Pontiac G8 Forum banner
1 - 20 of 27 Posts

·
Registered
Joined
·
45 Posts
Discussion Starter · #1 ·
Just bought 1 7/8" kooks long tubes with x pipe and cats. I'm trying the stock axle back setup to see if the sound is good (and more quiet) than an aftermarket axle back. Any tips for an easy install?

Also bought a rotofab CAI and am currently looking for a tune. There's a local place here in Southern IL but I'm not savy with the tuning world. Any help would be great.
 

·
Registered
Joined
·
1,042 Posts
We installed an OBX system two weeks ago on ShoNuff's G8, and those are Kooks rip-offs, so the install should be very similar. They are a bit different than my ARH system, but it generally worked the same.

First off, get a front 02 extension, you'll need it for the driver's side, passenger side doesn't need it.

Jack up the car and put it on jack stands, fairly high. Unbolt the four bolts that hold the metal plate under the middle of the car that spans the tunnel. It's about midway back or so.

Pop the secondary 02 sensor connectors off of the transmission, then disconnect the connector to free the 02.

Unbolt the mufflers from the mid pipes, and unbolt the midpipes from the cats. Slip the mid pipes at the rear off of the rubber hangers, then slip it off the front ones at the tranny cross member. Remove the midpipes from under the car. The 02 sensors can then be easily removed out from under the car. Some WD 40 or equivelent may be helpful.

Remove the plug wires, remove the pinch bolt and slide the steering shaft up off of the rack, being sure not to turn the road wheels or steering wheel while this is undone.

It worked best for me to unplug the primary 02 sensors from the harness, but they are tricky to get to, up behind the heads. I was able to get to the passenger side from below, and the driver's side from above with another person supporting it with a tool (screwdriver or pliers) from under the car.

Unbolt the dipstick tube from the head and rotate it out of the way. In my experience with the Kooks style headers, it doesn't have to come out. Not so with '08 GTs and ARH headers.

You can upbolt the exhaust manifolds and drop them out the bottom with the cats attached. I left the spark plugs in up until this point. Now they can come out.

Remove the primary 02s from the manifolds, apply anti-seize and mount them in the headers. Do the same for the secondary 02s.

I started with the driver's side. We almost didn't have the car high enough, but the heat shield on the firewall gave just enough that we were able to wiggle it through the tight spot and into place. It was easiest with a guy below shoving the header up and a guy above pulling and securing it with a bolt loosely.

I just realized that this is probably way more than what you asked for. Sorry.

One thing that we just had to change recently was to remove the springs that they used to bolt the ball flanges together. I don't get that system. They were tightened so much that the springs were completely compressed, and the exhaust was still able to shift and then rattle. We pulled out the springs and tightened the clamps without them. The tail pipes stayed in place and stopped banging against the Camaro diff.
We also never got the cinch clamps to fully close, even after visiting a muffler shop and having them snug them down. Hopefully Kooks has this part more accurate than the OBX copies.
We reused the stock manifold gaskets too, and they sealed up great.

Hopefully any of this dribble was helpfull.
Have fun.
 

·
Registered
Joined
·
45 Posts
Discussion Starter · #7 ·
Shane I'm in wood river IL, about ten minutes away. Ill be in touch

Ramjet that's perfect, thanks for the input. Now I have something to go back on and read step by step. luckily my neighbor has a nice new lift in his garage so I should have an easier time with it than I was expecting. As for an 02 extension, would a general car parts store have them or would you suggest ordering one online at Maryland Speed.
 

·
Registered
Joined
·
45 Posts
Discussion Starter · #9 ·
Thanks lptxz. Ill have to go get one.

I know there's hundred of exhaust threads but does anyone have an idea of an aftermarket axle back that's not as aggressive or somewhat quiet?
 

·
Registered
Joined
·
1,042 Posts
You bet! Yes, Maryland Speed, any of the vendors, or a guy that sells them on eBay (actually lives here in San Antonio). You'll have to zip-tie up the slack, but it's easy. The hard part is the connectors on the factory harness.

The dipstick tube will just bend over the #2 cylinder header pipe and bolt right back in place.

We did our best to make sure that the exhaust tubes were clear of everything, but within a week they were rattling against the flat metal brace and the Camaro diff. A little adjusting got it off of the diff, that and removing those dad-gum springs on the bolts, and a piece of scotchbrite wedged in between the exhaust and the brace hushed that. It isn't the most correct way, but for the time being it is working fine.
 

·
Registered
Joined
·
2,551 Posts
If headers are coated, get a tap to chase the threads on the O2 bungs in case some coating got in there. Actually, good practice even without coating.
 

·
Registered
Joined
·
45 Posts
Discussion Starter · #13 ·
They are coated so ill tap that out just for fun before the process starts. How long does the shipping usually take with them being coated at a different location? Like I said Im in southern Illinois, guessing it'll be awhile before I see them.
 

·
Registered
Joined
·
45 Posts
Discussion Starter · #14 ·
Just an update. RF cai is here and the x pipe back has arrived. Just waiting on the headers. I didn't get any hardware like bolts, nuts etc for the new system so I'm assuming I just use the Old stock bolts. Hopefully the headers will be here in the next week or so so I can get started.

Would anyone recommend a handheld or would you rather stick with a shop or person tune for your car? I've seen the cortex tuners everywhere and some people love them and some people hate them. Seem to be cheaper than a dyno tune and work just as well. Any info will help!
 

·
Car RamRod
Joined
·
1,795 Posts
Seem to be cheaper than a dyno tune and work just as well. Any info will help!


If that were the case, no one would have dyno tunes. Cheaper, yes. Work as well...nope.

I had VMS remote tunes for years. they were good, as I could get updates for SMALL changes free. After the cam, they wanted more money. I'd already invested over $600, so decided to just go dyno. Much closer tune, and a good tuner can adjust for small changes and fine tune the driveability.
As to your axle back question, you are going to do the research on this one. Check out youtube for clips of G8 exhausts. Find one you can live with. Many of us have tried several setups. I'm about to try my 4th one next weekend. You may like a set of turbo muffs...deep, and somewhat subdued. Nice idle. WOT does not scream.
 

·
Registered
Joined
·
45 Posts
Discussion Starter · #16 ·
Thanks Todd, guess you're right. Ill go with a dyno then. I'm gonna see how the stock ones sound and hopefully ill like them enough to keep it. I have been looking on YouTube and everything seems too loud. Id like to not wake the neighbors when I leave at 4am for work and them burn my house down before I get back.
 

·
Registered
Joined
·
45 Posts
Discussion Starter · #18 ·
I PM'd shane. Seems like a good guy and ill be going with him. So pumped to get it all done and see the results. Ill keep everyone posted, and ill most likely be asking more questions later lol.
 

·
Registered
Joined
·
786 Posts
I wanted a tame setup after longtubes as well. I have pacesetter longtubes with high flow cats, stock mid muffler, and stock axlebacks. Its way to quiet it sounds the same as it did stock unless I get on it but then you really only hear the engine more.

I got a magnaflow x pipe and some hooker custom axlebacks waiting to be installed. Wont be too loud but will sound deep and the way a 6.0L V8 should.
 

·
Registered
Joined
·
45 Posts
Discussion Starter · #20 ·
I'd love to have it quiet until WOT. I want people to think its stock haha. But ill see how the stocks sound. The tips are junk though, the finish is coming off from the previous owner not taking care of them. I like the slp tips, but Im not sure if the slp system will be too Much. We will see and go from there!
 
1 - 20 of 27 Posts
Top