jchappies

What needs to be done to make ZO6 manifold and mid-pipe and /or H pipe to work on an LS3 auto and how much time do you think it will take to do? I also have a Borla ATAK on my Vette now that i want to keep so i realize i need to go from 3in to 2.5in at some point in the exhaust.

VetteofSD

It will bolt right up. I'm in almost the exact same boat as you. LS2 auto. Have Z06 all the way back. Only difference is the 2.5 over axle pipe and muffler mod. Install is no different. I installed mine in less than a few hours with a friend. Having a helper is nice when trying to get the manifolds and cats on. If you're not careful you can catch the spark plugs. You'll need to keep the 2.5 over the auto trans. Some people got the 3" all the way back. I tried and gave up! just neck it down at either the end of the mid-pipe or just before the middle spring mount. I did just before the spring mount and used some quality clamps to make the alignment easier. A two piece mid-pipe is nice if you're doing work elsewhere.. As always, be sure to disconnect the battery since you'll be working right next to the starter. You'll also need O2 harness extensions so the sensors can reach the new mounting points. Some will tell you that you can unwrap the wiring harness a bit, but it's honestly not worth fighting when the harnesses are only like $50. Good luck!

jchappies

Do i need extensions for all 4 or just the fronts? and how long do the extensions need to be?

VetteofSD

No just the fronts. Just went back and double-checked. I got two O2 Sensor extension cables 24" for $29 on eBay. Assuming these are take-offs like mine were, I replaced the gaskets too since I was down there. They came with them, but figured why not put on new ones. Got all of them for ~$40 as well.

Mike's LS3

For an auto to retain existing mufflers just add reducers from the end of the 3" mid pipe to 2 1/2" before the mufflers. You will need two 02 extensions and I would have it tuned to maximize the performance.

jchappies

do you know if i can buy reducers or is it something that has to be made at an exhaust shop

jchappies

also do you get exhaust manifold gaskets for and LS3 or LS7?

parad1mg

What I did on my install (LS2):

- Z06 OEM manifold gaskets
- two 24" O2 extensions (amazon) for front sensors
- 3" to 2.5" reducer to 2.5" 6" pipe ( I mocked everything up, then welded the reducer assembly to the Z06 h-pipe) I bought the same clamp type from the stock 2.5" midpipe and welded that on to the end of the 6" pipe.

Took me a day to complete all of it. I also replaced the spark plugs and wires on mine (one wire was frayed).

I do not have a lift, all was done in my garage with jack stands and a 3ton HF low profile jack.

The headers went out very easily from the bottom. Installation was just reverse of how I took it out.

I have a stock of metric bolts (JIS 10.5) which I used on some of the stock flanges.

I used ratchet straps to pull sections of the exhaust apart when taking them off the car. I have an injured wrist and still going thru physical therapy so I can't bear down on it with brute force.

You can do it! We'll be here if you get stuck

OneBadLT123

Genuinely curious....

What would be the point of doing this mod, and sourcing these parts when you can buy long tube's + Xpipe and have a lot more noticeable gains for the amount of money + time in labor involved?

Just to say you have Z06 exhaust? I don't get it.

VetteofSD

In California, we cant have long tubes and such for smog reasons. The Z06 exhaust is the only smog legal "headers" you can use. Great gains and not bad price wise since they're usually take offs

jchappies

Do you have pics of the modification you had to do on the h pipe and axle back exhaust?

parad1mg

For Reference Only
No, I don't have any pics. I barely take any pictures of anything or anyone

Best I can do for you right now (See illustration attached).

I used a generic parts store aluminized steel parts for the reducer and straight section since I'm going to do a full 3" modification to my bi-mode mufflers.

My Z06 h-pipe is a 3.0".

The 2.5" OD straight section I bought is 18.0" un-cut. After mocking everything up, I believe I reduced the length to 13.0". Your mock-up and set-up may vary.

The reducer is welded to the sectioned 3.0" h-pipe.

The 2.5" straight pipe is welded on to the reducer/h-pipe assembly.

You need to create compression slits so that the clamp can compress the end of the straight pipe to the exhaust.

The OEM band clamps are from the stock 2.5" h-pipe and tack welded to the straight pipe section.

Hope this helps.

OneBadLT123

Oh wow I never even thought about you Cali guys. That makes total sense now. Thx for the explanation.

jchappies

Does anyone have the part numbers for all the exhaust gasket for the 7.0L Zo6?

jchappies

I took on this project because i had a bad cat so i ended up upgrading to ZO6 exhaust system on my LS3 base with A6.
It took me about 1.5hrs to remove the stock system and about 4hrs to install the ZO6 system all the way to the existing axle back exhaust. A second set of hands was very helpful in the installation of the ZO6 manifolds. A tip or trick that we learned is you need to bring the manifold up from the bottom and hold them just above the exhaust port until you bring the mid-pipes in then lower the manifold onto the mid-pipes. at this point you are able to get all 4 nuts started then you can attach the manifold to the head. Once the manifold is loosely mounted to the head you can attach your O2 sensors. 3 of the 8 mid-pipe nut are a little difficult to get to but a stubby ratcheting wrench helped a lot.
We had about another hour at the exhaust shop to modify the H pipe to go around the A6 then tie into the 2.5in Borla axle back exhaust. I had to rig up some soda cans to get it to the exhaust shop, not my best work but i only needed to go 2 miles.
Here are some pics of it finished