Gen 3 cats/downpipes

[KyleT]

My 06 has a bad cat. What is the difference between the 3.5 and 3.8 headers and downpipes?

What options are there as far as replacement tube headers? Australia has some but is there any in the us?


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[DSouth]

The 3.8 headers are different from the 3.5 due to the intakes being different.. On the 3.5 the drivers side header has the port to supply heat to the intake, on the 3.8 that's on the passenger side. I'm fairly certain they are not interchangeable. There aren't any legal header options for the California market, but in TX you might be able to import some headers from Australia. Go on one of the Aussie forums and do a search:

https://www.google.com/search?q=Paj...=Pajero+NP+Header+site:www2.pajeroclub.com.au

They look to have some good options.

 

[KyleT]

Yeah that's what I found.

Thanks for the 3.5/3.8 difference though. That's what I needed to know. The downpipes must be different to accommodate the header difference. The price difference is alot


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[KyleT]

So more looking; are the Catalytic converters downpipes the same between the NM and NP? Bolt up not function.


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[KyleT]

Bosal for a 01-02 fit my 06. About 90% the quality fit and finish of OEM. And much cheaper and built a lot better than any other aftermarket ones I've seen.


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[plh]

Did it clear your codes? Did you also put in new o2 sensors? My '05 is throwing cat efficiency codes again and is due for emissions check in September. I put in new Denso o2 sensors (4x) 2 years ago and the SE light stayed off for ~8 months, so guessing it really is the CATs.

 

[KyleT]

New sensors are on the way. I tried sensors in the old cats and it was good for a month. New after cat sensors are on the way. I didn't want to put the old ones in and swap them and timing to wait for the sensors didn't work.


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[AutoXSS]

Could you post your source for the part? Interesting thAt it was made for the 3.5 and it worked on the 3.8

 

[AutoXSS]

And curious, was their a difference in weight between the two parts?

 

[KyleT]

https://www.amazon.com/Bosal-099-18...qid=1472500774&sr=8-1&keywords=bosal+099-1818

Weight wise it felt about the same as OEM. I had to dig way deep to figure out that the only difference between NM and NP exhaust was the EGR. Now as far as the cat efficiency I have no idea but there has been a noticeable improvement in acceleration and less exhaust smell. My previous fuel economy had dropped to 13ish mpg. When i got this thing I could hit 18-20 same type of driving. I'll definitely report back when I get the sensors in.


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[nckwltn]

What codes were you seeing? I'm getting poor mpg in my 03, I think it may be related to a cracked exhaust manifold. I have codes that come up for a day or two, then go away. Last one was p0171. Went away after a day or two of driving

 

[KyleT]

P0430 p0431

P0171 might be a manifold. I don't get that one. I know mines cracked but it doesn't leak too bad. I've heard the new manifolds from Mitsubishi are welded steel in Australia but they are stupid expensive.


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[coffeegoat]

That's interesting that the exhaust on the 3.5 and 3.8 match. I just noticed my water pump kit is also supposed to fit both. I was expecting to have more in common with the gen 2.5 engine, apparently the gen 3 3.5 is stuck in the middle.

 

[JAVYPRO]

I had to replace the cats on my wife 2001. As with some aftermarket parts they needed some fine tuning to get them to fit factory tight, so one of the pipes needed to be heated up with a torch and bent. Since I lack a torch I went to this place here in Buford GA, they work on muscle cars and do all kind of custom stuff but the stupid :shakin: cut the connector on the passenger side and welded a piece of regular pipe to joint the downpipe with the cat pipe. He cut a stainless immaculate piece for a piece to do a hack job. I noticed it the next day I was fuuummminnngggg

That is why I have a hard time trusting my vehicles to someone, I should have done it myself afterwards it was a good excuse for more tools

Well it will not happen again.

Javy

 

[KyleT]

No cutting here and tweaking I did was pushing it into place by hand. Fit was good enough. I just got the after cat sensors so as soon as I get them in I'll report back.


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