Opinions On Nose Cones
03-29-2002, 01:14 PM
#11
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I read an articale, It could have been Teague in PB, that if you are running a conservative X dimen, read low, that the nosecone will give larger gains than if your drive is set up high and therefore the "gains only over 80mph" does not nessesarily ring true........Ill dig for the quote.
03-29-2002, 11:24 PM
#12
For you guys installing nose cones on the older drives with the front oil drain plug. What I did about the drain hole was to drill a hole larger than the drain plug centered over the drain plug. I then carfully tapped the hole in the nose cone for a 1/2 inch NPT brass plug. Be carefull because you have to thread it shallow since you don't want the plug to penetrate deeper than the inside surface of the nose cone. This procedure is done just before you mount the cone to the drive. Once the nose cone is mounted to the drive clean out any excess epoxie from the drain hole and any that gets into the threads. When the epoxie has set then thread in the BRASS plug untill snug - don't overtighten. Then cut off the part that sticks out beyond the side of the nose cone (leave a little so that you can file-sand it smooth to follow the same curve of the nose cone. Then drill two 1/8 inch holes about 1/8 inch deep into the face of the plug spaced as far apart as you can without getting too close to the threads. You can now use these holes to remove the plug to get at the drain plug underneath and there wont be the water flow disruption from the original big hole. I used two allen wrenches and a screw driver to twist out the plug but the y do make a tool for this type of plug - hole set up.
03-30-2002, 10:18 AM
#13
Nose cones or not
Hi!
I have a Phantom 25 w/Promax 300. I have experimented with nose cone and stock lower units. My set up is an outboard, but hopefully you can draw some ideas.
Set up is: Gears 1.75, CMC powerlift with 5,5 inches of setback, 26 inch labbed Tempest prop, propheight approx. 2.5 inches below bottom, positive trim, hull weight approx. 2.300-2.400 lbs.
My experience with a nose cone - Bobs Nose Cone factory installed with a high performance torque tamer - was not as advertised. Top speed with a stock lower unit was 76 mph on glassy water and no wind. With a nose cone, slip was reduced, but top speed was the same. The rpm dropped 100-150 rms. Midrange speed increased somewhat, approx. 1-1,5 mph. The boat runs 51 mph at 4.000 rpms. With nose cone approx. 52,5 mph.
To outweight the longer bullet of a nose coned lower unit, you have to in my experience either run in excess of 80 mph or run the propshaft higher to get less drag. In my case I could not rise the lower unit higher before rpms rincreased causing excessive slip. Water pressure with my TM lower unit was sufficent at all times.
So if you running more than 80 mph you should gain speed. If you also run a high x dimension / combination of the two, you should also gain speed. Please be aware of that if you use extendion boxes, your lower unit will be lower in the water (the water will hit the lower unit higher as more setback you have), but it will be easier to lift the bow with less trim = more speed. Best solution = shorter lower unit + extension boxes.....
Testing will only tell.
Cheers, Toffen G - Norway
I have a Phantom 25 w/Promax 300. I have experimented with nose cone and stock lower units. My set up is an outboard, but hopefully you can draw some ideas.
Set up is: Gears 1.75, CMC powerlift with 5,5 inches of setback, 26 inch labbed Tempest prop, propheight approx. 2.5 inches below bottom, positive trim, hull weight approx. 2.300-2.400 lbs.
My experience with a nose cone - Bobs Nose Cone factory installed with a high performance torque tamer - was not as advertised. Top speed with a stock lower unit was 76 mph on glassy water and no wind. With a nose cone, slip was reduced, but top speed was the same. The rpm dropped 100-150 rms. Midrange speed increased somewhat, approx. 1-1,5 mph. The boat runs 51 mph at 4.000 rpms. With nose cone approx. 52,5 mph.
To outweight the longer bullet of a nose coned lower unit, you have to in my experience either run in excess of 80 mph or run the propshaft higher to get less drag. In my case I could not rise the lower unit higher before rpms rincreased causing excessive slip. Water pressure with my TM lower unit was sufficent at all times.
So if you running more than 80 mph you should gain speed. If you also run a high x dimension / combination of the two, you should also gain speed. Please be aware of that if you use extendion boxes, your lower unit will be lower in the water (the water will hit the lower unit higher as more setback you have), but it will be easier to lift the bow with less trim = more speed. Best solution = shorter lower unit + extension boxes.....
Testing will only tell.
Cheers, Toffen G - Norway
04-01-2002, 06:23 PM
#14
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Location: st. clair shores mi ,us
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Toffen,
I just read an article explaing what you said
I found it surfing , I think it was from R & R propshop.
I know the box and shorter lower are the way to go but no $$ for that at the moment.
If I can at least go the same speed at a lower RPM that would be worth the nose cone. Of course a couple of MPH would be better !
I just read an article explaing what you said
I found it surfing , I think it was from R & R propshop.
I know the box and shorter lower are the way to go but no $$ for that at the moment.
If I can at least go the same speed at a lower RPM that would be worth the nose cone. Of course a couple of MPH would be better !
04-01-2002, 08:50 PM
#15
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decisions
I had a tough decision to make on the imco shorty.
I could use a 3 blade with the stock lower or I could spent all the bucks it takes to buy a shortie and install the parts then use a 4 blade. For only about 1.5 to 2 more MPH with the shortie.
I really liked using a 4 blade instead of a 3 blade. Commen sense said stay with the stock lower. But it didn't work.
I also thought sooner or later I will be putting in more hp and the shortie will shine even more when I get close to that 100 mph mark. The shortie will probably get me 6 mph instead of the 3.5 I am getting now.
I could use a 3 blade with the stock lower or I could spent all the bucks it takes to buy a shortie and install the parts then use a 4 blade. For only about 1.5 to 2 more MPH with the shortie.
I really liked using a 4 blade instead of a 3 blade. Commen sense said stay with the stock lower. But it didn't work.
I also thought sooner or later I will be putting in more hp and the shortie will shine even more when I get close to that 100 mph mark. The shortie will probably get me 6 mph instead of the 3.5 I am getting now.
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