02 Z06 H Pipe on 02 A4 - Any Issues - C4C5 Specialist?

[electronblue02]

To upgrade an 02 A4 car with an 02 Z06 H-pipe (no pup cats), aside from new doughnut and muffler gaskets, the swap looks pretty straighforward.

But..wanted to ask if there are any issues to consider, i.e. 02 sensors and/or tuning that may be needed.

My car is mostly stock, only mods are Z06 TI mufflers, Z06 airbox and Hypertech PP..used only for shift points and fan temps.

Having read posts about 02 codes from RT cats etc, I don't want to go there. Can anyone who has done this mod confirm that this is just a bolt in?

Thanks,
Erik

 

[c4c5specialist]

Hi there,
You will need the exhaust manifolds as well.
The angles of the flanges are different due to the pup cats.
Allthebest, c4c5

 

[electronblue02]

C4C5,

Thanks for the reply, your response threw me in a new direction.

I subsequently checked with 2 dealers who both stated that the part numbers for LS1 and LS6 exhaust manifolds are the same for years 2001 - 2004. Ditto for 02 sensors, which was my other worry.

They both said that exhaust manifold part number LH is 12561255 and RH is 12561256.

Thaought I'd run this past you once more before spinning any wrenches.

Thanks in advance, and Happy New Year.

 

[c4c5specialist]

HI there,
This is fresh information.
They have since changed the replacement manifolds to all cast iron.
I stand corrected.
Thank you for the information, and have a good day.
Allthebest, c4c5

 

[Mike Mercury]

if all you long for is no pre-cats, then you can "gut" them yourself on your current H pipe... and it costs nothing.

DIY link below:
mikemercury.home.att.net/precats.htm


.

 

[electronblue02]

Installed it today, simple bolt on, took about 2 hours.

The car runs super, it now sounds like a Z06, or pretty close to it, and has demonstrated no adverse drivability issues at all. Pushed it a bit after driving about 50 miles, and there is definitely a stronger top end charge above 4500 RPM.

Mike, I found an 02 Z06 H Pipe with 2100 miles for $300, intent is to keep all the stock pieces intact for trade in time or the next owner in a few years, and gutting the pre-cats would likely create some turbulence due to the wider opening of where the pre-cat was IMHO. Besides, the Z06 cats are designed to be emission legal w/o pre-cat, and also flow better than the LS1 cats without the pre-cats, or so GM says.

This is a recommended mod!

Thanks again for the feedback.