the normal stock ski but not a ECU reflashed ski, don't understand why top speed still remaining at 64.6mph.
- Discuss with dealer further and dealer suggests main variable is prop, given my prop was damaged slightly, and despite repair, may still be the issue given everything else has been checked out thoroughly and serviced/improved. Return to dealer with a friends close to 'as new' stock RXTX prop to replace mine and test.
- Hit the water again and find now doing less revs at 7850-7900rpm and less top speed at about 102kmh (63.4mph), and only in final run with literally no fuel in tank did I get 104kmh (64.6mph) again. So my ski now performing less than prior test with reasonably new prop (compared to my slightly damaged one).
- Discuss with dealer and dealer suspects likely still a prop issue and doesn't make sense that my ski now running less revs with undamaged prop v damaged prop, and even with damaged prop on and more revs at 8100rpm didn't get any more top speed from initial test with the constipated IC. So next step is to replace the prop with a brand new stock prop to test and isolate this is the issue or not.
Conditions for all tests were cool 15C and flat water, with mates skis pulling their usual full revs/top speed in same conditions. And I know my ski very well and in the past was always pulling full revs/top speed even in non-flat (<5knot) conditions with ease.
Anybody else experienced something similar? Any ideas what I should expect in rpm/top speed? Is it possible my ski at 144hrs is suffering some engine wear & tear that's causing loss of rpm/speed despite service and reflash?
08-11-2010, 11:08 AM #2
- Join Date
- May 2008
- Lake Havasu
My 08 RXT-X has over 160 hours on it, with only an R&D free flow exhaust, and the impeller has been "tuned", and I ran 67.6mph yesterday, with air temps in the mid 80's, and a full tank. When I rode in conditions like you had(15 deg C), I ran 69.1mph, again, with a full tank.
The first thing I would check is the bend on your impeller. They may have replaced it, but it could be that it's not bent correctly(I think it should be around 13/24-but I'm not sure). Right out of the box, most impeller are off a few degree's, and that could hurt you.
Dunno what kinda reflash you would get, that would allow your to run 8200-8250(never heard of that), but OK.
Also, check all your hoses(boost/intercooler) to make sure they are tight, and your are not losing boost. Also, check your oil level. If it's to full, you will lose RPM's.
I get that it's winter there now, so heat isn't going to be an issue for you.
And, check your spark plugs, then check your compression.
That's all I got.......
08-11-2010, 07:06 PM #3
I would also consider some sort of AFR monitoring, could be having a problem with fuel pump, pressure regulator, or an injector starting to fail. If you know how to properly read the plugs you can get a good indication of something failing in the fuel delivery system.
08-11-2010, 07:35 PM #4
Thanks guys that's great to know. I am guessing the ECU reflash is done by powerchip or superchip or similar (don't know). So am I over-estimating stock max rpm and/or post-reflash? What is typical stock rpm and typical ECU reflash rpm that others are seeing? ECU reflash was not intended to break rev limiter etc., but rather just give the ski some extra 'zing' across the performance band.
08-11-2010, 08:02 PM #5
So basically, you had a simple blockage and it sounds like your dealer charged you for a bunch of stuff you didn't need. Now he wants to sell you a new prop. Take your ski back to him, shove it under his nose and tell him to get off his azz and work on it/water test it until you get the performance you paid for.
08-12-2010, 02:36 AM #6
- Join Date
- Mar 2008
you need Mods to go faster...Out of the Box your T-X will run around 66mph...Simply reflashing the ECU won't do anything....
All you need do now is Get a 15/22r Prop, R&D intake grate, Riva Free flow Exhaust. and you will be doing 70mph at 8100....
Learn how to do this stuff yourself then you won't get ripped by a dealer telling you a reflash will make your ski faster
09-10-2010, 07:07 PM #7
For those interested in an update: Dealer accepted my ski for test run given there was nothing else that could be identified from workshop and had been checked end to end. Maybe I was too generous with my feedback. Dealer tested ski under load on flat water at our local watersports centre and found waterbox/baffle (?) was blown with a small hole. Not visible from workshop as is covered with insulation, not visible when running engine or flushing cause needed to be under load and at high revs. Was found by running ski on water high revs with seats off ... exhaust in engine bay. Now replaced and ready for next ride. Confident all stock performance should be well and truly back with much more punch, revs, top speed from ECU reflash.
09-10-2010, 09:57 PM #8
09-10-2010, 10:13 PM #9
- Join Date
- Sep 2009
- Aussie Land
Are you dealing with Melbourne Seadoo? (You better be, as the only competition, TG, has pretty low knowledge from the workshop guys on how to tune skis)
Jesus christ, how the hell do I achieve 115/116 km/h with the drop of a hat on any given day? Maybe I should try a different GPS to make sure speed reading is accurate.
What PSI are the pots holding?
09-14-2010, 04:55 AM #10
For those interested, now that waterbox problem identified and fixed, can confirm the following results:
- Stock ~8020rpm @ 107kmh/66mph (gps)
- ECU reflash ~8240rpm @ 111kmh/69mph (gps)
Test was in flat conditions, 9C ambient, full tank of petrol.
I'm happy now.
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