First I want to thank this site for the valuable information being given so freely and especially to Bert for his detailed install with pictures during his ARH install and taking the time to email me and making sure I was okay with additional information.

Also want to thank Branden owner of MarylandSpeed for helping with the purchase and delivery of my headers. Just want people to know living in Hawaii is terrible when trying to buy parts. Branden 2nd day aired my headers to me and then I discovered (on the Saturday before Christmas) that the hardware box was for a C5 (no way anyone at MarylandSpeed would have known). I contacted Brendan and he overnighted me the hardware and I got it on Christmas eve, now that is service.

To those that are going to do their own install, do what I did and search the forum and ask questions the knowledgeable members here are here because they want to help.

Due to all of the information from Jacking to the hints on the O2 sensors and the installation it was a smooth job. I took my time and the only difficulty I ran into was the installation of my Off Road pipes and X-pipe. I pre-assembled the parts and tried to install it as one piece but the alignment was slightly off and no matter how much I tried I could not get them to slip into my Borla Stingers. I disassembled the pipes and then installed the reducer (3" to 2.5") pipes individually onto the Borla Stinger tail pipes which went in easily. I then slipped in the X-pipe into the mid-pipes after a brief struggle and made sure the alignment was correct. I was then able to bolt the header flange to the X-pipe and then tightened everything up and then did a re-check.

I want to tell those who will be doing an install to find, make or buy some clips to hold the rear O2 sensor wires up in the transmission tunnel. Luckily I found two clips which worked out very well. Sorry wish I had taken pictures, those clips were from my Viper and they appeared to have been made for the O2 sensors.

Helpful hint on the header gaskets I used these new Carbon Fiber gaskets however the OEM GM gaskets are about the best as they are triple layered. Prior to putting the headers in notch the two outside bolt holes so that you can slip the gaskets in after you initially bolt the headers on with the two outside bolts. This makes things so much easier then trying to hold the gasket in place while trying to do the initial bolt up.

I also need to thank the members who hang out in the Scan and Tune section and especially Mike from Predator. Immediately after doing the install I hooked the Predator up and installed the header modified tune and turned off my rear O2 sensors as I am without cats (which is not illegal in Hawaii).

I started up the car and everyone was right the car smokes so make sure the garage is well ventilated What a sound and the real test the performance, with the Kooks 1 7/8" Off Road and X-pipes along with the new modified tune the car is a beast and works well with my other mods. My A6 C6 never did this before but it spun the tires in 2nd and no snaps my neck when I hit the paddles.

Drawback just one: Very loud drone at 1600 rpms and only at 1600 rpms once I clear that it disappears and the Borla Stingers scream.

I went with the bigger set-up 1 7/8 " with 3" collector for my down the road mods and I thought I would suffer some power and torque lost at the present. If there is any lost which should have been on the low-end I surely didn't feel it and the car just accelerates and I now shift at 6500 rpms and the car leaps forward.

Sorry for the long write up, but as you can tell I am one happy Vette owner.

So again Mahalo Nui Loa (Thank you Very Much) and Hauoli Makahiki Hou (Happy New Year).

 

Congratulations, Gary.

The smoke from the new headers goes away after a short drive. With both garage doors open that still stunk up my garage pretty good when I first fired mine up. The amount of smoke is pretty impressive, even if you are expecting it!

I too noticed some unpleasant cabin noise at 1500 RPM but only under a decent amount of load -- like driving up a grade at 70mph in sixth gear. Downshifting or lifting off the throttle a little makes that go away.

Most of the other increased cabin noise sounds pretty good though! I am happy that my Vette is no longer Cadillac quiet and now it sounds more muscular.

 

Thanks for the write up. I am going to be doing LT's some time this winter and I also have the Diablo Predator. Since it does delete the rear 02 sensors, is it still necessary to run the wires for the rears? I'm going to be running cats with mine but the rears will still be turned off. Am I missing something? Thanks.

 

GismoZ,

Yes, you can turn off the rear O2 sensors. in the Predator just turn off COT.

So just install the O2 sensor to plug the bung hole you still need to tuck the wire away, I would not advise cutting them off as you may need to use them in the future.

Bret again thanks my friend, for the email with GM tech article. Any and all information helped.

 

Glad it all worked out for you. I really was tempted to fly out and hand deliver the new hardware box rather than overnighting it...sure would be much nice weather in HI.