A rather exciting new development for Husabergs

Simon · Jun 10, 2005

Some of you on the site may be aware that a little over 2 years ago I got struck down by a virus that attacked and subsequently scrambled my nervous system. :roll:

As a result of that I've been off work for 2 years and still on the recovery path.

However, in an attempt to prevent myself from going completely mad I began a little project about 18 months ago that I have been slowly and quietly nibbling away at when I've been up to it.

Today, the final prototype was tested. This is it:

No, not the bike, but the exhaust system attached to it!

Due to the serious problems of noise we are experiencing I decided to set about designing a quiet yet powerful racing exhaust system and this system is the result. More photos:

The main design parameters were to design a system suitable for Supermoto racing and that would comply to sound testing of 96dba in accordance with the FIM testing procedure.

Today the tests revealed it successfully achieving 94.5dba and producing good power output

Riding it around a field with experienced Husaberg owners and a dealer the feedback was that it sounded like a 400 with enduro exhaust system, even when bouncing off the rev limiter.

As for power output, my own feeling is that it is much more responsive off the bottom and through the mid-range with perhaps a slight deterioration at the top end compared to a comparable existing race system such as Doma or FP etc.

I have already build a system that easily equals the power output of the Doma, in fact beating it on bottom end power and through a significant part of the mid range with traditional absorption silencer. This was only achieving about 98dba in tests however and came with the usual problems of packing etc.

I will be dyno testing shortly but the guy who does all my testing and has my entire test history file is on holiday so I'll just have to be a bit patient :wink:

So the tests show it is possible to make a system that is powerful yet also queit, even for a 650!

Anyway, the good news is that I may actually put this system into production for supermoto racing initially and subsequently, following some minor adjustments, try one out for enduro use, including a USFS approved spark arrestor.

The modified version would be built to a max 86dba.

The plan is to get some together for all other Husaberg capacities if there is interest and I am also considering having a go with other makes of bike.

The best part about this new system is that it is entirely based on harmonics and does not require any repacking at all and therefore it will not get any louder! Neither does it use any restrictive baffles or reversal of flow.

Anyway, I would be interested in hearing anyones questions, feedback, or even interest as this would definitely help me to gauge whether or not to talk to a fabricator and have a few made professionally.

Cheers,
Simon

rosey · Jun 10, 2005

very impressive!
but what is the bore on the headers??

Simon · Jun 10, 2005

rosey said:
very impressive!
but what is the bore on the headers??

Thanks rosey,

The bore on the headers is an interesting point. It's a very common myth that the bore is the determinent factor in performance. However, my headers are only slightly larger bore than the stock ones at a little over 32mm.

Cheers,
Simon

schwim · Jun 10, 2005

wowzer!

Hi Simon,

First, I hope you're getting on well. I've been working in the forum archive as of late and have been reading a bunch of posts from you concerning some really neat stuff you've done in regards to your bike. Thank you for continuing to hang out with us, and I hope you receive a clean bill of health soon, so you can enjoy your life and hobbies again.

Now, about the pipe

What's the over all length out the back compared to a stock system? How much farther will it poke out?

Will we have to modify the plastics to fit that can?

Would you be able to reduce the overall profile while keeping the noise down if you were to run a second smaller can? Is this feasible at all?

thanks,
json

Simon · Jun 10, 2005

Re: wowzer!

schwim said:
Hi Simon,

First, I hope you're getting on well. I've been working in the forum archive as of late and have been reading a bunch of posts from you concerning some really neat stuff you've done in regards to your bike. Thank you for continuing to hang out with us, and I hope you receive a clean bill of health soon, so you can enjoy your life and hobbies again.

Thanks for the support Jason - I do try to keep up to date with what's going on around here :wink:

I'm looking forward to being fully fit again because I would quite like to come over and terrorise y'all at the next big Husaberg ride out!! :shock:

schwim said:
Now, about the pipe

Yep, back to the important stuff :lol:

schwim said:
What's the over all length out the back compared to a stock system? How much farther will it poke out?

It is slightly longer than the stock system but it is designed so that it doesn't protrude beyond the end of the subframe. The angle I've taken the photos at makes it look like it sticks out but it is flush with the end of the subframe, therefore a bit of a length in from the mudguard. Basically FIM enduro regulations state the exhaust must not protude beyond any bodywork and was the basic length limitation I had to work with.

