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Prop Testing on E-Tec 175hp; finally
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| kamie |
Posted on 09/01/08 - 2:22 PM
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Well, after company left this weekend it was beautiful and the winds were fairly calm. I tossed the Vensura prop on the boat and it was time to do some testing.
Boat: 18 Outrage w/ Stern Seat
Engine: 2007 175HP E-Tec on Rite-hite 8 inch bracket
Temp: air ~75 / water ~ 80
Winds:10 -15 kts
water: flat
tabs fully retracted; canvas down
Speed via Garmin GPS
Fuel flow via Navman 3100
Laser II - 19p medium plugs
average of 2 runs
RPM - MPH - GPH - MPG
500 - 2.25 - 0.10 - 22.5
1000 - 4.85 - 0.45 - 10.9
1500 - 6.50 - 1.20 - 5.42
2000 - 7.30 - 2.30 - 3.18
2500 - 9.10 - 3.55 - 2.57
3000 - 12.00 - 4.65 - 2.60
3500 - 24.55 - 5.05 - 4.86
4000 - 30.65 - 6.35 - 4.83
4500 - 36.10 - 9.45 - 3.87
5000 - 40.45 - 12.80 - 3.17
5500 - 42.75 - 14.00 - 3.05
Vensura (Offshore) 17p solid plugs
average of 2 runs
RPM - MPH - GPH - MPG
500 - 2.95 - 0.30 - 10.75
1000 - 4.75 - 0.45 - 10.64
1500 - 6.25 - 1.10 - 5.68
2000 - 7.40 - 1.75 - 4.23
2500 - 8.85 - 2.75 - 3.21
3000 - 11.20 - 4.70 - 2.38
3500 - 16.30 - 4.50 - 3.62
4000 - 25.40 - 5.05 - 5.04
4500 - 30.35 - 6.60 - 4.60
5000 - 35.10 - 10.05 - 3.49
5500 - 39.10 - 12.20 - 3.20
5900 - 42.35 - 13.50 - 3.14
Not sure it's possible to raise the engine any more. The plate is out of the water on plane, when the engine is trimmed up. Also, not sure of the pitch of either prop since both were bought used from ebay. I left the Vensura on the boat, but may swap back and try the laser with solid plugs. With the two props I have, there is no way to push the boat faster than 43mph.
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| scrimshaw |
Posted on 09/01/08 - 2:55 PM
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Kamie, I've tested the Laser II and the Ventura also, solid plugs all around, The Laser II gives me more speed and can run 3 inches higher than the Ventura. I prefer the Ventura for every day use as it provides a better bite in a chop and my fuel burn at cruise shows it to be more friendly.
When I was looking for props I was told that the 19p Ventura would spin as if it were a 17p and saw no real difference in speed between a 17p Standard aluminium(Blackmax) and the Ventura 19p.
Edited by scrimshaw on 09/01/08 - 3:00 PM |
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| Ric232 |
Posted on 09/01/08 - 7:01 PM
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Kamie,
Based on your motor's operating range (4850 - 5850), it looks like a 17p in either prop would be just the ticket. Unfortunately, the Laser II does not come in a 17 so I would stick with the Vensura unless you want to try a different model of 3-blade in a 17p. Incidentally, your propeller efficiency with the Laser II fell off between 5000 and 5500 rpms (from 83.2% to 79.9%) which probably means you were slightly overtrimmed. All of the numbers fell in line on the Vensura. Looks like you were well one plane by 25 mph with both props although it looks like the Vensura was just starting to squeak you onto plane at 16 mph. I'd be happy to email you a spreadsheet if you want.
Anyway, I'd definitely stick with the 17p. You'll have better overall performance and a healthier motor in the long run.
Edited by Ric232 on 09/01/08 - 7:02 PM
Ric
2008 130 Sport
Merc 40hp 4-stroke |
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| Tom W Clark |
Posted on 09/01/08 - 7:54 PM
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Kamie,
There are a couple things I find remarkable:
Your boat only goes 43 MPH. I know we have talked about this before, but I am still surprised it is not faster. An academic observation.
