I need to tackle the exhaust manifold job for both sides on my 04 GX470. Has anyone used any of the aftermarket brands who can give me advice on fit? The oem exhaust manifolds are not horribly priced but the converter & pipe (oem part number 1741050360) is absolutely absurdly priced. Doug Thorley pieces are not currently available. Has anyone done this job with any other brand?
Exhaust manifold job
- Thread starter eseel
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Do Not buy Pacesetter parts
Mine cracked at the tubes after about 3 months.
I have Thorley long tubes now.
Mine cracked at the tubes after about 3 months.
I have Thorley long tubes now.
I would also suggest waiting for a set of DT headers, if you intend to keep your GX as a long term vehicle. The OEM and OEM-style manifolds will inevitably crack again - the design is just overall poor, and the tubes are very thin - so you or someone else will end up having to do the job a second time. A set of DT headers should never crack and they are a very nice performance upgrade.
I have a small leak that goes away once warm. I will do DT headers once it gets bad enough I can't stand it anymore.
Curious if anyone has successfully passed emissions with DT long tubes and retaining the secondary cats?
Curious if anyone has successfully passed emissions with DT long tubes and retaining the secondary cats?
Same questions, @jiggletits. Pretty much same situation. Curious about emissions with the long tubes, and the details on the install.
@eseel gonna echo the sentiments of others in this thread and suggest going with DT. If you dig into forums for the 4runner and tundra, too, you’ll find that the consensus for the 2UZ seems to be DT or bust.
@eseel gonna echo the sentiments of others in this thread and suggest going with DT. If you dig into forums for the 4runner and tundra, too, you’ll find that the consensus for the 2UZ seems to be DT or bust.
I had to do my drivers side manifold to pass safety where I live. The mechanic put on two different aftermarket brands because I wanted to go the cheaper route, but just could not get them to seat properly. I ended up biting the bullet and buying OEM manifold and gaskets. I would recommend OEM or Doug Thorley. It’s such a PITA job to do, so you want to make sure it’s done right the first time. I think I tried the Dorman and Walker brands
Regarding emissions with LT's, you'll need to trick the rear O2 sensors to get it from throwing PO420 and PO430 codes. You can do this with an O2 simulator box (requires hacking into your wiring harness) or a 90 degree defouler with a mini cat (easy install). I have the defoulers and have had zero codes since the install. So, if your emissions check just includes plugging a scanner into the OBDII port and checking for codes and making sure all monitors are working, you can install LT's and get a "pass".
If you have any kind of visual inspection the LT's will probably result in a fail, as the primary cats will clearly be gone. If you have a sniffer test, but no visual inspection, you'll probably fail too as you'll be operating at <50% total catalyst system efficiency with only the rear cats (as the front cats do most of the work since they are closer to the engine and get lots of heat to burn off pollutants). You might be able to get a passing test if you install some other cat(s) elsewhere in the system, but that would still be expensive and probably not as effective as the OEM cats as they wouldn't get all of the heat.
So - unless you have no emissions at all (which is my case) or just have the OBDII scanner check with no visual inspection/sniffer test, I would not recommend LT headers. You should go with ST's instead and retain the OEM cats. Even if you can get LT's to pass where you live now, if you ever move to a stricter area your GX might not pass emissions with the LT's. We have no plans to move, but it's something to keep in mind as a detraction to the LT's (which are otherwise an awesome upgrade).
If you have any kind of visual inspection the LT's will probably result in a fail, as the primary cats will clearly be gone. If you have a sniffer test, but no visual inspection, you'll probably fail too as you'll be operating at <50% total catalyst system efficiency with only the rear cats (as the front cats do most of the work since they are closer to the engine and get lots of heat to burn off pollutants). You might be able to get a passing test if you install some other cat(s) elsewhere in the system, but that would still be expensive and probably not as effective as the OEM cats as they wouldn't get all of the heat.
