Interest in Custom built 4th gen V8 4.7 Doug Thorley Headers

Would you like the DT headers to have a Highflow catalytic converter?

  • Hell no! Open and loud.

    Votes: 35 9.1%
  • Yes, I would like to be legal.

    Votes: 283 73.9%
  • I don't care either way as long as I get them!

    Votes: 65 17.0%

  • Total voters
    383
URD makes an O2 simulator that tricks the computer into thinking the cats are functioning properly even if they aren't there.

Have you used the URD simulators? I’m thinking of trying them to get rid of my CEL P0420 and the associated lights on the dash. Also considering spacers, but the URD seems like a really slick plug and play solution
 
Have you used the URD simulators? I’m thinking of trying them to get rid of my CEL P0420 and the associated lights on the dash. Also considering spacers, but the URD seems like a really slick plug and play solution


I haven't used them personally yet but i plan on using them when i install my DT headers and URD catless Y-pipe. Ive heard of a couple people on here using them with good results.
 
I haven't used them personally yet but i plan on using them when i install my DT headers and URD catless Y-pipe. Ive heard of a couple people on here using them with good results.

Thanks. My runner came with the DT headers which I was really psyched about when I was looking at different ones to potentially buy. In fact, it was one of the things that helped push me into buying this particular one. Someone did weld CATs into them, I’m assuming the factory ones. Once I read about the URD harness even working on catless systems, I was sold that it was the best route for me since I really don’t want to go through the expense of cutting and welding in replacements only to potentially have this issue because an aftermarket high flow model can sometimes still throw codes. If it wasn’t for the inspection issues here, I’d go the route you are planning and just eliminate them completely. For now though, I think the plug and play harness is a great option, I was just looking for someone that actually used them to solve this issue. I’ve read a few threads where they were discussed, but so far never saw anyone say they actually run them.
 
Thanks. My runner came with the DT headers which I was really psyched about when I was looking at different ones to potentially buy. In fact, it was one of the things that helped push me into buying this particular one. Someone did weld CATs into them, I’m assuming the factory ones.

Cool, how is your MPG? These do help a lot since the factory headers are VERY RESTRICTIVE.

There are two versions of these headers, 03-04 v8 and 05-09. There shouldn't be any rubbing except if you're lifted. Now, if you are you've lifted there's a small bolt you can replace on the steering column with a flush head to fix it.

For those that don't know, V8 4th gens are known to make a ticking sound from a leaky cracked factory header. These new headers fix that problem, add about 2-3 more MPG and a ton more HP. New Toyota headers are DOUBLE the price. Get in while you can.

Doug Thorley 03-04 headers

Doug Thorley 05-09 headers

Also, the Gibson catback, which pairs great with these headers.

Gibson 4th Gen exhaust

I also have the magnaflow high flow cats that will work with these, and I can do any and all DT headers, not just these, just call or text 717-319-2100 for anymore questions, to order, etc.

AND, if any of you are looking for a new Y PIPE, see here!

http://www.toyota-4runner.org/4th-g...high-flow-y-pipe-i-can-do-need-your-help.html
 
Cool, how is your MPG? These do help a lot since the factory headers are VERY RESTRICTIVE.

There are two versions of these headers, 03-04 v8 and 05-09. There shouldn't be any rubbing except if you're lifted. Now, if you are you've lifted there's a small bolt you can replace on the steering column with a flush head to fix it.

For those that don't know, V8 4th gens are known to make a ticking sound from a leaky cracked factory header. These new headers fix that problem, add about 2-3 more MPG and a ton more HP. New Toyota headers are DOUBLE the price. Get in while you can.

Doug Thorley 03-04 headers

Doug Thorley 05-09 headers

Also, the Gibson catback, which pairs great with these headers.

Gibson 4th Gen exhaust

I also have the magnaflow high flow cats that will work with these, and I can do any and all DT headers, not just these, just call or text 717-319-2100 for anymore questions, to order, etc.

