Mk4 ALH Exhaust Downpipe

mhintlian

Active member
Joined
Apr 8, 2010
Location
Frazier Park , Ca
TDI
03 Golf GLS
2003 Golf GLS Mk4 5 spd 369,000 miles, original owner. I rebuilt the engine and tranny 50,000 miles ago. Kept the original exhaust system. It appears that upon start up that exhaust fumes are leaking out of the flex part of the downpipes. Upon searching for a replacement downpipe there are numerous available. ID Parts, my trusted parts supplier, has a downpipes with a catalyst that has a disclaimer that the catalyst does not meet the peoples socialist republic of California standards. However, the "smog check" for a TDI is just a plug into the "D" plug under the dash, no exhaust gas analyzer up the exhaust pipe. So if I get the downpipe with the catalyst from ID Parts what is the probability that my vehicle will not pass the "smog check"? Or If I replace the downpipes with one that does not have a catalyst, will that effect the readiness reading? I still have the EGR connected and have no plans of removing it. Everything else is stock.

Any and all replies are truly appreciated.

Mhintlian
 

maxmoo

Veteran Member
Joined
Jan 19, 2011
Location
Lakefield, Ontario, Canada
TDI
2000 golf, 2001 golf, 2000 beetle, 2003 wagon, 2004 golf, 2004 jetta, all diesels
First off, I know nothing about Calif. emisions testing.

Here in Ontario, Canada the emisions test only checks for fault and rediness codes.
Deleteing the cat will not trigger any codes on ALH vehicles.

We have been using 2.5 inch catless downpipes from various venders for quiet a few years now.
I find it helps milage and performance slightly and it does lower exhaust gas temp significantly.
"Buzzken" makes a reasonably priced 2.5" dp that steps down to OE dia so you can easily connect to your original exhaust.
That way you can easily add a "cat back" 2.5" exhaust later if desired/needed.

http://www.fixmyvw.com/mk4-tdi-stai...buzzken-2-5-and-3-available-fits-bew-and-alh/
 

tyberesk

Member
Joined
Jul 20, 2011
Location
Denver, CO
TDI
2003 Jetta TDI
Just recently dealt with this, but in Denver, Colorado (which is now following California rules). Any modification between between turbo and outlet of cat must be OEM. I had to pull out my buzzken downpipe and cat and replace with OEM when I moved here as I failed the visual inspection (even though I passed the opacity tests). Lucky for diesels in CO, a replacement used OEM downpipe/cat was an acceptable loophole.

Edit: Catback exhaust modifications are allowed and not under scrutiny here. Also, universal cats (like a genereric magnaflows) are no longer being accepted here.
 
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BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Interesting. Here in Ohio they can't sell used catalytic converters.
Can you keep your Catalytic Converter, just replace the down pipe.
Or can you just install this?
For the mileage, the trouble, the inspections, you may want to get under there and see exactly where it is leaking. Perhaps you can r+r back to life.
 

Genesis

Top Post Dawg
Joined
Feb 26, 2003
Location
Sevier County TN
TDI
'03 Jetta Wagon
Are you sure out in CA they don't do a visual inspection to see if all the CARB-required bits are indeed present and stamped CARB-approved?

In a lot of areas they are visually inspecting as well nowdays as they've become wise to people being able to tune out the CEL or "readiness" bits not being set.
 

ToxicDoc

Veteran Member
Joined
Mar 1, 2018
Location
Virginia, US
TDI
2001 Jetta, S7, .216
If your vehicle is stock and needs all oem equipment, why not just price a downpipe/cat from VW? Get the part number and do comparison shopping
 

tyberesk

Member
Joined
Jul 20, 2011
Location
Denver, CO
TDI
2003 Jetta TDI
If your vehicle is stock and needs all oem equipment, why not just price a downpipe/cat from VW? Get the part number and do comparison shopping
I was quoted around 1200 for the oem downpipe/cat in PA and 1400 in CO. Until I found the used OEM cat loophole here, it was turning into a nightmare.
 

ToxicDoc

Veteran Member
Joined
Mar 1, 2018
Location
Virginia, US
TDI
2001 Jetta, S7, .216
I was quoted around 1200 for the oem downpipe/cat in PA and 1400 in CO. Until I found the used OEM cat loophole here, it was turning into a nightmare.
Wow, that's some real legislative BS. My personal solution would have been to try to disguise an aftermarket unit as OEM lol.
 
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FasterXR4ti

Veteran Member
Joined
Nov 14, 2004
Location
Gilroy, Kalifornia
TDI
Passat,1997,silver
Why not just remove your stock down pipe, purchase a replacement flex section, take to a welding shop, and have them replace just the flex section. I do my own welding, so that's what I did.
 

burn_your_money

Veteran Member
Joined
Oct 16, 2012
Location
Missouri
TDI
99 Beetle, 96 B4V, 05 Passat wagon
I've heard the BEW ones last longer than the ALH. You could swap in the whole shebang, cat and all.
 

sawmilldon

Veteran Member
Joined
Sep 19, 2016
Location
WA
TDI
2004 Wagon
I just replaced my exhaust from my 2004 Wagon. I cut it in half about 3 feet past the cat.

Sitting in the shop, gathering dust.
 

flee

Veteran Member
Joined
Sep 19, 2011
Location
Chatsworth, CA
TDI
2002 Jetta GLS wagon
I upgraded the downpipe on the 2002 and just sawed the cat to match the new diameter.
Then had it welded and it was better than new.
 
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