As part of the building process I've taken current FIM technical regulations into consideration in the design so there won't be any nasty surprises for anyone.

schwim said:
Will we have to modify the plastics to fit that can?

Not at all - it will fit with stock everything - even in current prototype form it is quicker and easier to remove and replace than the stock system and all other aftermarket systems on the market. All the prototype needs is a bracket to keep the rear plastic off the surface of the silencer (which I still need to build).

schwim said:
Would you be able to reduce the overall profile while keeping the noise down if you were to run a second smaller can? Is this feasible at all?

thanks,
json

Unfortunately this was the absolute minimum size I could use to achieve gas flow and silencing benefits. I am looking at a twin silencer design (which I have on the drawing board) where the silencers sit on each side of the bike but unfortunately this may mean modifications to the bike to fit. The other limiting factor in using a smaller can is that the chamber sizes reduce and thus loose a proportionate amount of effectiveness in sound attenuation as a result (for this specific design).

I also have 3 other possible designs awaiting my attention, one of which is an "ovalised" silencer which would make it taller but is would make is significantly thinner in profile with the additional benefit of increasing overall flow area and volume, the increase in volume also benefiting noise attenuation.

Cheers,
Simon

LINEAWEAVER · Jun 10, 2005

Hi Simon,
Happy to learn you are on the mend.

For the past twenty years homes have been cropping up near fairgrounds where once the unmuffled XR750 was allowed to sing. In an effort to reduce noise without power loss we use what is commonly referenced as a "boom can". Quite similar in outward appearance to that of your muffler it is a "giant glass pack" which does indeed work very well. It is unfortunately by design rather big. Your system looks great!

It sounds (pun intended) as if you have reached a good compromise regarding noise, size and performance. Good Job!

Please keep us up to date in particularly regarding power vs noise.

Sincerely,
Dale

Parsko · Jun 10, 2005

Simon said:
The best part about this new system is that it is entirely based on harmonics and does not require any repacking at all and therefore it will not get any louder! Neither does it use any restrictive baffles or reversal of flow.

Would you care to go further into this point. Feel free to include numbers, calculations, graphs, etc. if you made them. I am very interested in hearing how you approached this.

Get well soon, sir! Looks great!!

-Parsko

schwim · Jun 10, 2005

right-o, pip-pip!

oh wow, it'd be quite a treat if you came to visit during a meet. Are you entertaining the Canada ride in '06?

Well, concerning the pipe, it looked much longer than it is, so a second can would really be a moot point except for visual zoom factor(which I'm not discounting).

On your first production run, the UHE will buy one and give it away to some lucky bastage

, so let me know when you're getting close sir

thanks,
json

deaks · Jun 10, 2005

Hi Simon

That is really good news about your pipe project. It couldn't come at a better time. We are about to lose two good venues for supermoto soley due to noise, both lydd and rowrah are under a 'one more chance' stay of execution with the local councils.

If you would like to test the pipe on a smaller berg (my 470 !!!) I would be only too pleased to help.

PM me if you are interested.

I reckon you stand a good chance of selling a fair few of these given all the noise issues.

I was at gary's the other week, I asked him how you were getting on ;-)

I look forward to hearing from you.

Cheers

Deaks

husabutt · Jun 10, 2005

Hi Simon:

You seem to have taken everyones comments to heart when you asked for opinions regarding an aftermarket exhaust and developed a "quiet pipe with a spark arrestor". In a word awesome. Its the only type of exhaust I would consider purchasing. Think about a dual exhaust setup too. It would probably be even quieter and its appears that Honda will be going to a dual exhaust on the 06 CRF250X.

I hope good health finds you soon,

Eric

Simon · Jun 10, 2005

LINEAWEAVER said:
Hi Simon,
Happy to learn you are on the mend.

For the past twenty years homes have been cropping up near fairgrounds where once the unmuffled XR750 was allowed to sing. In an effort to reduce noise without power loss we use what is commonly referenced as a "boom can". Quite similar in outward appearance to that of your muffler it is a "giant glass pack" which does indeed work very well. It is unfortunately by design rather big. Your system looks great!

