allan 295 Report post Posted August 18, 2012 Have an exhaust system to modify and would like to hear from those in the know which is the best way to go. What if any performance drop off is their likely to be pipes are 50mm dia. The one system has a two pipe set up from start to finish the other is only at the front as can be seen in the photo. Can run the twin set up almost to the back muffler, black arrows then due to space shape etc need to us the other squarer type muffler. Could cut both mufflers open and run the extra pipe but a lot of work and for what gain I'm unsure. Have looked in Realoem.com and it shows the stock system as being reduced to one pipe in but two coming out thanks for your help and advice. Quote Share this post Link to post Share on other sites
kiwi535 538 Report post Posted August 19, 2012 the interesting thing about tubes is that the cross sectional area increases to the square of the radius a 25mm pipe has a cross section of 1963mm ,but a 50 mm tube has a cross section of 7853mm2 .So two 50mm tubes is 15707mm2 A single 70mm tube is 15393mm2.So by all means use a single tube but keep the above in mind Quote Share this post Link to post Share on other sites
smiddy 76 Report post Posted August 19, 2012 You will be lucky to see any gains while useing oem exhaust manifolds. They are a poor design and somewhat smaller than head exhaust port. Quote Share this post Link to post Share on other sites
hybrid 1044 Report post Posted August 21, 2012 Back on topic, replacing all single with double will give you more breath up top. Did it to the 330 best cheap mod ever. This was with standard headers. The reason it is done is for noise levels, you can order your car with different packages to reduce noise on the options list. Also different countries have different requirements. EG japan exhuast are different to kiwi ones etc. Quote Share this post Link to post Share on other sites
smiddy 76 Report post Posted August 21, 2012 Jappa imports were restricted just post cats as Josh says in an attempt to tone the drone. Is a killer to mid upper power. Common on E46 328/330. NZ new cars have different systems. Quote Share this post Link to post Share on other sites
smiddy 76 Report post Posted August 21, 2012 Search my post : E46 M52 Jap Exhaust Modds. May 22 2009. Documents one of the best modds you can do to free up power on import M52/54 E46 two into one exhaust. Quote Share this post Link to post Share on other sites
Neal 546 Report post Posted August 21, 2012 would this work instead of single pipe muffler ? http://www.trademe.co.nz/motors/car-parts-...n-505787387.htm Quote Share this post Link to post Share on other sites
