Jonny Posted February 20, 2009 Author Report Share Posted February 20, 2009 gents, i've tried this mod today. the valve was in the shut position, so i disconnected the pipe and screwed a screw in to it. I then tried to open the butterfly valve and it wasn't open. i applied some force with a crow bar and have slightly bent the valve. can anyone advise on how to open this or prise it open as it's not opening any further. thanks Try putting the crowbar right up to the valve on the side its going to turn on and tap the end of the crowbar with a hammer till you start to get movement. Take this slowly until its all the way open and this should save it bending. I see this was done a couple of weeks ago, did you get on any further at all? Link to comment Share on other sites More sharing options...
330Ci_Rick Posted February 21, 2009 Report Share Posted February 21, 2009 i think mine is permantly stuck on open so I guess I don't need to worry! lol I think this is the same with mine also. Happy days Link to comment Share on other sites More sharing options...
Will Lam Posted May 12, 2009 Report Share Posted May 12, 2009 roll on 5.30 because am going straight home and doing the mod but one thing, will this cause any long term effect on the car? thanks Will Link to comment Share on other sites More sharing options...
Keith Posted May 12, 2009 Report Share Posted May 12, 2009 My understanding is that the butterfly valve is there to alter the backpressure through the silencer at low revs to increase torque, a bit like the EXUP valve in the exhausts of Yamaha motorcycles. It is there for more than just to make the car quieter at low revs. As I started reading this thread I was thinking exactly this. I'm sure the back pressure is a contributing factor to provide addition torque at low revs. Nobody has responded to Bigbaz's query - is this because nobody knows? I would not like to do this mod just for a slightly deeper exhaust note, at the cost of even a single ft/lb of torque ANYWHERE throughout the rev range?!! I was under the impression that the a marginally restrictive exhaust gas flow, contibutes to lower RPM torque, and a less restrictive exhaust flow benefits power at higher RPMs? But then again it is a good point that aftermarket exhausts do not have this feature (or have to comply with German noise laws) and are considered to be much better for performance... Hmm. I just don't know what to think unless anyone can find me some conclusive evidence for/against either side of the argument. Anyone EDIT: Most of the internet research I found was in favour of the mod, but none has so far been conclusive of how it effects the torque low down, when it should be closed, most of it merely stating obvious theory that less restrictive = more power, but this is always stated in terms of HIGH revs, when it would ordinarily be open anyway... Link to comment Share on other sites More sharing options...
Jonny Posted May 12, 2009 Author Report Share Posted May 12, 2009 roll on 5.30 because am going straight home and doing the mod but one thing, will this cause any long term effect on the car? thanks Will No long term effects on your car at all. Only effect will be on your mouth as you grin a lot more hearing that extra burble As I started reading this thread I was thinking exactly this. I'm sure the back pressure is a contributing factor to provide addition torque at low revs. Nobody has responded to Bigbaz's query - is this because nobody knows? I would not like to do this mod just for a slightly deeper exhaust note, at the cost of even a single ft/lb of torque ANYWHERE throughout the rev range?!! I was under the impression that the a marginally restrictive exhaust gas flow, contibutes to lower RPM torque, and a less restrictive exhaust flow benefits power at higher RPMs? But then again it is a good point that aftermarket exhausts do not have this feature (or have to comply with German noise laws) and are considered to be much better for performance... Hmm. I just don't know what to think unless anyone can find me some conclusive evidence for/against either side of the argument. Anyone This has been answered and spoken about. There are no detrimental effects to power or low down torque at all. Only increase or decrease is in sound levels. Any effect of backpressure and therefore torque would be so so minimal no human would be able to detect it and increased flow therefore horsepower would counteract the effect. Link to comment Share on other sites More sharing options...
Will Lam Posted May 12, 2009 Report Share Posted May 12, 2009 Hi i have just done the tee mod and the exhaust does sound alot deeper.. but the flip wont stay open. just keeps flipping around, i can even move it with my finger. How do you guys stop it from flipping? as its sounds like a triangle lol Will Link to comment Share on other sites More sharing options...
