After reading this, I'm putting off my decision to go in on that GP for the FLP headers. I don't have a lot of time to work on the car and wouldn't want to be doing that by myself anyway.

As far as the banging of the x-pipe mentioned above, that is probably due to the x-pipe hitting the extended metal tab on the shroud for the fuel tank. With only 1/8" or 1/4" clearance, they will make contact on bumps or wheel-hopping, etc. I had the same problem and it went totally away after bending the tab back.

 

Hi CapeCodCoupe,

Yes there are two sizes of clamps with the larger clamp connecting the header to the cat and the smaller clamp connecting the aft end of the cat to the exhaust pipe which is pretty obvious. What I was talking about with the flanges is I think they would have a better seal and/or connection if they were the same size. The Flange on the forward end of the cat is slightly smaller than the flange on the collector end of the header and the flange on the exhaust pipe is slightly smaller than the flange on the aft end of the cat to where it mates together. These "V" type clamps are used quite a bit on commercial aircraft on pneumatic ducts and both mating flanges are always the same size to have more of a precise fit and better seal. When you mate the flanges together and install the V clamp, you will see that the cat flange can "float" around inside the clamp until its tight, and the same goes for the aft end of the cat where it mates to the exhaust pipe. Its no big deal really, mine seal just fine as im sure yours will as well. Im just being a little picky. The setup works, I just think that part could be better.

Now with the O2 wires. There are 4 O2 sensors, 2 in the headers and 2 in the pipes aft of the cats. There wasnt a problem with the forward 2 sensors with wire length. The aft 2 sensors ended up being a little too short of length.
When youre under the car, the aft O2 wires go along the side of the heat shroud and are held in place with these tight little clips. I pulled all of the clips off with some needle nose pliers and then disconnected the plug on the frame for both aft O2 sensors and then just let both wiring harnesses hang. Then after unbolting the exhaust pipes from the car, I pulled the entire assembly out from under the car. Then take the O2 sensors out and put them into the new pipes and slide the new assembly under the car, bolt it up to the mufflers and then to the headers. Then take the O2 harness and just tuck the wiring back along the side of the heat shroud using the same tight clips going forward to the plug. You will find that it wont reach the plug where its attached to the frame with a little plastic push-in piece, at least it didnt on mine, so now just take a small screwdriver and pry the little plastic piece away and the plug will slide off of it, then just connect it to the O2 harness and then use tie wraps to secure wiring in place to keep it off the headers.

With tightening the V clamps I used a ratchet. I dont think using a nutdriver will allow you to get it tight enough for a good seal. Using a 1/4 drive ratchet for many small items will usually prevent you from over tightening if youre worried about that, although I used a 3/8 drive ratchet for everything under the car and a 1/4 and 3/8 drive air ratchets for taking the exhaust manifolds, coil packs, and valve covers. Air tools will help you tremendously in taking those exhaust manifolds off, otherwise you will be there for a while and probably will have a few sore knuckles.

Hope all this helps, if you need any help feel free to email me. Check out this link if you havent seen it already.

http://www.stl-vettes.com/Headers/Header_Install.asp

to add a few things to this list, when putting the passenger side header in from the top i couldnt get it to clear the starter, so i pulled the 2 starter bolts out just to let the starter move around to get the welded bracket past it.. After getting the header in and loosely installed, put the 2 bolts back into the starter first and then position starter in place and then tighten the bolts. also remove the alternator and move it forward out of the way so you can get the driver side exhaust manifold out from the top. Dont take the wires off the alternator, just take the belt off and the 2 bolts and move it out of the way. When removing the oil dipstick, make sure you pull the dipstick out first before pulling the tube out or you will bend the end of the dipstick.


[Modified by Av8ter, 4:27 AM 11/24/2002]

 

Thanks Av8ter. Great install tips. I plan on putting in the off road pipes until inspection time next June and I'm going to try to mate up to my Bassani X pipe already in place. how's the interior noise level now?

Great Forum! Is the search function gone? :flag ;)

 

The interior noise is slightly louder but sounds great. Not too loud and no too quiet. But i have a Z06 that had only the 2 cats, i think yours has the precats as well, and if thats the case your going to have a significant change in sound from what you used to have. Im very please with the sound and i can tell the engine breathes much better. The stock Z06 exhaust was great for the stock motor but it had wayyy too much back pressure and couldnt get rid of the air with the procharger. I was thinking about putting in the straight pipes instead of the cats but i didnt want it too loud and plus im getting it dyno tuned and didnt want the pipes to change the tune. The last dynotune a few days ago with the pulley i had on the procharger and stock exhaust i was getting 10 psi. Now after changing to the flp system, the psi has dropped to about 6 or 7 which means the enging breathes much better and gets rid of the exhaust more effeciently.

 

Joe - Tell us more about the "upgraded clamps." I wasn't aware that was an option. Mine seem to be sealing fine, but if there are even more robust clamps, I would change mine out. Thanks.
Alan :seeya

 

Alan, yes there are heavier clamps available. The clamping bolts are larger in diameter and the clamp heavier in design. They were not necessarily an option but a design mod to the system. As mine was one of the first 25, I had the earlier design...they too worked fine.
Joe