| Author | Message | ||
     D_adams |
I've had this same argument numerous times over the years, my favorite answer was to send them to a top fuel dragster race. Hmm, no muffler there, pretty sure that motor makes _plenty_ of power with about an 18-24" long set of headers. It's not optimal for street use, but still, the argument is the same. Primary header diameter, length, steps, collector size, taper, diameter, outlet size, midpipe length and diameter, possible reversion cone on the pipe, intake length, lift and duration of the cams, valve size and timing, target powerband for peak power, there are SO many variables to take into account it's not even remotely funny. Exhaust wave attenuation (sound), speed, so much data to put together to build something that works. It's not going to be a "one size fits all" type deal either. You look for the best balance possible. Once upon a time, I was told by a pretty reliable source that 150 hp was pretty much the absolute maximum you could get out of stock 1125 headers due to flow restrictions of that size pipe. Fluid dynamics I guess was how they got the number via computer modeling. I have yet to see anyone get close to it. | ||
| Tbarker |
To answer the question on the D&D I personally think it is a good design but the length is not optimum for the engine. Dean blown engines don't really need scavenging, the pressure of the intake charge will get rid of any leftover gasses in the cyl. The top fuel engines are pushing so much fuel into the engine they are almost to the point of hydro locking. | ||
| T_man |
Crabby: Got it mint and barely used from a fellow badwebber who traded in for a Duc 1098. | ||
| Ridenusa4l |
here's some interesting facts on top fuelers....its CRAZY RIDICULOUS!! http://www.ultimatecarpage.com/forum/showthread.ph p?t=20271 Jake | ||
| Tbarker |
 do the math on one of those engines to figure out how many revolutions it turns in a 1/4 mile it will suprise you how low the number is. | ||
| D_adams |
Assuming it's at redline (7000 rpm?) the entire time (5 seconds) it's only a maximum of 35000 revolutions from start to finish. This doesn't account for idling up to the start line, burnout, backing up or anything else. Sound right? (Message edited by d_adams on November 30, 2010) | ||
| Curve_carver |
I can honestly say this thread has turned into a pile of steaming terds.  | ||
| Tbarker |
redo that math 7000rpm divided by 60sec x 5sec = 583 revolutions | ||
| Pmjolly |
Or he could just divide his 35000 by 60 seconds to get the same answer.  | ||
| Tbarker |
  yes he could | ||
| D_adams |
Ooops. I knew I forgot something... (Message edited by d_adams on December 01, 2010) | ||
| Dannybuell |
It is so embarrassing when someone asks a math related question at work and I start counting on my fingers. If the calc goes past 10? Don't ask. :-) | ||
| Tbarker |
very expensive revolutions danny that is usually me doing that. | ||
| D_adams |
Well, stop slinging them around and it won't happen. | ||
| Curve_carver |
Adams Just because you bought some over the counter parts and made some unrestricted free flowing exhaust doesnt make you an expert. On top of that what kind of college experience do you have ? What was the highest physics class or technical math you've completed.What are your credidentials? What makes you so knowledgeable over easy or barker? Nothing!! These bikes have been run wide with open exausts on a dyno to make stock power without tuning.The louder the more power. What does that tell you? This engine doesn't require much backpresure. Thats all.... }Primary header diameter, length, steps, collector size, taper, diameter, outlet size, midpipe length and diameter, possible reversion cone on the pipe, intake length, lift and duration of the cams, valve size and timing, target powerband for peak power YA....I Think everyone understands how an engine works dean. } (Message edited by Curve_carver on December 01, 2010) | ||
| Freezerburn840 |
I feel the love in the air.  | ||
| Father_of_an_era |
Bam! Boom! Bange! Holy fowled feelings Batman, people are getting angry in here.... lol  | ||
| D_adams |
Umm, I never said I was an expert. For all you know, I'm a high school drop-out that never got past the 8th grade. I have no credentials that would interest you, I'm just a mechanic and a Buell enthusiast. I have a welder and I had some ideas that I wanted to try. That said, if you've got something better, show the world, we'd love to see it. If not, well, I dunno what to tell you, but it sounds like you're a somewhat cynical person that might be a little bitter about something. Essentially, I have absolutely NOTHING to prove to you or anyone else. It's already been done by an independent third party utilizing a standardized test for all the systems they tested. I never said mine were the best out there either. Maybe I just got lucky. Formulas, dimensions, calculations, pfffft, who needs all that crap anyway? What I make isn't for everyone, but I'm pretty sure I don't have any unhappy customers. | ||
| Americanmadexb |
