Hi, everybody! I'm considering having a custom exhaust system built for my tC. I'm going for an Euro look in my car so opposite dual exhaust is the route to take, I also love symmetry (yes! I have a serious case of OCD XD). I know there will be a drop in performance and weight gain, for the latter reason I've decided to go the titanium route.

My question is, what are the sections that our stock exhaust consists of? Exhaust manifold, frontpipe, S-pipe, muffler and tip? And how it changes when a turbo and aftermarket exhaust is installed? Exhaust turbo manifold, turbocharger, downpipe, S-pipe, muffler and tip? If I'm wrong feel free to insult me

And last question, as for opposite dual exhaust system I've always seen two types for I4 engines: Y-Pipe with opposite individual mufflers and tips and opposite tips sharing one muffler. Which design is better performance-wise? Thanks in advance!

 

You're using this "opposite" word, and I do not know what you mean. I was assuming you were going to Y pipe it to have a driver side tip and a passenger side tip, in which case you will lose power. You can't split/divide air, you can only multiply it, which means you cannot go from one pipe to two pipes, you can only go from two pipes to one pipe. The only reason you would do this is for looks, but your bumper is made for this, so that will need to be customized as well to have a cut out for the unwanted tip.

Your car has a exhaust manifold to a down pipe to a mid pipe to an axle back. Nothing changes at all when going aftermarket with either of these four components I listed. If you swap the exhaust manifold for a turbo manifold, that is the only thing you swap. If you want swap the downpipe, same thing, just swap the down pipe. If you swap everything, everything swaps as is. That is the beauty of all of these performance brands putting in hundreds of hours on our cars to get everything to match up as it should.

If you go the Y pipe route, you'll be adding about 30 pounds to your car and will lose power. If you split up the muffler tip to be a dual tip, that is not big deal. You won't add any weight or lose or gain power. With the headache that it will be to customize your own exhaust, I'd just buy one. They are super cheap for good name brand stuff for our cars. Just do that. The only reason you'd customize one is if you are like me where I have my VW GTI and the turbo back exhausts are $1500, and you didn't want to pay that. If you make your own exhaust, you are going to save about $200, but you will also spend much more time manufacturing it. I've made dozens of custom exhausts from header back and it's not treat, but if you have the tools, then why not.

 

Right, when I say opposite I mean one exit on drivers side and one on passangers side. I want to do it this way for looks you are absolutely right, like I said I love symmetry, it's not even because it looks better or not it just bothers me visually just one exit so it's more of a personal issue than anything else. For weight I choosed titanium, even with the addition of the Y-Pipe and second pipe it will weight way less than stock or any of the aftermarket Stainless Steel options available. Thank you very much for your help and explanation!