So - unless you have no emissions at all (which is my case) or just have the OBDII scanner check with no visual inspection/sniffer test, I would not recommend LT headers. You should go with ST's instead and retain the OEM cats. Even if you can get LT's to pass where you live now, if you ever move to a stricter area your GX might not pass emissions with the LT's. We have no plans to move, but it's something to keep in mind as a detraction to the LT's (which are otherwise an awesome upgrade).
I Had pass side manifold fail, replaced with OEM at Toyota dealer ($1600ish IIRC), then 14 months later ANOTHER fail on this NEW OEM part. (OEM warranty is 12 months).. I later found a broken exhaust hanger (contributor?). I orderd DT shorties thorough Rogue off road knowing they were NOT in stock and there was no known lead time. DT builds them in batches and DT had no known lead for the next batch, but @ $7.99 from Rogue I pulled the trigger last December. It was about 6 months later, when they were built and shipped. I'd welded the manifold which bought me 5 months of quiet.
The leak returned, I rewelded that crack. then 2 weeks ago the driver side stock manifold cracked. I'm now running with both manifolds cracked and DT shorties in the garage.
SO. I went stock OE replacement from Dealer and that failed in 14 months. My experience may not be typical but is what I've gone through. Purchasing a pair of DT shorties (when I did last winter) was about half the price of installing ONE manifold from the dealer (again, this 'new stock part failed). So... While I don't have the finished product to report and compare, in my experience the poor (cat hanging off back of thin-walled tube (not cast manifold) design was exemplified. The design promotes cleaning the exhaust with having a cat as close to the output of the engine as possible, BUT I think materials selection was poor. I thought I'd get years on the new stock part since original stock lasted years but that ended up not being my case...
At this point its coordinating with a friend to dedicate a weekend and expect to be hosed in the process and be down the truck for days. I think we'll be fine whenever we can schedule the time and dig in and get this problem fixed.
I'm not ordering new studs or nuts as they're all like 2 years old now )oh wait that's just the passenger side... Hmm, maybe I should get a set of studs and nuts for the driver side now that I'm typing this out...). I ordered new engine mount isolators and a transmission mount. I went with stock gaskets, will weld the stock cats to the headers, and do all the shenanigans to seal it all from leaks. I went for shorties, despite the wait, to retain all cats (though I don't live in a smog area), for my own ethic on emissions of a v8. I'll appreciate the gain and hopefully peace of mind that a higher quality part RE: materials and craftsmanship is in there when I'm done.
Last I looked the DT shorties were now over $1,000 on DT site ...
The leak returned, I rewelded that crack. then 2 weeks ago the driver side stock manifold cracked. I'm now running with both manifolds cracked and DT shorties in the garage.
SO. I went stock OE replacement from Dealer and that failed in 14 months. My experience may not be typical but is what I've gone through. Purchasing a pair of DT shorties (when I did last winter) was about half the price of installing ONE manifold from the dealer (again, this 'new stock part failed). So... While I don't have the finished product to report and compare, in my experience the poor (cat hanging off back of thin-walled tube (not cast manifold) design was exemplified. The design promotes cleaning the exhaust with having a cat as close to the output of the engine as possible, BUT I think materials selection was poor. I thought I'd get years on the new stock part since original stock lasted years but that ended up not being my case...
At this point its coordinating with a friend to dedicate a weekend and expect to be hosed in the process and be down the truck for days. I think we'll be fine whenever we can schedule the time and dig in and get this problem fixed.
I'm not ordering new studs or nuts as they're all like 2 years old now )oh wait that's just the passenger side... Hmm, maybe I should get a set of studs and nuts for the driver side now that I'm typing this out...). I ordered new engine mount isolators and a transmission mount. I went with stock gaskets, will weld the stock cats to the headers, and do all the shenanigans to seal it all from leaks. I went for shorties, despite the wait, to retain all cats (though I don't live in a smog area), for my own ethic on emissions of a v8. I'll appreciate the gain and hopefully peace of mind that a higher quality part RE: materials and craftsmanship is in there when I'm done.
Last I looked the DT shorties were now over $1,000 on DT site ...
