John Vine Posted June 21, 2010 Share Posted June 21, 2010 Your help please... Does anyone have figures for R400D exhaust noise levels comparing cat and cat bypass? Both these items and the silencer are CC's standard issue. My experience so far is that, with the bypass, the exhaust note is certainly harder at over, say, 5000 rpm. It's possibly noisier too (I use earplugs), but it's all a bit subjective until I can get it tested at a trackday. With the cat fitted I get readings of 96.5 to 97. JV Link to comment Share on other sites More sharing options...
paul jacobs Posted June 21, 2010 Share Posted June 21, 2010 John, I can only comment on my 2.3 Dura, 260, but when I swapped out the cat for a straight bit of pipe, I really couldn't tell any difference in the noise level - much to my surprise. At anything over 5k I'm concentrating so hard on the blurred scenery whizzing by that I have no memory of any noise at all 😬 Paul J. Link to comment Share on other sites More sharing options...
John Vine Posted June 21, 2010 Author Share Posted June 21, 2010 Thanks, Paul. Even if the engines aren't really comparable, the blurred scenery does sound familiar. JV Link to comment Share on other sites More sharing options...
TJG Posted June 21, 2010 Share Posted June 21, 2010 John. Can't help with any readings and I'm a tad deaf but Mrs TJG (and the neighbours ) seem to think it's considerably louder without the cat. A much harsher note apparently. Tony Link to comment Share on other sites More sharing options...
akb Posted June 21, 2010 Share Posted June 21, 2010 My R400D with cat bypass and trackday silencer registered between 93 and 94 at 4,500 rpm today at Castle Combe Andy Link to comment Share on other sites More sharing options...
Pat the Plumber Posted June 21, 2010 Share Posted June 21, 2010 R400D without CAT, measured 99db's at Oulton. my R400 Link to comment Share on other sites More sharing options...
Tangerine Dream Posted June 21, 2010 Share Posted June 21, 2010 My R400D measured 98dB at Keevil last week. This was 4500rpm. I asked to try 5500rpm as some places will want that (being about the true 75% of max revs) and it just crept under 100dB. This is with the cat in place and a fat 7" exhaust supplied new with the car .. not a cost option. I will try with the decat pipe next time. ================================== R400SV in orange - so far unmodified! Link to comment Share on other sites More sharing options...
John Vine Posted June 21, 2010 Author Share Posted June 21, 2010 Thanks chaps. Very useful.A much harsher note apparentlyExactly what I felt. I haven't asked the neighbours yet!My R400D with cat bypass and trackday silencer registered between 93 and 94 at 4,500 rpm today at Castle CombeThat's impressive, Andy. The last time I was at Castle Combe, they measured me at 97 with a cat. What exactly is your "trackday silencer"? R400D without CAT, measured 99db's at Oulton.That's closer to what I'm expecting, which means I'll be in trouble at Goodwood or Donny (when they get going again).I will try with the decat pipe next timeI'd be interested in your noise readings with the bypass, TD. JV Link to comment Share on other sites More sharing options...
akb Posted June 22, 2010 Share Posted June 22, 2010 John, The silencer is the std CC trackday one. 93/94 does sound low but that was at 4500 rpm at Castle Combe. At Cadwell a few weeks ago it registered 98 at 6,500 rpm. Good luck, Andy Link to comment Share on other sites More sharing options...
John Vine Posted June 22, 2010 Author Share Posted June 22, 2010 Andy, 93-94 @ 4500 is practically silent, and 98 @ 6500 is equally amazing. Do you have a part no. for that silencer? Is it the repackable jobbie here by any chance? CC used to sell a repackable, so-called "quiet" silencer for the R500K, fabricated in titanium. I fitted one of those to my Supersport-R and very effective it was too, with a lovely deep note, and good noise suppression for trackdays. JV Link to comment Share on other sites More sharing options...
akb Posted June 22, 2010 Share Posted June 22, 2010 John, That is the one. Yes the noise from the exhaust is very low. Thank goodness they don't generally monitor drive by noise levels. The exhaust is nothing compared to the noise from the valve gear and drive train. Andy Link to comment Share on other sites More sharing options...
John Vine Posted June 22, 2010 Author Share Posted June 22, 2010 Thanks, Andy. JV Link to comment Share on other sites More sharing options...
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