jaymdee Posted March 2, 2008 Share Posted March 2, 2008 Since moving a few months ago, I usually run with the baffle in my RSR exhaust during the week so I don't upset the neighbours at 7:00. My journey to work is a (busy) winding road followed by being stuck in traffic in Bristol, so don't get a chance to boot it. The other day I used the ring road as I left work early and at full boost there is a really loud 'wooshing' sound coming from the engine bay. Without the baffle fitted I get no wooshing, just loads of exhaust roar Sounds like a big boost leak, but the gauge just sat at 0.9 bar (0.1 bar without baffle) What is causing this noise with the baffle fitted? I spoke to another member on the SEM meet yesterday, who had a similar experience. Is it the back pressure? Will it cause harm to anything? cheers Link to comment Share on other sites More sharing options...
Chris Wilson Posted March 2, 2008 Share Posted March 2, 2008 It is indeed back pressure, the pumping losses of the engine go sky high with a baffle, it's the worst and most inefficient way to quieten an exhaust. Link to comment Share on other sites More sharing options...
jaymdee Posted March 2, 2008 Author Share Posted March 2, 2008 Thanks for the response Chris, If I am only going to get one reply, at least it's from one of the club's most knowledgable menbers. Is it ok to run at WOT with the baffle in - just so I know if I'm doing any damage to anything ? cheers Link to comment Share on other sites More sharing options...
Chris Wilson Posted March 3, 2008 Share Posted March 3, 2008 It's not a good idea to use a baffle to silence an engine and then work it hard under boost. It's like asking you to run a marathon breathing through a drinking straw, it just makes a hard job intolerable for an engine, depending on just how restrictive the baffle is. Link to comment Share on other sites More sharing options...
merckx Posted March 3, 2008 Share Posted March 3, 2008 It's not a good idea to use a baffle to silence an engine and then work it hard under boost. How does this differ to a restrictor ring or a restrictive exhaust? I'm not doubting what you say Chris, I just like to try and understand such things. Do you mean using the baffle but using a boost controller to give you the same amount of boost you may have had before fitting the baffle and thus not allowing the engine not to breath properly? Link to comment Share on other sites More sharing options...
Chris Wilson Posted March 3, 2008 Share Posted March 3, 2008 Using a restrictor ring is far from ideal, but given turbos with too small a wastegate sizing one has few options. But adding further restriction to curtail sound will kill boost and raise EGT's dramatically. Sound should be absorbed, not throttled. Restrict as little as possible to control boost, silence with pipe length, bends, and decent silencer technology, bot by a baffle in the tailpipe. Link to comment Share on other sites More sharing options...
merckx Posted March 3, 2008 Share Posted March 3, 2008 I follow now, thanks. Link to comment Share on other sites More sharing options...
jaymdee Posted March 5, 2008 Author Share Posted March 5, 2008 Chris, Am I ok to use a baffle on a track day, considering this is when I'm likely to put the engine through more stress than normal road driving? Link to comment Share on other sites More sharing options...
Chris Wilson Posted March 5, 2008 Share Posted March 5, 2008 You would be far safer getting an exhaust system that silences enough without a (very restrictive) baffle, both performance and engine safety wise. The one I am most familiar with, as an off the shelf item, is the Tanabe Medallion Touring. I suspect a stock (cat bypass pipes back) system would be safer and more performance friendly than a restrictor in the tailpipe of something very noisy. It's easy enough to measure backpressure with a cheap pressure gauge connected to a nipple on the exhaust after the turbo(s). Link to comment Share on other sites More sharing options...
jaymdee Posted March 5, 2008 Author Share Posted March 5, 2008 Thanks Chris. I'm going to Marham, so will check if there's any noise restrictions. ALso going to Nurburgring in the Summer. Will do some digging Link to comment Share on other sites More sharing options...
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