Deacon 1357 Report post Posted March 16, 2017 On 15/03/2017 at 4:59 PM, Bfranklyn86 said: That's a lovely exhaust. Do you know what the pipe diameter is? I'm not sure - I'll measure it and get back to you 👍 Share this post Link to post Share on other sites
Deacon 1357 Report post Posted March 16, 2017 On 15/03/2017 at 4:59 PM, Bfranklyn86 said: That's a lovely exhaust. Do you know what the pipe diameter is? Just measured it as 2.5" 👍 Share this post Link to post Share on other sites
Tareim 343 Report post Posted March 16, 2017 1 hour ago, Deacon said: Just measured it as 2.5" 👍 OD or ID? Share this post Link to post Share on other sites
Deacon 1357 Report post Posted March 16, 2017 Outside Share this post Link to post Share on other sites
Ade 517 Report post Posted March 17, 2017 9 hours ago, Deacon said: Outside That's pretty normal, most are 2.5" O.D If you have a moment, could you measure the circumference and length of the Helmholtz?, as well as the pipe circumference and length that connects it to the main pipe? Share this post Link to post Share on other sites
Deacon 1357 Report post Posted March 17, 2017 27 minutes ago, Ade said: That's pretty normal, most are 2.5" O.D If you have a moment, could you measure the circumference and length of the Helmholtz?, as well as the pipe circumference and length that connects it to the main pipe? I'll try after work. At the moment it's repacked up in the box and a bit (lot in fact) of a git to get out and then put back! 1 Ade reacted to this Share this post Link to post Share on other sites
Ade 517 Report post Posted March 17, 2017 27 minutes ago, Ade said: That's pretty normal, most are 2.5" O.D If you have a moment, could you measure the circumference and length of the Helmholtz?, as well as the pipe circumference and length that connects it to the main pipe? I'll try after work. At the moment it's repacked up in the box and a bit (lot in fact) of a git to get out and then put back! No worries. Was just interested in the tuning frequency. Share this post Link to post Share on other sites
Deacon 1357 Report post Posted March 17, 2017 11 hours ago, Ade said: That's pretty normal, most are 2.5" O.D If you have a moment, could you measure the circumference and length of the Helmholtz?, as well as the pipe circumference and length that connects it to the main pipe? The Helmholtz is 360mm long and the circumference is 330mm. The pipe is approximately 130mm long and has a circumference of 140mm. Does that help @Ade? 1 Ade reacted to this Share this post Link to post Share on other sites
Ade 517 Report post Posted March 17, 2017 Yeap. I'll do the calculations tomorrow. Cheers 1 Deacon reacted to this Share this post Link to post Share on other sites
Deacon 1357 Report post Posted March 19, 2017 I dropped my car off at RRG yesterday for its second MOT, fourth year service and for the recall to be done. While I was there I had a good look around and sit in the facelift car. I wasn't a fan from pictures but I do think it looks much better in person. The inside is definitely a step up - I really like the new wheel and the alcantara touches definitely lift it. I also liked how much more finished the armrest seemed to make the inside so I've ordered one for my car today. Share this post Link to post Share on other sites
Paul 442 Report post Posted March 19, 2017 Armrest is one of those mods where the moment you have it you wonder how you lived without it! 1 Deacon reacted to this Share this post Link to post Share on other sites
Lauren 2259 Report post Posted March 19, 2017 17 minutes ago, Paul said: Armrest is one of those mods where the moment you have it you wonder how you lived without it! I think I must be one of the few that doesn't want one. Though I don't use the centre console for drinks (door bin is better for my coffee), I do like to have my sunglasses and vapouriser to hand in the centre console, so I've never wanted the armrest. It looks nice, but I'm not sure it's practical for me at least. Share this post Link to post Share on other sites
Paul 442 Report post Posted March 19, 2017 1 minute ago, Lauren said: I think I must be one of the few that doesn't want one. Though I don't use the centre console for drinks (door bin is better for my coffee), I do like to have my sunglasses and vapouriser to hand in the centre console, so I've never wanted the armrest. It looks nice, but I'm not sure it's practical for me at least. For motorway cruising etc I usually only have right hand on the wheel, I like being able to rest my left elbow on the armrest rather than having it sink into the armrest. I still leave the armrest open if I have a can of drink or something, and I still store bits and pieces in there, it's just nice that I can leave it down and rest my arm on it afterwards. Share this post Link to post Share on other sites
