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

[empty403]

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.

I'm in California and probably the strictest state for smog. If the vehicle has an OBD2 port, most test shops will just connect to that port and open the hood.

 

[Timberland]

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!

The weight of the cat attached to the manifold combined with its thin material is likely more of a cause than any twisting or flexing.

There are quite a few people running these headers (myself included) but in reality, that's a drop in the bucket when you look at the number of 4th gen 4runners sold. One look at the headers up close and you'll know they're a much stronger design. 304 stainless plus a lifetime warranty should put your mind at ease.

Any decent mechanic with welding and fab skills should be able to handle the install no problem. As others have stated, it's nearly the exact same process as installing a new OEM manifold, just with a bit of cutting and welding for the cats.

Tim

 

[yippyskippy]

Thanks all, appreciate the input!

I'm still wondering if there is another factor, maybe being lifted 3", or motor mount wear or something else being worn could have caused an early failure (thus likely to repeat) or why the F___ I have a cracked manifold when previous owner replaced the manifolds only ~25K miles ago...

Talked to a local exhaust shop and was quoted about the same price ($1300) for either:
1) labor to weld cats onto the headers and install (this includes cost of the cats but does not including cost of the headers)
2) parts and labor to replace one side with an OEM equivalent part (manifold + cat assembly)

For option (1) I still have to order the headers, so whatever they cost is the difference. I drive less than 10K miles / year and tend not to keep a vehicle for more than 2-4 years, so leaning toward the OEM equivalent replacement on just the one side, but if it happens again or the other side ends up failing while I still own it, I will regret it.

One other question for those who have done this: I know there are the spacers for the 02 sensors which will prevent throwing a code, but has anyone done this with only 2 cats, used the spacers and passed emissions somewhere that they not only scan for codes but have the tail pipe sniffer thing???? Thanks!

 

[Jason B]

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!

1) No, but it could flex during natural motor sway when offroading with a lot of travel.

No again. THe oem manifold is a flawed design and a known issue with Toyota. This is a complication with all V8 03-09 4Runners and GX's and another reason why Toyota switched to a V6 motor.


2) DT has had those headers on customer vehicles since 2015. They have been 0 warranty replacements to date for cracked or failing header and that is based upon the 14 gauge T304 RATH Stainless Steel.

3) Is that close to Bend, OR? vip performance, auto repair shop, 503-257-1110

If you look at the factory oem manifold, it's one full component from the front to the back, there is no break. The only way to have a bolt on headers would be to remove the cat, but most need to retain them, headers would have to be designed to retain the front cats. I'm happy to report I've been working with DT and these are IN PROCESS be carb legal soon, for CA, etc.

Doug Thorley 03-04 headers SALE!

Doug Thorley 05-09 headers SALE!

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.

 

[rickashay]

Any decent mechanic with welding and fab skills should be able to handle the install no problem. As others have stated, it's nearly the exact same process as installing a new OEM manifold, just with a bit of cutting and welding for the cats.

Tim

Hey Tim, curious - do the cats need to be welded onto the DT headers while the headers are installed? Like do you have to mock up/install the headers, tack weld the cats in the correct place/orientation, then remove the headers to fully-weld the cats on? I'm just thinking of the install process as a whole with the fabrication included.

Starting to get the P0420 code and if I'm replacing a cat, you can sure as shit bet I'm doing the whole shibang! You happen to have a sound clip anywhere?

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.

Jason, maybe you can also shed some light on my question to Tim above? Curious what the Magnaflow cats are worth for the 05-09 setup. Feel free to PM.

Thanks,
Addison

 

[Terminator03]

Hey Tim, curious - do the cats need to be welded onto the DT headers while the headers are installed? Like do you have to mock up/install the headers, tack weld the cats in the correct place/orientation, then remove the headers to fully-weld the cats on? I'm just thinking of the install process as a whole with the fabrication included.

Starting to get the P0420 code and if I'm replacing a cat, you can sure as shit bet I'm doing the whole shibang! You happen to have a sound clip anywhere?



Jason, maybe you can also shed some light on my question to Tim above? Curious what the Magnaflow cats are worth for the 05-09 setup. Feel free to PM.

Thanks,
Addison

Just so you know... spending the money to have CATs welded in with these headers is no guarantee that it will make the p0420 go away. I bought my truck with the DT headers already installed (with welded in CATs) and very shortly after buying it developed that CEL. Upon closer inspection, there are also 2 spacers screwed in with one of the O2 sensors, which tells me that clearly someone before me tried to fool the sensor to make it go away. What I don’t know is when the headers were installed, or whether they reused the old CATs during the install to try to save money. It IS a headache though, especially if you live in a place where there is mandatory emission inspection! So, in short, I have some really sweet headers WITH CATs, and still have the code!

