i'm doing a build on a customers truck , and have a question for the "pros" or just people with some experiance with these headers .

I have some Thorley headers going on , and am redoing the crossover to dump on the L side .



Thorley dosnt use a "flex" joint ? I dont think this is such a good idea .. as obviously toyota put it there for a reason which we all know is "reasonable" . I'm going to install one on the crossover build anyway , but i'm just wondering if anyone has had any issues / problems with out one ?


also .. dosnt the front O2 sensor mount seem to be to close ? i'm using a wideband on this build , so I will have to modify it anyway , but from what I know it should be at least 24"'s from the manifold ?

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A flex pipe is a great idea! and yes that o2 port seems to be way to close.
Is that 3" pipe ??? Man I need to work in some headers on my swap.
Could you post a pic from the other side? It may be okay depending on how far that flange sticks out.

 

Doug thorley also make a set of headers that are long tube. These are a bit more expensive and aren't listed on their site. but if you call to ask, they have them.

 

it's 2 1/2 " . I picked up some mandrel 90* + a new flex section . I may end up cutting the drivers side header as well and change the direction of flow .

I should have just started from scratch ... hmmmmmm


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Those are sweet! I'm jealous. I just finished pulling my stock modified crossover off yesterday to intall the flex joint because it cracked where the pipes meet on the drivers side. This was not fun! had to drop the trans to get it off. I would install the flex pipe just in case so you can avoid problems later.

Here you can see where I welded and grinded the crack. I also wrapped the pipe w heat wrap but not completely. I read it causes it to get too hot so I left part of the pipe uncovered.

 

Slacker if you could make a good set of headers for the 3.4 swaped trucks. I would be very interested in a set.

 

^^^ i would be as well whenever i get around to the swap.

 

I have thought long and hard about this (since I built my Trekker) , and honestly , I dont know why nobody is doing it ? .. pretty sure we're going to be doing this in the VERY near future


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Just a thought but I have done 2 swaps with the crossover going under the trans. It all bolts and unbolds with trans in. Has anyone else tried this. It just makes good sence to me. I would post some pics but i cant figure this site out.

 

i'm not convince it works as well .. buddy has done that on his build , but I believe the o2 sensors and cat are to far back in the system to be as efficent as the are supose to be


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Make sure it can be used with the auto column shift so all the RV swappers will be happy Depending on price, I will be the first one at your door!!!

 

i am using a set of t 100/4runner obx headers and modifying them to crossover underneath, in front of the transmission pan, with flanges at three points for access. the obx headers are shorter and more compact than the thorleys shown on the drivers side. will post some pics when i get a chance.

 

I havent heard any good things about the OBX headers , so i would be interested to see fit and finish pics .
I personally dont know , I have never used or seen a set , so i'm curious


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so called Thorley .. and left a message . wonder if they'll call back ?

anyway .. I suspect the reason the flex joint isnt in there is because of "flow" , so hopefully , we'll see what they say


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well of course I never heard back from Thorley , I didnt really expect to !

anyway , I decided to add the flex joint anyway . I think the "trade off" will be negalable .
I dont want to double post , so you'll have to go here https://www.yotatech.com/forums/f209...-build-250286/ to see my work



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This mod says its okay to double post. Having a seperate crossover thread is a good idea as i'm sure your other thread will get cluttered with questions about it.

 

ok , here it is so far

little work on the crossover ..









just "tacked" together .. not sure i'm happy with it just yet



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ok .. so now with a few modifications to the pipe ( this is why we spot weld first) i'm VERY confidant it will fit .





and with the heat shield





I want to do an actual test fit .. just to be sure , and also build the header/ O2 pipe , before I send it off for ceramic coating ..
wont fit in my ovan !


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I would make sure you have that heat shield properly mounted. Otherwise it will wear out the insulation inside and rattle like crazy.

 

ohh for sure .. it's just sitting there for clearances right now


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