!!Doug Thorley Headers 4.7L V8!!
- Thread starter BootyFister
- Start date
That's really awesome to hear and confirms the theory on a properly spaced rear sensor clearing the CEL with no issues. Glad you're up and running with no CEL.
AuSeeker
Elite Member
"SAIS" stands for "Secondary Air Injection System", this started on the 2005 year models, 2003 and 2004 don't have the SAIS.
If you Google "Toyota SAIS" you get some results.
"Mild steel flanges" means exactly what is says, the flanges ARE NOT stainless steel.
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Thank you for the prompt reply! It's good to know that I do have the SAIS on my 07.... now I just have to finally pull the trigger, ($1057 - $1360 Canadian, OUCH), on these headers which Doug Thorley does have in stock.
mr_skittle
New member
I'm currently fartin' around with a pair of spacers trying to get my CEL to stay off. It's been a struggle so far but I'm encouraged that other folks are getting it to work.
So, coming late to the party. I bought a set of the Thorley headers back in ‘16, and they’ve been great…until now. I have a lovely exhaust leak - my usual shop tells me the secondary air intake runners to them are now rotting apart - those aren’t stainless.
Anyone know of any options aside from buying new $$$$$ assemblies and ripping it all apart and starting again?
Anyone know of any options aside from buying new $$$$$ assemblies and ripping it all apart and starting again?
FNG!!
New member
Questions from a new owner
Hi All,
I am a proud new owner of an '04 Limited V8 with about a quarter million miles on it. Can't tell from the exterior, though, it was garage kept by the original owner!
My 4Runner is all stock and I am debating on installing some headers. I had heard good things about the DH headers up until I registered for this forum and found this thread (thankfully).
I have to say people's experiences here have made me question using DH headers given the long lead time for fabrication, and also the rusting/corrosion issues.
I'm looking for potential alternatives that might make more sense to avoid rusting/corrosion issues - any suggestions?
For that matter, my initial thoughts were to consider the following aftermarket upgrades:
1. Cold Air Intake
2. Exhaust Headers (DH)
3. Performance Exhaust (Magnaflow)
Any suggestions on specifics ("avoid X brand or type, consider Y)? I'd be very grateful for any advice. In a nutshell I am looking to get a bit of extra "oomph" from the V8 in terms of both horsepower and engine growl, but without going into installations that would require a lot of maintenance/upkeep and potentially damage the engine or cause a failure of emissions spec (I live in NC). Call it "Upgrade Lite", if you will.
I have to take care of her as she will be my daily driver...
I am aware of potential issues with the rusting on the DH headers and I do know that whatever aftermarket installations I might get done with regards to 1-3 above could potentially cause warning lights based on O2 sensors, etc. That said, I am a relative newbie (hence my tag name...) so please do feel free to dumb it down!
Thanks in advance for any help you might be able to offer. I'm more than happy to provide more information if that helps.
Hi All,
I am a proud new owner of an '04 Limited V8 with about a quarter million miles on it. Can't tell from the exterior, though, it was garage kept by the original owner!
My 4Runner is all stock and I am debating on installing some headers. I had heard good things about the DH headers up until I registered for this forum and found this thread (thankfully).
I have to say people's experiences here have made me question using DH headers given the long lead time for fabrication, and also the rusting/corrosion issues.
I'm looking for potential alternatives that might make more sense to avoid rusting/corrosion issues - any suggestions?
For that matter, my initial thoughts were to consider the following aftermarket upgrades:
1. Cold Air Intake
2. Exhaust Headers (DH)
3. Performance Exhaust (Magnaflow)
Any suggestions on specifics ("avoid X brand or type, consider Y)? I'd be very grateful for any advice. In a nutshell I am looking to get a bit of extra "oomph" from the V8 in terms of both horsepower and engine growl, but without going into installations that would require a lot of maintenance/upkeep and potentially damage the engine or cause a failure of emissions spec (I live in NC). Call it "Upgrade Lite", if you will.
I have to take care of her as she will be my daily driver...
I am aware of potential issues with the rusting on the DH headers and I do know that whatever aftermarket installations I might get done with regards to 1-3 above could potentially cause warning lights based on O2 sensors, etc. That said, I am a relative newbie (hence my tag name...) so please do feel free to dumb it down!
Thanks in advance for any help you might be able to offer. I'm more than happy to provide more information if that helps.
I can't speak to the Thorley headers or intake but I love my Magnaflow 10416 with resonator delete. Sounds great and really helped with throttle response
https://www.youtube.com/watch?v=YC64axPSZv0&feature=youtu.be
FNG!!
New member
04SR5sam, thanks! Wow, that Magnaflow sounds pretty awesome!
Did you have any other mods done to your 4runner from that video or was it a straight up swap out from the stock muffler to the Magnaflow 10416?
Sorry for the ignorance, but when you say "with resonator delete" what does that mean? Is that something that was spec'd through Magnaflow or was that a mod that was made?
Any other unintended side effects from the change to the Magnaflow? How long have you had it and has it held up (i.e. any corrosion?)
Thanks again for the suggestion!
The exhaust is the only performance modification I've done. The stock exhaust also includes a resonator I think to help with droning but I just cut mine off during the exhaust install.
No unintended side effects and thus far (18 months) its held up well. A tiny bit of corrosion but still the best looking piece of equipment on the bottom of the truck lol
FNG!!
New member
Thanks a lot for the explanation, what you wrote makes sense. I definitely will consider this mod and also cutting off the resonator. Great to know it has lasted 18 months with no issues and almost no corrosion. I appreciate you taking the time to explain the resonator mod and giving me your feedback on your experience!:thumb:
Just a quick update for anyone considering these. Contacted Doug Thorley about the rust through issue, got a quick response asking for photos - and have since been ignored, despite multiple follow-ups. If you’re looking for customer service and standing behind a product, apparently you need to look elsewhere. 
limitedlifted
New member
Looking to purchase the shorties version to pass emission. I just want a replacement headers that are reliable. Obviously oem is out of the question due to it being a natural defect. Does anyone know another set of headers that are comparable reliability wise and will pass emissions?
Flybynight
New member
Do the shorties bolt up once the stock manifolds are removed? I will sell the stock ones with cats to a scrapper and hopefully cover the cost of the headers, or most of it. The tick tick tick is annoying as heck.
they'll bolt up to the block just fine, but you'll still need to weld some cats on...
Flybynight
New member
Are there any options that delete the cats and bolt up to stock exhaust? Long tubes? Or something a competent exhaust shop could work with. I dont need to worry about e-tests
I had long tubes installed on my rig a couple months back. They eliminate the first set of cats and bolt directly to the stock midpipes, which it sounds like is your end goal. I live in AL so I don't need to worry about emissions either.
Unless you're lucky, you'll get CEL codes (mine still has them). The lights don't bother me a ton since I know why they're on, but O2 sensor spacers have eliminated them for plenty of folks. I'll probably get some put on myself soon and see if that clears codes.
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