Thread: Seadoo XPDI
03-25-2009, 06:57 AM #1
Just had a couple questions about these machines...
What should they top out at rpm wise? (Mine is 6800-6950rpm at 3400 feet)
When i have the trim all the way down the nose dives under water and becomes so unstable i can't stay on is that normal? (Like were talking the water surface is hitting where its black on the hood.) The machine leans really bad going fast with trim down to one side and steering practically doesn't work feels really lose.
If I'm half throttle and pin it there's a slight hesitation up to 3 seconds before it opens up what can that be?
03-25-2009, 08:19 AM #2
The RPM is about right for a stock engine. You will gain a little with lower fuel levels and the right trim depending on your intake grate, surface conditions, and riding position. Some may turn a little more, some a little less as engines and hulls vary somewhat.
As for trim on an XPL hull, you want to stay fairly close to neutral for the most part. If you are in a no-wake zone you will want to trim it up to keep the nose from stuffing under. Other than that, just above neutral for good water. In rougher stuff, when you start to feel unstable at speed, just below neutral should calm her down.
You may want to check how the trim rod is set (it is adjustable, at least it was up until '02). I always run the motor all the way up and then set the rod to hold the nozzel as far up as it will go without hitting the venturi. I may lose a little bit at the bottom, but I am never going to run trimmed all the way down since it will try to submarine, as you have discovered.
Most XPL hulls are fastest near neutral trim. The hull itself will tend to lift and too much up angle on the nozzle wastes thrust lifting when it should be pushing. You will have to find the sweet spot on the trim for your hull. On my '99 it is about two needle widths above neutral with my feet at the back of the footwells. This will differ for your boat since they vary and we are likely different in height and weight. The amount of fuel in the tank alters this point as well. On mine, more fuel=more trim up. Since the tank is at the midline it is not as critical as on a front tank boat like the RX. Still, the weight of the fuel requires compensation.
Of course, if one is just cruising, none of this matters much but you will run more efficiently near neutral.
As for the hesitation. That is not uncommon on carbed boats. I have ridden some DIs, but not in that hull. IMO, the DI seems to be more responsive over the entire RPM range than a carbed engine overall, but a carbed engine will run just as well within the zone that it is tuned to. Any system will have to compensate for a sudden, drastic, change in throttle position.
Hopefully an XPLDI guy will shed some light on that one.
03-25-2009, 12:41 PM #3
- Join Date
- Jan 2007
I used to race an '03 XP DI in Supercourse races. I liked it because I didn't have to mess with tuning it all of the time. Mine never had the hesitation you speak of. However, I had a heck on a time on the race starts because if you hit the start button and mash the throttle immediately, if freaks the computer out and the ski either stalls or goes into limp mode and you have to pull the lanyard and restart. So, it could be something with the computer.
03-25-2009, 08:55 PM #4
Hey if you trim it down all the way and punch iit it will submerge completely and go about 10-15 feet and pop up like a cork and throw the fool that did it off
03-25-2009, 09:13 PM #5
- Join Date
- Jul 2005
Dude, I didn't think this ski was yours? What story is there now?
Common sense says if you trim down and the ski goes under the water and drives crooked maybe you shouldn't do that.............
I think they ONLY advise this guy has listened to was from Dan/Dsolie, so let let him answer LOL
03-25-2009, 11:29 PM #6
Great.. Bring me into this lol.. I am not sure how the ski is set up now.. There has been too many hands into it since we built it years ago (and it ran like a raped ape)..
Nathan, I saw your video on youtube.. with you riding in the FREEZING water.. That could mess with your hesitation.. Air that cold and thin. with the F/A's on the ski, you could be right at the edge of the stock mapping for the fuel/air mapping..
Also, are you still running the outerwears on the F/A's??
03-26-2009, 12:43 AM #7
- Join Date
- Jul 2005
oh my god, he's running stock mapping on a DI ski with F/A's...how stupid is that? no wonder the hesitation is there. This is just too funny and extremely SAD at the same time.
03-26-2009, 02:35 AM #8
I'm not having a pissing contest with you TLR.
Now back on subject...I'm sorry but I don't know what FA'S is..
The machine just came out of the shop for its tune up before heading down south. This hesitation I speak of is just very slight...I'm talking like a few seconds.. No big deal just wanted to know if im going to have another 4,5,6,7,8 computer problems.
The machine runs perfect now but doesn't compare to the rxp-x by a long shot. I am aware of the nose diving under water but how much is what concerned me. I thought maybe something was wrong with the controls.
Going across the lake at 40mph pushing trim all the way down in 0c water in wintertime caused quite a horrific crash. Good thing my brother wasn't hurt. I will have to remember to tell people the warning ...extremly unstable... "Do not touch trim!" lol
Thanks for all the help specially KrunchovXPL-GTX-RX that was quite a write up. In 3 days I'll be in 25c-30c weather and thats why the machine was out on the lake. (In wintertime)
This F/A's Please let me know what that is..Speaking to my mechanic tommarow and ask him why or why not there there...He knows im leaving. Is FA/s (Flame Arrestors) if thats the case I still don't know anything about them. You would think a seadoo mechanic of 35 years would know his stuff?
03-26-2009, 06:46 AM #9
I would not call an XPL "extremely unstable." An HX is extremely unstable.
My old '95 XP with a 717 engine would act, well, odd with full down trim.
Your best bet is to keep inexperienced riders off an XPL. The ARE unstable. You will roll it pulling yourself on if you do not pay attention. Even those familiar with other boats need to be told, as you said, DO NOT TOUCH THE TRIM. Trimming all the way up will get you some interesting movement when crossing a wake at speed also.
Hulls are a compromise between agility and stability. The more agile, the less stable.
I do not want to get into the middle of the rest of this since I consider Reg a friend and by extension Dan (and have known TLR via the internet and various rides for a long time as well).
Still, I want to make a statement. You do not want to run open Flame Arrestors on a DI with a stock MPEM. I am sure there are guys out there who do it and say it is fine and think I am conservative and think they are safe right up until the thing melts a piston into a snowcone.
Your mechanic may be experienced, but if he is telling you to run anything but the stock air box on a DI with a stock MPEM he is flat out WRONG! The little that you may gain from them is far outweighed by the danger.
DIs run very, very lean compared to a carbed engine. They have extra cooling capacity because they do not have enough fuel in them to keep the crankcase cool. If you are letting in more air (and IMO, more air than the computer is programed to account for) your crank is that much hotter, the intake air/fuel is that much hotter, and the most sensitive to heat, the pistons, will thus be hotter. Hot=death on a two-stroke.
That said, I will retire my dog from the fight and wish you luck.
03-26-2009, 10:16 AM #10
At 3500+ feet, with F/A's and outerwears, the DI is able to handle it. For some reason, at that level, it brings everything back into mapped rage.. The cold weather though, may have just been enough to freak the computer out at holeshot, and it may have taken the MPEM a few sec's to adjust correctly.
F/A's at sea-level?? DUMB! But, it has been done... this ski was built at 223', tested at 212' (2ish hours), but was tested KNOWING that there could be an issue, so extreme caution was taken.
Yes Nathan, FA'a are Flame Arrestors, outerwears are the little socks that go over those FA's to keep water out and also helps keep some better restriction with the incoming airflow..
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