2017 XFS Carbon Core

Robbie8984

Robbie8984

Location
Uk
Anyone know any more info on these?
upload_2016-10-31_12-10-13.png

Wondering if they have the comp large pump tunnel, de-foamed rear tray etc and a price.

Cheers
 
Paulk1

Paulk1

Location
Candlewood Lake
From what I understand all the bells and whistles of xfs textreme just with a little more weight than textreme/carbon or less than glass. The xfs hull is insane to begin with, and weighs very little. So pretty much all the benefits and a lower price point. I think homerun if u don't want to spend 11k. My .02.
 
Robbie8984

Robbie8984

Location
Uk
Cheers, got a 2016 glass XFS and really want the larger intake just can't justify spending that much on the comp.

Hopefully the exchange is better when they are available next year
 
Christian_83

Christian_83

Xscream
Location
Denmark
Can someone explain to me why the XFS comp intake would perform better, than the "normal" 155mm XFS pump intake? Given that the intake on the normal 2015+ XFS is at least equal in area to the 155/160mm pump shoe.
 
Proformance1

Proformance1

Liquid Insanity
Location
New York Crew
Christian_83 said:
Can someone explain to me why the XFS comp intake would perform better, than the "normal" 155mm XFS pump intake? Given that the intake on the normal 2015+ XFS is at least equal in area to the 155/160mm pump shoe.
Click to expand...

You are asking the right questions. Pump tunnel design is the reason why different skis, pumps, props, pump tuning etc all vary and its difficult to offer an answer from one set up to the next. Ask P&P performance why he has to spend hours tuning each particular boat. These are not plug and play performance items. You can get close but real tuning takes work, constant work.

I'll explain it from an experience we had. XScream KDX, 155 tunnel, 148 shoe. Took everything tuned properly in the KDX and moved it to a stock Yamaha SJ hull. Would not work properly, Imagine a 100 mm pump tunnel, with a 200mm pump. Your pulling through a small opening into a pump. Search flow through an orifice. Very interesting stuff. That Xscream tunnel was far superior in design and water feed to the pump that was the older designed SJ hull. The SJ intake tract was designed for a 650 motor and a 140 mm pump, IMO.

The competition XFS intake is supposedly designed superior, I havent tried one back to back myself, I have ridden one but not built one and then a regular XFS to do a full comparison. From building a new XFS and Edge, the tunnels are large, but you can see in the video different. There is a restriction at the shoe area. I know you're probably thinking why not use the best design possible where ever possible. IMO, if you do that the smaller motors and pumps wont work as well. That is why Rickter has designed two tunnels for the XFS.

Who wants to buy both, build one, then swap all parts over and see how they compare? Let me know how that goes. :)
 
Christian_83

Christian_83

Xscream
Location
Denmark
Proformance1 said:
You are asking the right questions. Pump tunnel design is the reason why different skis, pumps, props, pump tuning etc all vary and its difficult to offer an answer from one set up to the next. Ask P&P performance why he has to spend hours tuning each particular boat. These are not plug and play performance items. You can get close but real tuning takes work, constant work.

I'll explain it from an experience we had. XScream KDX, 155 tunnel, 148 shoe. Took everything tuned properly in the KDX and moved it to a stock Yamaha SJ hull. Would not work properly, Imagine a 100 mm pump tunnel, with a 200mm pump. Your pulling through a small opening into a pump. Search flow through an orifice. Very interesting stuff. That Xscream tunnel was far superior in design and water feed to the pump that was the older designed SJ hull. The SJ intake tract was designed for a 650 motor and a 140 mm pump, IMO.

The competition XFS intake is supposedly designed superior, I havent tried one back to back myself, I have ridden one but not built one and then a regular XFS to do a full comparison. From building a new XFS and Edge, the tunnels are large, but you can see in the video different. There is a restriction at the shoe area. I know you're probably thinking why not use the best design possible where ever possible. IMO, if you do that the smaller motors and pumps wont work as well. That is why Rickter has designed two tunnels for the XFS.

Who wants to buy both, build one, then swap all parts over and see how they compare? Let me know how that goes. :)
Click to expand...
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Yeah i aware of obvious diffrent design, I've done some testing myself through diffrent hulls and pump setups :)

My question was, what the theoretical difference is. Because the XFS 2015 glass is announced to accommodate 155pumps, assuming the intake duct is at least 155mm to feed the 155mm pump. The only difference i can see with the competition pump intake duct, is the intake duct beeing longer, and i cannot see how it should be able to flow more water through the comp intake than the "normal 155mm" intake, giving they both use the same 155mm pump setup. The flow is given by area x velocity, the area being the intake duct/pump shoe - i cannot see how the comp intake would be able to flow more than the normal 155mm intake, anyone? :)
Only advantage i can think of, would be the longer intake duct would (theoretical) hold a bit water, with going going out of the water (a bit like the setback pump)
 
Proformance1

Proformance1

Liquid Insanity
Location
New York Crew
You would have to measure both. You are correct, theoretically, but we dont know the specific designs all the way through the duct. The reg XFS narrows at the shoe. The comp is longer, but is all else the same? I would think not. Look again at the W shape of the XFS vs. the straight lines on the Comp. The Comp being longer COULD have a larger intake radius, therefore minimizing the "losses through a pipe". The larger the radius, the less "head losses". The intakes on Jet pumps are elbows, not straight ducts. IF.. they designed it that way. Again you would need a cross section, or back to back testing. Even if you had that and tested theoretically, then everyone would make a +2" design, then a +4", etc. At a point the intake tract is too far forward of the pump and it will begin to suck air too soon or you would have to make the drive line higher so that the radius is less severe.

If the pump tunnel is moved way forward a vacuum break will occurs earlier and the pump will no longer load. There is a sweet spot. I'm not stating the comp is better just stating different.
Your question is good, but the answer lies with RRP and only they know the answer. Or people who have back to back tested. That's marketing and design. ;) If we knew the real answer and made it public there are individuals that would immediately copy their design if its superior. The roll out lip on the side of the tunnel to the first chine plays a role also, as does the second chine. If you allow any water on a turn to find its way into the pump tunnel it breaks vacuum, and you lose grip and acceleration.

I worked with the Rage Composite guys a bit widening their tunnel and moving it up 2". I'm no expert, and always willing to learn, but like to play. IMO, XScream and Rickter XFS have the best tunnels on the market today, for flat water, from what I have tested.

As a side note you will notice that other manufacturers have smaller tunnels, for a good reason, and smaller pumps sometimes are recommended. There are quite a few surf riders that wont run a 155, it grips too much and will not allow the ski to loosen up the rear.
 
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kevbo

kevbo

Location
dfw
Use a longer inlet for high speeds. Go as wide as you can up to the bulkhead for flat water freestyle. Japanese hulls take this concept to the extreme.
 
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