# Exhaust size for 2.0L MK4 Golf?



## vwracer00 (Jan 4, 2004)

I need to get a new cat because mine is starting to rattle. I was thinking of getting a new after market cat or just gutting out the stock cat. What size piping is the stock exhaust? And if I gut the cat out will it give me any problems with the engine?


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## DJKeebler (Dec 6, 2001)

*Re: Exhaust size for 2.0L MK4 Golf? (vwracer00)*

You may get a CEL if you gut the cat since there are two O2 sensors; one before the cat and one after. Gutting the catalytic converter may throw off the readings and throw a CEL. There has been a couple people trying to figure out how to bypass the second O2 sensor but I didn't see any resolution to their questions. 
Unless your car is heavily modified or you plan on doing lots more mods later, you should be fine with a good quality 2 1/4" catback exhaust. There are quite a few good companies making kits. Techtonics Tuning is one of the most popular and I've had Autotech systems on both my previous MkII's. Just make sure the system has mandrel bends(smooth bends, not crimped) and you'll have a much better chance of not having exhaust leaks if you have the system welded together instead of using the clamps that come with most systems. If you are gonna go forced induction later (supercharger or turbo), you may want to step up to a 2 1/2" catback so you have the extra breathing room.


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## vwracer00 (Jan 4, 2004)

*Re: Exhaust size for 2.0L MK4 Golf? (DJKeebler)*

Thanks for the info. Do you know of any good websites with good prices were I could buy my cat. And yes my next project is turbo just saving up some $$$. What size cat do you think I should get?


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## ramylson (Dec 11, 2001)

*Re: Exhaust size for 2.0L MK4 Golf? (vwracer00)*

Autotech
Techtonics
Personally, I just purchased a high-flo unit from Techtonics due to my OEM unit completely crapping out. Good piece with solid workmanship.. 
As far as which size you should go with.. I guess it kind of depends on which way you plan on going, how far down the road you're thinking, etc. The OEM unit actually flows quite well, but if you're looking at a forced induction system relatively soon, you might as well look at the larger unit (with the appropriate exhaust diameter as well).


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