You are seeing 5 MPG at the typical 4000 RPM range and it is with the underpitched VenSura. Man! I wish I could see fuel mileage like that with my boat ;-)
Your top speed is essentially the same with the VenSura as the Laser II. The Laser II is known as a fast prop, the VenSura is not.
Though the WOT range of the E-TEC 175 is 4850-5850 RPM, as Ric correctly notes, the optimum WOT range is 5500-5600 RPM.
Jim correctly notes that the VenSura tends to perform like a prop with less pitch (the Laser II does too to a smaller extent) so I would definitely recommend you try the 19". Do I remember that you already have?
The other prop I think you should really test is the Mercury Enertia in the 18" or maybe 19" pitch.
As far as motor height, it is fine for the Vensura where it is at. The Laser II, like the Stiletto Advantage, will tolerate higher motor mounting heights.
Edited by Tom W Clark on 09/01/08 - 7:57 PM |
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| Tom W Clark |
Posted on 09/01/08 - 8:00 PM
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A follow up on the Mercury PVS vent plugs: Like Jim, I recommend you try the Laser II with SOLID vent plugs. It will perform better on your boat.
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| kamie |
Posted on 09/02/08 - 1:56 PM
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Tom W Clark wrote:
Kamie,
There are a couple things I find remarkable:
Your boat only goes 43 MPH. I know we have talked about this before, but I am still surprised it is not faster. An academic observation.
.................
Jim correctly notes that the VenSura tends to perform like a prop with less pitch (the Laser II does too to a smaller extent) so I would definitely recommend you try the 19". Do I remember that you already have?
The other prop I think you should really test is the Mercury Enertia in the 18" or maybe 19" pitch.
Tom,
I am surprised as well that the boat only goes 43. The only remaining explanation is the bottom paint. The T-Top is gone, the boards are gone, nothing else left to blame lack of speed on. the funny thing is, I am getting almost the same speed as I was with the old 150HP Merc.
maybe it's the first day back from vacation, but are you recommending that I try a 19P Vensura? I have not tried one yet, but I could look for one. I could also look to pickup an Enertia and try that.
Mercury Recommendations are as follows ( using performance numbers for Vensura)
For Handling: Vensura - 19P
For MidRange Crusing: Vensura - 19P
For overall good performance
Enertia - 19P
Laser II - 19P
Vensura - 19P
Mercury Recommendations are as follows ( using performance numbers for Laser II)
For Handling: Vensura - 19P
For Mid Range Crusing: Vensura - 21P
For overall good performance
Enertia - 20P
Laser II - 19P
Vensura - 19P
For Top Speed:
Laser II - 19P
Vensura - 19P
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| Ric232 |
Posted on 09/03/08 - 4:35 AM
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Kamie,
How heavy was your load in the boat when running these tests? I've always tried to prop my boats toward the upper end of the WOT range when running a light load. That way the rpms should fall within the optimum range Tom describes above when you have a moderate load. On the other hand, if your goal is top speed, you want your WOT rpms to be right at the peak horsepower point for the motor (basic laws of physics), but that often results in lackluster acceleration. I don't know where the peak falls on your motor, but with most motors, it falls right in the middle of the WOT operating range (5350 in your case). I personally don't recommend propping with that goal in mind, especially if you're testing with a light load. Anyway, I'm not trying to second guess Tom by any means. These are just my opinions.
Ric
2008 130 Sport
Merc 40hp 4-stroke |
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| kamie |
Posted on 09/03/08 - 6:40 AM
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Ric,
I have actually tried to prop the boat for a typical load, that being myself with the tank 1/2 to full; which is what I typically run with. I could lighten the load a bit if I ran less than 1/2 tank of gas and removed the stern seat which adds 100# but since I usually run along, why not prop for that.
My performance goals are generally mid-range cruising or overall good performance. The published optimum range for the E-tec 175 is 5500-5600 RPM's, switching to a 19P Vensura would bring be to the low end of that range. Looking at the prop calculator on CW, the slip at WOT for the Laser II is 19.65% and for the Vensura it's 17.07%. Both of those seem high to me?
