After "moving" the alternator out of the way I feel that I can see and feel a whole lot from underneath the car. So of course I start to take stuff apart before I dedicate myself to remove the upper part of my CAI, and my upper plenum of the intake manifold.
At this point, it really helps having finished the front side first (you know where all of the bolts, nuts, etc. are). From underneath the car, you can see a little less than half of the bolts that you know you have to take off in order to remove the stock manifold. But, if you squeeze your arm up there (on the driver's side of the exhaust manifold), you can feel them all. And, if you can get a finger or two on a bolt, you can get a 12 mm wrench on that bolt as well.
Here is where it is an advantage to have small hands, but a disadvantage to having short, stocky arms. I can get my fingers on the bolt, but I squeeze/scrape the hell out of my forearms trying to reach them.
Oh well... I have quite a few scrapes and patches of sore skin, but I was able to do everything from underneath the car and did not have to touch my CAI or upper intake manifold.
First, reach up and remove the 3 bolts holding the heat shield onto the manifold.
After removing the 3 bolts holding the heat shield in place I could not get the heat shield out of the engine bay. So, you kind of have to move it around and out of the way of whatever nut you are trying to loosen next.
After the heat shield, I removed both O2 sensors.
With the alternator and the heat shield out of the way I could loosen all 7 of the nuts holding on the manifold.
This is where patience becomes a virture, as you can only turn a wrench or ratchet about 1/16th of a turn at a time!! But, eventually I got all seven of the manifold nuts off.
Now that the manifold is free of the head, the heat shield can fall right out. (Watch out that it doesn't hit you in the face... :LaughHard: ) And the manifold will quickly follow...
*PITA, oh... I mean "Challenge"*
OK, three problems arose: the top middle, driver's side top, and driver's side bottom unscrewed with the entire threaded rod/nut assembly. (All the rest, including the front manifold, just the nut unscrewed from the head bolt, now 3 of the 7 nuts came off with the threaded rod they were bolted onto.) Now, I have a nut stuck on a threaded rod that is supposed to be attached to the cylinder head.
Here's a pic of my firewall-side cylinder bank with 3 missing head bolts.
After soaking the nuts in WD-40 and thinking for a while of how to break loose nuts seized onto a threaded rod without damaging the threads, my live-in girlfriend, out of the blue, suggests screwing them back into the head without a manifold or header so that the rod bottoms out in the head and the nut breaks free, and then the nut is "broken".
(You gotta love having a fellow experimental physicist as a girl friend...)
Low and behold, it worked beautifully and I broke the nuts loose from the threaded rod and got the rods to stay in the head at the same time. (It also took a little vice grip action on the non-threaded part to get the rod to stay in the head as I unscrewed the nut.)
Now, bolt up the new back header. Once again, patience is a virtue because you can tighten the nuts by about 1/16 of a turn at a time...
Once the back header is bolted on, install the pre-cat rear O2 sensor. Lube up the threads with anti-seize lube, but be VERY careful to never touch any part of the O2 sensor that sticks out past the threads (the oils from your fingers are not good for it...)
A good tip for installing the sensors is to twist the sensor about 5 or 6 turns counter-clockwise (as though you are unscrewing it). That way, when you screw it into the bung hole... :LaughHard:... (sorry, I just had too) the wires are not twisted or stressed.
Re-attach the alternator that you loosened earlier
Now reattach the serpentine belt (remember, you sketched out the belt path before...)
Connect the positive battery terminal back to the battery. (You should have disconnected it before moving the alternator.)
At this point, I think that I might have mentioned everything that needs to be reattached, retightened, etc. for anything that has been altered in the install process. But, I probably am forgeting something so keep paper or very good mental notes yourself of what you have done in the install so that you can "redo" it at the end.
OK, the only thing that should be left at this point is to attach the "Y" downpipe.
At this point I was so excited I just could not tighten the 6 bolts of the downpipe fast enough! ;D
But, once again, my philosophy is to stop and think about everything that you loosened, reattached, etc. to make sure there are no loose nuts or anything you forgot.
Here is an undercar shot of the finished install of my prototype OBX headers to my GReddy catback.
After this, my brother (whom I have to thank for much needed help for many critical steps in this install, as well as all of the great pics) and I took it out for a test drive... and..
WooHooo! Holy Sh!t! G@d d@mn!
Definitely the most satisfying mod I have done! My first mod, my CAI comes in a close second.
To close it off, here is a pic of my current engine compartment
Total install time
Day 1 3-1/2 hours: remove front manifold and install header
Day 2 2-1/2 hours: remove back manifold and reattach head bolts
Day 3 2 hours: install back header, down-pipe, and cleanup misc. other reattachment jobs
But the satisfaction of doing it all myself...
worth every penny and every second!
This second DIY was contributed by "KrAzzi"
Just another perspective with some different stuff. Using both DIY's is pretty much all anyone would need and would answer any questions they may have about this install.
Another DIY OBX Header Install