andyberg Posted December 28, 2009 Report Share Posted December 28, 2009 Whats the advantages in 'Wrapping' your exhaust? Ive heard it increases gasflow and thus produces more HP, if thats true why aint more bikes done? Anyone know the answers or is it all just 'hot air'? Link to comment Share on other sites More sharing options...
spacemonkey Posted December 28, 2009 Report Share Posted December 28, 2009 Whats the advantages in 'Wrapping' your exhaust? Ive heard it increases gasflow and thus produces more HP, if thats true why aint more bikes done? Anyone know the answers or is it all just 'hot air'? As far as I can gather it is not about gas flow, it is more to do with keeping the temperature up and hence effectively altering the tuned length of the exhaust. Link to comment Share on other sites More sharing options...
andyberg Posted December 28, 2009 Author Report Share Posted December 28, 2009 As far as I can gather it is not about gas flow, it is more to do with keeping the temperature up and hence effectively altering the tuned length of the exhaust. So is there any significant advantage..if so, what and why dont more people do it? Link to comment Share on other sites More sharing options...
Bernster Posted December 28, 2009 Report Share Posted December 28, 2009 I thought it were from ye olde days before sensors and such? These days your better off fooling your system by fooling the sensor's than going mechanical, Ronienige will tell you. I also thought it was to prevent you burning your bodywork and your body or heat reaching areas like your rear shock, as well as preventing gases escaping cr@ppy joints? Link to comment Share on other sites More sharing options...
spacemonkey Posted December 28, 2009 Report Share Posted December 28, 2009 So is there any significant advantage..if so, what and why dont more people do it? Well depending on the length of the pipe, etc you might need more/less wrap and the only way to find out is by testing on a dyno or such. Very few people are willing to spend time/money developing their bike in that way. Link to comment Share on other sites More sharing options...
cagimaha Posted December 28, 2009 Report Share Posted December 28, 2009 As far as I can gather it is not about gas flow, it is more to do with keeping the temperature up and hence effectively altering the tuned length of the exhaust. Careful here, the altering the tuned length thing is for two strokes. It dosen't alter the tuned length of the pipe though. Because a two stroke relies on sound waves travelling up and down the pipes heating the exhaust gas (lowering the density) alters the speed of sound and therefore the power characteristics. On a four stroke they are advantageous because hotter exhaust gases will move quicker. This only makes a noticeable difference when flat out though which is why you see most drag bikes with wrapped exhausts. Link to comment Share on other sites More sharing options...
spacemonkey Posted December 28, 2009 Report Share Posted December 28, 2009 Careful here, the altering the tuned length thing is for two strokes. It dosen't alter the tuned length of the pipe though. Because a two stroke relies on sound waves travelling up and down the pipes heating the exhaust gas (lowering the density) alters the speed of sound and therefore the power characteristics. It effectively alters the tuned length because the speed of sound is different at different temperatures/pressures. I'm not suggesting the pipe magically shortens because it is wrapped. Four strokes also use sound waves to scavenge don't they? Isn't that why the length of the pipe makes a difference? Link to comment Share on other sites More sharing options...
cagimaha Posted December 28, 2009 Report Share Posted December 28, 2009 Must.... Read.... Post.... Properly... Before.... Clicking... Reply..... Link to comment Share on other sites More sharing options...
Twobad Posted December 28, 2009 Report Share Posted December 28, 2009 It effectively alters the tuned length because the speed of sound is different at different temperatures/pressures. I'm not suggesting the pipe magically shortens because it is wrapped. Four strokes also use sound waves to scavenge don't they? Isn't that why the length of the pipe makes a difference? Yes that's why F1 cars etc have such tortuous pipe runs. The tuning only works for specific revs though. Link to comment Share on other sites More sharing options...
spacemonkey Posted December 28, 2009 Report Share Posted December 28, 2009 Must.... Read.... Post.... Properly... Before.... Clicking... Reply..... Looking back at that post I can see how easily it can be misread.... I could have written that better! Speaking of F1 cars.... Does anyone know why the F1 cars have those stepped headers? What is the purpose of those? Link to comment Share on other sites More sharing options...
andyberg Posted December 28, 2009 Author Report Share Posted December 28, 2009 So basically a waste of time and money in the real world? Link to comment Share on other sites More sharing options...
Twobad Posted December 28, 2009 Report Share Posted December 28, 2009 So basically a waste of time and money in the real world? Not if you want to control local heat problems or want the bike to just look cool. Most of the car fraternity only use it to control tempertatures under the bonnet. Link to comment Share on other sites More sharing options...
Cibbersicks Posted December 28, 2009 Report Share Posted December 28, 2009 Is it me or does this just look silly? Gorgeous... but silly... 8 straight diagonal slash-cuts poking out of the bonnet will do just fine... won't they? Link to comment Share on other sites More sharing options...
blow_away Posted December 31, 2009 Report Share Posted December 31, 2009 Here is one from the V10 days - absolutely top notch tube bending and welding work Link to comment Share on other sites More sharing options...
spacemonkey Posted December 31, 2009 Report Share Posted December 31, 2009 Here is one from the V10 days - absolutely top notch tube bending and welding work The have the big steps in them too... What do these achieve? Link to comment Share on other sites More sharing options...
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