GodISmE Posted October 12, 2016 Share Posted October 12, 2016 (edited) Guys, I was told that it's best to just remove the cats and leave the stock exhaust in because the aftermarket ones eat up a few HP and even more tourque. True? Even if they do, the exhaust in HR weighs a lot and replacing it with a single 3'' cat-back would probably more than compensate for it. True? I was also told that test pipes should be resonated as I would hate the sound without it - that I know for a fact now but what is the difference between test pipes with built-in resonators... https://www.torqen.u...8-370z-res.html ... and the ones with external tubes? https://www.torqen.u...pes-md-001.html My HR is a track car so my priorities are: 1) power 2) less weight 3) bassy sound What do you recommend? Edited October 12, 2016 by GodISmE Quote Link to comment Share on other sites More sharing options...
Ekona Posted October 12, 2016 Share Posted October 12, 2016 You'll need to run cats and a relatively stock exhaust, as otherwise you won't be getting anywhere near a track I'm afraid. It'll be just too loud. Personally I'd go with some quality hi-flow cats (Berks et al) or just run the stock ones, and then probably get a custom exhaust made to enable tunable baffles to be fitted for ease on track. Strict limits means you can add more easily, on a noisy day you can then happily remove if you want. As a track-only car, you really shouldn't be concerned about tone or how loud it is at all: Your responsibility should be to keep the noise as low as possible to stop NIMBYs complaining and getting tracks closed/restricted. Quote Link to comment Share on other sites More sharing options...
GodISmE Posted October 12, 2016 Author Share Posted October 12, 2016 (edited) It's not a track-only car yet. I'll be driving it daily for a year or two before I get something else for daily driving. I don't want it to be louder than 96 dB and mufflers can take care of that even if cats are removed. I don't get why I should not be concerned about the tone even if it's a race car - as long as the power&tourque are maxed out and weight is reduced, a nice bassy sound would be great! Anyway, what should be my detailed specs for a custom built full exhaust from the headers to the tips - keeping my 3 priorities in mind? Edited October 12, 2016 by GodISmE Quote Link to comment Share on other sites More sharing options...
Ekona Posted October 12, 2016 Share Posted October 12, 2016 Because any effort you put into the tone is wasted, and better spent on making it go faster. If it sounds great then wonderful, but keeping it quiet is more important unless you're going racing. Track days are already getting restricted by too much noise, no need to help the NIMBYs out and do their jobs for them. 96dB is a reasonable target, you'll probably get that with just dropping a Cobra or Scorpion exhaust on I reckon. Removing the cats will make it A LOT louder, and it'll also sound raspy and horrid. As it's not going to be a track car at all for another year at least, I'd stick to something like that. Spend the extra on a set of R888Rs for the track Quote Link to comment Share on other sites More sharing options...
Jetpilot Posted October 12, 2016 Share Posted October 12, 2016 (edited) It's not a track-only car yet. I'll be driving it daily for a year or two before I get something else for daily driving. I don't want it to be louder than 96 dB and mufflers can take care of that even if cats are removed. I don't get why I should not be concerned about the tone even if it's a race car - as long as the power&tourque are maxed out and weight is reduced, a nice bassy sound would be great! Anyway, what should be my detailed specs for a custom built full exhaust from the headers to the tips - keeping my 3 priorities in mind? Not a chance in hell a single exit with decats will pass any static noise test, let alone 96db, even with decats and std muffler you wil struggle. I kept getting noise boards at Bedford (which means on the limit) of their drive by and that was with a true dual and hfc's, i know Bedford is one of the strictest but at least it gives you an idea. Imho, swap out the exhaust, leave the std cats and you will be fine pretty much anywhere, 20 bhp "possible" gain from decats on a 1.5 ton is hardly worth the worry. If you want to go faster on track, your 1 - 3 priorities should be: Tyres Brakes Suspension P.s forget a custom built exhaust, just buy a Milltek Edited October 12, 2016 by Jetpilot 1 Quote Link to comment Share on other sites More sharing options...
Tarmac@TarmacSportz Posted October 12, 2016 Share Posted October 12, 2016 Berk Decats and a Milltek exhaust are a good combo for track days to keep the volume down. Quote Link to comment Share on other sites More sharing options...
GodISmE Posted October 12, 2016 Author Share Posted October 12, 2016 (edited) Which Berk decats - what are their exact specs? Same question for that Milltek system. I am getting everything done by a guy who builds whole systems for sports cars - from headers to the tips. I just want to know that whatever he proposes as a solution is the optimal one for this car. I can definitely get more power&tourque, less weight and a more bassy sound with a custom system, I just need to know how. He says it won't be too loud with resonated test pipes, stock diameter exhaust and an absorbing muffler(s). I guess I need to find our exactly what he proposes - I'll be seeing him on Saturday so I'll let you know after that. Edited October 14, 2016 by GodISmE Quote Link to comment Share on other sites More sharing options...
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