| Author | Message | ||
     Johnboy777 |
Thought I would start a proper thread on the Muffler Valve Mod, with the correct heading, for easier searches and the like. I wired my muffler valve open at the actuator. Just wondering if anyone has done the same, and their results. So far, my results appear great for such a quick, no-cost mod. Louder, throaty idle, and smoother running at lower RPM and speeds. I have the temperature oil dipstick, and it appears to run cooler (185deg. vs. 212deg), as well. Any thoughts? John    ....... Here's a diagram of how our muffler's work: 'VALVE CLOSED'  'VALVE OPENED'  .................... | ||
| Johnboy777 |
At Endoagain & EG, I'm not real clear on the 'magnetic spoke pickup' device that you're using to hold the muffler valve cable open. Can someone post a picture of this? Thanks, John | ||
| Nopork |
I just did my 08' Uly, and wow what a difference in slow speed drive ability and at lower rpms. I too was having trouble taking off in first wanting to feel like it was going to die all the time. This is gone now. I haven't taken it far enough to see if the oil temperature has dropped or not yet. All things considered this seems to work! | ||
| Pso |
I am going to do it to Sara's 06 Scg this weekend. She has been noted that she has the same problem taking off. She says the engine seems to want to die. She also wants more noise rom her bike, even thought I think the Scg exhaust sounds better than my Uly. I think I will do it and not tell her and see if she notices any change. | ||
| Rwcfrank |
I just tried this and here are my first ride impressions; Definetly louder at idle and lower rev ranges, sounds pretty good actually. Instantly noticed a slight drop in midrange but I will let the ECU learn the mod before I switch back. It kind of changed the bike into a more mid to top ride rather than the low to mid short shifter. First time I opened it I hit the limiter in first gear way earlier than I expected or hat hit it before. It seems to freewheel more or that could be my imagination. Cold it popped a little more than usual, or at least I heard more popping. It certainly has gained on the top, no doubt about it....More to come...So far the jury is out on this one... | ||
| Jammin_joules |
I had a Direct Link dyno tune on my 2007 with stock muffler with the gate valve tied open. Much nicer, about 1.5ft-lbs more peak torque and close to 2% more peak ponies. | ||
| Jammin_joules |
By the way, I use the right side air scoop which reduced the amount of fan run time, and often having it run at all. Once the map was richened up with the Direct Link dyno tune, it is noticeably cooler with even fewer fan cycles. Jury still out on gas mileage. Next I will have a muffler gutted and Jet Coated thus reducing weight, improving flow, and removing the whole gate mechanism. Then another trip to the dyno. ~jammer | ||
| Jb2607 |
John, Couple of questions... #1 Do you have full tension on the cable or just a bit of slack? #2 What is the purpose of the "interactive exhaust valve"... (?) Is it for EPA requirements, noise.... just what "necessary" function does it provide. Plus, I have fabricated my own bracket and it has rained all day, so I have not tried it out except in my barn. It does have a "deeper throatier" more mellow sound... not as "tinnie" sounding. Joe | ||
| Johnboy777 |
Hey Jb2607, #1 Cable Slack. My thoughts were that I did not want my cable fully tight - thinking that it might over-stress it, at some point, so I backed it off slightly, when installing the bracket. For me, the key to all of this, is the ability to return it to stock for service or if I sell the bike, at some point in time. I've dissected two stock mufflers over the winter to try to understand how they work, and found that even if the muffler valve is only 3/4's the way to fully open, for all intents and purposes, its fully open. So the cable doesn't need to be guitar string tight, a little slack is a good thing. #2 What is the purpose of the "interactive exhaust valve" That's a good question that I can't answer. I have no knowledge of the specifics on this, whatsoever. My guess is that it allows the exhaust to be quiet enough to pass certain 'specific' noise requirements during testing, and then open to allow better performance (via ECM EEPROM programing) at certain operating parameters - (e.g., throttle position, engine load, RPM, etc.) Personally, it seems to me to be a solution to a problem that shouldn't exist in the 1st place. And the actuator; another