AND, if any of you are looking for a new Y PIPE, see here!

http://www.toyota-4runner.org/4th-g...high-flow-y-pipe-i-can-do-need-your-help.html

Well, it’s funny you should ask about MPGs... I have pretty bad mileage right now. Display shows 13.8, calculated is about 1 MPG better. I have the CEL on with the VSC/Trac off lights also illuminated (P0430), so I’m thinking that may have something to do with it, but not sure. I definitely don’t want to replace the CATs, so I’m hoping that maybe the URD electronic thing can solve this, but I may replace the O2s anyway just in case it’s from faulty, high mileage sensors. I suppose there may also be a leak, but I haven’t found one yet from the looking around I’ve done so far. I’m really hoping it’s something simple. Love the headers though, and would eventually like to add to the system to make it sound the way it should. I love the growl from the headers even with the stock system, so I can only imagine how nice they will sound with a good flowing catback.
 
Well, it’s funny you should ask about MPGs... I have pretty bad mileage right now. Display shows 13.8, calculated is about 1 MPG better. I have the CEL on with the VSC/Trac off lights also illuminated (P0430), so I’m thinking that may have something to do with it, but not sure. I definitely don’t want to replace the CATs, so I’m hoping that maybe the URD electronic thing can solve this, but I may replace the O2s anyway just in case it’s from faulty, high mileage sensors. I suppose there may also be a leak, but I haven’t found one yet from the looking around I’ve done so far. I’m really hoping it’s something simple. Love the headers though, and would eventually like to add to the system to make it sound the way it should. I love the growl from the headers even with the stock system, so I can only imagine how nice they will sound with a good flowing catback.

I got the codes after putting on the headers too. It might be related to flow. URD definitely mentions this as a result of headers. I tried to make my own circuit, but that ended up causing other codes. I eventually bought the URD and the codes went away. Since then, I have found some adapters that sink the O2's back out of the flow a bit. I always wondered if that would fix the codes.
 
I got the codes after putting on the headers too. It might be related to flow. URD definitely mentions this as a result of headers. I tried to make my own circuit, but that ended up causing other codes. I eventually bought the URD and the codes went away. Since then, I have found some adapters that sink the O2's back out of the flow a bit. I always wondered if that would fix the codes.

I'm running no cats in the headers, so I have 3 spacers on one side and 2 on the other to not have rear o2 faults. They are catalyst efficiency monitoring sensors only and do not effect performance so to me it's a cheap and acceptable solution.
 
I got the codes after putting on the headers too. It might be related to flow. URD definitely mentions this as a result of headers. I tried to make my own circuit, but that ended up causing other codes. I eventually bought the URD and the codes went away. Since then, I have found some adapters that sink the O2's back out of the flow a bit. I always wondered if that would fix the codes.

That’s good to hear that the URD device worked for you. I was trying to find someone that had used it for this application with good results because it’s pretty expensive if it doesn’t solve the problem! Those adapters do work for some, and they even have some that have catalyst material in them, so they are like mini CATs to clean the sample prior to the sensor. My headers were installed by a previous owner and have CATs welded in, but I don’t know if they were the originals cut and spliced in, or if they are replacement ones. One thing I did notice though, is that the previous owner must have had this issue before because there is already an O2 spacer on the driver side. I’m worried with the new inspection process here in MA that they will fail it for the spacers since I’ve heard that they now put it up on a lift and film the exhaust from underneath. At least with the URD, if installed carefully, it could be made to look completely stock.
 
I'm running no cats in the headers, so I have 3 spacers on one side and 2 on the other to not have rear o2 faults. They are catalyst efficiency monitoring sensors only and do not effect performance so to me it's a cheap and acceptable solution.

Here is what many have done Check-Engine-Light-Eliminator-Adapter (2) of them. This whole setup can get very confusing and most call me when they are ordering since it's a large purchase, but if you can't call, I try to explain everything here so someone doesn't get these and not know what else they might need.

Doug Thorley 03-04 headers [] Doug Thorley 05-09 headers [] the Gibson catback, which pairs great with these headers. Gibson 4th Gen exhaust

I also have the magnaflow high flow cats that will work with these, call or text 717-319-2100 for anymore questions, to order, etc.

http://www.toyota-4runner.org/4th-g...high-flow-y-pipe-i-can-do-need-your-help.html
*NEW. Those looking for a new Y PIPE, please chime in ^above^. I'm working with Doug Thorley to get this done and they've agreed to do this if we get enough members:
 
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jesus christ, this thread would be 40 pages less without Jasons plugs every third post. WE GET IT DUDE YOU SELL STUFF.

Makes it annoying to try to read through shit.
 
So I ended up throwing a P0420 after install the DT headers and HFC. I purchased two of the adapters you linked, but just want to confirm they go on the rear O2 sensors on the midpipe correct? Also, can anyone tell me the O2 sensors socket size needed?

