The search engine doesn't give me the answers I'm looking for, so I apologize if this has been discussed already.

I have an '04 Z06 that's stock other than Blackwing and GHL Magnum cat back. I have a GMPP aftermarket warranty and I want to add long tube headers, high flow cats and X pipe.

I realize it depends on the dealership, but most don't seem to have a problem with headers and cats, as long as they don't throw codes. So I'd like to hear from everyone who's installed headers that didn't throw codes.

Editing out codes or adding 02 sims isn't an option, as this will raise an eyebrow as far as the warranty is concerned. So I'm trying to have my cake and eat it too.

So if you're engine is stock other than the long tubes, high flow cats and X pipe, and you didn't throw codes after the install, please let me know which headers/cats/X pipe you installed. TIA

 

You may have a code thrown with high flow cats, and may not. It really just depends on your car, and what LT's you go with. Mine for instance, threw codes due to the cats, they just flow to well. I had Edit done to turn off the rear 02's.
It's really what your car and the high flow cats do when they are together. I know that's really not a great answer for you, but I really believe you won't know until after the install.
Hope this helps in some way.
Will

 

My 04 threw codes with just the Halltech Stinger as do many 04s. With the Longtubes it was worse. I got a tune at LG Motorsports and all is well. Get it tuned and don't worry about it.

 

Thanks Will. That's a good answer. Which headers and cats did you go with? I really don't want to spend the time and money just to put the stock exhaust back on.

Steve

 

Thanks for the info.

I haven't had a problem with my Blackwing setting codes, although I've heard of others who did.

Do you have LG headers?

When you say you got a tune and all is well, does that mean they turned off the 02 sensors, or they were able to tune it to get it to stop setting codes with the sensors enabled?

Let me try and explain again... I have an aftermarket warranty and I don't want to have to worry about getting turned down for warranty work, so it's important to me that the sensors remain enabled. That's the whole purpose of this thread. I'm trying to figure out if I can put headers on without setting codes and having to pull them back off again. If enough of you respond and say I can't do that, because your headers set codes, then I'll forget about it. The warranty is way more important to me than an additional 25 rwhp. However, if there are certain brands of headers that don't seem as prone to setting codes, then maybe I'll try those. That's why I'm interested in which brand of headers everyone is using, and whether or not they set codes

 

I have LGLT headers on my 04 Z and it never threw a code, but before I did the headers I installed a Halltech Stinger and air bridge and this install did bring up lean codes, I did the air box under the shroud mod as instructed by the guy's on the forum and that took care of the lean code, after the header install I took it up to A & A to have Charlie do one of his super tunes and it's never brought up a code since.

Do your header install, you will be amazed on how much just these two mods made, after the tune it dynoed at 388.6 HP and 375 TQ and has a much crisper throttle responce. This car will just eat C6's alive

 

Thanks for the info RoHo.

I hate to keep asking this, but did he program it to ignore the sensors or tune it so it doesn't set codes?

Steve

 

I have kooks w/ cats and after a year w/o codes it started throwing codes for the cats. They flow too much and the car senses that as an issue. I had mine tuned out and no codes for the cats at all since.

 

Steve,
I put Supermaxx LT's in mine. The biggest problem is that all our cars are different. For instance, my car ran really lean in the upper rpm's, but way rich down low. Every car is different there, some are great from the factory and some aren't. Some will accept the new high flow cats, and some won't. My LT's did lean the car out more but not enuff to throw a code which surprised me. Dyno tuning brought mine back into line. I know what you're asking, but I'm not sure I've seen that type of consistency with any one brand. A search may be helpful but I imagine you would have to be so general in the search that it would bring up alot of info to go over.
My recommendation would be, that after you get an idea of which ones you want. Put them on, but have a back up plan for the cats atleast. Put together a plan to run stock cats behind the headers. Of course you will require the help of an exhaust shop unless you can do that work yourself. With what I've seen, the high flow cats cause the most codes. (Some may not agree, just what I've seen here and in life)
Now, the biggest problem will be if the LT's lean out the car to much and cause a code to be thrown themselves. Again, from what I've seen, this does not happen alot at all.
The only issue you may want to think about is this. Although you may not throw a code, you may lean the car out so much that it just always runs lean. Just food for thought I suppose. Have you dynoed your car to see your A/F ratio? If lean already, I would discuss here and with your dyno guy, (preferably someone who dyno tunes) what Lt's might do for you.
I know this seems complicated, but with your standards it kinda puts you in a spot. If you see what I'm saying. Hope this helps.
Will

 

Steve, they are two different things. Atleast I think that's what you are asking here. You can only shut off the rear O2's when they set off codes. The tuning of the car will only be needed if your LT's themselves run the car to lean. You're actually talking about two different codes being set off.
1. (The most common) The cats flow to well. They must be turned off through a tuning program, or run sims.
2. (The least common) The LT's run the car so lean it sets off a code that way. Only cure is to tune the car. No turning anything off or simming.
The 04 C5's induction systems seemed to set alot of cars way to lean. That would be a tuning issue although some have found small ways to correct the problem. I imagine the car still runs lean to an extent though. The type of lean he is referring to though, is a tuning problem.
Sorry if this isn't what you were looking for here, but it's what I thought you were asking.
Will

 

Hey Will, (and everyone) thanks a million for your comments.

I think I'm screwed. A friend just reminded me that I'll have to have a tune with headers to get the most from them, and that's where the problem with the dealership comes in. If they re-flash the PCM to the stock tune and it sets codes, then they have a bitch. So it looks like I can't have my cake and eat it too. I guess I'll have to think about it more and decide what's more important to me - the warranty or more fun.

Thanks again for the info.

Steve

 

Buy LS1_edit and tune it yourself. Then if the dealer reflashes your PCM for any reason (which is very rare anyways) you can just upload your tune again.

I bought LS1_edit already because I plan on adding mods and I want to tune for them myself.

I also have a GMPP extended warranty, but my chevy dealer doesnt discriminate agains mods.

 

I have kooks with their hi-flo cats. My car threw 420&430 which is cats inefficient in both banks. No big deal, you just turn off the light for those two codes with HPTuners or whatever you or your tuner uses.

 

Mine threw codes because I did not have rear O2s and also codes for Slow O2 sensor response when its cold. Just got the car tuned and codes deleted. Now I can have them scan the computer and still get an inspection sticker without a problem.

 

no big deal!

 

My 01 Threw a few codes. Was saying that the cats where not working properly. A tune at CAM last weekend removed the check engine light and picked me up 30 rear wheel horsepower. What a differnece a tune made.

 

Mine occasionally throws a code (I believe it's 1135) for slow rear O2 sensor switching. I'm thinking about getting the rear sensors taken out in the tune or buying O2 sims.

 

Just make sure you do your mods and then get it tuned, once this is done you won't see any more codes