Cat Delete Result

[TSTUBB]

New guy here! I have a 2003 A4 1.8T Quattro and have done a res delete and replaced the stock mufflers with dual magnaflows. I didn't get the sound I was hoping for. I don't want straight pipes (too loud) or a fart can (shitty sound). Hoping these magnaflows would give it a lower/louder tone.

Anyways I bought a 3" Cat Delete. What kind of gains will I see if any? Also will it make my exhaust louder since I already have free flowing mufflers?

[eljay]

It will make the exhaust a little bit louder. The gains can vary depending on other mods. I'd say ~15hp gain on stock turbo.

[KHARDa4]

15hp gain by deleting the cat is doubtful

[Blockis]

15hp gain by deleting the cat is doubtful

Yeah, maybe right out of the factory...

[diagnosticator]

Cat delete will most likely cause annoying drone also.

[Pothole]

I added a high flow cat and it made the turbo spool much faster. No cat I'm sure would be even more then mine.

[UCFQuattroguy]

Cat delete on my B5 1.8T added a nice little bump in torque. Thing about it: You're removing a restriction from the place containing the most heat/energy and expansion. Boost/torque onset is much more aggressive. Granted, it's been about 8yrs or so since I've run the OE cat, but I seem to remember usable torque starting at about 3,000rpm with torque peak around 3,600rpm with a sharp drop-off after 4,500rpm. Now I start getting good usable torque about 2,700-2,800rpm and the acceleration plot being pretty flat from 3,000-4,500 and the hard drop-off doesn't really start until after 5,000rpm. More area under the curve = better.

I can't speak to the sound/drone, as our exhausts are completely different. Deeper? Yes.

[CyberPMG]

Must be nice to live in an area where emissions testing is not required. A test pipe (deleting the catalytic converter) can help to produce a deeper and slightly louder tone. You may also experience possible droning carried into the cabin, but I would imagine you would have already experienced that when you eliminated the center resonator. Another thing you'll have to deal with are the codes thrown from the O2 sensors. If you have a tune, see if they can code out the cat so you don't get codes (which can cause your engine to behave differently).

[USAF Long]

Mine doesn't drone and I have test pipe, dual bullet mufflers in middle, no rear mufflers, 4" tips. I get some interior resonance at cold start, but its my sunroof switch plate I need to put some rubber or something behind it and tighten it. Other than that, its louder than stock in car but not unbearable. Its loud outside though. Cold start pisses the neighbors off.

[GhoStXraceR]

Must be nice to live in an area where emissions testing is not required. A test pipe (deleting the catalytic converter) can help to produce a deeper and slightly louder tone. You may also experience possible droning carried into the cabin, but I would imagine you would have already experienced that when you eliminated the center resonator. Another thing you'll have to deal with are the codes thrown from the O2 sensors. If you have a tune, see if they can code out the cat so you don't get codes (which can cause your engine to behave differently).

Im running a test pipe and have the P0420 code (cat function below threshold) and haven't noticed any difference in performance other than what the test pipe itself gave me.

[PreciseD]

Mine drones like crazy and I love it haha....

[dmanisgnarly]

You'll get an incorrect flow code that will have to be coded out form a tuner. You'll also notice a stronger gas odor when outside of the cabin but the performance is worth it! Faster spool up!

Edit-Me and my brother have tried the 90 degree 02 spacers on the B6 & B5 with no good results. Still get the pesky CEL after a few hundred miles.

[TSTUBB]

I'm still trying to get the gf's sister's boyfriend who's dad owns a shop to install it for me. I have all the tools and the mechanical ability but no car lift and I know it will be a bitch on jack stands/ramps alone. MY flex pipe must of recently got a hole in it because it's very loud now. Sounds like straight pipes. Am thinking I wanna install this test pipe and fix the flex pipe, then straight pipe it. I cant find any place near Duluth to install the Cat Delete (obviously) wish I had a lift so it wasn't s bad.

[TSTUBB]

Unless you think the test pipe combo with a new flex pipe and the magnaflows will sound as loud as the car does right now with a hole in the flex pipe.