Clive Posted October 20, 2015 Share Posted October 20, 2015 On my spit I currently have a well used "wheelbarrow" sports exhaust. It is OK in terms of passing noise limits, at Brands it registered 89/91db, the marshal said I will be OK at any track in the country. So that was good news.The bad news is that although it passes, it still is not exactly refined. On the 10CR the drone gets to be a pain, in fact it is not pleasant for even shortish jaunts up the motorway, and pressing on during normal driving makes talking to the lady wife difficult (some may see this as an advantage)So I want to find an exhaust that is both quiet and efficient. I don't want to drop precious power, but I do want more refinement. I know this is asking a lot.So far I have thought of cutting open and re-packing the silencers. I know this does help, but I doubt it will be enough.I could possibly squeeze a small diameter cherry bomb type silencer early on in the system. Not sure how big would bit between the chassis rails though?I have also considered getting a silencer made, maybe a transverse one with entry at one end, perforated tube in a elongated U exiting at the same end as entry, and off to the tailpipe. Make it a nice long silencer in a small package? I am also working on an airbox to reduce the not inconsiderable induction noise, hoping that will help a bit too.So chaps, any pointers? Quote Link to comment Share on other sites More sharing options...
Jonny-Jimbo Posted October 20, 2015 Share Posted October 20, 2015 Ear plugs? That's what I use when in transit - like on the way back from the Essex rally. AJ and I could still talk to each other but cut out a lot of the extraneous noise, and felt good whilst driving and didn't get a headache etc. But also if I want to have a good noise to the car, I can just pop the ear plugs out. Quote Link to comment Share on other sites More sharing options...
Clive Posted October 20, 2015 Author Share Posted October 20, 2015 Nope, needs a quiet exhaust. Youare welcome to discuss this with the management, but take a tip from me, don't try Besides, I like talking to people when I am driving. The 10CR was great in the mountains where we were not flat out (far from it, we had 2 saloons and a stag with us!) but the motorways were a constant drone. I suspect, in reflection, a box close to the manifold may not last too well, and would get its filling destroyed by the heat. We are taking immediately after the manifold, so with 15" of pipe from the head. However, happy to be told otherwise. Quote Link to comment Share on other sites More sharing options...
sparky_spit Posted October 20, 2015 Share Posted October 20, 2015 I'm following this with interest because, as we discussed on Sunday, I have exactly the same issue as you. My car was measured at 95dB when scrutineered before a recent CMC event and it's close to their limit as well as being a bit anti-social at night in the country lanes. If you arrive at a good (and cheap) solution I'll steal your idea, if I may, to try on mine. If not, I'm going to try the Marcus-mod and make a removeable plate on the silencer so I can re-pack it. Quote Link to comment Share on other sites More sharing options...
Velocita Rosso Posted October 20, 2015 Share Posted October 20, 2015 I have one of theseear plugs and able to talk without shouting!Mike you should not need one .....you dont go fast enough http://www.maplin.co.uk/p/motorcycle-intercom-ye23a Quote Link to comment Share on other sites More sharing options...
uksnatcher Posted October 20, 2015 Share Posted October 20, 2015 Clive GT6 center resonator (full flow).......Bell sports back box (Full flow)Same system is on Stes GT6 too ....... soooo much quieter than wheelbarrows..... with full flowSorry , link no longer available Quote Link to comment Share on other sites More sharing options...
GT6 M Posted October 20, 2015 Share Posted October 20, 2015 Need a BiGGG donger of a center box, wid a resonator bit in the front bitthis, and re pack,n the rear boxes = 75 Db at last countAND, plenty of sound proofing too ole BeanOR, look at a MX 5 back box, twin outlest , yan each endlook ok too.https://www.google.co.uk/searc.....bih=569&dpr=1.25M Quote Link to comment Share on other sites More sharing options...
Clive Posted October 20, 2015 Author Share Posted October 20, 2015 OK, looks like a large centre box. Have seen a 26" long jobbie, 3 1/2 diameter with 2" in/out. Marcus, saw somewhere you squeezed in a 4" box. Is that a pic of it?As to MX5, quiet as a whisper, but I bet the box is full of restrictions. And that is a deffo no-no.Somewhere I have a scopion back box from an RS turbo. That was on my last car and actually survived. Maybe I should give it a go, pretty big oval silencer.EDIT. Just read your post again Marcus. What do you mean a resonator at the front?? Quote Link to comment Share on other sites More sharing options...
ferny Posted October 20, 2015 Share Posted October 20, 2015 I've been mulling this over for the rbrr. My plan is another back Bix but fitted to the rear valance. Testing will happen soon... Quote Link to comment Share on other sites More sharing options...
GT6 M Posted October 20, 2015 Share Posted October 20, 2015 Clive, a resonator at front is a space which is void of owt a all,just a free space where gasses can expand, slow and loose noise.mines only aboot 6 inch long, but it seems to work OKpipe was 4 inch, and I got it in by get,n a big adjustable, and bending the chassis lip straight doon,get another 3/4 inch at least this wayBUTT, it still moved a wee bit, so bunged the whole lot innto me vice,an ovalated it, so its noo 3/3/4 and it deffo dont touch nooBUTT,its still got the capacity , so still quietthe wee after market ,ns aint got enough space to quietn things doon.Mke yer own Clive, mine was home made, just go get some SS pipe, get some inside pipehe perfroated stuff, an weld up, simples, save ye a smalll fortune.mine must be 30 odd ear olde noo.M Quote Link to comment Share on other sites More sharing options...
Dannyb Posted October 20, 2015 Share Posted October 20, 2015 I used one of these on my Goldstar silencer which made a difference. Easily taken in and out too. Quote Link to comment Share on other sites More sharing options...
GT6 M Posted October 20, 2015 Share Posted October 20, 2015 Clive, get one of thee,s really will quieten a noisey exhaust. http://kalecoauto.com/index.ph.....xksknqVp8q5CJwUemTd0M Quote Link to comment Share on other sites More sharing options...
Clive Posted October 20, 2015 Author Share Posted October 20, 2015 Danny, a passable idea to quieten the exhaust on long journeys, but would rather do a permanent fix. And quieter on track would be good too.Marcus, I have welded exhausts before, and it usually works out fine. But my little mig is not clever with stainless, neither am I. Tig would be ideal.However, how about this? I will have a look at the weekend to see if I can get a 4" in there, but it sounds like even you found it a bit too tight!http://www.ebay.co.uk/itm/2-50.....1:g:KeEAAOSwKIpWAC3F Quote Link to comment Share on other sites More sharing options...
Clive Posted October 20, 2015 Author Share Posted October 20, 2015 And cheers for that Marcus. You have obviously heard me. Quote Link to comment Share on other sites More sharing options...
thescrapman Posted October 20, 2015 Share Posted October 20, 2015 Custom Chrome used to make an insert for their Cherry Bomb silencers that they called a DIVER (in fact they still do - http://www.custom-chrome.co.uk/Cherrybombs.html )I had one in the side pipe on my Moss, made it way too quiet so i took it out. Quote Link to comment Share on other sites More sharing options...
tiggrr1 Posted October 23, 2015 Share Posted October 23, 2015 Go with Gaz's suggestion It works and no need to mess about 😉Killed the drone at 2000 to 2500 rpm on the GT6. Quote Link to comment Share on other sites More sharing options...
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