SB17 vs SB18

[Mille aka Fredrik]

What is the difference between the these two mufflers on a SZH?
Best choice?

[DavidH]

18 is a little longer than 17 by about 25 millimeters.
I would recommend the SB 18 on the SZH

David

[Mille aka Fredrik]

I've read that a new SB will be out for the SZH, rumor or true?

[DavidH]

I don't know when it will be available. But I understand there is suppose to be an SB 19.
There is a couple of pilots that have them now I believe.

David

[JohnSSN700]

I have the SB-17, says "SZH" right on the box. Seems to work great for me.

[G MAN]

THE MUFFER SECTION IS LONGER ON THE 18 THAN THE 17,THE TUNING IS THE SAME.DOUG

[Mille aka Fredrik]

Have read that SB18 is for motor RPM over 15700 and SB17 under 15700.

So the SB17 suits the 8.18 gearing better?

Have order a SB18 at Rick's, but he waits to get to them this week.....
Should I order a SB17 instead?

[JohnSSN700]

I have the 17(actually three of em) and it works great. Same power as the 18 but just shorter. I think the 18 was designed for Raptors wasn't it? Anyway, shoot get the 17, you'll love it.

John

[G MAN]

Eric Larson helped with the development of the SB17&18. He said they are the exact same except the muffler section is a little longer on the 18,They both have the same power.

[DavidH]

Fredrik,
There is a new muffler coming shortly. The designation will most likely be the SB 19. In your email you might want to ask about it since it is set up for the SZ.

David

[Jerry]

The SB17 and SB18 work well with the SZH. In the constant search for more power it was decided to try to improve on an already good platform.

Many pilots have been testing an updated version of the SB17 and SB18 for several months. 2 weeks before XFC we began flying the production version, which works especially well with the SZH engine.

As of last week (July 23 or so) Hatori USA began shipping the updated 17/18 to dealers.

There will be no 'SB19' designation.

You can tell the difference between an updated SB17/18 and the original by comparison.

Most won't have one of each, so I will try to post some dimension differences when i have them.

The updated version has a larger internal tube. Insertion of a ruler in the header opening will yield a lower number with the updated pipe. (approximately 2.5mm)The updated pipes are also about 10-15mm longer than the originals.

Everyone has been asking which works better - the 17 or the 18. Perhaps a bit of background on how we ended up with a 17 and 18.

In early 2005 HatoriUSA began working on a pipe that would work well with the OS91 Cspec. At the time the MP2 was the popular choice for that engine.

The original prototypes that were tested were long - especially when compared with the SB16 we were all used to seeing on YS equipped helis. The pilots that tested the new pipe were extremely pleased with the long version. The only issue we seemed to have was the tendency to develop exhaust leaks between header and engine. This lead to beefing up the thickness of the header itself, and also eliminating the YS mounting holes.

It was thought that a slightly shorter version would also eliminate some leverage from the header, and aid in this problem. So a shorter version was born.

We all thought the shorter version worked great - but there was just something a little special about the longer one in certain applications.

The shorter version was decided to become the JK nitro pipe.

At some point, Alan Jr got these in his hands, and he preferred the longer version. Alan was running 827 gearing and turning the engine close to or at 16000 rpm. He preferred the longer one as a result .

It was then decided to offer two versions of the OS nitro pipe. The shorter SB17 and the longer SB18.

The 17 worked at the lower engine speeds, while the 18 worked really good at higher rpm's.

The same held true when these were bolted to the SZH. Engine speeds above 15700 worked weith the 18. Below 15700, the 17 worked great.

Theres the full story.


Jerry

[Mille aka Fredrik]

Jerry,

Thank you very much for the information!

So the new pipes/mufflers has already been released. That's great.

[Altimat]

The only thing that doesn't make sense to me here is that shortening a pipe tunes it for higher RPM and vice versa which contradicts the story on SB 17,18. Can anyone explain this?

[JohnSSN700]

Thanks for the info Jerry, interesting.

[G MAN]

Because it's muffle section thats longer on the 18,the tuned part is the same lenght.