Doug Thorley headers...successful install stories.

[Runabout36]

2005 Toyota 4runner Sport 4.7l V8. Just got my DT headers. Want to hear successful install stories and what you used. Question 1...did you change out the cats? If so what did you use? Question 2...did you use an O2 simulator or spacer. Want to avoid CEL . Question 3...did you put a cat back exhaust system on?

 

[Habitant]

I just did mine a few weeks ago. Decided to stick with stock cats even though I bought 4 aftermarket ones. I have the full set up too, Volant intake, DT headers and mag aglow exhaust. Sounds great and the overall driving feel is good. The car feels lighter which I equate to more power.

 

[Runabout36]

How old were your stock cats (miles)? I have 175,000 miles and it seems foolish to not change them at the same time as installing the DT headers. Was thinking of using Magnaflow high flow cats. Did you use an O2 simulator or spacer. I was told by DT/Mike Johnson if using stock cats no simulator or spacer is needed.

 

[blackoutt]

1. Used someones old headers to build a wooden jig to weld on 2.5" pipes and flanges instead of cats, non inspection state. If I were to do it again I would reduce to 2.25" and flanges to better mate to the stock or even aftermarket y pipes.

2. O2 sensor spacers with no cats was a must, at least two on each side.

3. "stock" exhaust piping from the headers back. Muffler and side exit but otherwise it's all factory piping still.

There was a noticeable increase in power but I've since added weight and tire size and wind resistance so I've effectively offset it.

 

[Habitant]

How old were your stock cats (miles)? I have 175,000 miles and it seems foolish to not change them at the same time as installing the DT headers. Was thinking of using Magnaflow high flow cats. Did you use an O2 simulator or spacer. I was told by DT/Mike Johnson if using stock cats no simulator or spacer is needed.

About 140k miles on the stock ones. I was adviced to run them until they malfunction and then install the new ones. I bought the O2 sensor bypass thing too. If you want the 4 cats and the bypass I could sell them to you!

 

[0verland]

Question 1...did you change out the cats? If so what did you use?

yes, Flowmaster HFCs. I don't see why anyone wouldn't over 100k, but thats just me.

Question 2...did you use an O2 simulator or spacer.

O2 spacer. Blox Racing BXFL-00108

Question 3...did you put a cat back exhaust system on?

Yes, Gibson Side Exit aluminized version coated in matte black high temp paint. I don't deal with really any corrosion here in the desert but I put on the coating to keep the rust off if any, your mileage may vary.


I went above and beyond on for my install by ordering new studs and gaskets. I went with the Stage 8 8919 4.7L V8 Toyota 10MM Header Kit and OEM Toyota manifold gaskets.

 

[Keros]

I used magnaflow high flow cats and a sensor spacer when the shop did the headers.

They built a custom system up to the muffler, I think it's 2.25"

Sounds amazing. Butt dyno says it makes more power... I haven't had time to take it to a real dyno yet.

 

[dsieber]

Did mine about a year and a half ago. Kept the stock cats (had to - emissions), and stock exhaust.

 

[toyotaguyMT]

did mine over the summer, removed the cats (was planning on the diy o2 simulator but that didn't work), running with CEL but still in closed loop so i don't care. Definitely more responsive and got 2mpg or so back after the lift and bumper took it down to 16mpg. still running stock exhaust otherwise, i like it being quiet when I'm on back roads for a few days camping.

 

[Ed_C]

Flowmaster HFCs

O2 spacer. Blox Racing BXFL-00108.

Since you do have converters, why did you still install O2 spacers? Preventative measure or were you getting a CEL without them?

 

[0verland]

Since you do have converters, why did you still install O2 spacers? Preventative measure or were you getting a CEL without them?

The DT headers still throw a CEL for bank 2. The CEL Eliminator is necessary regardless from my understanding. I didn't believe it myself initially until I ran it without for a few weeks and with no success of getting rid of the CEL I threw them on per J Burtman's recommendation (granted it stated this in the first place) ...haven't seen a code since. :shocked:

I personally wanted the cats on there regardless to tone down the exhaust to a level I would be comfortable with for hours of driving on the highway.

 

[Morphyne]

Exhaust newb here: So a complete system upgrade would look like:

1. DT headers
2. Magnoflow high flow cars
3. Gibson side exit muffler and exhaust
4. New 02 sensors?
5. What else?

 

[0verland]

1. DT headers
2. Magnaflow high flow cats
3. Gibson side exit muffler and exhaust
4. O2 spacer. Blox Racing BXFL-00108
5. Stage 8 8919 4.7L V8 Toyota 10MM Header Kit (NOT REQUIRED)
6. OEM Toyota manifold gaskets. (NOT REQUIRED)


Due to my personal preference I also got OEM gaskets and new manifold studs

 

[Runabout36]

Overland...many thanks for the info. Could you tell me what the product number is on the Magnaflow Cats? There seems to be two recommended on Magnaflow website....#51205 and #99205HM which is just a couple bucks more.

 

[0verland]

Overland...many thanks for the info. Could you tell me what the product number is on the Magnaflow Cats? There seems to be two recommended on Magnaflow website....#51205 and #99205HM which is just a couple bucks more.

I didn't use Magnaflow HFCs in my setup, I went with FlowMaster.

Clicky

Honestly though you can go with any 3" Inlet/outlet cat thats roughly 10.5" or around there. If you have a good exhaust guy they shouldn't have a problem mating it up. I prefer the spun cats though since they don't have all that shielding to get in the way.

 

[Runabout36]

Thanks! I realized after reading your previous post that you used Flowmaster cats. Were they a better fit than the shielded Magnaflow?

 

[0verland]

Thanks! I realized after reading your previous post that you used Flowmaster cats. Were they a better fit than the shielded Magnaflow?

Can't say I've never used the shielded but the spun ones fit perfect.

 

[mavrick1903]

Thanks! I realized after reading your previous post that you used Flowmaster cats. Were they a better fit than the shielded Magnaflow?

Are the Magnaflow shielded? I just ordered the set from Burtman.

 

[meltdowner]

Would you guys mind stating what kind of tools would be required to do this job? Is welding involved, for example? etc etc

 

[alia176]

Speaking of cats, I see that Magnaflow has cats for Federal vs non Federal so make sure you order the correct ones for your state. One of them has more precious metals inside for cleaner exhaust, I think