Hello , I am new to this so any help is greatly appreciated. I have installed a Lingefelter CAI and Borla exhaust with x pipe on my c6. I am seriously considering headers but I have some questions :

1) Can you use the stock cats with a headers system ?

2) Would it make a big difference to go ahead and get high flow cats with the headers ?

3) Will installing headers cause me to fail an emissions test ?

4) Will I have any problems hooking it to the Borla exhaust ?

5) I have read on some threads that a dyno tune is necessary to get the most out of the headers . Is it really necessary ? How do I find a place to do that ? ( I live in St.Louis ) .

6) I have also read on some threads that people are having a problem with the check engine light coming on after the headers / tune ? Can this be avoided ? Or what do I do if it comes on ?

Like I said I REALLY want to do this , I just dont know if the trouble is worth it. I dont want to have the Check engine light come on , I dont want to fail emmisions , and if a tune is necessary I dont know where to turn.

If any of you have any answers please let me know. Thanks in advance.

 

I'll try to answer a few of these. I recently had LG headers installed (with tune).

1) Can't use the stock cats.

2) I recommend getting the high-flow cats. I have them on mine. I believe Lingenfelter tested with and without high-flow cats and the gain was only 1-2 HP without them. Probably won't pass emissions without them.

3) I don't think that installing headers would cause you to fail emissions unless you have a visual check of sorts that doesn't allow them.

4) Shouldn't have any problems with the stock or aftermarket exhaust.

5) Definitely recommend a tune. I had one from MTI Racing and it was probably worth 25 HP. Just an estimate though. I didn't have with and without tune runs. I went from around 343-353 HP to 397 HP with LG headers, Honker intake, plug wires, 160 stat, and tune. TQ is also at 396. SIGNIFICANT difference in power from stock. Also, the tune will get rid of CAGS (and annoying light) and torque mgmt (I don't have specifics here though).

6) No CEL with proper tune.

Headers are definitely a great mod. They will benefit you even more as you add additional mods. I have stock exhaust. The stock exhaust is just pitiful, IMO. Headers will wake up the stock exhaust so that the sound is significantly different. It's still not loud enough, but it's much better after headers. You could probably do a mail-order tune if you don't have a tuner locally. Not ideal, but it would probably suffice.

 

Another factor is that with long tube headers you will probably get persistent engine lights and codes --- usually P0420 and P0430. These are cause by the cats and the O2 sensors being further back than the stock location. The cats don't heat up enough to be efficient.

This can also be corrected by a tune --- they just delete the codes. It should not affect your emissions testing, unless the code is still showing during the test.

 

The better solution is to ceramic coat the headers so the gases will still be hot when they reach the cats. Then they'll work as designed and you won't get any codes.

 

Since you are messing with the cars computer , wont a tune void your factory warranty ?

 

If you have a visual inspection during the emissions testing in your state then you WILL fail it. If the state goes by the CARB, then they will want to see your exemption paperwork. Since there are no headers for the C6 with an exemption, then they are gonna fail you. Probably not gonna be any exempted long tube headers in the future either as the EPA forbids tampering with the cats (except under recall or failure). Since our cats are on the manifold, you're not supposed to touch them, and long tube headers do... well, you get the idea.

If you have visual inspection, then you really have two options:
1. Don't get headers
2. Save the manifolds and throw those back on every time you need inspected. (note: car may run like crap if you do this because the car is gonna be tuned for LT headers)

 

I have Jet Hot ceramic coated headers, still got codes.

 

Virginia has visual inspection, and I have never failed an inspection due to headers, either with my 2004 C5 coupe or my '99 Camaro SS. I did fail on the '99 because the air pump was disconnected, so I just took it to another inspection station.

 

Missouri doesnt have a visual emmissions test. They hook a computerr to your cars computer and do some sort of reading. On older cars they hook a hose to your exhaust and test the actual emmissions.

I guess on newer cars they are testing the efficience thru the cars computer , I am not sure.

Anybody know if headers / tune will void the factory warranty ?

 

I have Dynotech headers with their high flow cats and NO codes.


I bet when they hook up to your computer they are just looking for codes, some dont always light the cel and keep it on.There is not much they can tell about your emissions output from looking at the computer other than codes and if everything is operating ok as in 02 sensors, etc...

Headers will be frowned upon at most if not all GM dealerships, you might find a mod friendly GM shop but they are few and far between. If your failure that you bring it into the shop resulted from more power than the factory power output like say the auto tranny goes you you pop the rear end I doubt they will cover it.

 

I'm sorry if this sounds stupid , but like I said I am new to this. When you say no codes , does that mean you did something with the tuning to eliminate them ?

It sounds like getting the headers is not that big of a deal , I am getting more concerned with the tuning part . For one I have no idea where to get that done anywhere close to St.louis.

Is it just a matter of finding a shop that has the capability to do it ? I guess what I am wondering is :

1) What all is involved with the actual tuning process ? Do they hook a computer to your car ? Or how is it accomplished ?

2) How in the world do you go about looking for a local person / shop to do it ?

Any ideas ?

 

My car is using stock tuning and I dont get any codes with the aftermarket exhaust system and headers with aftermarket cats.

1) They will flash a new tune in your computer usually done on a Dyno so they can see what its doing after each flash.

2) Post here! You can also do a mail order tune with a hand held programmer. There is tons of info about this and everything else you need to know. Find it by doing searhces on these forums.

 

Are you saying that it could be as easy as buying a handheld programmer and doing it myself ?


Years ago I bought a hypertech programmer for my 1997 z28 , I am assuming it is similar to that ? Any idea what companys sell them ?


Actually if you are saying you didnt do a tune and everything is good , maybe I will go that route myself.

Thanks.

 

Which code? The coating should eliminate the converter low efficiency code that's normally thrown with LTs. There can be other problems which require tuning that could throw a code though.

 

You should get a tune not only to avoid a CEL, but mainly to optimize the air/fuel parameters for the increased airflow. It's nothing like hooking up the Hypertech Power Programmer. Talk to LG Motorsports (or whatever header manufacturer you choose) about what they would recommend regarding a tune. You could either do a mail-order or, preferrably, drive to the nearest tuner that you can find that is familiar with C6s (do a search) and have them install the headers and do the tune at the same time.

 

You can do custom tunes with a Diablo Sport Predator hand held tuner, and YES its just like using your old Hypertech except you will have a shop custom make you a tune, send it to you through email, put it in your Predator and then flash it into your car.

 

That sounds great.

Thanks for the info.

Now , whats the best way to find a shop to get the program from ?

 

There is a forum vendor in Flordia that does it, they adervtised recently the tuner with six months of free tunes. Search the for sale section you should be able to find it there.

 

I appreciate all of your help today. Like I said I am new to doing mods to cars. I still would like to find a shop that can do the install and tune all at once , but at least now I have options if that becomes too difficult. I have posted a request for a shop near St.louis on the tuner thread , so hopefully someone knows of one.


Thanks again for all the info , you have been a big help.

 

No problemo, here's the thread for the Pred tune info and dealer. Just want to let you know I have not used this tuner but it sounds cool IF you go with a tuner that is used to working with this unit and this tuner sounds like he does.Let us know how it works out!
Matt

http://forums.corvetteforum.com/show...=predator+tune

Edit to add, I was wrong their not in FL they are in AL and they are only for the 05 at this time.