needless electronic gadget that can fail. Just because you can engineer it in, doesn't, necessarily, mean you should - just for its own sake. Now, in all fairness to Buell, they have to live within specific noise guidelines imposed by the various governing agencies within the countries in which they sell their product. At any rate, try it out in all of the operating conditions you can think of (what's normal for you)- if the ECM can adapt to Drummers and SecOps, it should adapt to this mod, easily, I would think. And, of course, if it doesn't work for you, you can always go back to stock. Just one final note, if you look at the "Valve Open' drawing I made, this is a VERY open design, really. Going from the header to the front expansion chamber, and then, from the front expansion chamber, straight out. And its not all that loud, either. Just a nice throaty rumble. With the mod, its slightly loader than stock, with a great sounding idle. I could care less if a gain or lose a few HP here or there. For me, it sounds better and gives me better drivabilty. YMMV though. Hope this helps. John | ||
| Jb2607 |
Thanks John... I've read up on some of your previous posts regarding this mod. How long have you been using this mod? Has it had any ill effects on the ULY? I am not an engineer but I can comprehend that less back pressure should add up to more HP and better fuel mileage. I am going to test it over the next few days for performance and fuel mileage. The long road trip is coming up Wednesday so I am doing final preps. The notes/posts that have peaked my interest are those that state better low speed performance. I am planning two VERY long off road excursions on the trip, so any low speed performance improvement would be a plus. I would enjoy having a clutch for the return trip... LOL. The swapping out of the primary gears/chain to lower ratios sounds like an ideal move, but I will not have the time to go that avenue. When you say you dissected two mufflers, were they from 08's? Joe | ||
| Rwcfrank |
I did this mod and rode about 20 miles. It does seem to rip a lot better and it has smoothed out... You may be on to something here....I think it lost a hair on the mid and low but its much better on top, so much better it is worth the trade. I wonder why it does so much better on top if the exhaust valve is open on the top end anyway? | ||
| Jammin_joules |
Exhaust valve closes after mid-range. | ||
| Jammin_joules |
Any mods to improve flow, and subsequently richen up the lean stock air to fuel ratio mixture, will have adverse effects on gas mileage. | ||
| Rwcfrank |
I found this To retain a fat torque band, the new XB1200 engine is equipped with a Buell InterActive Exhaust. An electronic actuator activates a butterfly valve housed in the muffler to adjust back-pressure by alternating between two gas flow paths. The engine ECM monitors engine speed and throttle position while activating the valve to optimise torque and horsepower for the riding condition. At wide-open throttle, for example, the valve is opened at low rpm to reduce back-pressure so the engine can gain rpm quickly. The valve closes in the mid-range to increase acceleration torque, and then opens again at high rpm to maximize horsepower. http://www.popularmechanics.com/content/imageview.cfm?img=http%3A//media.popularmechanics.com/images/buellxb12s2exh-lg.jpg&caption= (Message edited by rwcfrank on June 15, 2008) (Message edited by rwcfrank on June 15, 2008) | ||
| Ratbuell |
My understanding is, it's a variable length exhaust. Longer pipes give better low-end torque, free-flowing pipes give better high rpm power. The valve allows the same exhaust system to do both jobs. Think of the valve as the "anti-dip" mechanism when you're looking at the dyno chart. I could be wrong though. Happens every day, lol. | ||
| Dick_stilton |
I have been watching this thread with interest. Being spanner shy the mod appeals to me because its simple to do. I have a question though. Couple of friends of mine who run Street Bobs welded their exhaust valves open, then to compensate had to get bigger air filters and change chips (Stage 2 is it?) Does the same apply here? Sorry to sound dim but a mechanic I aint. Cheers. Dick  | ||
| Electraglider_1997 |
A quick, easy, cheap, and reversible way to hold the cable open is with one of these fishing lead weights called a split shot that can be had at Walmart or anyplace that sells fishing supplies. Pull on the cable to open the valve and pinch on the split shot with a pair of pliers so that the cable spring can't pull the cable back. Probably get a whole bag of 1/8 or 1/4 oz split shot for a buck or two.  | ||
