I have dual after market mufflers in place of the rear “suitcase” muffler on my Touareg. I’m wanting to also remove the secondary muffler/resonator on the system, I was wondering what the differences were between running straight pipes, a H-pipe, or a X-pipe. Anyone with knowledge on the subject, your help would be appreciated.
I don’t think it is a simple answer. All the different possible configurations and different cars and drivers make it almost impossible to give a definitive answer. For example we don’t know what your goal is.
Do you want more power, more noise, less noise better mileage etc.
Having said that, you may get lucky and someone with Touareg experience may be able to give you some useful general information.
Any additional information on what you hope to accomplish by making those changes, would help anyone who might be giving you advice. For example if you have made modification to the fuel system or intake, then the advice for exhaust modifications may well be dependent on what modifications you may have or plan to make.DO NOT do this if the truck is still under warranty–it is guaranteed to void any future warranty claims.
Check with your state motor vehicle dept. before ordering any parts. You need to keep it legal for registration and emissions purposes.
If you are talking CAT back, it makes little difference in performance…What you are “tuning” are various noise levels and frequencies…
Maybe a conversation with a factory rep or after market exhaust specialist. There is so much going on electronically from intake to exhaust, it could lead to other problems.
You’re not going to change much beside the noise as long as you’re only talking cat back, like Caddyman said. VW does a good job designing their engines and exhausts.
This sounds like you’re grasping for more horsepower and fuel economy with these changes. It won’t make any noticeable difference as long as the converters are in place as the converters are the main restriction in an exhaust system.
Remove or gut the converters and you then begin the list of very potential problems
"you’re not going to change much from the converter back"
I’m with Jos. And mliech
Many modern cars monitor the exhaust temperature comparatively to the what it decides to do at the intake with fuel and air for emission purposes. I guess you are all saying that any non factory, after market set up after the converter will have no affect on the temperature and/or performance or the emissions ? Maybe…but that will need a conversation with more then some independent not familiar with EXACTLY what OP is trying to do. You all want to say it’s OK , fine, not me. Hopefully OP guesses right and never moves to California.
Several years ago, I converted the single pipe exhaust system on my '02 Chevy Silverado, with its office-trash-can-sized muffler, to a dual-pipe system with a pair of low-restriction Flowmaster mufflers; mine is also a true dual exhaust system (not a “Y” pipe) because the truck was factory-equipped with 2 catalytic converters, so 2 separate pipes could be installed behind them. As far as performance, I may have gained an extra 10 horsepower by doing that, but it’s not enough to make a noticeable difference in “seat-of-the-pants” feel with fast acceleration; it sounds good, though, and I’m sure the addition of a dual exhaust system helps the engine breathe a little better. If a noticeable gain in performance is what you want, that can be achieved by having a “power chip” installed in the vehicle’s computer, but it’ll cost you some bucks. And, I agree with mleich, DO NOT DO ANYTHING to alter the vehicle if it’s still under warranty; wait till the warranty expires and then you can do what you want.
Good example of how this won’t make much/any difference: this month’s Car and Driver has a long-term test of a Suzuki where they replaced the dual muffler setup with straight pipes (!) What did they get for the ‘sounds like a chains saw’ noise? NOTHING as far as 0-60 time goes, very slightly faster to 100. What a waste of money!