Rich 378 Report post Posted March 19, 2017 I don't like armrests either, just get in the way. Share this post Link to post Share on other sites
Deacon 1357 Report post Posted March 19, 2017 I did feel the same on the armrests to be honest. Share this post Link to post Share on other sites
Mike 458 Report post Posted March 19, 2017 Another one for not liking them, got annoyed with it in Keith's car driving the whole of 2 minutes to JAE Share this post Link to post Share on other sites
Ade 517 Report post Posted March 20, 2017 On 3/17/2017 at 7:19 PM, Deacon said: The Helmholtz is 360mm long and the circumference is 330mm. The pipe is approximately 130mm long and has a circumference of 140mm. Does that help @Ade? According to my calculations the helmholtz will be tuned to 3800rpm @ 180C gas temperature ( that is a guess based on mine being 150C at the back box but will vary depending on how hard you drive and the airflow under the car). Could be designed to tune a particular resonant frequency or for the sound they wanted. Either way Its one of the nicer sound exhausts IMO. Interestingly the website says it has 60mm diameter pipe. Must mean internal as 2.5" is 63.5mm. 1 Deacon reacted to this Share this post Link to post Share on other sites
Deacon 1357 Report post Posted March 20, 2017 7 minutes ago, Ade said: According to my calculations the helmholtz will be tuned to 3800rpm @ 180C gas temperature ( that is a guess based on mine being 150C at the back box but will vary depending on how hard you drive and the airflow under the car). Could be designed to tune a particular resonant frequency or for the sound they wanted. Either way Its one of the nicer sound exhausts IMO. Interestingly the website says it has 60mm diameter pipe. Must mean internal as 2.5" is 63.5mm. Excuse my ignorance as I know nothing of this but does it make a difference where the Helmholtz is? So on your h&s system it's on the back boxes whereas on the hks it's on the centre pipe? Share this post Link to post Share on other sites
Ade 517 Report post Posted March 20, 2017 Just now, Deacon said: Excuse my ignorance as I know nothing of this but does it make a difference where the Helmholtz is? So on your h&s system it's on the back boxes whereas on the hks it's on the centre pipe? Well firstly I will say I am not an expert on Helmholtz resonators, but they basically act in the same way as a wind instrument or a relex port of a speaker box works. So based on that, no it shouldn't make much difference to the amount of attenuation assuming the chamber is designed with the correct gas temperature. However the way the other silencers react may make a difference but I dont have any experience with that. Share this post Link to post Share on other sites
nerdstrike 186 Report post Posted March 20, 2017 It does sort of matter where you attach it, but you can adjust the length/diameter to suit the temperature of the gasses in that part of the system. The decompression into the muffler will drop gas temp, but most of the fall-off will happen by the time you get to the second cat position 1 Ade reacted to this Share this post Link to post Share on other sites
Ade 517 Report post Posted March 20, 2017 2 minutes ago, nerdstrike said: It does sort of matter where you attach it, but you can adjust the length/diameter to suit the temperature of the gasses in that part of the system. The decompression into the muffler will drop gas temp, but most of the fall-off will happen by the time you get to the second cat position Yes that's what I was trying to say, you have to adjust the chamber volume to match the gas temperature for the target frequency but once that has been done, I cant see it making much difference. On mine I stuffed a thermocouple in the exhaust as well as used an IR Thermometer externally on the dark welds to measure gas temperature at the mounting point before I did the calculations. Share this post Link to post Share on other sites
Deacon 1357 Report post Posted March 20, 2017 New gearknob arrived today. Can't decide now if I'd prefer it without the oval around and with the bat in black with the shift pattern left red? Share this post Link to post Share on other sites
shiftspark 41 Report post Posted March 20, 2017 Saw your car today,looks great but couldn't see much of the Motons Share this post Link to post Share on other sites
Deacon 1357 Report post Posted March 20, 2017 4 minutes ago, shiftspark said: Saw your car today,looks great but couldn't see much of the Motons At RRG? You're welcome to have a look at any of the meets 👍 1 shiftspark reacted to this Share this post Link to post Share on other sites
shiftspark 41 Report post Posted March 20, 2017 Yes at RRG how longs yours there for ? mines gone in for P000C fault. only had a quick look as had to get back home as Mrs shiftspark was taking me home. Share this post Link to post Share on other sites