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| Buckda |
Posted on 09/03/08 - 9:15 AM
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Kamie -
I share the suprise at the relatively low speed produced by teh 175 E-TEC. It makes me wonder if that motor isn't more closely related to the shared-block 150 than advertised.
I used to see 47 MPH with my Merc 150 Black max on my 18...with no arch. Now, with the arch and twin 90 HP E-TEC's, I'm seeing 49 MPH in basic prop testing (190 HP, unless those 90's are "hotter" than advertised). You should be seeing 45-47 MPH at least.
Are you fully trimming the motor out until you ventilate and then trimming back in? I need to trim the motors "WAY" out to get the top of the RPM band and max speed.
Finally - have you weighed Evenstar? Let's hope that you don't have a problem there.
Can bottom paint rob you of 5 MPH off the top end??
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| kamie |
Posted on 09/03/08 - 9:46 AM
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I need to recheck the weight, but I estimated the hull at 1390#. The scale I use is not a certified scale, but probably close (local lumber mill). I don't remember how stripped down I had her when I did the weight I know there is some water, but really how much is always the question.
The bottom paint, is in really bad shape and I suspect that could account for some of the loss of top end speed.
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| Ric232 |
Posted on 09/03/08 - 4:45 PM
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Kamie,
If your prop test was done with your typical load, you can stick with the 19p if you wish. But if you ever have 3 or 4 people in the boat, it will struggle. Anyway, I agree that the slip numbers are high. 20% slip is typical for a high-performance boat with a stepped/ventilated hull, high x-dimension, and 4-blade props. I don't have enough experience with Whalers to know what typical slip is for them, but I suspect the condition of the bottom is hurting things. I also agree with the comment that you should make sure you're fully trimmed out when doing your test. As I mentioned earlier, your prop slip increased with the Laser II between 5000 and 5500 rpms, which suggests you were overtrimmed. Or it could have just been an anomaly. I'd re-run the test with the Laser II. FWIW, the new 190 Outrage with a 150 Optimax has 10% slip at WOT (5750 rpm).
I don't see the optimum rpm range on the Evinrude site. Is it in the owner's manual?
Edited by Ric232 on 09/03/08 - 5:01 PM
Ric
2008 130 Sport
Merc 40hp 4-stroke |
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| kamie |
Posted on 09/04/08 - 1:22 PM
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http://forums.etecownersgroup.com/too...id=2671224
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| kamie |
Posted on 09/04/08 - 3:30 PM
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I will test again,remembering to trim really far out, and including testing the Laser II with solid plugs but for now, there is a hurricane coming so the boat is heading for dry land.
ric,
I prefer the 4 blade over the 3 blade, from a ride perspective. The rev limiter kicks in at 6100 RPM's on the engine and I have had the Offshore prop up to 6000 at wide open, probably with less than 1/3 of a tank of gas. I figure that if I go to the 19P Vensura that will drop the RPM's into the 5500 range
Tom, how does the Mercury Enertia compare to the Vensura for ride?
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| Blue_Northern |
Posted on 09/05/08 - 7:10 AM
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Kamie - this is great information. Thank you for sharing with the rest of us. I am looking to power with the 150 e-Tec but I think the variables should remain somewhat close to the 175. Great information! 
Rob
1973 Outrage/Lo-Pro Conversion |
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| Tom W Clark |
Posted on 09/05/08 - 5:40 PM
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Kamie,
I wrote a lengthy reply last night and tried to post it...twice, and it would not post and I lost it. I'll try again in a little while...
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| kamie |
Posted on 09/05/08 - 5:54 PM
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Wow Tom, and I thought that only happened to me
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| Whaler27 |
Posted on 09/06/08 - 6:21 AM
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Several observations.
