gamefreakgc
Elite Member
I've not seen a good resource for the Doug Thorley Shortie Headers for our 4Runners, so writing this for future reference for all members & 4Runner enthusiasts.
Below you'll find the Short Review (if you don't want to read it all) and the Full Review.
Short Review:
The headers give a nice grunt across the entire powerband. It’s not going to blow your socks off, but a subtle increase in power. You'll notice an increase for passing, accelerating, or flooring it. The installation for 96-98 Autos is a complete nightmare. I am unsure about 99-00, but for 01-02 years it would fit better, or better yet, a manual transmission. Tacomas have an easier time as well than 4Runners.
Ratings:
Install – 2 out of 10, barely fits. Lots of fabrication needed for 96-98.
Power – 7 out of 10, nice increase with a supercharger. Not huge, but just the next step in building out a 4Runner with a supercharger. It's like the difference between having your A/C on, then turning it off to free up HP.
Noise – 5 out of 10, noisier under heavy throttle but the sound isn’t my favorite.
Overall – 5 out of 10. There’s a reason why this was one of the last performance mods I’m going to do on my 4Runner. It’s expensive, difficult, but once it is on, you never have to worry about it again.
Full Review:
I purchased the Doug Thorley Headers, Part #: THY-507-C from Auto Acessories Garage: https://www.autoaccessoriesgarage.com/Exhaust/Doug-Thorley-Header?set-vehicle=1. With a coupon code, I paid $665.00, which is the cheapest price I could find anywhere. Since I live in the red-tape filled state of California, having it 50-state smog legal is imperative, which it is. You might be asking, why even bother with headers? My answer:
My vehicle is also supercharged but with a 10 PSI pulley and methanol injection, so the gains might even be higher for me since I’m cramming even more air into the engine, and it needs to get out quickly.
Upon arrival, here’s what the parts looked like:
I was missing the relocation bracket and the weld-on flange, so I had to contact Auto Accessories Garage about getting the missing parts. I must say, they were extremely polite and very fast to contact Doug Thorley Headers to get what I needed. Sothern hospitality at its best! So if you do order headers, make sure all the parts are included before diving in. I liked their customer service so much, I bought some other items from them as well.
After calling around looking for a shop that would be willing to do the the installation, I was recommended to All Automotive here in my town of Citrus Heights. If anyone in the Sacramento area ever needs a quality mechanic that does top notch work, Gardner is the best I have ever seen. Treated my 4Runner like I would treat it and went above and beyond what was expected to not only install it, but make it look good in the process: Home | All Automotive Service. Seriously though, I will never go to another shop for custom work or fabrication again.
Install – 2 out of 10
The installation was a complete nightmare. I knew it was going to be bad, but once he showed me all that was needed to be done I can’t believe he didn’t just chuck the headers out of the shop and tell me to find someone else to do it. It took him 10 hours, but he only charged me for 7. That put the cost of installation at $742 (before ya’ll freak out, this was about what I was expecting).
The transmission dipstick tube had nowhere to go. He ended up bending it and creating a new bracket to hold it in place:
The transmission kickdown table had nowhere to go and had to be bent (it is protected from heat at least though):
The exhaust flange did not weld on the piping since the downpipe is 2.25” piping (why Toyota, why?), compared to the headers which is 2.5” so he had to weld a section of 2.5” on (note in this photo, you can see the flange welded to 2.5" pipe, then welded to the 2.25" pipe):
Various hoses and wires did not fit right so he had to re-route some.
I have no welding capacity, so I knew this was out of my league from the start. Add on a wideband sensor bung and some gaskets, my total cost was…
$1432.49. Yes, you read that right.
Like I said at the beginning, this is one of the last performance mods I will ever do to my 4Runner. For half the cost of a supercharger I added 16 HP and 11 lbs of torque, maybe a little bit more. If you have a stock engine and are thinking about adding headers, I hope this points you to a blower instead.
Power – 7 out of 10
It did exactly what I thought it would do. Nothing more, nothing less.
My best comparison is like if you are doing some pulls and had the A/C on, then turned it off. That's about the power increase you'll get with these headers.