Jonny Posted May 12, 2009 Author Report Share Posted May 12, 2009 Hi i have just done the tee mod and the exhaust does sound alot deeper.. but the flip wont stay open. just keeps flipping around, i can even move it with my finger. How do you guys stop it from flipping? as its sounds like a triangle lol Will Never had that one before Will! Sounds like you need some rust in there lol I dont really have an answer for that but i would post a new thread in the tuning and peformance thread rather than use this one and see what people say. Link to comment Share on other sites More sharing options...
nellers Posted May 12, 2009 Report Share Posted May 12, 2009 If you look at the pictures in the previous posts it looks like the vacuum operates a mechanical arm which then opens/closes the valve?! If you don't fancy putting lots of salt in the exhaust to build up some rust is there any way you can jam the mechanical arm on top of the exhaust so that it stops moving and hence should keep the valve open?! Link to comment Share on other sites More sharing options...
nellers Posted May 12, 2009 Report Share Posted May 12, 2009 Just went out and spent 5 minutes sorting this out! I now have a valve that is open permanently Only noticed while looking before I did it that mine did open and close but with a squeak each time!! Definately noticed a difference on just a light revving so shall take it out in a bit and see what difference there is! Cheers for putting this on here Jonny! Link to comment Share on other sites More sharing options...
///MARKYBHOYSBM Posted May 12, 2009 Report Share Posted May 12, 2009 On mine I removed the flap altogether!!! Link to comment Share on other sites More sharing options...
Jonny Posted May 12, 2009 Author Report Share Posted May 12, 2009 Just went out and spent 5 minutes sorting this out! I now have a valve that is open permanently Only noticed while looking before I did it that mine did open and close but with a squeak each time!! Definately noticed a difference on just a light revving so shall take it out in a bit and see what difference there is! Cheers for putting this on here Jonny! No worries On mine I removed the flap altogether!!! Yeah or that lol Link to comment Share on other sites More sharing options...
///MARKYBHOYSBM Posted May 12, 2009 Report Share Posted May 12, 2009 No worries Yeah or that lol lol When i had prized mine open due to it bein seized there was a rattling noise coming from the flap so i just removed it!!! Link to comment Share on other sites More sharing options...
Will Lam Posted May 12, 2009 Report Share Posted May 12, 2009 lol When i had prized mine open due to it bein seized there was a rattling noise coming from the flap so i just removed it!!! how did you do that? Link to comment Share on other sites More sharing options...
Keith Posted May 12, 2009 Report Share Posted May 12, 2009 This has been answered and spoken about. There are no detrimental effects to power or low down torque at all. Only increase or decrease is in sound levels. Any effect of backpressure and therefore torque would be so so minimal no human would be able to detect it and increased flow therefore horsepower would counteract the effect. It has been spoken about, yes. But no, it hasn't been answered conclusively with proof anywhere in this thread, only with general thoughts. I can see the common sense in the idea, but I would like some kind of back-up to all the talk about the mod NOT affecting performance in any way - from what I can tell, so far its only been in the shape of people saying they cannot feel any difference, and that not conclusive enough. As mentioned before, it is specifically incorporated into motorbikes (I'm not sure about sports bikes as someone on here did mention) but I know that some Harley's use a butterfly specifically to improve low down torque. Link to comment Share on other sites More sharing options...
///MARKYBHOYSBM Posted May 12, 2009 Report Share Posted May 12, 2009 how did you do that? it sounds nasty but a hammer and chissel!!! I gave it a few smacks in the middle where the flap is attached to the motor, its only thin metal so its easily removed, sounds alot better now when sitting idleing Link to comment Share on other sites More sharing options...
Jonny Posted May 12, 2009 Author Report Share Posted May 12, 2009 It has been spoken about, yes. But no, it hasn't been answered conclusively with proof anywhere in this thread, only with general thoughts. I can see the common sense in the idea, but I would like some kind of back-up to all the talk about the mod NOT affecting performance in any way - from what I can tell, so far its only been in the shape of people saying they cannot feel any difference, and that not conclusive enough. As mentioned before, it is specifically incorporated into motorbikes (I'm not sure about sports bikes as someone on here did mention) but I know that some Harley's use a butterfly specifically to improve low down torque. Well what exactly are you looking for Marsden. No ones going to go and do a dyno run for the removal of a butterfly valve are they. In which case the only solid answer your going to get is that of the conclusive general consensus on this forum, that answer being, there is no discernible difference in performance. This is not a performance mod. Its an aesthetic mod purely for noise. It will not take a rocket scientist nor even an educated guess to tell you that any possible difference it could make would not even be noticeable. You do not own a sports car, so there's no point worrying about something your never going to notice. I don't mean for any of this to sound brash or rude but your talking as if you expect a bunch of car enthusiasts to come up with an answer that's not only not worth testing but is going to be a time consuming or costly one at that. Its a golf tee in a tube. Its not splitting the atom, and doesn't need any kind of scientific or mechanical factual backup. In any case what your asking for is just being anal (no gay jokes please people! ) and your not going to get the solid evidence your looking for unless you yourself or someone else steps up and does a dyno in which case i dare say even that would be hard pressed to distinguish between the loss or gain of its removal. If you want to do it, do. If not, no point quibbling about its effects. Try it, see if you can tell any difference. If its not to your liking, change it back. No win, no fee situation Link to comment Share on other sites More sharing options...
muly Posted May 12, 2009 Report Share Posted May 12, 2009 There was an email floating around the net where someone had asked bmw about the flap and Bmw replied stateing it was only used for sound and had nothing whatsoever to do with performance, its a good free mod with a litttle extra burble at idle Link to comment Share on other sites More sharing options...
