!!Doug Thorley Headers 4.7L V8!!

[atalarico]

Just had mine installed and I've noticed a few things. First, I reset my mpg calculator since the road between the shop and my house is mostly highway and I was getting 21.6. I was over the moon. After a few days of city driving though it's down in the 15's again. I'm not sure if that's because I'm driving it harder now because it is definitely faster, or if the MPG gain promises are overblown.

I'm going to let it calculate for a couple weeks and see what the average comes out to be. That being said, I didn't get this car to hypermile, but it was a nice selling point to hear it would get me back to pre-33" tire MPG territory. I'll be impressed if it does.

 

[That_Titanium_4RNR]

Just had mine installed and I've noticed a few things. First, I reset my mpg calculator since the road between the shop and my house is mostly highway and I was getting 21.6. I was over the moon. After a few days of city driving though it's down in the 15's again. I'm not sure if that's because I'm driving it harder now because it is definitely faster, or if the MPG gain promises are overblown.

I'm going to let it calculate for a couple weeks and see what the average comes out to be. That being said, I didn't get this car to hypermile, but it was a nice selling point to hear it would get me back to pre-33" tire MPG territory. I'll be impressed if it does.

Care to give some info on the specs you went with. Cats Y/N? Muffler? Price for install? I will need these too and want to see what people charging genrally

 

[Timberland]

Just had mine installed and I've noticed a few things. First, I reset my mpg calculator since the road between the shop and my house is mostly highway and I was getting 21.6. I was over the moon. After a few days of city driving though it's down in the 15's again. I'm not sure if that's because I'm driving it harder now because it is definitely faster, or if the MPG gain promises are overblown.

I'm going to let it calculate for a couple weeks and see what the average comes out to be. That being said, I didn't get this car to hypermile, but it was a nice selling point to hear it would get me back to pre-33" tire MPG territory. I'll be impressed if it does.

Factory computer readings are known to be untrustworthy. Calculate it by hand and it'll give you an accurate reading. I did that and found a 1-2 mpg improvement which is what I lost from the bigger tires!

 

[atalarico]

Care to give some info on the specs you went with. Cats Y/N? Muffler? Price for install? I will need these too and want to see what people charging genrally

Just the headers. $750 (quoted 600-800) at Lakewood Muffler and Brake.

 

[atalarico]

Factory computer readings are known to be untrustworthy. Calculate it by hand and it'll give you an accurate reading. I did that and found a 1-2 mpg improvement which is what I lost from the bigger tires!

But wouldn’t it follow that if I am comparing my current computer calculated mpg to the previous computer calculated mpg, it would be consistent (albeit consistently inaccurate)?

 

[4RunnerAquasport]

[MENTION=9]Jason B[/MENTION] makin it happen!

 

[Inv4drZm]

[MENTION=9]Jason B[/MENTION] makin it happen!

Those look nice. I'm praying to the 4Runner gods that it works well with a body lift.

 

[volkinator]

So a genuine questions. What are advantages/disadvantages of long vs short tube headers? I've got the V8. I'm saving for when I start hearing the tick and will eventually work my way to these. Love supporting the local people and contributors to the forum. But seriously don't know the differences.

Thanks!

 

[Inv4drZm]

So a genuine questions. What are advantages/disadvantages of long vs short tube headers? I've got the V8. I'm saving for when I start hearing the tick and will eventually work my way to these. Love supporting the local people and contributors to the forum. But seriously don't know the differences.

Thanks!

Long vs short some say the long tubes are better for high-end power while the short tubes have more low-end response but it depends on what article you read, some actually say the opposite. The tube diameter seems to make a larger difference in performance.

The biggest difference, specific to our application, is that the DT short tube headers don't have a flange welded to them, which means you can add cats to them but you have to make a jig and get them welded in the correct position to match up to the factory piping. These new long tubes travel all the way to the flanges, deleting the cats, so these are purely 'bolt on'. No need to pay a welder or spend a bunch of time getting it set up.

Dyno numbers between the two might be interesting but they'll both be way better than stock.

 

[volkinator]

Long vs short some say the long tubes are better for high-end power while the short tubes have more low-end response but it depends on what article you read, some actually say the opposite. The tube diameter seems to make a larger difference in performance.

The biggest difference, specific to our application, is that the DT short tube headers don't have a flange welded to them, which means you can add cats to them but you have to make a jig and get them welded in the correct position to match up to the factory piping. These new long tubes travel all the way to the flanges, deleting the cats, so these are purely 'bolt on'. No need to pay a welder or spend a bunch of time getting it set up.

