Ok I have a straight bore 61x nozzle but since I'm planning on putting trim on, I figured now is a good time to try the taper bore. The question I have is the veins are smaller than the exit diameter. I've been hogging out the exit side of the veins about an inch to create a smoother transition but do I need to try and shave the rest of the veins down a couple millimeters?
Boring 62t nozzle
- Thread starter Waternut
- Start date
#ZERO
Beach Bum
- Location
- Florida - U.S.A.
Keep the nozzle veins intact and taper bore the 61X nozzle around 2.2-degrees.
You should be able to blend the transition at the end of the vein section.
I don't know what you're hogging with but this needs to be done on a lathe to ensure accuracy.
You should be able to blend the transition at the end of the vein section.
I don't know what you're hogging with but this needs to be done on a lathe to ensure accuracy.
Sorry for the confusion. I'm leaving the 61x alone for now and boring the 62t right now. The problem is the stock 62t nozzle has/had about 1" between the end of the veins and the end of the nozzle. The 61x nozzle has 2.5" between the end of the veins and the end of the nozzle. After boring/blending the 62t nozzle now has 2.25" between the end of the veins and the end of the nozzle. They're both bored to 85mm now but the 62t veins are much taller and longer so appear much more out of place.
Here are some pictures of what I'm talking about. The first two are the 62t nozzle where I blended the veins to smooth the transition. The last pic is a straight bored 61x nozzle.
Here are some pictures of what I'm talking about. The first two are the 62t nozzle where I blended the veins to smooth the transition. The last pic is a straight bored 61x nozzle.
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#ZERO
Beach Bum
- Location
- Florida - U.S.A.
The 61X use a 25.5-degree reduction angle and the 62T uses a 21.0-degree reduction angle with a 3.5-degree nozzle angle so it will contact the fins sooner. If you use the stock angles when taper boring the nozzle they don't contact the fins more than a centimeter. I'd recheck your nozzle angle because it appears to be more than is actually needed IMO. If you're looking for more bottom end using a trim setup, I'd recomend using the 61X nozzle with the steeper reduction angle and weld some mounting tabs for the trim ring before it's taper bored.
#Zero, you are the exact person I was hoping would answer these questions but you're a tough person to please...lol. The 62t nozzle is spot on at 21° on the reduction angle but I guess I messed with the nozzle angle some because it's 2.5° and the transition between the reduction and nozzle angles are much smoother/longer than before (I'm guessing that's actually bad for bottom end).
What makes the higher angled 61x better for bottom end? Is it something to do with turbulent flow or higher pump pressure or what?
What makes the higher angled 61x better for bottom end? Is it something to do with turbulent flow or higher pump pressure or what?
#ZERO
Beach Bum
- Location
- Florida - U.S.A.
Using a steeper reduction angle will increase the pump pressure before it exits the nozzle and is more suited for bottom end performance.
A shallower reduction angle nozzle with a longer tail cone will create less drag and is more suited for mid range & top speed.
A shallower reduction angle nozzle with a longer tail cone will create less drag and is more suited for mid range & top speed.
That makes some sense in a way...but at the same time so many people bore the nozzle and add a stubby pump cone to reduce the pressure for better bottom end performance. I'll probably end up playing with pump cones anyway to see if I notice a difference.
Good to know people with fancy toys... thanks man.
- Location
- Barrie, ON
Check the thrust readings every 1000 RPM that should show you a difference.
I did, the static thrust follows rpm to about 300lbs then the pipe hits and it jumps to 500. At this point your about half throttle with a pair of 46s, three fourths throttle with 38s. The thrust stalls at 600 while the engine will rev a little more. Im working on a 155 conversion to see if I can improve static thrust. I will get numbers (thrust, RPM, and GPS) on this mod as well as some 650-750 Kawasakis in a couple of months.
masterblaster
X-H2
kev...any follow up to this experiment?
For static thrust I use a 3" Bimba air cylinder filled with diesel and a 100psi guage. I measure dynamic pressure with a pitot tube behind the nozzle.
masterblaster
X-H2
still interested to see how these comparisons turn out, to reduce pressure with the 62t nozzle or increase it with the 61x is the question,I just dont get the reason behind increasing it though,if we are boring the nozzle to decrease pressure and expell more water faster for low end,whats the point of using a 61x to increase it ?