2004 3.9L Catalytic converter replacement

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07-29-2005, 03:01 PM

Rob_TN

Thread Starter

Join Date: Jul 2005

Posts: 2

2004 3.9L Catalytic converter replacement

Great site you guys have here. I just signed up and this is my first post.

I have a 2004 V6 with the 3.9L engine. Due to a mishap involving a teenage driver and some off-road adventures, the lower two catalytic converters have become crushed and plugged. When calling around to local parts places, they tell me there are no 2004 model year specific cats on the market yet and I will have to either go back to the dealer ($1148 for the entire 4-cat system and Y-pipe) or find an aftermarket replacement.

That being the case, I have decided to upgrade the exhaust system in the process. Tons of places offer performance exhausts for the 3.8L V6, but I am not finding any for the 3.9L. That brings me to my questions.

1. Are exhaust systems designed for the 3.8L interchangable with the 3.9L? (Same header flanges, pipe dimensions, hanger locations, etc.)
2. Should I just replace the cats or replace the whole system?
3. What type/brand/model system do you guys recommend?

Thanks in advance for your opinions/advice.

07-29-2005, 03:10 PM

StangMan04

2nd Gear Member

Join Date: Jul 2005

Location:

Posts: 210

RE: 2004 3.9L Catalytic converter replacement

Quote:

ORIGINAL: Rob_TN

Great site you guys have here. I just signed up and this is my first post.

I have a 2004 V6 with the 3.9L engine. Due to a mishap involving a teenage driver and some off-road adventures, the lower two catalytic converters have become crushed and plugged. When calling around to local parts places, they tell me there are no 2004 model year specific cats on the market yet and I will have to either go back to the dealer ($1148 for the entire 4-cat system and Y-pipe) or find an aftermarket replacement.

That being the case, I have decided to upgrade the exhaust system in the process. Tons of places offer performance exhausts for the 3.8L V6, but I am not finding any for the 3.9L. That brings me to my questions.

1. Are exhaust systems designed for the 3.8L interchangable with the 3.9L? (Same header flanges, pipe dimensions, hanger locations, etc.)
2. Should I just replace the cats or replace the whole system?
3. What type/brand/model system do you guys recommend?

Thanks in advance for your opinions/advice.

1) Yes, the 99-03 exhaust systems should be the same as the 04. the 3.9 isnt much different from the 3.8.
2) I would just get a whole new exhaust system.
3) I haven't seen any kits for the complete V6, I would just get a exhaust shop to custom make you a new setup. Shouldn't cost $1k either.

07-29-2005, 05:26 PM

04blkstang

1st Gear Member

Join Date: Jul 2005

Location:

Posts: 147

RE: 2004 3.9L Catalytic converter replacement

I have a 2004 V6 also I know about the 3.9L not sure if all the 04 V6's came in the 3.9L or not but I have one and put a 3.8L true dual flowmasters on there with only 2 cats but they are the stock cats. Put the flowmaster 40 series mufflers on there it sounds real nice and give it a month or to to break in and sound even better. If your goin to upgrade the whole exhaust you should do it all. Intake(K&N FlipK Gen II under 200 on ebay), high flow cats(around 100 each), go with an H-pipe should get it with exhaust mine was only 585 after labor and tax, get some headers mac shorty headers would do they r only 218 and upgrade your MAF sensor. after all this it would be around 1500 and you get a great exhaust but you could just go with a regualar dual exhaust set up for around 600 installed like i did got the air intake later. good luck

08-01-2005, 12:24 AM

Rob_TN

Thread Starter

Join Date: Jul 2005

Posts: 2

RE: 2004 3.9L Catalytic converter replacement

I found THIS KIT for those who are interested.

My plan is this. I think I've found a used factory setup CHEAP, so I'm going that route. If I can't get it cheap, I'm going with the kit above.

Thanks for the replies.