| Electraglider_1997 |
Ratbuell, Longer pipes means more resistance to flow because you have molecules forced under pressure moving further to escape to atmosphere. | ||
| Tiberius |
I have joined the experiment as well. I love the sound, it may have lost a smidge mid range....but it's really hard to tell. I'll see how it goes over the next few days. I think over the winter, I'll be sending my can to Drummer. | ||
| Jb2607 |
Johnboy, road 141 miles today with the valve held open. Noticeable improvement at slow speeds, maybe a tiny bit less responsive midrange (difficult to detail because only ride this bike in SLOW and GO), but I feel improvement in the upper power ranges. Also, cannot swear to it, but I also believe the engine was not quite as hot. At least my right thigh did not feel as warm as usual. MPG(?)... 142 miles, 3.3 gallons. These numbers would be at the top end of my averages. Maybe 1-2 more than normal... but with the mellower sound, I may of dug a bit more out of corners. I will leave it open as I begin my journey, as the piece I manufactured to hold the valve open, also allows me to redo to original in seconds. Needs more testing... but so far I like the mod. Thanks Johnboy... Joe | ||
| Turk |
Longer pipes means more resistance to flow because you have molecules forced under pressure moving further to escape to atmosphere. But that's ignoring the pressure waves. At different rpms the ideal length of exhaust is different because pressure waves are reflected back towards the cylinder head when there is a drastic change of impedance (ie where the header goes into the muffler) it will then reflect back again at the next change of impedance (header to cylinder head). When timed properly, that pressure wave will help scavenge the exhaust gases from the cylinder, and actually decrease backpressure allowing a better intake charge to fill the cylinder resulting in less pumping losses and more horsepower. This is the reason for tuned exhausts and the driver for the exhaust valve (different lengths for different rpms) and wiring it open will hurt midrange power. It's also why a lot of times someone will put on a set of straight pipes only to be disappointed when they see a dyno sheet. | ||
| Johnboy777 |
Hey Jb2607, Glad the muffler valve mod is working well for you. It appears to be the consensus here, that you do lose some of the mid-range with the mod. I'm wondering if any one has noticed any MPG increases with this mod, along with the lower operating temps that I've noticed on mine. I have never really keep an accurate track of my MPG though, so I can't say. John . | ||
| Growl |
I wired mine open as a brief experiment and felt a loss of torque at very low RPMs which matters when riding on challenging dirt roads (I did not remap the ECM). I did notice that the engine ran cooler - judging by the fact that the fan ran less. It is interesting to hear that some of you also experienced this. I suppose getting the exhaust out of the pipe sooner allows less heat to rise up through the engine. I think an electric switch to activate the actuater at will would be cool... | ||
| Electraglider_1997 |
I should know tomorrow if the gas mileage is worse, the same or better at least for a tank full. I'll report tomorrow evening. | ||
| Prichmon |
When I opened mine the bike started coughing more regularly especially when cold. | ||
| Johnboy777 |
Whenever changes are made, the bike needs to run at a steady 2,800 - 3,500 RPM for 5 plus miles or so, to relearn and adapt to the changes. Just thought I'd mention that, FWIW. . | ||
| Electraglider_1997 |
I got 155 miles before it went on reserve which is better than my last few tanks by probably 10 miles. My oil seems a bit warmer though which seems to run counter to what others are saying. I think I'll shut the valve and see if the oil goes down in temp. | ||
| Adamd |
Guys, Where exactly is the cable? | ||
| Froggy |
Take off the airbox cover, its 4 torx T27 screws. 2 up by the gas filler, and 2 under the front of the seat. Take that cover off, you will see a contraption on the top of the inner airbox, that its the exhaust servo, and the wire coming of it there is 2 things coming off of it, the wire for the power and signal, and then the cable thats connected to the silver piece that pulls on the cable. | ||
| Adamd |
Thanks Froggy, I'll do the mod tonight and report back. |
