A rather exciting new development for Husabergs

LINEAWEAVER said:

Hi Simon,
Have you given this a go http://www.proracingsim.com/ ?
It is a really helpful program.

Sincerely,
Dale

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Thank you very much for the tip Dale.

I hadn't used any simulation software at all in this development, other than the tools I put together myself on my computer to do the calculations for me, a few spreadsheets and some CAD/CAM with 3D modelling capabilities.

The simulation software I'd thought would be completely out of my budget but the above stuff looks pretty reasonable. When my budget is there I'll have a good gander.

Thank you,
Simon

DaleEO said:

By the way, is the 96db sound limit applicable to moto cross and enduro too?

Or do they have different requirements? I have gone to the FIM web site in the past and have not been able to find this information.

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Thanks for your input DaleEO,

I selected the 96dba mark as is it rumoured this will be the forthcoming limit for supermoto racing here in the UK (possibly next season). Current limits are 98dba in MX and supermoto. In national level MX this is strictly enforced at scrutineering, in supermoto it is just beginning really with proactive noise testing.

FIM limits for Enduro are currently 94dba and no more than 80dba at 5 metres distance from the bike through 360 degrees.

Regards,
Simon

Grok said:

Simon! Good to see you post and good to see you putting your enforced downtime to good use!

You've done a good job making a quiet design as small and powerful as possible.

If you make it our way when you visit Canada, I'll show you some of the best dirt/road riding and a nice little SuperMoto track.

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Hiya Grok, good to see you too!

funnily my partner and I had begun planning a trip to Canada a couple of years back, so if we do make it over, I will deffo be in touch and take you up on your offer!

Cheers,
simon

JoeUSA said:

Hello Simon, and welcome back.

I will definitely watch for your continued progress on an 84 db spark arrested system for my 40 550.

As to the bracket you mentioned needing to design, Husaberg introduced one on their 04, part number 800.08.014.100, and a grommet part number 582.14.069.051, (generic 16x10,8x3). It mounts onto the berg using the same bolt as the rear muffler attachment.

Best regards,

Joe

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Cheers Joe! I've had a look at the bracket but unfortunately I'll need a slightly different one due to diameter differences between mine and the stock one.

I'll keep you up to date regarding the next quieter evolution.

Kind regards,
Simon

Update following dyno testing

I completed dyno testing of the prototype quiet system today, with very positive results so far.

It is producing peak power equivalent to the OEM open MX race system (55 horsepower at the rear wheel) with low end and midrange equaling that of the full Doma racing system (so much more than the OEM open pipe).

I still need to do the proper and accurate figures but at a glance it looks like this system improves low and midrange by about 10% compared to the stock system with a reduction of only about 6% in peak power compared to that of the Doma at peak power.

I have some modifications I need to make following these tests but otherwise everything is looking pretty good going forwards.

Cheers,
Simon

Update:

completed further modifications to the silencer and the result is another .5db(A) reduction in sound pressure levels.

I also back to back tested the silencer on my 2001 650 and found it just as effective in silencing as the enduro exhaust. In addition it really works well with the Lineaweaver LX2 camshaft too with the exhaust noise being a further .5db(A) quieter - very interesting.

First tests on a 450 were also very promising.

I'm currently seeking and receiving some help contacting manufacturers to produce the first proper prototype of this system. If anyone has any suggestions or could provide contacts/introductions on this front, I would be very appreciative.

Cheers,
Simon

DaleEO said:

How's that muffler project coming along?

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Hi DaleEO,

The muffler project is coming along on both the positive and negative sides :lol:

Development has continued and I am the stage where I have put together and tested a much smaller and lighter silencer that provides a very good broad spread of silencing across the entire rev range - it also gives some pretty good results on the dyno, but still needs to be improved somewhat as during testing the baffles and end cap had a tendency to be pushed out of position due to exhaust gas pressure.

Below is a link to a photo of a variety of silencers I've put together and tested, including the original design. The top one is the smaller one that I've thought would be most suitable to take further for development as an "enduro" silencer, because is is so efficient:

Prototype silencer photos

There is still a significant amount of development still to do on the quiet version. It is so far providing good broad attenuation acroos the entire rev range but it is still too loud for my own target of 86 db(A) - it is currently a good 92 db(A) on static tests so would still be OK for current enduro limits and MX next season.

The race only, Supermoto designed system, I have experienced some interesting results that have set back development, but that's what happens, eah?

As a result, I've had to delve much more deeply into the subject of acoustics - not the simplest of matters on any day - to understand more and as there isn't much of an availability of public information on silencers, I've had to do some pretty rigorous research. However, I've pretty much got the information I need and intend to take it further over the winter months, funds permitting.

The result, I'm hoping is a yet more efficient step in the right direction! both for the race silencer and for the queit one!

Then the next step after that for the quiet silencer is the design of a good spark arrestor. At present is pointing towards a centrifugal type as this could be incorporated quite easily into the silencer body - we'll see.

Cheers,
Simon