Mission Raceway easing up on aftermarket exhaust

sand.man

sand.man

Well-Known Member
A message posted by WMRC club president Dean Drolet on the club's forum:

"June 20th and August 1st experimental rounds

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88db. 4 characters that are very important to our club. 88db is the limit, and we race within it. Since we've implemented the rule, complaints against our club are no longer a concern. That was 5 years ago, and was a very unpopular decision by our club. Al Beck, past president, took a lot of crap over that decision, but that decision also kept us at the track.

Now that 5 years have past, Europe has also implemented quite a few restrictive sound laws. As a result many aftermarket exhaust manufacturers have really brought their exhaust noise down over the last few years. Enough that we might want to try to allow *some* aftermarket systems in on our 750cc and under inline4 race bikes. Remember, that it's not only the decibel level, but also the pitch or note that the exhaust system makes that can cause complaints as well.

In an effort to try to bring some riders back to us, we will allow aftermarket exhaust systems for the next 2 rounds as an experiment. These systems will face the same and possibly a little more scrutiny with regards to sound. I've been told by many riders that these new systems are *quieter* than stock. Here's your chance to prove it! Any bikes that wish to try will be allowed through tech, however, as they approach even 87db, the rider will be warned. 88db or over and they will be meat-balled.

If the experiment is successful, we will lift the restrictions for the final rounds, and remove it from the rulebook. If it fails, we just fall back to normal. I've already cleared this with our referee Rick, race director Dave, and track representative Al."

Here's the thread to follow for updates, etc:

http://www.westwoodracing.com/forums...1221#post31221
 
Fireman

Fireman

Well-Known Member
The systems are being allowed, but the noise limit is the same. If your high revving 600 cc bike with a aftermarket exhaust can pass 88db as measured by their tech, you can race.

BTW, many 1000cc bikes need silencing, and 600-750cc bikes tend to be louder. I am guessing that they will have a tough time coming under that level.
 
sand.man

sand.man

Well-Known Member
My understanding is that previous to this change they were saying absolutely no aftermarket exhaust for < 750cc regardless of their DB output, but they are now going to allow testing for aftermarket pipes on the smaller displacement bikes.

Requirements are the same like you said @ 88db, but they are now entertaining the idea of allowing quiet aftermarket pipes.
 
R

rustysgsxr

Member
My stock exhaust-minus the cat blew a 92. I'm assuming that with my aftermarket exhaust which allows more airflow I WOULD NOT pass tech. But, I would still like to try.
 
Fireman

Fireman

Well-Known Member
sand.man said:
My understanding is that previous to this change they were saying absolutely no aftermarket exhaust for < 750cc regardless of their DB output, but they are now going to allow testing for aftermarket pipes on the smaller displacement bikes.

Requirements are the same like you said @ 88db, but they are now entertaining the idea of allowing quiet aftermarket pipes.
Click to expand...

Yup, exactly. They made stock cans mandatory till now. Quiet cans that can pass 88DB will be permitted for time being.
 
D

Dean

Active Member
Hi Guys. Allow me to officially clarify some points to this. I have had MANY riders tell me that the newer systems are actually quieter than stock and much better. Not wanting to be a constant naysayer, we are going to try this. Are we confident that many systems will meet the requirement? Not at all. As a matter of fact, we expect most to fail, and we will be very quick to pull them too, which is why in a later post, I suggested riders bring both, so they can salvage their day. As the original post states, as riders approach 87db, they will be warned. 88db and over, and they will be meatballed.

What we do hope to gain out of this is:
If some systems DO manage to pass, we will list those specific systems as being allowed.

That does mean that not all systems will be allowed. We will list the allowed ones in our rulebook, with no exceptions. One of the main problems with the smaller 600s and 750s is not just the decibel level, but also the pitch they make. ZX6Rs and 600RRs from Kawi and Honda have such a high pitched whine that even at 88db the sound seems to go up the mountain and cause people living there to complain. Twins and bigger bore engines seem to have a much deeper note, which doesn't bother the residents that much.

Also, if we get a single complaint about noise while doing this experiment, we will scrap it too. Keeping ourselves on the track is too important to lose over a non-stock exhaust system. Again, we have our doubts, but we have to try to allow them to see if anything has changed in 5 years.
 
D

Dean

Active Member
That's a very easy answer. The drag racing organization and the motocross organization have a 99 year lease with the City of Mission and do not have sound limits. Between the two organizations, they bring in over a million dollars in revenue to the city. Road racing does not, and the city is quick to shut us down over noise complaints, but cannot do anything about the louder events, because they have permission for the next 80+ years.
 
D

Dean

Active Member
Those organizations are limited to use either the drag strip or the motocross track. Sadly, even if we were affiliated, we'd be forced to just use the straight or the dirt. Besides, non of those organizations want any part of us.
 
R

ronin26

Active Member
I hate to say it but I think you should leave your rule unchanged...people are going to complain when their system is 89db and the guy beating them is using an aftermarket exhaust at 87db.

Good luck.

I am unaware of any aftermarket system quieter than stock, and I see quite a few.
 
sand.man

sand.man

Well-Known Member
The main advantage is probably weight shaving, isn't it? If you can cut out 5-10lbs worth of pre-mufflers and cats and all that emissions jazz then install a silencing tip to get you under the limit wouldn't it be worth it?
 
jetfixer15

jetfixer15

Active Member
My SV650 has a full system Yoshimura RS-3 and it was within sound regulation when I went to Mission in 2009. The RS-3 comes with an insert that can be removed/installed with 2 bolts from the end cap, which makes the exhaust quieter. The system was designed to run with it installed for street use. I have seen the homemade restrictor plates that have been put on aftermarket exhausts at Mission and my theory of them producing too much back pressure seems to have been proven. If I had a system that was over the Mission decible limit I would re-pack it and then have it measured by the decible meter at Stratotech, that way you know in advance.

Once we are all racing electric bikes it will be a moot point anyway. ;)
 
Fireman

Fireman

Well-Known Member
YZF1000jon said:
I'm not sure, Justin? Was it?;)
Click to expand...

Worked great...on a 1000cc big bore with a 12000 rpm limit. A 600 singing at 17000 might be tough to mask. I blew a head gasket by putting a silencer in my 05 race bike. I would have been better off with stock. Which is what I did last year.
 
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