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Author Topic: Production/Production exhaust question  (Read 3122 times)
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cranberryroo
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« on: June 03, 2010, 02:09:46 AM »

This question is BUB specific. I am not looking to run at SCTA meets.
I found this in the archives:
Quote
As for exhaust, it has to appear stock.  That means stock can with the outlet in stock location. That means you can modify it internally like remove baffles or exhaust packing.  That is allowed. But no aftermarket cans allowed...
Quote
The exit diameter of the muffler cannot be enlarged. You can gut the rest of it. Anything you can't see is fair game. The rest that is visible has to be stock.

Here is the best picture I could find of the exhaust I will be modifying (don't have it in my hands yet):


The can has a big tip on it, then a plate that two smaller pipes come out of. One of the small pipes is visible in the picture. My question is: can I remove the plate to the size of the tip or do I have to keep the plate and the two pipes? I guess, which part is the legal "exit diameter"?
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fredvance
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« Reply #1 on: June 03, 2010, 09:28:45 AM »

You have to keep the plate. The two small pipes are the exit diameter.
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WORLDS FASTEST PRODUCTION MOTORCYCLE 213.470
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AHG
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« Reply #2 on: June 03, 2010, 12:29:09 PM »

2010 AMA/BUB Supplemental Rulebook
http://www.speedtrialsbybub.com/2010_event/AMA-BonSR%27s-2010.pdf

* CHAPTER 4 * PAGE 26 * 1st Paragraph *

 cheers
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cranberryroo
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« Reply #3 on: June 03, 2010, 09:57:42 PM »

Quote
and (unmodified) exhaust system.

I read that, but I am also reading that only outside appearance counts. I'm not looking at the aftermarket cans, just what i can do to this one.
It also says original engine, but cams, pistons(same size), rods, cranks, valves and such can all be changed?
I read the rulebook many times and there seem to be a lot of gray areas. I'm trying to feel out those areas before I actually drive all the way to Bonneville.
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wobblywalrus
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« Reply #4 on: June 03, 2010, 10:20:23 PM »

Roo, us racers and the tech inspectors can interpret the grey areas of the rulebook different.  It is always a good idea to take the some unmodified parts with you to the salt, just in case. 
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cranberryroo
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« Reply #5 on: June 03, 2010, 10:30:34 PM »

So if they don't like it can you go back to the trailer, bolt on the spare, then go back through tech? I didn't realize you got more than one shot.
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Randall Parker
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« Reply #6 on: June 03, 2010, 11:19:19 PM »

The Injection system must also remain the same size.  You cannot bore out the venturi.  Injection system must remain stock.  That essentially makes it a restrictor plate motor.  You can only pump as much air as the stock intake hole and stock exit hole will allow.  A very simple and elegant way to limit horsepower I think.  It is like needing another aerodynamic engineering degree only for the inside.  That is where the thinking and engineering come into play, just like in NASCAR.  That is why I so love the Production Classes.
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maj
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« Reply #7 on: June 04, 2010, 02:13:45 AM »

So if they don't like it can you go back to the trailer, bolt on the spare, then go back through tech? I didn't realize you got more than one shot.
No you can find out after you think you set a record that its illegal for that class
then its back in line to do it all again with the right parts
pre race Tech inspection is not necessarily going to pickup on class eligibility,
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Stainless1
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« Reply #8 on: June 04, 2010, 08:44:45 AM »

Read the Bub Production rules again, think 5 minutes, then re-read
Do that 3 or 4 times a day for a week....

You may be mixing scta and bub rules together... stop think....

Then proceed....

Good luck
see ya on the salt
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Stainless
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« Reply #9 on: June 04, 2010, 10:24:30 AM »

On the exhaust thing they are the same! I wish I could have used that chrome cap for the exit orfice, I could have gone faster. grin I can assure you someone will have 100 bucks to prove that wrong. cool
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WORLDS FASTEST PRODUCTION MOTORCYCLE 213.470
Vance&Forstall Racing
WOS 2011 235+MPH
Engine by Knecum, Tuned by Johnny Cheese.
Sponsers Catalyst Composites, Johnny Cheese Perf, Knecum Racing Engines, Murray Headers, Carpenter Racing
Uncle Jimbo
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« Reply #10 on: June 10, 2010, 11:20:36 AM »

As suggested earlier - page 26, 1st paragraph, last sentence. = "unmodified exhaust system." The simple word "unmodified" kind of spells it out. 
You'll still have fun, and always the obtion to go to a modified class if you choose to change the stock exhaust.

Have fun, go fast, be safe    grin
Jimbo
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From days of old, when knights were bold, and rode Iron Horses
24 Land Speed Records
M/PP 1350 AMA/BUB - M/CPG 1350 - M/CPF 1350 - LTA
M/PG 1650 - M/PF 1650 - AMA/BUB
A/PG 1650 - A/PF 1650 -  ECTA - LTA
Top speed to date 194.664
wobblywalrus
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« Reply #11 on: June 11, 2010, 01:37:19 AM »

Protest are always a possibility if a person sets a record on something that does not fit the rules.  It is not always the tech inspectors that detect and challenge a possible rule infraction.  Other people can do it too.

 
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cranberryroo
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« Reply #12 on: June 11, 2010, 11:11:27 PM »

So here's the impression I have of this board. 
1. The rule books aren't very specific
2. Most questions posted on here receive a reply of "go read the book"
3. Most other replies are disputed by everyone else.

I've come to the conclusion that I shouldn't trust anything said on here. Am I wrong?

I've sent Delvene enough emails she probably swears every time she reads my name, but I don't know where else to go with my questions.
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Peter Jack
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« Reply #13 on: June 12, 2010, 01:10:52 AM »

The first two replies were very clear. The rule on page 26, "(unmodified) exhaust system", is crystal clear. The second reply was from the tech guy you're going to have to deal with in impound. Why not send him an e-mail or pm him. This board is generally very helpful if you choose to listen.

Pete
« Last Edit: June 12, 2010, 01:20:24 AM by Peter Jack » Logged
AHG
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« Reply #14 on: June 12, 2010, 12:03:24 PM »

So here's the impression I have of this board. 
1. The rule books aren't very specific
2. Most questions posted on here receive a reply of "go read the book"
3. Most other replies are disputed by everyone else.

I've come to the conclusion that I shouldn't trust anything said on here. Am I wrong?

I've sent Delvene enough emails she probably swears every time she reads my name, but I don't know where else to go with my questions.


cranberryRoo,
If you have never been to the BUB Speed Trials and or Bonneville then perhaps you may consider some these people's answers as being correct, because they have been involved with both the rules and event. It bothers me when a new competitor feels badly about things, because he or she feels their questions are not answered properly.

Please consider...the shortest distance between two points (e.g. question - answer) is a straight line.

I am an AMA/F.I.M. technical steward for the BUB event, and will be happy to assist you to the best of my knowledge, and in as timely a fashion as I am able.

Drew Gatewood
(Chesterton, Indiana)
219-926-5647
gears55@verizon.net

p.s.
...and on a totally non-bonneville related topic,
my Chicago Blackhawks Hockey Team won the 2010 Stanley Cup
WOOOOO HOOOOOOOO!!!
sorry, just can't help myself right now


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