For those of us who are supercharged, I read in advance it would do a curious thing of reducing boost. Turns out, that is true. There’s less backpressure in the exhaust now so the air evacuates the combustion chamber faster, allowing for more air in and less pressure built up in the supercharger. I need less fuel to run the same 2.1” pulley now, which I’m expecting to also translate into MPG savings. I topped out at 10.5 PSI the last time I had a boost meter hooked up before the headers, will have another soon so I’ll see how much it’s gone down.
For those of you with superchargers fighting ping or lean conditions, this might be a solution or alternative to fuel mods, and it’s smog legal. For a reference point, with the setup at WOT I was running at about 12.8ish AFR's. After putting on headers, the AFR's decreased to 10.7. I needed less fuel for the same amount of boost.
One other thing I've noticed is a reduction in exhaust temperatures, as well as engine temperatures. I'm no engineer so I don't know the full effects of this benefit, but I know that superchargers put off a lot of heat because of the compressed air and excess heat is not good for any engine. Less heat may = more timing, and my initial runs have confirmed the ECU is running more timing advance than before.
Noise – 5 out of 10
Some people like big, gurgling V-8’s rolling down the road. I am not one of those people. I don’t do any mods for the sake of noise or appearance (except for the TRD decals), purely for function or performance. At little throttle you won’t even hear the headers. At moderate throttle you’ll get a gurgling noise. At full throttle or WOT it blares a bit more, not obnoxiously but once again, I'm not a huge noise person. Some people might like it more than I do. It does sound more like a V-8 than a V-6 now though. At WOT, the supercharger is much louder than the headers, but that's partly because of the smaller pulley I have on there.
Overall – 5 out of 10
In a rating scale of 1 to 10, 1 to 5 is the lower half of the scale. I put it as a 5 because it gave the power I was looking for, but the installation totally kills any “fun factor” of modifying your engine. At the end of the day though, I’m glad I had the funds to have it done and am satisfied with the results.
Hoping this will help future 4Runner owners decide if headers are right for them and what might be required to make it all work.
MPG ratings to come once I can get myself to stop stomping on the throttle at every stop! Feel free to ask any questions and I'll try my best to answer.
UPDATE: Noticed a slight gain of 0.5-1.0 MPG's after install. Not drastic, but helps a little bit.
Below you'll find the Short Review (if you don't want to read it all) and the Full Review.
Short Review:
The headers give a nice grunt across the entire powerband. It’s not going to blow your socks off, but a subtle increase in power. You'll notice an increase for passing, accelerating, or flooring it. The installation for 96-98 Autos is a complete nightmare. I am unsure about 99-00, but for 01-02 years it would fit better, or better yet, a manual transmission. Tacomas have an easier time as well than 4Runners.
Ratings:
Install – 2 out of 10, barely fits. Lots of fabrication needed for 96-98.
Power – 7 out of 10, nice increase with a supercharger. Not huge, but just the next step in building out a 4Runner with a supercharger. It's like the difference between having your A/C on, then turning it off to free up HP.
Noise – 5 out of 10, noisier under heavy throttle but the sound isn’t my favorite.
Overall – 5 out of 10. There’s a reason why this was one of the last performance mods I’m going to do on my 4Runner. It’s expensive, difficult, but once it is on, you never have to worry about it again.
Full Review:
I purchased the Doug Thorley Headers, Part #: THY-507-C from Auto Acessories Garage: https://www.autoaccessoriesgarage.com/Exhaust/Doug-Thorley-Header?set-vehicle=1. With a coupon code, I paid $665.00, which is the cheapest price I could find anywhere. Since I live in the red-tape filled state of California, having it 50-state smog legal is imperative, which it is. You might be asking, why even bother with headers? My answer:
My vehicle is also supercharged but with a 10 PSI pulley and methanol injection, so the gains might even be higher for me since I’m cramming even more air into the engine, and it needs to get out quickly.
Upon arrival, here’s what the parts looked like:
I was missing the relocation bracket and the weld-on flange, so I had to contact Auto Accessories Garage about getting the missing parts. I must say, they were extremely polite and very fast to contact Doug Thorley Headers to get what I needed. Sothern hospitality at its best! So if you do order headers, make sure all the parts are included before diving in. I liked their customer service so much, I bought some other items from them as well.