Thanks in advance!

Yes, outlet O2 sensors. I believe it's a 21mm O2 sensor socket. Or just use a wrench, there's plenty of access to the outlet sensors.
 
Yep, they go on the 2 rear o2 sensors not sure of the size, but you can use an open end wrench but there is a also a special O2 socket available at most auto parts stores.
 
Got ya and Just to confirm the O2 spacers need to be run on the Y-Pipe in order not to throw any codes?

You can remove the rear Catalytic Converters and you won't receive any codes. However, if you remove the front Cats you will get an CEL. If you remove the front CATs or have a front CAT(s) failure, you'll need to add a 2" O2 spacer to each side to prevent a CEL for the missing or damaged CAT.
 
Did anyone with a '05-'09 start getting an air injector pump sound during cold start up after installing these?

I didn't have the noise before I installed them, and was fairly careful not to bend the tubes while fitting the headers in, and can't smell any exhaust, or hear any exhaust noise after the pump goes quiet, so don't think I cracked them. It's also been over a year since I installed, so I'm pretty sure the pump isn't on the way out either.

It doesn't bother me at all, but I'm considering selling my 4runner this fall and think the noise might dissuade some potential buyers.
 
You can remove the rear Catalytic Converters and you won't receive any codes. However, if you remove the front Cats you will get an CEL. If you remove the front CATs or have a front CAT(s) failure, you'll need to add a 2" O2 spacer to each side to prevent a CEL for the missing or damaged CAT.

I’d love to just be able to add the spacers, but I’m pretty sure they visually check for that stuff here in MA during the new inspection process. Don’t know for sure yet because I haven’t had a car go through since they changed the process at the end of last year. That’s why I was leaning toward the far more expensive URD simulator since it would be virtually undetectable if the box was hidden, and the harness was covered in wire loom. My truck has one spacer on the driver side rear sensor that was there when I bought it, and it looks like it’s been there for many years, so I suspect it was done to correct the CEL back when the headers were first installed. If I install the URD harness, I’ll probably just remove the spacer since it won’t be needed, and it won’t draw unnecessary scrutiny to the exhaust.
 
jesus christ, this thread would be 40 pages less without Jasons plugs every third post. WE GET IT DUDE YOU SELL STUFF.



Makes it annoying to try to read through shit.



Agreed. If someone has not already made the decision to buy shít from you by now, they’re not going to.

I appreciate the enthusiasm but I think a discreet PM would be appreciated by all


Sent from my iPhone using Tapatalk
 
Hi all, I just bought a 2007 with 120K in December, previous owner said he replaced manifolds around 90K but one is now cracked... Having done some searching and reading up on this thread, I have a few questions as a noob to this vehicle and this forum:

1) Could part of the manifold cracking issue have to do with flexing / twisting of the motor?
1a) If so, would off-roading increase flexing (I would assume so, but no idea how much)
1b) If so, could replacing motor mounts help?

2) Do we have enough history of people using DT headers to really determine if they are, in fact, less prone to failure?

3) Has anyone in the Portland, Oregon area had them installed and could recommend a shop?

I like the idea of getting these, but wondering if they actually hold up better long term and seems like the welding / custom install aspect adds a lot of unknown in cost (unless I could find a shop that has already done one).

Thanks!
 
I have them and cant say that they are any better when it comes to future failures but Im sure they are. The design of the stock headers are bad. But why pay to have someone do the work to replace a bad design? Especially with the performance gain of the DTs. And their really is.

As for installers...Black Works Inc in Bend has put them in I believe. May want to contact them.

Sent from my SM-G935V using Tapatalk
 
I have them and cant say that they are any better when it comes to future failures but Im sure they are. The design of the stock headers are bad. But why pay to have someone do the work to replace a bad design? Especially with the performance gain of the DTs. And their really is.

As for installers...Black Works Inc in Bend has put them in I believe. May want to contact them.

Sent from my SM-G935V using Tapatalk

Very valid point since the install process is virtually the same, other than welding on the CATs or extension tubes if not wanting CATs. Having seen the stock manifolds, there is no doubt in my mind that these will perform better, and allow better breathing efficiency for the engine. I’m glad they were already installed when I bought the truck, but in a way I almost wish I had been able to drive it first just to feel the difference.
 

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