First, the 19P Laser II is not performing like a 19 inch pitch propeller. If it was performing like it had 19 inches of pitch, you should see 29 to 30 MPH at 3500 RPM (a 19 inch pitch on a 1.85:1 gear ratio tends to run about 5 MPH slower than the tachometer x 100, i.e., 25 MPH at 3000 RPM, 30 MPH at 3500 RPM). A 17 inch pitch will tend to run about 10 MPH slower than the tachometer x 100 (i.e., 25 MPH at 3500 RPM, 30 MPH at 4000 RPM...) The data suggests its performing more like a 17 inch pitch or there is a tremendous amount of slip.
Second, the 17P Vensura is not performing like a 17 inch pitch propeller, but more like a 15. Perhaps the running height is too heigh for this propeller.
Finally, when properly loaded, a 175 E-TEC should be burning about 16.5 GPH at WOT and about 8.5 GPH at 4000 RPM. Yours is only burning 14 GPH and 5 to 6 GPH at 4000 RPM. Is the F3100 calibrated properly?
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| Ric232 |
Posted on 09/06/08 - 6:31 AM
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We've already discussed above that the calculated slip is unusually high at approx. at 18-20%. If this was just one propeller doing this, I'd say try another. Since both have similar slip, I'd say it's either an issue with the bottom of the boat or the data is inaccurate (i.e. tach or GPS). If the tach is reading high, that would mean the motor is not achieving adequate rpm's (which it should with the pitches being used). Again, that points back to the bottom of the boat generating excess drag.
Whaler27's comments about the fuel consumption are a very good observation. If the GPH numbers are accurate, that could mean the tach is reading high (as much as 500 rpm).
Kamie, do you have another GPS and/or tachometer you can try, just in case yours are off? We might as well eliminate as many variables as possible. Keep us posted. This is a mystery we need to solve. The more I think about this, the more I'm thinking we've got inaccurate data somewhere.
Edited by Ric232 on 09/06/08 - 6:54 AM
Ric
2008 130 Sport
Merc 40hp 4-stroke |
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| Tom W Clark |
Posted on 09/06/08 - 9:07 AM
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As a general statement, too much is made of propeller slip. More slip is not necessarily bad. If the boat is faster (or more fuel efficient, accelerates better, whatever your goal is) with a higher slip, then so be it. The proof of the pudding is in the tasting.
Now having said that, we have become familiar with the *typical* slip figures for many common models of propellers when used on common Whalers. Some props will always have high slip figures. The Laser II, VenSura are among them. Likewise, some will always have relatively low slip figures like the MIRAGEplus, Revolution 4 and Stiletto Advantage.
In Kamie's case, I do not think that the tach is wrong. The boat speed is still low compared to other comparably powered Outrage 18s. It was slow with her old motor as well. I have long suspected that the hull is wet. Certainly bad bottom paint will take a huge toll as well.
Kamie -- I do think you should try the 19" VenSura/Offshore or the 18" Enertia.
Edited by Tom W Clark on 09/06/08 - 9:08 AM |
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| kamie |
Posted on 09/06/08 - 10:41 AM
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I doubt the Tach is wrong since it it nothing more than a head unit for the engine, that would imply that the engine didn't know it's RPMs. I am running I-Command Digital gauges, not your standard analog. As for the GPS, it's possible that it could be off, but since I don't have a spare, this one will have to do. The GPS is a Garmin GPSMAP180, with an external antenna. The Navman 3100 has been calibrated, and I will check the calibration before I do more testing, because I need to fill the tank, while I have the boat pulled out for storm avoidance. It is possible the 3100 is slightly off, I know that it and the engine often disagree about fuel flow, although not by much.
According to my calculations the hull is holding about 150# of water if you believe that the standard configuration of an 18 Outrage is 1250#. I will weigh the hull again when I strip off the excess junk and fill the tank for winter, but I think that 1250# is on the light side.
I like the ride of the vensura, and will look to pickup a 19P to try out. I was looking for an Enertia, but didn't see one on the used market. In the mean time, I will retest the Laser II with solid plugs and work on trimming out more. It is also possible that the Vensura is being run higher than it would like but no blowout on turns, even at high speed.
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