What's the difference in regs?

[diverrick]

I recently picked up a new Scubapro MK18/G250 on sale at a LDS for my wife. I don't see it mentioned on SP's website.
I was wondering what the differences are between a MK 16 and the MK 18, is the 18 a better reg or just different?

 

[DA Aquamaster]

The Mk 16 and Mk18 are very similar and internally are essentially the same design with the same internal arrangements and the use of a hemispherical chamber to increase the internal volume of lP air. Both use the same annual service kit.

The difference is that the MK 18 uses a swivel port turret. This has an obvious impact on hose routing but also further increases the internal volume of the IP areas of the reg which creates a bit more IP air to draw upon on inhalation. The air moves from the orifice and poppet in the center of the first stage through ports to the turret.

The Mk 16 in contrast has no swivel turret and the hoses route directly out the sides of the first stage. The air flows directly from the area of the orifice and poppet. A port is identified for use with the primary second stage that uses a venturi assist to boost flow rate which compensates for the potential lag that may otherwise occur in high demand situations due to the reduced internal volume compared to a Mk 18.

Both are good performing regs with flow rates around 90 SCFM and very stable intermediate pressures. I personally prefer the MK 18 due to the convenience of the swivel port. The Mk 18 is not shown on the SP website and it is also not widely marketed in the US but is much more widespread in Europe.

SP is supposed to be developing an even better diaphragm first stage - the MK 17, but I have not heard anything on this lately.

 

[WarmWaterDiver]

The Scubapro MK18 can be viewed at the Scubapro United Kingdom site, but not their North America site.

http://www.scubapro.co.uk/products.asp?P=330

 

[ElectricZombie]

SP is supposed to be developing an even better diaphragm first stage - the MK 17, but I have not heard anything on this lately.

Interesting. Hopefully SP will make a simpler diaphram 1st stage similiar to the Apeks ones.