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riverman
Joined: 12 Dec 2010 Posts: 23 Location: Grande Prairie
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Posted: Tue May 10, 2011 5:14 pm Post subject: sportjet impeller repitch |
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I am about to send impeller to "IMPROS" to be repitched , it is a 4 blade hi-skew , my motor is 175 sportjet . My objective is to pitch up to reduce rpm . Just wondering if anyone has done this , or has some input ? Thanks |
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Rapid Transit
Joined: 20 Jun 2005 Posts: 206
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Posted: Wed May 11, 2011 11:37 am Post subject: |
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I would be a little cautious about that, those engines need rpm to develop hp, if you over impelor them they will be pulling all of the time and not running freely, and you gas consumption will go way up, therefore all you tried to acomplish was a waste. just ask the other 175ers what happens to their fuel burn when they load their boat heavy and the engine has to pull hard
just my 2$ |
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riverman
Joined: 12 Dec 2010 Posts: 23 Location: Grande Prairie
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Posted: Wed May 11, 2011 12:38 pm Post subject: |
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Yes not all experiments have a happy outcome , I will post my comparison / results when it goes on . |
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RPM
Joined: 17 Dec 2006 Posts: 189 Location: Nechako
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Posted: Wed May 11, 2011 9:13 pm Post subject: |
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how is the condition of your stator ? repairing any damaged vanes and building them up closer to the impeller will help the effienecy . the 3 blade impeller showed some improvement with a little tweaking but the 4 blade already has enough pitch for the 175 . probably more to be had looking at your boat , getting rid of any weight possible , dents , etc . that increase planing surface and drag . hadn't heard of "impros" so i googled it , plenty of people in your area or Red Deer or even here in P.G. with lots of experience , why send it to a jet-ski shop in Calif ????? _________________ Rick's Precision Machine
Prince George B.C.
Machining - Welding - Repairs |
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riverman
Joined: 12 Dec 2010 Posts: 23 Location: Grande Prairie
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Posted: Wed May 11, 2011 11:29 pm Post subject: |
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Stator has some wear but not too bad , I will look at it while changeing impellers and build up if it's getting too wore down . I went with IMPROS as I have not heard of anyone repitching a sportjet impellor so I had no idea who could do it so I googled it and IMPROS showed up and I phoned them to see if they had done sportjet impellers , they said they had and seemed pretty knowledgeable so I thought I would go with them . I am sending the impeller out tomorrow but if there is some one more local who has the expertise to do the job properly (all impros does is impellers and they sound pretty knowledgeable on the subject) I would defineatly use a more local shop if they are knowledgable and experienced with repitcing sportjet impellors (which are a lot like jetski impellors ), any suggestions ? Do you do this ? |
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shallow draft
Joined: 15 Jun 2005 Posts: 134 Location: Rocky Mountain House
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Posted: Wed May 11, 2011 11:37 pm Post subject: |
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Before you send your Impeller to California call Steve at Firefish.
Do you have a steel wear ring? If not that is the place to start.
I would doubt that a 175 can efinciently pull much more of an impeller than a High Skew 4 blade. _________________ You are not lost if you Don't care where you are |
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RPM
Joined: 17 Dec 2006 Posts: 189 Location: Nechako
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Posted: Thu May 12, 2011 9:13 am Post subject: |
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riverman , your right impellers all have similarity not doubting impros ability to rework yours . pretty sure i've seen lots of guys posting from Grande Prairie over the years doing this . yes i've rebuild impellers from jet-skis to 15" industrials and could pitch yours but like i have already said as have others a hi-skew has enough . one of my reworked 3-blades will hold a 175 at 5300 , with yours at 5400 with a hi-skew makes me think you might have something causing a little cavatation , maybe a dent or plastic not fitting right in front of the intake or maybe a bent grate distrubing the water flow or sucking air from between the easy clean and hull . just some things to check if you haven't already . i read your other thread where you mentioned the noise was why you wanted the rpm down , ya sport-jets are noisey little buggers for sure , maybe some sound deading in the doghouse would help . good luck _________________ Rick's Precision Machine
Prince George B.C.
Machining - Welding - Repairs |
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Rapid Transit
Joined: 20 Jun 2005 Posts: 206
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Posted: Thu May 12, 2011 3:09 pm Post subject: |
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lay a mudflap on your swim grid that will get rid of the most noise...for cheap |
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On-Track
Joined: 15 Jul 2010 Posts: 79
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Posted: Thu May 12, 2011 10:30 pm Post subject: |
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While on the topic on Sj impellers has anyone else heard of a new aftermarket 3 and 4 blade Hi-Skew SJ impeller coming out market? I wonder how much of a difference in design and performance from the current SJ 4 blade Hi-Skew it will be? |
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riverman
Joined: 12 Dec 2010 Posts: 23 Location: Grande Prairie
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Posted: Fri May 13, 2011 11:31 am Post subject: |
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I here claude at E X Welding in Prince George is having some different 3 &4 blade S.J. impellers cast and should be out soon , good to see some innovative ideas for sportjets. |
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On-Track
Joined: 15 Jul 2010 Posts: 79
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Posted: Mon May 23, 2011 9:42 pm Post subject: |
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riverman:
Any results with your repitched impeller? I believe the new 3 blade and 4 blade Hi-skew's should be ready for trials in a month or so. Very interesting to see how they will work with thicker blades compared to a stock impeller. |
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riverman
Joined: 12 Dec 2010 Posts: 23 Location: Grande Prairie
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Posted: Tue May 24, 2011 9:45 am Post subject: |
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Impeller just arrived at Imoros monday (7 days UPS)they say 5-7 days backed up ,so should have it installed in about 15-18 days (june 10ish). I will gps baseline and post my findings with repitched impeller , my present impeller is still nice and tight so should be pretty fair comparison. The new impellers sound like they should be way tougher and hold an edge for a lot longer so I suspect I will be ordering one once Claude @ E.X.Welding has finished testing them . |
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shallow draft
Joined: 15 Jun 2005 Posts: 134 Location: Rocky Mountain House
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Posted: Wed Jul 06, 2011 1:35 pm Post subject: |
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Any updates on this project? _________________ You are not lost if you Don't care where you are |
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On-Track
Joined: 15 Jul 2010 Posts: 79
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Posted: Wed Jul 06, 2011 10:59 pm Post subject: |
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It will be interesting to hear the results with the repitch. With the blades being so thin and not heat treated I don't know if they would stay repitched. |
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On-Track
Joined: 15 Jul 2010 Posts: 79
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Posted: Sun Aug 07, 2011 3:51 pm Post subject: |
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Any reason Impros didn't repitch your hi-skew when they rebuilt it? I notice a photo of the new SJ impellers posted on another forum. They look good but are sure taking some time getting out on the market. I am sure there must be reasons for such a long delay. That 3 blade hi-skew will be interesting to see how it will work with a 175 SJ. |
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