 

[rickashay]

Just so you know... spending the money to have CATs welded in with these headers is no guarantee that it will make the p0420 go away. I bought my truck with the DT headers already installed (with welded in CATs) and very shortly after buying it developed that CEL. Upon closer inspection, there are also 2 spacers screwed in with one of the O2 sensors, which tells me that clearly someone before me tried to fool the sensor to make it go away. What I don’t know is when the headers were installed, or whether they reused the old CATs during the install to try to save money. It IS a headache though, especially if you live in a place where there is mandatory emission inspection! So, in short, I have some really sweet headers WITH CATs, and still have the code!

Thanks for the info. Truth is, the 2UZ is VERY picky with exhaust setups. In my previous 04' Tundra (non-vvti) I had purchased a set of unicorn TRD longtube headers for the 2UZ. They were brand new, never installed. My factory manifolds were starting to tick so I installed the TRD longtubes, bought new Magnaflow highflow cats, had a custom crossover/center section built and put everything back together. (Had a Borla catback system already installed) My truck had no codes before the install and would periodically throw a P0430 or P0420 (can't recall exactly) after all the fancy new exhaust parts. And again... these were Toyota longtube headers with California compliant hi flow cats.

Photo below showing the factory Tundra manifolds next to the TRD Longtubes (bolt on too!!!):

IMG_4488.jpg by Addison Rickaby, on Flickr


IMG_4461.jpg by Addison Rickaby, on Flickr


IMG_4460.jpg by Addison Rickaby, on Flickr

And the custom center section/crossover made by BAMufflers:

IMG_4605.jpg by Addison Rickaby, on Flickr

Me having the stock cats and a P0420 code tells me that I have a cat not working up to efficiency within the factory system. (Could also be a bad 02 potentially). But my thinking is if I have to replace a single cat, I am going to replace and upgrade the whole system - new magnaflow hi-flow cats, headers, and crossover. I do not expect the headers alone to remove my problem.... but hopefully I can replace everything and gain some performance/economy while removing the code.

 

[sprygsxr]

I understand welding cats onto these headers is the easier approach, but for just a few more dollars you could make your own y-pipe section. It will have better flow, and you can weld your cats to the y-pipe and have it easily removable from the headers for servicing.

On top of this, you can have your ECU tuned to take care of any codes which would even work if you decided to go with no cats.

 

[Jason B]

Upon closer inspection, there are also 2 spacers screwed in with one of the O2 sensors, which tells me that clearly someone before me tried to fool the sensor to make it go away.

That's exactly what you want. I know of over 20+ customers are using those spacers with new cats and it fixes everything. They are about $9, vs the electronic fix which does the same thing, but costs over $150. One of my customers was one of the first to figure this out and those spacers are awesome.

https://www.ebay.com/itm/BLOX-Racin...nator-Adapter-CEL-O2-Sensor-Ext-/322275221365

You need two and the reviews don't lie. If you have a CEL you need these so the computer does't start to learn and try to run rich. Best $10 ever spent, easy install.

To see if you have aftermarket cats, try to get under the truck the next time you can and snap a pic for us.

 

[yippyskippy]

Just so you know... spending the money to have CATs welded in with these headers is no guarantee that it will make the p0420 go away. I bought my truck with the DT headers already installed (with welded in CATs) and very shortly after buying it developed that CEL. Upon closer inspection, there are also 2 spacers screwed in with one of the O2 sensors, which tells me that clearly someone before me tried to fool the sensor to make it go away. What I don’t know is when the headers were installed, or whether they reused the old CATs during the install to try to save money. It IS a headache though, especially if you live in a place where there is mandatory emission inspection! So, in short, I have some really sweet headers WITH CATs, and still have the code!

This is my biggest concern at this point

That's exactly what you want. I know of over 20+ customers...

Sounds like he has them and it didn't fix the issue for him. Can others who have tried the spacers comment? Worked / didn't work? I know there are a few within this thread but not 20+

On top of this, you can have your ECU tuned to take care of any codes which would even work if you decided to go with no cats.

I just called 2 shops in my area (Portland, OR) who both told me that Toyota ECUs are totally locked down from the factory and can't be custom tuned (these are shops who do custom ECU tuning). Does anyone know a company who has figured out how to tune Toyota ECUs?

 

[sprygsxr]

I just called 2 shops in my area (Portland, OR) who both told me that Toyota ECUs are totally locked down from the factory and can't be custom tuned (these are shops who do custom ECU tuning). Does anyone know a company who has figured out how to tune Toyota ECUs?