Dyno numbers between the two might be interesting but they'll both be way better than stock.

Thanks for the clear response! Super helpful and definitely makes the decision easier for the future. MN doesn't do inspections, so I'm guessing I'd be fine without the cats

 

[Inv4drZm]

Thanks for the clear response! Super helpful and definitely makes the decision easier for the future. MN doesn't do inspections, so I'm guessing I'd be fine without the cats

I think even with cats welded on it still wouldn't pass inspections but I could be wrong, others can chime in if I am. Not that it matters in your scenario. It seems like these new headers make the old ones 'obsolete' unless the dyno graphs vary greatly.

 

[That_Titanium_4RNR]

I think even with cats welded on it still wouldn't pass inspections but I could be wrong, others can chime in if I am. Not that it matters in your scenario. It seems like these new headers make the old ones 'obsolete' unless the dyno graphs vary greatly.

what makes you think that the shorties with correct cats wouldn't pass inspection?? I am in NC and they currently still do emissions testing and I was planning on running shorties with cats welded on and stock y-pipe

 

[blackoutt]

If they made a bolt on shorty and bolt on long tube I'd go with the shorty based on anecdotal internet debates for more torque as mentioned. I'm guessing that the butt dyno will show so much improvements with both that no one will care but I would also be interested to see the difference in real dyno numbers. My shortys were welded on with no cats anyway.

 

[Inv4drZm]

what makes you think that the shorties with correct cats wouldn't pass inspection?? I am in NC and they currently still do emissions testing and I was planning on running shorties with cats welded on and stock y-pipe

I'm not an expert on that but I know the headers aren't CARB legal. Maybe it would work if you welded in stock cats but I don't know for sure.

They talk about it a little on this page:

05-09 4.7L Doug Thorley Headers, group buy

 

[4RunnerAquasport]

Those look nice. I'm praying to the 4Runner gods that it works well with a body lift.

Yea I have the 1" RB lift, but my biggest problem is the tower gussets. Might have to pull the 4.7 just to access the old manifold bolts. Didn't think that one through :doh:. Going w the Y pipe for now.

 

[sumday]

what makes you think that the shorties with correct cats wouldn't pass inspection?? I am in NC and they currently still do emissions testing and I was planning on running shorties with cats welded on and stock y-pipe

long tube headers with factory y-pipe cats or aftermarket y-pipe cats (without restricted crimped tubing) would allow for no welding. however by adding o2 sensor bungs after the cats can it be made to keep the cel off?!?!

 

[That_Titanium_4RNR]

long tube headers with factory y-pipe cats or aftermarket y-pipe cats (without restricted crimped tubing) would allow for no welding. however by adding o2 sensor bungs after the cats can it be made to keep the cel off?!?!

It still wouldnt pass visual inspection if you ran the long pipes though. But to answer your question, yes. There are a few ways to keep the cel off. I didn't want to have to do any of that though. I just want a solution that allows me to get better performance while also fixing the exhaust leak. I also want to make sure that my modifications are not subject to any prying questions by an inspection tech or a cop if for some reason I get pulled over.

 

[Ed_C]

what makes you think that the shorties with correct cats wouldn't pass inspection?? I am in NC and they currently still do emissions testing and I was planning on running shorties with cats welded on and stock y-pipe

It appears NC doesn't look for CARB EO numbers on aftermarket replacement exhaust manifolds/cats like in California,New York,and recently Maine. Magnaflow and Walker do sell EPA-legal weld-on cats to replace the manifold-connected ones. They also offer replacement Y-pipes with the converter, but it appears Magnaflow's version has the better Y-pipe design, the "Y" itself is the same ones sell separately and use on their performance exhausts, plus the bends look a lot smoother than the OEM and Walker ones.

The 2003-2004 Magnaflow Y is shown in this thread Worst Y-pipe Design ever - 2003 V8 4runner

 

[sumday]

where i live they dont look, only plug in. since i have an 03 i will have to buy 05+ y-pipe with both cats, add and plug bungs, and possibly buy o2 harness extenders

 

[atalarico]

I'm still not seeing the MPG increase after my headers were put in over a week ago. It actually went down, but that was because my recently replaced steering rack was coming loose! After that was re-torqued it went back to what it was before the headers were put on.

Anyone else have this experience or am I the odd one out?