Fat Cat mod

FL/COtdi

Veteran Member
Joined
Mar 30, 2009
Location
Aspen CO
TDI
2003 Jetta wagon
or the title could be called my beginner attempt at metal fabrication:D

I've got this cool 3" exhaust
http://forums.tdiclub.com/showthread.php?t=311633
but it's missing a catalytic convertor, so I get one of these:
http://www.race-mart.com/MagnaFlow_49_State_Converter-MGS-93009D.html

I bought it from another website for cheaper, $125 I believe. I smaller cat would be an easier fit, but it would not be called a fat cat! Let's call a smaller set up a kitty cat or kitten!
I used these tools:


I recommend installing the whole exhaust before the adding of the fat cat. An impact gun REALLY helps to tighten down the clamps. Gloves are important when you get to cutting the pipe because those fresh cut edges are very sharp. This pipe cutter work very well:
http://tools.ntxtools.com/search/index?query=KAS-974A&x=0&y=0
I would use this technique for starting to cut the pipe:
http://www.youtube.com/watch?v=2EbcDtNJv-k

After you get the groove deep enough you can revolve the pipe cutter completely around the pipe. This is faster. I also recommend that you tighten the cutter is small increments. If you try to go too fast by applying too much pressure you will warp the pipe losing its circular form and then you will need a grinder to do your cutting. That's a major pain in the . . .


On my install and in my opinion I found the section after the downpipe to be a little too long. The tunnel bridge mount was stressed to the point of not fitting. So when I installed the fat cat I made this section a little shorter. I hesitate to give how much I left off because I think anyone doing the same mod as me needs to pay particular attention to their application and be the responsible one for determining what will make the best fit. Definitely measure twice and cut once.


The type of clamp being used is especially important because space is an issue. You will need clamps which are slim.


Again measure twice and cut once. Here is the fat cat and the clamps to keep it in place. There is a little wiggle room, but not much.



I welcome most any comment. Funny mice stories are cool but I would rather not get into a discussion about the pluses and minuses of having or not having the fat cat mod on your car. This is covered very well in other threads. Another added plus with this setup is there is absolutely no drone;)
 

Redneck Truck

Gone, but not forgotten
Joined
May 3, 2009
Location
Plano, TX
TDI
2008 Touareg V10, 2001 Audi TTQ Roadster TDI 6-speed, 2005 Jetta Wagon TDI 6-speed
This is a very interesting write-up, and I will be using it this week to get my A6's cats installed precisely.
 

FL/COtdi

Veteran Member
Joined
Mar 30, 2009
Location
Aspen CO
TDI
2003 Jetta wagon
Yeah gladly. Let me get a stick shift with some power mods and I will post some egts.
 

FL/COtdi

Veteran Member
Joined
Mar 30, 2009
Location
Aspen CO
TDI
2003 Jetta wagon
Still no power mods, but I will very soon;-) Jimbote did give some great advice for final fitment. Cut four notches into both ends of the cat 90 degress apart then the clamps will surely make an air tight seal. A hacksaw metal blade makes that happen so easily!
 

FL/COtdi

Veteran Member
Joined
Mar 30, 2009
Location
Aspen CO
TDI
2003 Jetta wagon
Installed bpp 764. Egts are up. Hit just over 1200f at wot. I'm very happy to be putting this exhaust to its intended use. I'm sure a stock setup would hold the car back during wot.
 

deejaaa

Veteran Member
Joined
Apr 15, 2007
Location
Baytown, Texas
TDI
FOR SALE, 2002 Jetta GLS, 5 speed
Installed bpp 764. Egts are up. Hit just over 1200f at wot. I'm very happy to be putting this exhaust to its intended use. I'm sure a stock setup would hold the car back during wot.
do you have any before WOT info?
 

FL/COtdi

Veteran Member
Joined
Mar 30, 2009
Location
Aspen CO
TDI
2003 Jetta wagon
That's a great idea! We are leaving on a cross country trip tomorrow. To Co naturally. Got up to 1400f at wot but IQ was 3.5. Set to 7.8 now.

I will post from the road
 

FL/COtdi

Veteran Member
Joined
Mar 30, 2009
Location
Aspen CO
TDI
2003 Jetta wagon
This is towing a loaded 5x8 covered u haul trailer. So I'm giving max fuel when accelerating through the gears. Shifting to the next gear at 3000 rpms
1st 800-900
2nd-5th just over 1000
Flat sea level cruising at 75 mph 1100-1200
Rolling Mississippi hills same speed 1200-1400
Driving through the front range between Denver CO and Cheyenne WY 75 mph hit over 1500, thinner air here.

Getting a Malone tomorrow and then going over the front range into steamboat springs on tuesday. Will post the numbers taking on the mountain elevation and long lasting incline
 

FL/COtdi

Veteran Member
Joined
Mar 30, 2009
Location
Aspen CO
TDI
2003 Jetta wagon
Still towing the trailer. Drove up to Steamboat yesterday. Definitely had to downshift to fourth with the sustained steep incline before the Eisenhower tunnel. I downshifted at 1500f. I know the turbo is good to 1650f but I didnt want to take the chance of going over that. The road off the interstate to steamboat doesnt climb too steeply and stayed in fifth the whole way.

diesel is $4.29 here, most expensive i have ever paid!
 
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FL/COtdi

Veteran Member
Joined
Mar 30, 2009
Location
Aspen CO
TDI
2003 Jetta wagon
Drove back to Denver, east on I40. No trailer, 1200s going up the steep incline to Johnson tunnel at 70mph
 

FL/COtdi

Veteran Member
Joined
Mar 30, 2009
Location
Aspen CO
TDI
2003 Jetta wagon
Got a lucky break headed west up to the Eisenhower tunnel. There was enough clear space to go 100mph for about a quarter mile:) 1300 and 1400s egt
 

FL/COtdi

Veteran Member
Joined
Mar 30, 2009
Location
Aspen CO
TDI
2003 Jetta wagon
Almost 40,000 miles with this setup and the magnaflow 93009d doesnt seem clogged
 

FL/COtdi

Veteran Member
Joined
Mar 30, 2009
Location
Aspen CO
TDI
2003 Jetta wagon
The Eastern Catalytic #75330 Diesel CAT Converter with 3" pipe is a smaller alternative. If you go that route please post results here . . .
 

FL/COtdi

Veteran Member
Joined
Mar 30, 2009
Location
Aspen CO
TDI
2003 Jetta wagon
The cat did clog just shy of 80k miles. Egts went up. Removed it. Put it back with out any guts and it sounds really good. Much more quiet than I remember when it was just a straight pipe with the built in resonantor. I’m thinking the empty cat acts like an extra resonantor.
 
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