Just another exhaust manifold leak. 07 GX470

[zannis]

Hi guys like the title says my car has an exhaust manifold leak and it really bothers me . So I was thinking to get the DT long tube headers but I saw that they are not using cats . I used to have an 03 BMW M3 long time ago with no cats and the smell it was terrible . So anybody knows if I can use the OEM cats with the Doug Thorley headers? Any other options ? I checked at Lexus parts to buy new exhaust manifolds and the cost here in NY is $1100 for the pair . So I don't know what to do . Thanks guys

 

[Rednexus]

You can use the OEM cats with the Doug Thorley short tube headers. It requires the cats to be cut off the OEM manifolds and welded to the new headers. There are no other header options for the GX.

FYI DT headers for the GX have been backordered for months. I ordered a pair in December and still don't have them.

 

[asticot]

Hi guys like the title says my car has an exhaust manifold leak and it really bothers me . So I was thinking to get the DT long tube headers but I saw that they are not using cats . I used to have an 03 BMW M3 long time ago with no cats and the smell it was terrible . So anybody knows if I can use the OEM cats with the Doug Thorley headers? Any other options ? I checked at Lexus parts to buy new exhaust manifolds and the cost here in NY is $1100 for the pair . So I don't know what to do . Thanks guys

Having done just my driver side Manifold I feel for your problem. I would absolutely recommend not going for non-OEM parts for this job. I recognize DT may be the exception. I had to change mine because it would not pass safety here although I didn’t even hear any ticking and noise. My mechanic tried to incorporate 2 different non-OEM parts and they were not good. I bit the bullet and ordered OE manifold.
I’m surprised by the price you got though, mine were $950CAD for the manifold and gasket from Lexuspartsdirect.ca.

 

[zannis]

You can use the OEM cats with the Doug Thorley short tube headers. It requires the cats to be cut off the OEM manifolds and welded to the new headers. There are no other header options for the GX.

FYI DT headers for the GX have been backordered for months. I ordered a pair in December and still don't have them.

Thanks for the info !!!

 

[zannis]

Having done just my driver side Manifold I feel for your problem. I would absolutely recommend not going for non-OEM parts for this job. I recognize DT may be the exception. I had to change mine because it would not pass safety here although I didn’t even hear any ticking and noise. My mechanic tried to incorporate 2 different non-OEM parts and they were not good. I bit the bullet and ordered OE manifold.
I’m surprised by the price you got though, mine were $950CAD for the manifold and gasket from Lexuspartsdirect.ca.

Wow yes it is very annoying to listen to this ticking noise every day ! The prices here in NY are crazyyy brother ! I will take it to a exhaust muffler shop to see where is the problem, but I believe is the drivers side . So if they tell me that I can put the OEM cats on the DT headers I will do it , if they say to me to go with OEM manifolds I will do that .. but I really want to go with the DT lol . lets see... Thanks for you reply brother !

 

[JerG63]

I run the DT Long Tube headers with URD Y-Pipes and Magnaflow overland series. The sound is amazing and yes, it does smell horrible. Obviously very illegal, so this setup depends on your risk tolerance.

 

[zannis]

I run the DT Long Tube headers with URD Y-Pipes and Magnaflow overland series. The sound is amazing and yes, it does smell horrible. Obviously very illegal, so this setup depends on your risk tolerance.

OMG I'm so jealous ! If it wasn't for the smell trust me I would do the same exactly setup ! Do you have any sound clips or videos ? Thanks for your reply

 

[TxGX470]

You can use the OEM cats with the Doug Thorley short tube headers. It requires the cats to be cut off the OEM manifolds and welded to the new headers. There are no other header options for the GX.

FYI DT headers for the GX have been backordered for months. I ordered a pair in December and still don't have them.

Did you ever receive your headers? And who did you get them through?

I’m having a hard time getting ahold of any. Lots of forum posts sent me to Jason at Burtman Industries, but I’ve been trying to get ahold of him for almost 6 weeks with no luck.

 

[Rednexus]

Did you ever receive your headers? And who did you get them through?

I’m having a hard time getting ahold of any. Lots of forum posts sent me to Jason at Burtman Industries, but I’ve been trying to get ahold of him for almost 6 weeks with no luck.

I did receive them back in May or April (see my build thread) and did get them from Burtman.

However, it was not seamless. I ordered them back in December. I called/texted Jason multiple times and kept getting the "in a few weeks" line (mostly from DT to Burtman). Sometime in Feb/Mar I found out that DT had no hard plans to make another batch of the short tube headers in the near future. I looked on their website and saw they had 1 pair of LT headers in stock and had Jason get them for me, as I was done waiting for ST headers at that point and wanted them installed before our CO/UT trip.