I can honestly say this thread has turned into a pile of steaming terds On top of that what kind of college experience do you have ? What was the highest physics class or technical math you've completed.What are your credidentials? What makes you so knowledgeable over easy or barker? Nothing!! Says the uneducated man himself! Last time i checked its spelled TURD! | ||
| Aseecobra |
Paul, Why does a 4 cycle engine need back pressure? How much back pressure have you measured with the stock or aftermarket muffler? | ||
| Cowboytutt |
Don, thanks for handling this situation so well. You are well respected around here as you know. There's a whole lot this guy is not telling us. Something is pretty wrong. Mr. Barker thanks for posting. You and I have talked prior to and after the exhaust shootout and I'm very happy with your pipe and so is my best friend! Thanks for what you do Sir. -Tutt | ||
| Oddball |
Never knew noisily venting gas would result in such arguing. Can't decide which side to choose. Cheek up or cheek down?  | ||
| Bettybuell |
So, back to the original question on this thread. I put the stock exhaust back on my 1125 because the bike is so much more pleasant to ride quiet. My other bike is a Goldwing. For my track bike I bought a used Erik Buell Racing full race exhaust because it is light and makes more top end power. So, anyone want to buy my used perfectly good TM Torque Hammer exhaust for $500? It is on ebay. | ||
| Curve_carver |
Ah Betty has seen the light. Did you actually notice a huge loss in power without a aftermarket pipe? I didnt | ||
| Dannybuell |
Curve_carver * = your original complaint: --- = my answer: * made my bike jerky on off throttle ---stiffen up the suspension so the extra power won't make your bike act like grandmothers rocking chair with on/off throttle changes---- * decel is horrible ---that is a function of the ECM, the Idle air control (IAC) setting.--- * blow out my eardrums --- I have the same concerns, what brands were you using? most have some type of silencers available.--- * on the throttle out of corners its clunky 1.---a restrictive exhaust system can give torque at lower RPM's. if your suspension is too soft the additional power during roll on will give you grandmothers rocking chair again and that can seem clunky.--- | ||
| Curve_carver |
Dannybuell I understand your POV. I tried to stiffened the bike up but after setting sag,compression, and rebound settings It's right where it should be. The bike handles great. I just notice when I let off throttle into a sharp curve and get back into it out of the apex the engine clunks forward. But with the back pressure its not so harsh as I engage the throttle.When I use the stock configuration and ecm it's gone.Ive tested 3 exhausts with the stock tune and two ebr calibrations but had same results. Its not slop in the suspensions its engine clunk.The open pipe/ebr tune isn't the smoothest. I feel like the ebr tunes are pushing me into the corners.Like it has a high off idle? Are these characteristics familiar to anyone? | ||
| Dannybuell |
Curve_carver - Yes when you said; "pushing me into the corners.Like it has a high off idle? Are these characteristics familiar to anyone?" That is the IAC setting, tell them you want it like stock and everything improves after that. I have decellerated sharply with both ECM's and at apex throttled only to learn that I needed to downshift 2 gears. Once you get used to that it becomes second nature. | ||
| Xodot |
Curve carver said :when I let off throttle into a sharp curve and get back into it out of the apex the engine clunks forward. I'm putting this out here in case someone can help me understand what is happening to me. I have not attributed my similar sensation to the engine clunking forward rather it feels as if I have accelerated sharply when all I have done is tried to smoothly twist the throttle from around 3000 rpm in first or second gear. It's like "twist the smallest motion (nothing) twist the smallest motion (nothing) twist the smallest motion (nothing) twist the smallest motion -BANG! on comes the power" and the bike gets unsettled with that rush of power to the rear wheel. Maybe I should not be chopping the throttle going into the sharp bend? Should I keep the throttle on a little (throttle position consistent with 3000 rpm even though I am doing 5000 or so) then trail brake keeping the throttle open a bit? Then when I finish getting off the brakes near the apex the throttle roll on won't "snap" on because the engine will already be at the RPM I need. Just guessing here - any points? | ||
| Dannybuell |
Xodot- good point. decellerating with the throttle closed works great but getting back on with that closed throttle can be troublesome. On any bike I prefer having the throttle at 3000 rpm or more so there are two directions I can go, less throttle or more throttle. Moving up to higher revs depends on your comfort level. Being older and coming from an S1 I am more than happy with 6000 rpm as an upper shift point on the street. Any faster than that and I feel 'at risk' of cops and idiots. (Message edited by dannybuell on December 03, 2010) | ||
| D_adams |
7000 rpm is where it really starts coming alive. 8k and up it feels like your arms are going to get pulled out of their sockets. 10k rpm is a rush. |