Jonny Posted May 12, 2009 Author Report Share Posted May 12, 2009 There was an email floating around the net where someone had asked bmw about the flap and Bmw replied stateing it was only used for sound and had nothing whatsoever to do with performance, its a good free mod with a litttle extra burble at idle Exactly. Link to comment Share on other sites More sharing options...
Will Lam Posted May 12, 2009 Report Share Posted May 12, 2009 hammer and chissel?!! i may do, but is there other way of doing it? Will Link to comment Share on other sites More sharing options...
///MARKYBHOYSBM Posted May 12, 2009 Report Share Posted May 12, 2009 hammer and chissel?!! i may do, but is there other way of doing it? Will I know it sounds harsh m8! I was aprehensive about doing it but it came out fine with no damage done. I just didnt like the rattle! Link to comment Share on other sites More sharing options...
Keith Posted May 12, 2009 Report Share Posted May 12, 2009 Johnny, please dont get defensive just because I am curious about the mod that you have performed. I am happy that you are pleased with the mod and some many other people are too. I expect it will do exactly as you say, but I was just asking the question as to whether anyone reading this (a vast pool of knowledge from fairly informed people) could offer anything based on fact to the discussion - is that not what forums are for?!! I'm also well aware its not 'splitting the atom', but forums are here for topic to be discussed, whether or not some people that read them consider the questions 'anal'. I'm not quite sure why you have taken personal exception to this, to the point where you are telling me that I do not own a 'sports car' (maybe no 911, but still a sports car I'm sure many people will agree on here) and trying to dismiss me as anal. I did not want to offend you, just ask a question that I wanted to know an answer to. If you can not answer it then there is no need to get quite so tetchy, maybe just let someone else try answer it. Link to comment Share on other sites More sharing options...
Whistle Posted May 12, 2009 Report Share Posted May 12, 2009 After reading this, i want to go out now and have a go but its a little late. Will deffo do it tomorrow. Link to comment Share on other sites More sharing options...
Will Lam Posted May 13, 2009 Report Share Posted May 13, 2009 Was going to chissel the valve off this morning but my hand was shaking lol isnt there any other ways? Link to comment Share on other sites More sharing options...
Jonny Posted May 18, 2009 Author Report Share Posted May 18, 2009 Johnny, please dont get defensive just because I am curious about the mod that you have performed. I am happy that you are pleased with the mod and some many other people are too. I expect it will do exactly as you say, but I was just asking the question as to whether anyone reading this (a vast pool of knowledge from fairly informed people) could offer anything based on fact to the discussion - is that not what forums are for?!! I'm also well aware its not 'splitting the atom', but forums are here for topic to be discussed, whether or not some people that read them consider the questions 'anal'. I'm not quite sure why you have taken personal exception to this, to the point where you are telling me that I do not own a 'sports car' (maybe no 911, but still a sports car I'm sure many people will agree on here) and trying to dismiss me as anal. I did not want to offend you, just ask a question that I wanted to know an answer to. If you can not answer it then there is no need to get quite so tetchy, maybe just let someone else try answer it. Marsden, please do not take any offense to my post at all, that really and honestly was not my intention. I certainly was not trying to be offensive nor was I being at all defensive about the mod. (I'm aware some of my posts can come across as quite blunt, were all flawed and I'm constantly working on it lol i'm really a very nice guy ) I think its fantastic that your curious and I welcome and am happy to answer any questions, I was merely trying to point out that there is was no point trying to pursue results of the mod you weren't going to find, because i don't think anyone will ever do any kind of RR results for it and i'd rather set the record straight then leave you with an open question. I definitely did not want it to come across as "tetchy" or volatile in any way and i hope you don't think thats the case. Link to comment Share on other sites More sharing options...
Keith Posted May 18, 2009 Report Share Posted May 18, 2009 No worries Pal - thanks for the PM Keith. Link to comment Share on other sites More sharing options...