I found the best way to get ahold of Jason is to call him. They are probably backordered at DT and DT does not seem to put these headers on their priority list. You'll get them eventually, just who knows how long it will take. I will say the LT headers had excellent build quality and fit great, and gave the GX quite a bit more power, despite being a PITA to install.

 

[TxGX470]

I did receive them back in May or April (see my build thread) and did get them from Burtman.

However, it was not seamless. I ordered them back in December. I called/texted Jason multiple times and kept getting the "in a few weeks" line (mostly from DT to Burtman). Sometime in Feb/Mar I found out that DT had no hard plans to make another batch of the short tube headers in the near future. I looked on their website and saw they had 1 pair of LT headers in stock and had Jason get them for me, as I was done waiting for ST headers at that point and wanted them installed before our CO/UT trip.

I found the best way to get ahold of Jason is to call him. They are probably backordered at DT and DT does not seem to put these headers on their priority list. You'll get them eventually, just who knows how long it will take. I will say the LT headers had excellent build quality and fit great, and gave the GX quite a bit more power, despite being a PITA to install.

Thanks for the info. I might go with the long tubes as well, and just put a cat right behind it. Is that what you did or are you going cat-less? I’m glad to hear there were noticeable performance gains. That’ll be a nice bonus.

 

[Rednexus]

Thanks for the info. I might go with the long tubes as well, and just put a cat right behind it. Is that what you did or are you going cat-less? I’m glad to hear there were noticeable performance gains. That’ll be a nice bonus.

I left the two OEM secondary cats and Y-pipe in place, so I'm running 2/4 of the OEM cats. It's slightly smellier than stock at idle but overall not bad at all. I was able to get $585 for the OEM cats from a local metal recycler, which paid for most of the headers. The problem with deleting the primary cats is you won't pass emissions if you live in an area with sniffer tests or visual inspections (zero emission tests or inspections here so that's no big deal) and you might throw P0420 and P0430 codes since the cats are missing. I installed two 90 degree defoulers with a mini cat for the downstream O2 sensors and have yet to throw a code.

Power gains were big...off-idle and WOT are about the same but midrange power increase was huge. My GX will now put you back in the seat when you punch it. I also picked up around 1 mpg. Best engine upgrade you can make for GX. Definitely go with the long tubes if you live in an non-emissions area.

 

[TxGX470]

I left the two OEM secondary cats and Y-pipe in place, so I'm running 2/4 of the OEM cats. It's slightly smellier than stock at idle but overall not bad at all. I was able to get $585 for the OEM cats from a local metal recycler, which paid for most of the headers. The problem with deleting the primary cats is you won't pass emissions if you live in an area with sniffer tests or visual inspections (zero emission tests or inspections here so that's no big deal) and you might throw P0420 and P0430 codes since the cats are missing. I installed two 90 degree defoulers with a mini cat for the downstream O2 sensors and have yet to throw a code.

Power gains were big...off-idle and WOT are about the same but midrange power increase was huge. My GX will now put you back in the seat when you punch it. I also picked up around 1 mpg. Best engine upgrade you can make for GX. Definitely go with the long tubes if you live in an non-emissions area.

Yeah they do smog tests in Austin and the surrounding areas. I actually found someone who says they can get LT but that shorties are tough to get right now.

I wonder if I can put another cat between the Y and the muffler. It looks like there might be enough room.

 

[NudeLobster]

Yeah they do smog tests in Austin and the surrounding areas. I actually found someone who says they can get LT but that shorties are tough to get right now.

I wonder if I can put another cat between the Y and the muffler. It looks like there might be enough room.

I have LTs and while I don't mind the smell for sports cars, it's REALLY annoying for a 4x4 that may need to idle in camp. My truck smells way worse and I really want to get a larger diameter mid pipe made up with 4 cats if possible. between budget and trying to find a shop that will touch a modified system that is missing things, it hasn't materialized yet.

 

[Rednexus]

I have LTs and while I don't mind the smell for sports cars, it's REALLY annoying for a 4x4 that may need to idle in camp. My truck smells way worse and I really want to get a larger diameter mid pipe made up with 4 cats if possible. between budget and trying to find a shop that will touch a modified system that is missing things, it hasn't materialized yet.

Did you keep the two downstream cats? I have the 2 downstreams still and my GX is only slightly stinkier than stock at idle, even with the 2 upstreams removed. If you still have the downstreams perhaps they are plugged or otherwise not functioning very well.

FYI, my plan, if things were stinky to the point of annoyance, was to install an aftermarket cat behind the Y pipe and in front of the muffler. There is a long, straight stretch of muffler there where it would probably be easy to install an aftermarket cat, giving the GX a total of 3 cats instead of 2.