It sounds (pun intended) as if you have reached a good compromise regarding noise, size and performance. Good Job!

Please keep us up to date in particularly regarding power vs noise.

Sincerely,
Dale

Hi Dale,

You should have seen my first prototype - it looked like it had a bike attached to it :wink:

Interestingly in my research I came across some of the d/t silencer work. In particular it seems Ron Woods is a man who has a bit of a reputation in the area?

I'll definitely keep you informed on the power/noise figures.

Kind regards,
Simon

Simon · Jun 10, 2005

Parsko said:
Would you care to go further into this point. Feel free to include numbers, calculations, graphs, etc. if you made them. I am very interested in hearing how you approached this.

Get well soon, sir! Looks great!!

-Parsko

Now that is some request!

Regarding the silencer all I have done is fight fire with fire - used sound to cancel out sound in the lower frequencies (up to about 1400 htz) using chambers tuned to specific levels of harmonics and in order to muffle the higher frequency sounds the design utilises the gas boundary layers to create the necessary viscous drag for damping.

There are some problems inherent in doing this as at some point the combined attenuation of some frequencies causes amplification of others so it took a good number of attempts to get the thing working in "harmony" (if you pardon the pun).

As for the rest of the exhaust system I first took the approach of understanding exhaust system design etc. etc. Then I got all the available systems on the market for the 650, measured and dyno tested them all, analysing results v. the measurements to understand what worked where and how etc. etc.

The background reading was definitely the most challenging.

Then I went out & bought some tubing and a set of bending rolls, did some calculations, drew up some plans and got out and tried them out, ripped them up, did more, and round we go in circles.........until we finally got to today.

What I can say is that exhaust design really is just as much of an art as it is a science - some of the stuff just came along through a lets just try it and see what happens if I do approach - some of those went very very wrong, some went very very right

Cheers,
Simon

LINEAWEAVER · Jun 10, 2005

Simon said:
LINEAWEAVER said:

Hi Simon,
Happy to learn you are on the mend.

For the past twenty years homes have been cropping up near fairgrounds where once the unmuffled XR750 was allowed to sing. In an effort to reduce noise without power loss we use what is commonly referenced as a "boom can". Quite similar in outward appearance to that of your muffler it is a "giant glass pack" which does indeed work very well. It is unfortunately by design rather big. Your system looks great!

It sounds (pun intended) as if you have reached a good compromise regarding noise, size and performance. Good Job!

Please keep us up to date in particularly regarding power vs noise.

Sincerely,
Dale

Click to expand...

Hi Dale,

You should have seen my first prototype - it looked like it had a bike attached to it :wink:

Interestingly in my research I came across some of the d/t silencer work. In particular it seems Ron Woods is a man who has a bit of a reputation in the area?

I'll definitely keep you informed on the power/noise figures.

Kind regards,
Simon

Hi Simon,
I am proud to say Ron is a dear feriend and that I have built many a Wood Rotax over the years.

http://www.rotax.net/

Best Regards,
Dale

Simon · Jun 10, 2005

Re: right-o, pip-pip!

schwim said:
oh wow, it'd be quite a treat if you came to visit during a meet. Are you entertaining the Canada ride in '06?

I am definitely entertaining Canada in 06 as a possibility. Otherwise I may have to come over and do some SM.

schwim said:
Well, concerning the pipe, it looked much longer than it is, so a second can would really be a moot point except for visual zoom factor(which I'm not discounting).

On your first production run, the UHE will buy one and give it away to some lucky bastage , so let me know when you're getting close sir

thanks,
json

In the hope that it gets that far, the UHE can have a system from the first production run.

Simon

madero · Jun 10, 2005

hello simon,

indeed very impressive ,even when you have more low end power than the DOMA system.loo forward to your dyno ratings.

I like the black headers+can looks great.

Greetings Mathieu

Simon · Jun 10, 2005

deaks said:
PM me if you are interested.