After calling around looking for a shop that would be willing to do the the installation, I was recommended to All Automotive here in my town of Citrus Heights. If anyone in the Sacramento area ever needs a quality mechanic that does top notch work, Gardner is the best I have ever seen. Treated my 4Runner like I would treat it and went above and beyond what was expected to not only install it, but make it look good in the process: Home | All Automotive Service. Seriously though, I will never go to another shop for custom work or fabrication again.
Install – 2 out of 10
The installation was a complete nightmare. I knew it was going to be bad, but once he showed me all that was needed to be done I can’t believe he didn’t just chuck the headers out of the shop and tell me to find someone else to do it. It took him 10 hours, but he only charged me for 7. That put the cost of installation at $742 (before ya’ll freak out, this was about what I was expecting).
The transmission dipstick tube had nowhere to go. He ended up bending it and creating a new bracket to hold it in place:
The transmission kickdown table had nowhere to go and had to be bent (it is protected from heat at least though):
The exhaust flange did not weld on the piping since the downpipe is 2.25” piping (why Toyota, why?), compared to the headers which is 2.5” so he had to weld a section of 2.5” on (note in this photo, you can see the flange welded to 2.5" pipe, then welded to the 2.25" pipe):
Various hoses and wires did not fit right so he had to re-route some.
I have no welding capacity, so I knew this was out of my league from the start. Add on a wideband sensor bung and some gaskets, my total cost was…
$1432.49. Yes, you read that right.
Like I said at the beginning, this is one of the last performance mods I will ever do to my 4Runner. For half the cost of a supercharger I added 16 HP and 11 lbs of torque, maybe a little bit more. If you have a stock engine and are thinking about adding headers, I hope this points you to a blower instead.
Power – 7 out of 10
It did exactly what I thought it would do. Nothing more, nothing less.
My best comparison is like if you are doing some pulls and had the A/C on, then turned it off. That's about the power increase you'll get with these headers.
For those of us who are supercharged, I read in advance it would do a curious thing of reducing boost. Turns out, that is true. There’s less backpressure in the exhaust now so the air evacuates the combustion chamber faster, allowing for more air in and less pressure built up in the supercharger. I need less fuel to run the same 2.1” pulley now, which I’m expecting to also translate into MPG savings. I topped out at 10.5 PSI the last time I had a boost meter hooked up before the headers, will have another soon so I’ll see how much it’s gone down.
For those of you with superchargers fighting ping or lean conditions, this might be a solution or alternative to fuel mods, and it’s smog legal. For a reference point, with the setup at WOT I was running at about 12.8ish AFR's. After putting on headers, the AFR's decreased to 10.7. I needed less fuel for the same amount of boost.
One other thing I've noticed is a reduction in exhaust temperatures, as well as engine temperatures. I'm no engineer so I don't know the full effects of this benefit, but I know that superchargers put off a lot of heat because of the compressed air and excess heat is not good for any engine. Less heat may = more timing, and my initial runs have confirmed the ECU is running more timing advance than before.
Noise – 5 out of 10
Some people like big, gurgling V-8’s rolling down the road. I am not one of those people. I don’t do any mods for the sake of noise or appearance (except for the TRD decals), purely for function or performance. At little throttle you won’t even hear the headers. At moderate throttle you’ll get a gurgling noise. At full throttle or WOT it blares a bit more, not obnoxiously but once again, I'm not a huge noise person. Some people might like it more than I do. It does sound more like a V-8 than a V-6 now though. At WOT, the supercharger is much louder than the headers, but that's partly because of the smaller pulley I have on there.
Overall – 5 out of 10
In a rating scale of 1 to 10, 1 to 5 is the lower half of the scale. I put it as a 5 because it gave the power I was looking for, but the installation totally kills any “fun factor” of modifying your engine. At the end of the day though, I’m glad I had the funds to have it done and am satisfied with the results.
Hoping this will help future 4Runner owners decide if headers are right for them and what might be required to make it all work.
MPG ratings to come once I can get myself to stop stomping on the throttle at every stop! Feel free to ask any questions and I'll try my best to answer.
UPDATE: Noticed a slight gain of 0.5-1.0 MPG's after install. Not drastic, but helps a little bit.
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