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| 7000' = poor performance https://www.smwebhead.com/phpBB3/viewtopic.php?f=3&t=6338 |
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| Author: | KNEEOIL [ Sun Aug 08, 2010 11:09 pm ] |
| Post subject: | 7000' = poor performance |
We just got to Park City and dropped our '08 H210 in the reservoir. I had just swapped out the stock prop for a 4-blade 19" aluminum prop. With the 5.0L GXi @ 270 HP, I thought that would be a nice improvement. But the boat is very sluggish getting on plane. I'm assuming the altitude here is the main factor, but also wondering if I should've gone with a 3-blade 19" prop instead. I'm new to boating, so not quite sure what would help. Any insight would be appreciated. |
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| Author: | 230 Mike [ Mon Aug 09, 2010 1:17 am ] |
| Post subject: | Re: 7000' = poor performance |
Since more than one thing changed it's a bit of a moving target. But I too would bet the altitude is most if not all of the problem. |
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| Author: | Y-Guy [ Mon Aug 09, 2010 1:33 am ] |
| Post subject: | Re: 7000' = poor performance |
Isn't the GXi a fuel injected motor? If so altitude shouldn't play a huge factor I would think, but that comes from my ATV experience not boating. |
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| Author: | BrentC5Z [ Mon Aug 09, 2010 8:35 am ] |
| Post subject: | Re: 7000' = poor performance |
Y-guy, you are correct on the FI part. Carbs require re-jetting for altitude as you suggest but not FI. However, less dense air still make for less HP even with FI. The prop should be adjusted in my opinion. |
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| Author: | TX H210SS [ Mon Aug 09, 2010 8:41 am ] |
| Post subject: | Re: 7000' = poor performance |
maybe i'm wrong, but thought if you go from the 3 blade to the 4 blade then you have to make a change on the pitch??? You have a lot more surface area on that 4 blade than you had before with the 3.....from what I've always understood the 4 blade is a hole shot prop - you should be gaining hole shot and losing a little on the top end. |
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| Author: | KNEEOIL [ Mon Aug 09, 2010 8:57 am ] |
| Post subject: | Re: 7000' = poor performance |
Yes; the stock 3-blade is a 21" pitch; we went to a 19" 4-blade. Had fun all day either way. Bought an Airhead G-Force towable which should see some action today. Yesterday was some wakeboarding which went well - first time pulling someone w/the boat. I guess at altitude, the only thing we can do is add twin turbos and a supercharger. 
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| Author: | Indy Steve [ Mon Aug 09, 2010 9:43 am ] |
| Post subject: | Re: 7000' = poor performance |
KNEEOIL wrote: Yes; the stock 3-blade is a 21" pitch; Interesting, I've got the same year boat/engine and mine came with a 19" pitch. What was your top speed at lower elevation? |
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| Author: | Y-Guy [ Sat Aug 21, 2010 10:48 am ] |
| Post subject: | Re: 7000' = poor performance |
Brent87LT1 wrote: Y-guy, you are correct on the FI part. Carbs require re-jetting for altitude as you suggest but not FI. However, less dense air still make for less HP even with FI. Boy I really noticed this after our last trip, we were up about 5,000' and then last night back home which is about 400' I was really shocked how much more power I had. I figured the power loss I was feeling was due to having 5 passengers, but your comment was dead on. |
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| Author: | hellasnow [ Mon Aug 23, 2010 9:03 am ] |
| Post subject: | Re: 7000' = poor performance |
i'm in Denver Colorado. i'm generally boating around 5200-5500 feet close to home lakes. we also go to a lake in the mountains where my wife is from it's 8000+. when we bought the boat it had a 19" on it. at 8000' it's a pig. around here 5200-5500 it's managable but still could use some more. we just went to Powell for 2 weeks and before leaving i bought a 17" prop (both are 3 blade aluminum). now powell is much lower for us, 3636 was water level when i was just there. the 17 screameeeed at powell and would get my WOT (wide open throtle) at about 4900-5000 RPM's, just a bit high, while the 19" WOT around 4400-4700 RPM. we ended up running the channel alot so i put the 19 back on it while doing marina trips and sight seeing but would put the 17 back on for wakeboarding and man what a difference in holeshot! i have not had the boat out on the water in the higher elevations around Denver with the 17 yet but i'm guessing it would perform perfectly for this elevation. we have a 2000 19' horizon with the 5.0, i've never jetted it just playing with props. motor always seems to run smooth at any altitude. i'm anxious to get back up to 8000 with the 17 cause i'm sure it will run like the 19 does at 5000'. my 2 cents.... |
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| Author: | KNEEOIL [ Mon Aug 23, 2010 12:18 pm ] |
| Post subject: | Re: 7000' = poor performance |
So, I just figured out a big part of the equation. We keep our boat in storage, so when I went to order a lower pitch prop, I mistakenly thought our '08 H210 came with a 21" prop (I think based on some online research) so I thougt stepping back to a 19" would solve the issue. Turns out that stock was a 19" prop. All that being said, I have a brand new 19" 4-blade prop for sale! $75. |
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