Doug Thorley Y Pipe , Long Tube Headers, and URD 02 Sim install tips

[lonelydriver]

Just got done partially installing the y pipe and headers.
I was looking for some install tips before and couldn't find any so I thought I'd jot some down, to help the next poor guy to install these.


1.PB Blaster is your friend. and wear goggles as crap will fall in ur eyes when ur under the rig.

2. Make sure you get a 02 sensor socket, you can rent them for free at autozone. I tried using a crescent wrench and boogered up the edges and stopped before I made it worse. The 02 sensors are REALLY stuck on there, and they are expensive so take your time here and use the right tools.

2.Y pipe removal was fairly straight forward. On the driver side above the catalytic converter is this rainbow shaped brace that arcs over the Cat. I had to remove this to get the Y Pipe out.


3. Removing the headers, remove the y pipe first, and undo the bolts on the bottom side of the manifold(feel around, helps if you have long skinny monkey arms, if not wear long sleeves as my arms are all scratched up from the various sharp edges in the vicinity ), and then do the top bolts. Un plug the 02 sensor near the top of the tranny ( I had an easier time accessing this from underneath the rig) and then proceed to undo the bolts at the collector and then finally the last support bolt that attaches to the frame. On the driver side, I had a hard time dislodging the exhaust manifold as the support brace was blocking it, I undid one of the bolts that attached the support frame to the chassis and manged to wiggle it out.

4. URD 02 sim,
The instructions for the 02 sim install are pretty good. You need to actually cut 2 ecu wires and connect them to the wires off the 02 sim, and tap into another 2 wires a total of 6 wires I believe, so for those worried about warranty issues or are not sure about cutting ecu wires, this may not be for you, and you may want to pay extra and go for the plug and play kits.


Currently I have the 02 sim installed, and the stock stuff out, and need to go rent the 02 sensor remover from autozone to finish up.

Some pics measuring the pipe diameters for comparison between the Doug thorleys and OEM. Hopefully this will help people decide if they feel like the Doug Thorleys are worth it.

Where the headers meet the block



The collectors



Y pipe side that connects to collectors



Y pipe width








The stock y pipe has this really terrible choke point, that will only get more crushed while wheeling, unless you have skids.



02 sim



Will update with my impressions when I finish the installation, may take a few days as I won't have time to work on it till the end of the week.

[layonnn]

Good stuff lonelydriver.

I talked to URD the other day, and they said that there are 1 time use gasket between all the mounts and one big one at where the y-pipe meets up with the intermediate pipe (i believe it can be seen in your 8th picture, i transferred it over to the new ypipe).
URD said they will have these gaskets on the site soon. Just a heads up.

[lonelydriver]

Thanks for the heads up, Don't think it'll be too hard to replace the 3 gaskets.... But i'm sure not looking forward to removing all this stuff again for smog.. good thing its a few years away.

[FJCcrawler]

Thanks for the tips, good info to know. BTW Sweet headers and y-pipe!!!

[majorMarvin]

I dreamt of that system for my Tacoma but since traded it on my FJ..... I bet it sounds awesome and also opens up the top end of our 4.0's.....

[lonelydriver]

update: Note i have an automatic.

Got everything on, and got a check engine light for the passenger side a/f ratio sensor... great. 200 bucks and thanks to trdsource, I had the parts next day, and back on the rig.


Even with the 02 sensor wrench, the a/f sensor took a beating. It actually snapped the 02 sensor wrench in half, and luckily I had a back up. I am not looking forward to when I will have to reinstall the stock stuff.


With all the check engine lights gone, I took it out for a drive. Disclaimer, the below is all subjective and my OPINIONS from the butt dyno.

Power

Noticable loss in the initial lower end. I was quite dissapointed with this and should have known better, after looking at the dyno sheets.

However, the car quickly picks up and I can feel an improvement in acceleration. After I put on all the armor and gear on my car, it felt sluggish compared to stock, but after these mods, it feels a lot less portly. On the highway, without dropping a gear, the car is much more responsive.

Sound

This is hard for me to describe. It sounds deeper, but has a Rasp in the mid to higher RPMS. Not sure if this is from the Y pipe or the headers. I've heard if you swap the muffler to a magnaflow, the rasp goes away according to some on the taco forums. When the engine is lugging, higher gear low rpms, I hear what seems like a clanking kind of sound. I've heard this before the headers and y pipe, and feel like this just made the sound noticable. Anyone else get this?

Overall, the sound is not too loud or annoying, but the clanking sound is not very pleasing, and sounds like something is wrong with the rig.


Overall impression,

I think if you are spending most of your time rock crawling, this mod is not worth it, as u lose low end torque,

If you are more into higher speed baja kinda stuff, I'd say it's definitely worth it.

I'm gonna see if my mpg's improved or not, and may end up removing the headers and y Pipe if it's not much better.

[Ti Tank]

Keep us posted. Im interested in the Y pipe and losing 2 cats.