 

[TxGX470]

Did you keep the two downstream cats? I have the 2 downstreams still and my GX is only slightly stinkier than stock at idle, even with the 2 upstreams removed. If you still have the downstreams perhaps they are plugged or otherwise not functioning very well.

FYI, my plan, if things were stinky to the point of annoyance, was to install an aftermarket cat behind the Y pipe and in front of the muffler. There is a long, straight stretch of muffler there where it would probably be easy to install an aftermarket cat, giving the GX a total of 3 cats instead of 2.

That’s likely my plan. Looks doable

 

[Rednexus]

That’s likely my plan. Looks doable

Are your emissions in Austin just a simple check for trouble codes and monitor using an OBDII scanner or a visual/sinffer test? You can probably get long tubes to pass with the 90 degree defoulers I linked if they just use the OBDII scanner (as the ECU will still think the cats are present and you shouldn't have any codes) but they definitely won't pass a tailpipe probe sniffer or a visual inspection.

FYI I lived in Austin in the late aughts while at UT for grad school. I still miss the food.

 

[TxGX470]

Are your emissions in Austin just a simple check for trouble codes and monitor using an OBDII scanner or a visual/sinffer test? You can probably get long tubes to pass with the 90 degree defoulers I linked if they just use the OBDII scanner (as the ECU will still think the cats are present and you shouldn't have any codes) but they definitely won't pass a tailpipe probe sniffer or a visual inspection.

FYI I lived in Austin in the late aughts while at UT for grad school. I still miss the food.

The food has gotten even better. Traffic is way worse, and housing prices are skyrocketing, especially after Rogan and Musk got places here and started shouting from the rooftops about how great it is haha.

From what I can find online, they do tailpipe smog tests as well as scanner checks. Hopefully a 3rd cat in the mid pipe will do the trick.

 

[NudeLobster]

Did you keep the two downstream cats? I have the 2 downstreams still and my GX is only slightly stinkier than stock at idle, even with the 2 upstreams removed. If you still have the downstreams perhaps they are plugged or otherwise not functioning very well.

FYI, my plan, if things were stinky to the point of annoyance, was to install an aftermarket cat behind the Y pipe and in front of the muffler. There is a long, straight stretch of muffler there where it would probably be easy to install an aftermarket cat, giving the GX a total of 3 cats instead of 2.

Yup, still has the 2 down streams, I was theorizing that they just weren't getting hot enough to light off well with the reduced back pressure. Adding a cat post Y pipe is a good idea, that would be much easier to do. I never was very interested in after market mufflers/catbacks for a 4x4 SUV but the magnaflow "overland" *cringe* has got me reconsidering. perfect opportunity to chop it and sneak a cat in before it goes into the truck

 

[alpineimages]

Hi guys like the title says my car has an exhaust manifold leak and it really bothers me . So I was thinking to get the DT long tube headers but I saw that they are not using cats . I used to have an 03 BMW M3 long time ago with no cats and the smell it was terrible . So anybody knows if I can use the OEM cats with the Doug Thorley headers? Any other options ? I checked at Lexus parts to buy new exhaust manifolds and the cost here in NY is $1100 for the pair . So I don't know what to do . Thanks guys

I just replaced my leaking left side manifold and the still good right side one, with the DT short headers and DT y-pipes for the GX470. The manifolds were done at a good shop, a job I did not have to fight with, but they did, Not easy. Carefully done, I now have my original primary cats solidly welded to very durable headers.

I replaced the y-pipes myself before the shop did the headers. That was not hard, just a bit of patience needed to transfer the rear OP2 sensors.

The resonators on the y-pipes appear sufficiently like the secondary cats, and I live in a state where only an OBD2 check is done for emissions. I'm guessing that this makes the GX470 only a very low emissions vehicle, not ultra-low. But between the headers and y-pipes, the throttle response is noticeably better. Too early to tell if it nets MPG.

 

[ArBrnSnpr]

That’s likely my plan. Looks doable

It's definitely doable.

That's what I did.

I have the DT long tube headers. I had a URD catless mid pipe and magnaflow overland exhaust.

There seemed to be no back pressure and my bottom end torque was terrible (and I'm running 4.56 gears).

I reinstalled the OEM mid pipe with cats and added O2 extensions and installed a universal free flow cat behind the factory Y-pipe.

I get some scent on a cold start for about 2 minutes, but besides that, it smells normal.

My down the road plan is to cut up the URD mid pipe and install free flow cats in there. Hopefully it will be better than the factory pipe, perform well and keep the CEL off.

Maybe I should get an intake...?