TTFS is out of Maryland but might be able to find someone near you to help you out. Not many have figured out and Im pretty sure I was the first 4th Gen T4R for these guys cuz they were more excited than me when they figured it out.

Performance Engine Tuning and Dyno Facility | Tuning Tech FS

 

[Terminator03]

That's exactly what you want. I know of over 20+ customers are using those spacers with new cats and it fixes everything. They are about $9, vs the electronic fix which does the same thing, but costs over $150. One of my customers was one of the first to figure this out and those spacers are awesome.

https://www.ebay.com/itm/BLOX-Racin...nator-Adapter-CEL-O2-Sensor-Ext-/322275221365

You need two and the reviews don't lie. If you have a CEL you need these so the computer does't start to learn and try to run rich. Best $10 ever spent, easy install.

To see if you have aftermarket cats, try to get under the truck the next time you can and snap a pic for us.

Jason, I will take a pic when I get a chance, but as I said, my truck already had the 2 spacers installed previously, AND I have the CEL still, so at this point I’m considering the URD device to make it go away because I will never pass MA inspection in November when it’s due again as it is. I wish it was as simple as just buying the cheap spacers for me.

 

[Jason B]

Jason, I will take a pic when I get a chance, but as I said, my truck already had the 2 spacers installed previously,

Yea, then it's something more involved if it's still doing with the spacers, maybe a bad cat. If it has a lot of miles could be a bad cat or when they were cut out and re-welded, but the other device does the same thing as the spacers. Let us know.

 

[Timberland]

Hey Tim, curious - do the cats need to be welded onto the DT headers while the headers are installed? Like do you have to mock up/install the headers, tack weld the cats in the correct place/orientation, then remove the headers to fully-weld the cats on? I'm just thinking of the install process as a whole with the fabrication included.

Starting to get the P0420 code and if I'm replacing a cat, you can sure as shit bet I'm doing the whole shibang! You happen to have a sound clip anywhere?

You're dead on. Mock everything up, tack them in place, then remove them to weld completely.

I don't have any sound clips but honestly, on an otherwise stock exhaust, there's no change in sound at all. I'd imagine there would be a noticeable change with an aftermarket cat back though.

Perhaps if Jason B were to cut me a deal on a Gibson system, I could provide more help haha.

 

[sfjohnson722]

563-ss needed asap

If anyone happens to have a set of THY-563-SS-C (for a 2006 V8) which they are willing to part with, please PM me directly. I have a set on rush from DT set to arrive in a few weeks, but I find myself in a very unfortunate situation of needing to pass inspection. *** Willing to pay premium *** Thanks in advance.

 

[yippyskippy]

QUESTION: has anyone done DT headers and with the double spacers and been able to PASS emissions testing in a place where they test both OBD2 port scan and also stick whatever the sensor thing is into your tail pipe?

Preventing CEL is one part of it, but I'm wondering if people are actually passing emissions testing, or if most of the people getting these headers are in rural areas with no testing.

Thanks all!!!

 

[neoprism]

how much hp did you get?

 

[XPdriven]

I couldn't bring myself to go through all 51 pages of the post. Does anyone know if these are California legal?

 

[Jason B]

how much hp did you get?

Around 30

QUESTION: has anyone done DT headers and with the double spacers and been able to PASS emissions testing in a place where they test both OBD2 port scan and also stick whatever the sensor thing is into your tail pipe? Preventing CEL is one part of it, but I'm wondering if people are actually passing emissions testing, or if most of the people getting these headers are in rural areas with no testing.

From what my guy at DT says, it will pass, as long as no CEL. And for Cali, it will still pass, but it needs to Carb sticker certification which DT has submitted and will be legal in CA soon.

I couldn't bring myself to go through all 51 pages of the post. Does anyone know if these are California legal?

Been working with DT on this and YES, they will be soon, paper work has been submitted, etc. It costs like $1,200 per part # to do this for CA. Costly.

Doug Thorley 03-04 headers SALE! IN STOCK RIGHT NOW, if you have a 05-09 you can get these to work and save a little. Call or PM for more info, 717-319-2100

Doug Thorley 05-09 headers SALE! - out of stock for a few weeks after ordering.

 

[Jason B]

I couldn't bring myself to go through all 51 pages of the post. Does anyone know if these are California legal?

They will be soon for CA, paper work submitted. That means you CAN order them now, and when they are, will send you the plate and then they will pass for CA.

Back in stock finally!!If anyone wants these ORDER soon, when they go out of stock, it's 3-4 weeks easy.

Doug Thorley 03-04 headers in stock Doug Thorley 05-09 headers in stock!