Hey guys I'm looking into getting a pair of test pipes for my 07. My question is this, would it be possible to unbolt the headers from the block and unbolt the end of the cat from the main exhaust and take the header/cat off together? If it is possible, I might look into buying Stillen Headers along with some test pipes so that I can replace the stock combo, with this new combo so that intern, I wont have to worry about stripping the bolts connecting the stock cat to the stock header which intern would allow me to switch to stock config for smogging.

 

You should be able to take them out like that, might require some muscle and or removing other stuff to actually slide the parts out. If you Strip and/or break the cat bolts its not that big a deal to replace them once the pieces are out of the car.

 

Awesome good to know. Knowing that the cat bolts wont be a big deal, will taking out the 02 sensors be manageable with good tools and luxuries like a breaker bar and bolt grease in a garage? I really do not want to have to worry about buying replacement 02 sensors in consequence of replacing my cats..

 

I don't know about your Z, but my 08 with 8K miles was PITA to remove the stock cats and o2 sensors.

The installer broke 2 bolts on the cats and stripped both o2 sensors. Now I'm selling the Berk HFCs because I couldn't use the stock o2 sensors and don't want to spend another $250 for the new o2 sensors. Would a different outcome if he had use PB blaster or WD-40.

 

That's the scenario that is holding me back from making this purchase. I don't want to go into this knowing that this predicament is only waiting for me.. Is there a common strategy to go about this removal/install that has shown problem free results?

 

Oh, it's a pain in the *** alright. The easiest way to get the headers out is to unbolt the motor from the mounts and lift it, allowing easier access to the headers. The easiest way I've found to remove the cats is to heat the bolts with a torch and break them loose quickly while the bolt is still red hot. If you're going into this project thinking it's going to be a piece of cake, then you're better off staying stock, because it most certainly isn't easy.

 

It's going to be damn near impossible to get the stock manifold off with the cats. I just did mine and it's like ten extra minutes to unbolt everything. Just spray it with some WD-40 and come back in a half hour. And as far as the headers go. You have to drain the radiator and remove the coolant hardpipe on the passenger side to get all the bolts off. It won't be something that you will want to do over and over again every year. Promise.

ALSO, here's a complete walk-through: https://my350z.com/forum/engine-driv...tallation.html

P.S. I've still got open wounds from my install 3 weeks ago

 

I removed my headers with the cats bolted to them. They sit in my attic just like that to this day.

 

Agree. Possible but not wise. It is more work yes, but remove the catalytic converter first. Get them out of the way, and you will have more room to work with the exhaust manifold.

 

There are lots of exhaust manifold remove threads here. You are not the first.

 

Great thanks for the info guys, much appreciated!

 

removing the stocks cats/installing test pipes was a huge challenge for me. I went into the job thinking it was going to be a piece of cake, but ended up expending about 4 hours over 2 days with the install (this was my first time doing this install). As far as removing the o2 sensors from the stock cats, i went to my local advanced auto parts store and rented an o2 removal kit. also, i hit the sensors with pb blaster prior to removal and let them sit for a while. lastly, now that i have experience, i can probably do this job again in an hour and a half. fyi, i did this on my 2003 g coupe, but it's the exact set up as the same year z.

i referred to these diy guides for help.

http://www.350zmotoring.com/forums/g...tallation.html
http://g35driver.com/forums/intake-e...est-pipes.html

as i look back, i'm very happy with the final product. i love the new sound and my car never got the dreaded cel. only draw back is the gas smell that creeps into the car when sitting at a stop.

 

Cubs great info! Unfortunately for me and the rest of the HR community, the stock cats on the HR have been prone to having over-tightened flange bolts that more often than not, have to be cranked off with destructive results to the bolts. However, I will still take the same approach to taken them off as you described in your post. Patience, wd40/pb blaster, and brute force seems to be the way to attack this. I did not know about the o2 removal kit so will definitely be looking into this. Again thanks for the info, I know its a tedious thing to reply to but I'm just trying to get some good, direct input. BTW how do you guys think GTM test pipes matched with my Greddy Evo-TT will sound? Saw the GTM tp's on their site for a rather reasonable price and I just figured, its GTM, has to be good!

 

i am very surprised to hear anyone say they have done it like this and i am very curious to know if they came out from the bottom because i just dont see how that is possible but if it has been done i guess it has to be..honestly think it would be easier to take the cat/test pipes off first then do the headers

 

Agreed Tyler, I just though that if it was not too much more difficult to take them off together, it would allow me to switch back and forth and thus not resulting in destroying the bolts from the cat to the header. As I now know, it's just not worth the trouble to do this and my best bet is to do as you have said, piece by piece.

 

If you have access to a lift Its not that bad. I had the radiator out at the time because I was trying to install my Stillen crank pulley but I had no way of holding the flywheel at the time. So that never did get installed. But they can be removed from the bottom.

 

Have you considered a long header setup? True PITA to install though, but then again they all are, long and short.

 

I figured the same but was at Zcargarage recently and one of the guys mentioned the Tomei's long tubes on the Gabe's G35 were "easier" to install than the shortys.

 

Yeah the ones his car are individual (per cylinder) and you can slip in the tight places a little easier.

 

If you have access to a breaker bar removing the cats isnt near as hard as its made out to be. I went in expecting the worst after reading on the forums and found it to be no worse then removing any other bolt thats been installed since the car was brought off the line.

Iv seen a DIY on taking the headers out without lifting the engine but it looks hard as hell to do.