PM being drafted as we speak

Simon · Jun 10, 2005

husabutt said:
Hi Simon:

You seem to have taken everyones comments to heart when you asked for opinions regarding an aftermarket exhaust and developed a "quiet pipe with a spark arrestor". In a word awesome. Its the only type of exhaust I would consider purchasing. Think about a dual exhaust setup too. It would probably be even quieter and its appears that Honda will be going to a dual exhaust on the 06 CRF250X.

I hope good health finds you soon,

Eric

Thanks Eric. Just got to listen to what people want.

Simon

LINEAWEAVER · Jun 10, 2005

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

Sincerely,
Dale

DaleEO · Jun 10, 2005

Hi Simon,

No, I hadn't heard that you had taken ill. I am glad to hear that things are getting better for you, and that a full recovery is expected.

SOUND, yes this has become quite an issue here in the states as well. Out here in sunny southern california, come september we will have mandatory sound testing at all of our desert races. The current plan is to test the odd numbered bikes on the odd numbered dates of races, and evens with evens, so that 100% testing will be achieved within a month. This is quite an undertaking since on average there are about 350 riders in a given desert race, and I have seen up to 675.

Out here the manufacturer's have provided sound testing rpm's concurrent with the SAE J1287 procedure. The procedure states in section 6.1 that engine will be run at one half the rated engine speed. I am not exactly sure what that means, but, have been told that it is one half the rpm of the torque curve at a point where it starts to drop off. Honda did a great job of making sure that the CRF450X will pass with a system similar to your design by manipulating the torque curve, and that particular bike is to be tested at something like 3700 rpm. While the CRF450 is tested at I believe 4600 rpm. The current list does not even list Husaberg's, so it will be left to the default rpm of 306,000 divided by the stroke in mm's for high performance racing motorcycles. I am wondering what the test criteria is in the empire? Using the aforementioned criteria, that means that my 04 550 will be tested at 4371rpm, and with the stock exhaust that will be a challenge to make 96db, I know it will pass at 4000 rpm. And since there is no data provided by Husaberg to the state, I think I can get away with telling them that the 306,000 should be divided by 80 instead which will put me at 3825 which I know the bike will easily pass at. So, I am really glad to see that you have spent the time, money, and energy to develop a system that not only is quiet with good power, but without the use of packing.

There has been allot of discussion of sound testing on the district 37 message board ( http://www.district37ama.org/forums/index.php? ) about exemptions for races which is listed the california dmv (department of motor vehicles) codes. But, the AMA, which is a step child of the FIM has called for all 96db. It's rather interesting b/c the off road car races that race in the same location as we race, do not have to abid by the 96db code.

I have asserted for a while that eventually someone would come with a large can type silencer that would offer the same performance as a more open exhaust, but with less sound. And it would be great if it was even at 86db with a little power loss, but, from what I am reading into your post the low end and possibly the mid range would be better with only a loss at higher rev's which would be fine with me since the majority of my racing riding is at those lower rpm ranges. Perhaps there could be one "can" with an insert to go from 96db to 86 with the insert. This would be exceptionally good for myself as I would run the 96 in the desert, and then when riding in the national forest I would run the 86. I believe the difference between 86db and 96db is something on the order of a factor of 8 times, since an increase of 3db is supposed to be twice as loud. Please correct me if I am wrong.

I do like the idea of the oval can as it would be a slimmer overall package. And from what you have said, it would also make it quieter as well.

I think that your design would definitely give FMF a run for their money as they are pretty much the only game in town when it comes to quiet, but still powerful exhaust system. But, as you might expect they don't make a pipe for Husaberg's. And I think your design would probably be a hit with the desert racing crowd as you would not have to repack the system. More so in fact since there is much talk within our little racing group of trying to figure out a way of not having to get sound tested but, maybe once or twice a year by having the can sealed somehow like they used to do in the ISDE. This would be achieved by the fact that your can could be welded on all seams.

Again Simon, my sincere thanks for making this system.

DaleEO · Jun 10, 2005

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.

Search

Search

A rather exciting new development for Husabergs

Simon

rosey

Simon

schwim

Simon

LINEAWEAVER

Parsko

schwim

deaks

husabutt

Simon

Simon

LINEAWEAVER

Simon

madero

Simon

Simon

LINEAWEAVER

DaleEO

DaleEO

Similar threads

Register CTA

Recent Discussions