Guest Posted January 4, 2019 Share Posted January 4, 2019 Hey all =) As a part of some other work that was being done to my car recently I had to replace the exhaust as it was screwed. At the time I was unable to find an OEM exhaust for a sensible price so ended up with Berk decats, HKS Y pipe, and Cobra (ish, it has some welds for some reason) back section. I quite like the noise but there are 2 problems, firstly the drone at cruising speeds between 60 and 70 is bad. My options are lower gear or break the speed limit. 2nd issue is the level of noise. I am quite happy with my car barking, but a miserable bugger a few houses away came out to complain this evening, and I would guess he would gear up for a complaint if I don't try to take steps, even though I am respectful with my revs in the built up area I live in. The reason I don't want to change everything necessarily is that it has just been mapped to this spec about 2 weeks ago -_- So I am seeking options to fix this! The main problem is noise levels, is it as simple as putting the old cats back in? I am assuming this would affect power negatively. Are there other more preferable avenues? Ideally given what I have just spent on other work on it I don't want to have to spend much >.< The secondary and less pressing issue is the drone, is that a function of the decats or the back box? Thanks in advance for advice =) Luke Quote Link to comment Share on other sites More sharing options...
Jack94 Posted January 4, 2019 Share Posted January 4, 2019 I think in order of volume/drone it goes stock cats, HFCs then test pipes so one option could be to swap the decats for HFCs and see how you get on. Alternatively you could try swapping the exhaust from the Y piece back with one that's known to be tamer (e.g. Miltek). Lastly you could try getting someone to weld an extra silencer or two into the setup you've got now. Quote Link to comment Share on other sites More sharing options...
Andy_Muxlow Posted January 4, 2019 Share Posted January 4, 2019 (edited) I would get rid of the de cats really, they cause drone as has been said above you can try hfc's but stock cats would bring the drone down but also the noise. I have just fitted hfc to my gemini exhaust on my 370z and I get no nasty droning at all. Edited January 4, 2019 by Andy_Muxlow 1 Quote Link to comment Share on other sites More sharing options...
Guest Posted January 5, 2019 Share Posted January 5, 2019 Any idea what impact on HFCs will have on on flow? Would it badly affect a map that had been done with the current decat setup or would it be minimal? Quote Link to comment Share on other sites More sharing options...
nissanman312 Posted January 5, 2019 Share Posted January 5, 2019 3 minutes ago, Doom said: Any idea what impact on HFCs will have on on flow? Would it badly affect a map that had been done with the current decat setup or would it be minimal? Best to ask the guy who mapped it for a solid answer Is it a 350 or 370 Quote Link to comment Share on other sites More sharing options...
Guest Posted January 5, 2019 Share Posted January 5, 2019 Hey there, 350z. Yes I guess that would make sense Quote Link to comment Share on other sites More sharing options...
Guest Posted January 5, 2019 Share Posted January 5, 2019 Would something like the ART test pipes reduce amplitude and drone? Quote Link to comment Share on other sites More sharing options...
Jack94 Posted January 5, 2019 Share Posted January 5, 2019 Yes, that's what the Helmholtz Chambers are for. Taken from the motordyne website- "ART pipes provide the quietest, smoothest, deepest sound of any test pipe while greatly reducing or eliminating rasp and drone." 1 Quote Link to comment Share on other sites More sharing options...
Guest Posted January 5, 2019 Share Posted January 5, 2019 Any idea if the ARTs would be quieter than HFCs? No worries if not, I can see that some research is going to be required ^_^ Quote Link to comment Share on other sites More sharing options...
nissanman312 Posted January 5, 2019 Share Posted January 5, 2019 My friend and I both run invidia gemini I run de cats he runs art pipes We tested both set ups with a decibel meter there was 1 or 2 decibels between the two set ups Inside the car however his has less drone and is a lot quieter but I know he has extensive sound deadening in place ...in the boot in the doors everywhere and it's a hr350 and I'm in a 370 with no extra sound proofing Quote Link to comment Share on other sites More sharing options...
Jack94 Posted January 5, 2019 Share Posted January 5, 2019 I don't think they're as quiet as HFCs but that's only from what I've heard. Like you say, probably best to do some research Quote Link to comment Share on other sites More sharing options...
350Butcher Posted January 5, 2019 Share Posted January 5, 2019 I ran ART pipes on my DE and HR 350z's mated to XYZ y pipe and Tanabe Medalion Touring system and can assure you there is no drone from them or nasty rasp. As far as dB all I can add is I needed no additional silencing at Donington track days so its under 98dB. The start of this sound clip was with the above setup Quote Link to comment Share on other sites More sharing options...
Guest Posted January 7, 2019 Share Posted January 7, 2019 Quote I ran ART pipes on my DE and HR 350z's mated to XYZ y pipe and Tanabe Medalion Touring system and can assure you there is no drone from them or nasty rasp. As far as dB all I can add is I needed no additional silencing at Donington track days so its under 98dB. The start of this sound clip was with the above setup Thanks very much for the input =) That sounds like quite a deep note (good imho) and pretty civilised by comparison to mine currently! Much of that may be down to the other parts of your exhaust but I guess I will find out soon enough as I have just ordered the ARTs. It might lead to me having to change the rest of the exhaust but I will see whether it is an improvement as a first step. If it makes the old man down the road go away then I'm already onto a winner. The after setup in your video sounds lovely, and surprisingly well-mannered given all of the things that you have done to it!! Quote Link to comment Share on other sites More sharing options...
350Butcher Posted January 14, 2019 Share Posted January 14, 2019 On 07/01/2019 at 20:48, Doom said: Thanks very much for the input =) That sounds like quite a deep note (good imho) and pretty civilised by comparison to mine currently! Much of that may be down to the other parts of your exhaust but I guess I will find out soon enough as I have just ordered the ARTs. It might lead to me having to change the rest of the exhaust but I will see whether it is an improvement as a first step. If it makes the old man down the road go away then I'm already onto a winner. The after setup in your video sounds lovely, and surprisingly well-mannered given all of the things that you have done to it!! The ART pipes do give a very nice tuned tone without sounding nasty and overly loud.......system will obviously play its part but cats/decats make a big difference Don't be too fooled by the "after" idle, the intake and exhaust make themselves known when it's opened up........bear in mind this is with baffles installed to keep below 98dB........its 102dB without baffles (hope this link works!) https://www.flickr.com/photos/167602387@N08/31801860687/in/shares-83a4go/ https://www.flickr.com/photos/167602387@N08/46018794414/in/shares-83a4go/ 2 Quote Link to comment Share on other sites More sharing options...
Guest Posted January 14, 2019 Share Posted January 14, 2019 Sounds great, I'm a little envious! Quote Link to comment Share on other sites More sharing options...
57jam89 Posted January 15, 2019 Share Posted January 15, 2019 I have some hfc which i don't need. Quote Link to comment Share on other sites More sharing options...
Guest Posted January 15, 2019 Share Posted January 15, 2019 2 hours ago, 57jam89 said: I have some hfc which i don't need. Thanks very much for the offer dude, but I now have ART pipes on the way. Hopefully they will help at least a little. Quote Link to comment Share on other sites More sharing options...
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