Heat X
07-11-2008 | 10:39 AM
#21
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From: Missouri
07-11-2008 | 07:57 PM
#23
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From: CDA, ID
07-11-2008 | 11:43 PM
#24
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From: Missouri
On a 3700 pound dry weight Nordic Rage assuming the 28P labbed Bravo 1 is actually a 27P (per Throttle Up) I was getting13% - 15% slip at WOT at 5350 RPM. I am just trying to deternmine if the prop is working properly. If it is so be it. If it is not I want to know that and get it working properly. I added a lot more HP/Torque over the winter and now when I mash the throttle at about 3000 rpm it is almost like borderline cavitation. It is like the additional torque is over powering the prop at that point. The engine revs up more than the boat speeds up though the boat is significantly accelerating. With the additional HP I am now up against the rev limit. I am increasing the rev limit to 6000 rpm to let the engine find its new WOT speed/rpm (the new internals will accomodate this).
07-17-2008 | 04:17 PM
#27
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From: CDA, ID
The "X dimension" is the vertical (not measured along the transom angle) distance between the driveshaft, and the bottom of the boat.
I use a flat or square yardstick taped to or held against the pad. Then, you can measure off the top of the yardstick with a framing square, to the tilt pins on the side of the gimble bracket. The tilt pins are located at the same height as the drive shaft.
It does help to level the yardstick, and check the framing square for vertical alignment.
Since I know mine is 19.25" measured this way, I thought you might want to measure yours "the easy way" along the transom from the bracket to the top of the notch. If your's measures 6 3/4"s, you're at the same height. Above (unlikely)or below that, would give you something else. Either way, you would have a known height to work from.
For instance, 19.25" is generally too high, and a 1" spacer usually results in much better slip %s with a 4 blade. If your "bracket to notch" measurement is more like 6"s to 5 3/4"s, you are lower by 3/4" to 1" and closer to what we have generally found to be a better performing XD on a Heat.
What Imco is asking you for is propshaft depth. Another practical way to determine gearcase and propeller depth. That is partly how they determine whether or not a nosecone, standard length Imco case, shorty, or spacer would help a specific boat.
What did they say?
Good luck and keep us posted with your progress.
Steve
I use a flat or square yardstick taped to or held against the pad. Then, you can measure off the top of the yardstick with a framing square, to the tilt pins on the side of the gimble bracket. The tilt pins are located at the same height as the drive shaft.
It does help to level the yardstick, and check the framing square for vertical alignment.
Since I know mine is 19.25" measured this way, I thought you might want to measure yours "the easy way" along the transom from the bracket to the top of the notch. If your's measures 6 3/4"s, you're at the same height. Above (unlikely)or below that, would give you something else. Either way, you would have a known height to work from.
For instance, 19.25" is generally too high, and a 1" spacer usually results in much better slip %s with a 4 blade. If your "bracket to notch" measurement is more like 6"s to 5 3/4"s, you are lower by 3/4" to 1" and closer to what we have generally found to be a better performing XD on a Heat.
What Imco is asking you for is propshaft depth. Another practical way to determine gearcase and propeller depth. That is partly how they determine whether or not a nosecone, standard length Imco case, shorty, or spacer would help a specific boat.
What did they say?
Good luck and keep us posted with your progress.
Steve
Steve,
From the bottom of the keel, measured vertically from a level, I measure 18.25" to the pivot point/drive shaft.
Your thoughts?
07-17-2008 | 04:24 PM
#28
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From: Nashvegas, TN
I heard through the grapevine that the factory had come to their senses, and dropped their X dimension 1". Probably from the suggestions of their dealers, and what they have read here.
I can tell you from my boat and several others of the earlier ('01 to '06) models that all of us (here), have lowered our drives. It seems like 1" has been perfect on 90% of our Heats, which is exactly the same as your 18.25"s.
I think you are right where you need to be.
I would play with props. Have you tried a P5-X?
Best Regards,
Steve
07-17-2008 | 04:47 PM
#29
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From: CDA, ID
Interesting,
I heard through the grapevine that the factory had come to their senses, and dropped their X dimension 1". Probably from the suggestions of their dealers, and what they have read here.
I can tell you from my boat and several others of the earlier ('01 to '06) models that all of us (here), have lowered our drives. It seems like 1" has been perfect on 90% of our Heats, which is exactly the same as your 18.25"s.
I think you are right where you need to be.
I would play with props. Have you tried a P5-X?
Best Regards,
Steve
I heard through the grapevine that the factory had come to their senses, and dropped their X dimension 1". Probably from the suggestions of their dealers, and what they have read here.
I can tell you from my boat and several others of the earlier ('01 to '06) models that all of us (here), have lowered our drives. It seems like 1" has been perfect on 90% of our Heats, which is exactly the same as your 18.25"s.
I think you are right where you need to be.
I would play with props. Have you tried a P5-X?
Best Regards,
Steve
I've been towing with the idea of a labbed mirage (3 blade).
I have no hook-up issues what-so-ever coming out of the hole so I figured what the hell, see what it does.
07-17-2008 | 11:22 PM
#30
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From: Nashvegas, TN
Tried a worked 25 PX5 and didn't really like it. Felt like to much stern lift for my boat. In terms of performance, it ran about 2mph slower compared to the B1 and the R's were about the same.
I've been towing with the idea of a labbed mirage (3 blade).
I have no hook-up issues what-so-ever coming out of the hole so I figured what the hell, see what it does.
I've been towing with the idea of a labbed mirage (3 blade).
I have no hook-up issues what-so-ever coming out of the hole so I figured what the hell, see what it does.
The P5Xs, properly labbed, are as fast or faster on my boat, and much more efficient in midrange, and much quicker under hard acelleration than B1 4 blades.
I haven't run a Mirage on a Heat, but on my last boat (24' Baja H2X with 600HP), it broke loose under hard accelleration and cornering. Slightly faster (maybe 1 MPH) with a light load on a long stretched run. Still very weight sensitive.
Steve
Last edited by Steve Zuckerman; 07-17-2008 at 11:25 PM.
