CandyRedRC46 Posted January 20, 2015 Share Posted January 20, 2015 Smart as in plug the exhaust up enough to pass noise emissions regulations until (RPM @ PEAK POWER)/2, at which point it not longer has to meet those noise requirement and the flap opens and allows it to flow as much as a standard muffler? Link to comment Share on other sites More sharing options...
satariel Posted January 20, 2015 Share Posted January 20, 2015 Akrapovic flap works exactly the same with 5 hp increase. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted January 22, 2015 Share Posted January 22, 2015 Sweet Link to comment Share on other sites More sharing options...
Tamworth Posted January 22, 2015 Share Posted January 22, 2015 I am just curious, why do you want to replace the OEM muffler? The OEM muffler is "Smart" and changes the exhaust configuration after 5000 rmp. I'd hardly call an exhaust system with restrictor valve "smart". It's just a valve that operates at a certain rpm Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted January 22, 2015 Share Posted January 22, 2015 I want to hear more about this sweet akrapovic valve Link to comment Share on other sites More sharing options...
satariel Posted January 22, 2015 Share Posted January 22, 2015 There`s nothing to explain mate: Link to comment Share on other sites More sharing options...
lshark Posted January 22, 2015 Share Posted January 22, 2015 i have the Akro on my 1200.....i have the flapper cable hanging on my garage wall....i disconnected the stock cable the first day i had the bike Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted January 22, 2015 Share Posted January 22, 2015 There`s nothing to explain mate: My neighbors would love this Link to comment Share on other sites More sharing options...
lshark Posted January 22, 2015 Share Posted January 22, 2015 it's not loud Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted January 22, 2015 Share Posted January 22, 2015 That is why they would love it.... Link to comment Share on other sites More sharing options...
Tamworth Posted January 22, 2015 Share Posted January 22, 2015 The Akro. valve does not have an effect on the loudness of the exhaust. Also the valve pictured above has nothing to do with the 1200 Akro. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted January 22, 2015 Share Posted January 22, 2015 kewl Link to comment Share on other sites More sharing options...
satariel Posted January 22, 2015 Share Posted January 22, 2015 The Akro. valve does not have an effect on the loudness of the exhaust. Also the valve pictured above has nothing to do with the 1200 Akro. The valve in akrapovic end pipe does have an effect on the loundess. The photo was posted for a reference only - pipe valve part looks exactly the same. The one posted before is vaccum controled, vfr1200 akrapovic utilize the stock exup sero motor. They both create the same effect. I know becouse I have one. Link to comment Share on other sites More sharing options...
vfrflanders Posted January 22, 2015 Share Posted January 22, 2015 Although a lot has to do with emission nowadays, the exhaust valve seems to have a "possitive" effect on low RPM performance. At lower RPM the valve is creating a higher pressure between the exhaust and the engine, so the O2 sensors can have a better A/F reading. This way the ECU has "better information" to optimize the engine performance at lower RPM. . Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted January 22, 2015 Share Posted January 22, 2015 Oh I never thought of that! That actually makes a lot of sense! I like that a lot more than the old redneck science "Back pressure adds torque" idea. This makes a lot of sense with a fully closed loop system with wide band o2 sensors. On the vfr800 they have narrow band o2 sensors that only go closed loop under steady light throttle cruising. I am not sure how the vfr1200 works, but if its a narrow band open/closed loop set up similar to the 800, then the o2 sensors and exhaust valves might as well be disabled and trashed.... Link to comment Share on other sites More sharing options...
satariel Posted January 23, 2015 Share Posted January 23, 2015 Although a lot has to do with emission nowadays, the exhaust valve seems to have a "possitive" effect on low RPM performance. At lower RPM the valve is creating a higher pressure between the exhaust and the engine, so the O2 sensors can have a better A/F reading. This way the ECU has "better information" to optimize the engine performance at lower RPM. . Low rpm in VFR1200 is screwed anyways but you are right, the idea of the flap was to meet the noise and emission regulations and to create the back pressure in the low rpm range. However with what they succeed...I dare to say this whole back pressure myth is a one big nonsense. Sound is only slightly muted with this valve - as 1200 engine is muted anyways due its unique crank-pin position(lambo-audi v10 and vw W12 does that too) but that`s a different story. Oh I never thought of that! That actually makes a lot of sense! I like that a lot more than the old redneck science "Back pressure adds torque" idea. This makes a lot of sense with a fully closed loop system with wide band o2 sensors. On the vfr800 they have narrow band o2 sensors that only go closed loop under steady light throttle cruising. I am not sure how the vfr1200 works, but if its a narrow band open/closed loop set up similar to the 800, then the o2 sensors and exhaust valves might as well be disabled and trashed.... Never heard of the wideband OEM sensor - they all use the narrow band cheap ones. I use to play with converting my carburated v-max 1200 to efi. I must admit that I do not believe in the true closed loop system with narrow band o2 sensor. You go high low elevation and your sensor is out of range...vfr1200 system like almost all modern vehicles creates the low and mid range closed loop which works only in a specific range and conditions - just where exactly they believe it should and that would be only in the steady, speciffic and controlled rpm just to do the bloody emission/noise test. The PC and other piggy back fuel controllers do not utilize the OEM sensors because they have nothing to do with high performance tuning. Link to comment Share on other sites More sharing options...
CandyRedRC46 Posted January 23, 2015 Share Posted January 23, 2015 The new rapid bike evo and racing modules can tune with the factory narrow band sensors in semi closed loop, but wide band o2 sensors are optional (1, 2 or 4. I am running 4 wide band o2 sensors.) It is closed loop in that it is self tuning, but there is a bit of a delay to it, with the wide band o2 sensors being more precise and gathering data faster. Link to comment Share on other sites More sharing options...
Member Contributer swimmer Posted January 23, 2015 Member Contributer Share Posted January 23, 2015 Although a lot has to do with emission nowadays, the exhaust valve seems to have a "possitive" effect on low RPM performance. At lower RPM the valve is creating a higher pressure between the exhaust and the engine, so the O2 sensors can have a better A/F reading. This way the ECU has "better information" to optimize the engine performance at lower RPM. . Low rpm in VFR1200 is screwed anyways but you are right, the idea of the flap was to meet the noise and emission regulations and to create the back pressure in the low rpm range. However with what they succeed...I dare to say this whole back pressure myth is a one big nonsense. Sound is only slightly muted with this valve - as 1200 engine is muted anyways due its unique crank-pin position(lambo-audi v10 and vw W12 does that too) but that`s a different story. Oh I never thought of that! That actually makes a lot of sense! I like that a lot more than the old redneck science "Back pressure adds torque" idea. This makes a lot of sense with a fully closed loop system with wide band o2 sensors. On the vfr800 they have narrow band o2 sensors that only go closed loop under steady light throttle cruising. I am not sure how the vfr1200 works, but if its a narrow band open/closed loop set up similar to the 800, then the o2 sensors and exhaust valves might as well be disabled and trashed.... Never heard of the wideband OEM sensor - they all use the narrow band cheap ones. The PC and other piggy back fuel controllers do not utilize the OEM sensors because they have nothing to do with high performance tuning. Using a wide band O2 sensor on my WR250R in conjuntion with PCV and Autotune. Link to comment Share on other sites More sharing options...
Headhunter Posted February 6, 2015 Share Posted February 6, 2015 Akra is beautiful on the 1200 Link to comment Share on other sites More sharing options...
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