Thread: 05 GTX SC
02-17-2008, 09:59 PM #1
05 GTX SC
2005 SeaDoo GTX SC (not intercooled) with the Riva Stage I, Riva free-flow exhaust and iridium plugs. The decision to upgrade to the Stage I was kinda easy since I had to replace my wear ring/impeller after ingesting a huge rock.
Making a very long stoy short...I messed up the pump, trying to remove the impeller. Riva sent me the newest RXP pump including the wear ring/impeller as a bolt-on unit. After mods, I got 55 mph top speed at 7450 rpm.
After making the trek two hours to Baton Rouge to the nearest dealer (Alexandria, LA), the dealer stated I had compression of 115 in each cylinder, and 44 ft pounds of torque on the SC. I thought I had a warranty to cover whatever my problem of 55 top speed at 7450 rpm. I do have an extended warranty, not from SeaDoo, but from aftermarket from the dealer.
I called the dealer I bought the ski from and told them the situation, and we concluded, it would be best to travel the 3.5 hours to Tyler, Tx. After 2 weeks, the dealer called and said they had no problem getting 60 mph with 20 mph wind, rough water, full tank of fuel and 220 lb rider.
Man! They act like nothing is wrong. Man! Riva site reads 67 mph at 7600 (http://www.rivayamaha.com/pwc_perf_p...c_stg1_kit.asp).
The dealer, not knowing what impeller I had, said it seemed sluggish, "...like it had too much impeller." The kit includes a 13/20r. the "r" is suppose to be for Riva-modified. Who knows?! Any ideas on what impeller I may need on this kit, OTHER than the Riva recommeded?
Is the dealer's ride experience accurate? Think I would get faster speeds without wind/water/rider conditions? Hell, I could get 60 with stock set-up before my impeller/wear ring fall out. --Jeremy
02-17-2008, 10:25 PM #2
'r' stands for "pitched blocked for accuracy" riiiiiiight.
Make sure they are testing with a GPS.
02-17-2008, 10:35 PM #3
GPS...brilliant! What are your, and everyone else's thoughts/experiences with these impellers? What do you recommend with my mods? --Jeremy
02-18-2008, 08:34 AM #4
67 with just a stage I isn't really realistic...more like 65-66(imo)
02-18-2008, 09:17 AM #5
- Join Date
- Oct 2005
jpe: 115 compression sounds low, did they warm the cylinders prior to testing, you should be around 122`s cold - 132-135 hot for a mechanically sound engine.
also they upgraded you to RXP pump?
Housings are the same. The wear rings are different inside diameters, 155mm and 158mm.
your RPM`s are down by 150+, you should be seeing 7600. 7650 is max R`s for that machine.
also 55 mph top speed, somethings not right. You should be near or at 63-64.5.
SC slip is measured in " inch pounds" not foot pounds. I`m not sure where they got that measurement from.
Theres def something not right
are you experiencing cavatation?
Does the ski feel strong?
sounds like you def want to have the SC looked at, and the engine tested again the proper way. If your compression is to low, you may not be getting enough ummmph to spin that 13\20R.
if you have access to another prop stock or 12\20 try that and see where you ski is at...
also don`t believe the Dreamometer for accurate speeds, but they are close.
02-19-2008, 12:01 PM #6
Thanks for the posts guys...
The ski felt stock to me beside feeling a bit more out of the water because of the wedge, I guess. The dealer in Tyler, Tx told me he was 225 lbs, full tank of fuel, 25 mph winds and rough water and got 60 mph on the ski's speedometer. He did say the ski felt "sluggish" like the prop 13/20r impeller was wrong. He tested the cylinders warm and got a higher compression. He also said the SC was tight, and looked very good (props to me - woohoo).
1) Opinions on impeller? Riva sells this in their Stage I kit. Several of the members here have written previously, that they believe the 13/20r is not correct with my set-up.
2) Is there a way to increase boost pressure in stock SC with metal washers?
3) With dealers riding conditions, what are your thoughts on what the ski should be able to do? Consider 225 lbs, 25 mph wind, rough water, full tank of fuel, and MAYBE "sluggish" impeller.
The way it sounds, I spent $700 for 2 mph tops??? --Jeremy
02-19-2008, 01:21 PM #7
02-19-2008, 01:23 PM #8
02-19-2008, 02:46 PM #9
Yes, a month or two ago, I was about to take it to the first dealer. Since I have taken it to the second dealer, which found nothing wrong with the ski, besides saying it was sluggish, regarding the impeller. He did replace my iridium plugs for OEM, however he did not say anything regarding iridium performance...he just doesn't like them. Nice, eh?
Tell me how to tweek the impeller, or point me to a thread, please. Is there anyone near central Louisiana with tweeking experience? --Jeremy
02-19-2008, 02:56 PM #10
Therefore I think 67 mph highest potential with Stage 1. Is not impossible but not all will see those speeds in my opinion. It just depends on what the stock ski was on gps to begin with.
As far as pitching a prop, you can find in the how to section. Since you are in lousiana, you might just send it to Jerry to have it done.
IF you have not yet, you need to baseline the ski yourself with gps and make note of rpm,s, air temp, water temp, and any other conditions that can affect performance. He or you must know these things in order to be able to pitch the prop correctlly.
Last edited by skoepp; 02-19-2008 at 02:58 PM.
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