Headers

[crsmith1496]

So I'm looking into buying a rre header for my 2006 GS and was wondering if anyone had any problems with them throwing codes or turning on the "check engine" light

[Chris05]

You will throw codes unless you get spacers for them which you should

In before the potential flaming.

[FeaRlezZ]

comes with L spacers. it is still possible to throw some bank codes

[crsmith1496]

So what would I have to do to not throw any codes

[pat_08GT_Spyder]

search, tinker with the spacers by drilling the hole a bit bigger, it's more like trial and error than a proven science... or just live with the light and get a OBD2 reader to clear it...

[crsmith1496]

So pretty much no matter what I do ill throw codes

[mwaterous]

You'd think... they would modify the design... just enough... because this is only the forty millionth thread about it just since I've been here, let alone the years before that. How come they don't just make them properly right off the line?

[crsmith1496]

Bc if they did that would make them to easy to install

[pat_08GT_Spyder]

"by design", headers will throw codes as they hugely increase the air flow going by the O2 sensors, which get them all messed up...
try something... grab a sponge, put it on your mouth, and blow through it, and see how much air you get on the other side (stock cats)
now, take the sponge off, and do the same thing...

see how your O2 sensors can get messed up??? if you guys are so brilliant, fill your boots and design new headers !!!!
the spacers will basically restrict the air flow hitting the O2 sensor, making it think that your stock cats are still there... there is no design flaw on the headers.

[crsmith1496]

So do the spacers help or would it be easier to get a OBD2 and wipe the check engine light

[pat_08GT_Spyder]

Spacers do help, and you need them if you want to have a chance of being CEL-free.
they come with the headers i believe, so you might as well install them and see. if you feel like tinkerin with them, you could make it work.
or, just get an OBD2, use it to wipe your CEL and diagnose other potential issues...

[crsmith1496]

Yea thats true

[pat_08GT_Spyder]

to give you an idea, i have the RRE on my GT. the light comes on every 500-600 miles, nothing crazy... i have an OBD2 reader, check the code, same old P0421, delete, done...

[crsmith1496]

Oh ok that works then
u use the spacers

[pat_08GT_Spyder]

yes, but i just installed them, and never touched them again...

[Mdixon23]

I'm thinking about headers too. Just don't want the damn p0421 code. O course I do have a code reader.

[pat_08GT_Spyder]

trust me, the extra 20-25whp you get is worth the 30 seconds it takes to clear the light every other day...

[mwaterous]

Hey Pat, nobody is claiming to be a genius, least of all me. I also understand the basic physics of it, I'm not claiming to be a moron either.

The point I was trying to make, or better yet the question I was trying to ask; if adding spacers is all it takes for most people to avoid a code being thrown, why is RRE not making the spacers part of the design? I am assuming there's a reason.. maybe you can switch out the o2's, that's the part where I'm not a genius. It seems like there would be a reason not to include what's allegedly working for most. If they come with, but aren't welded to... there has to be a reason somebody would choose not to use them.

[mwaterous]

Oh and the other thing... isn't the information provided by the o2 sensors crucial to the ECU deciding on how to mix the air/fuel on the other end? Doesn't the fact that they throw a code mean it's going to adjust that wrong?

Alright fine. I'll search, I'm sure somebody has to have asked stupid questions like this already.

[pat_08GT_Spyder]

Originally Posted by mwaterous

Hey Pat, nobody is claiming to be a genius, least of all me. I also understand the basic physics of it, I'm not claiming to be a moron either.

The point I was trying to make, or better yet the question I was trying to ask; if adding spacers is all it takes for most people to avoid a code being thrown, why is RRE not making the spacers part of the design? I am assuming there's a reason.. maybe you can switch out the o2's, that's the part where I'm not a genius. It seems like there would be a reason not to include what's allegedly working for most. If they come with, but aren't welded to... there has to be a reason somebody would choose not to use them.

Originally Posted by mwaterous

Oh and the other thing... isn't the information provided by the o2 sensors crucial to the ECU deciding on how to mix the air/fuel on the other end? Doesn't the fact that they throw a code mean it's going to adjust that wrong?

Alright fine. I'll search, I'm sure somebody has to have asked stupid questions like this already.

nevermind, yeah i came across a bit harder than i wanted to
you have a good point about "welding those in", but at the same time it's not a 100% proven solution either, as you'll still throw a code once in a while... this is something that RRE came up with as a "fix", not a final solution.
and yes, the ECU does adjust fueling based on the info received from the O2 sensors... (and other variables obviously)... that's why if you really wanna get the most out of your headers, a tune / FIC is a great addition...
from there i'll let you search, or let other people chime in with more info

[mwaterous]

I've read about six different threads on it so far, there's definitely no shortage. Clovisman seems to have a good idea, but his answers were directed at different questions that only shed little bits of light at a time. The rest of the general consensus seems to be "solution X worked for me" with absolutely no background as to why. Some people like the L spacers, some the spark plug defoulers, others don't have a darn thing and seem to not get codes.

I hate it when I have to go back to school just to answer a question.

PS, no harm no foul, I read things pretty quick sometimes too.

[gser7]

I just installed mine, and also put in the spacers. And it still threw a code. I guess after a few hundred miles it will go away. Like Pat said though... It is DEFINITELY worth it. Wouldn't mind reseting or clearing the light every now and then. I'm sure when you step on it, you'll forget about the light

[nokiauser]

You guys make it sound like you're driving something that's permanently broken. The errors are usually from the bottom O2 sensors which are only there to indicate damage to the cats. If the precats (the ones closest to the exhaust ports on the exhaust manifold) get damaged, hotter gases go down and trip the sensors.

I really don't know what to say other than people who claim to get CEL (aka SES) lights show up on the dash after headers get those lights regardless of spacers so WHY keep buying them?

When you don't update the exhaust profile after the headers, the hotter gases (thanks to the headers) and more pressure build up because of the narrow stock piping. Putting spacers only masks the issue.

On the other hand, folks like me who have aftermarket or custom header backs with larger diameter piping don't get SES/CEL on their dash. Driven in over 100 degree temps and below 0 degree temps from hard acceleration to normal driving. Also have logged multi-hour nonstop trips.

The only problem with a larger cat-back is your lose bottom end torque but at least you don't see a christmas tree on your dashboard.

[Daxenth]

my car actually lifted off the ground after i installed my headers... the added gains made it levitate... to much power for the ground.

and im code free

[mwaterous]

"You lose bottom end torque" is a great way to not sell a product. That's exactly where I want my power to be raised, not lost; I already pull just fine at 4-6k, I want to pull better at 2-4k.

[pat_08GT_Spyder]

Nokia - spacers come with the headers (new), no need to buy them
I still run stock piping behind my headers, with some mods, maybe thats part of my issue... I dont really care for the light though

[mwaterous]

The cat back sold by RRE is 2.5 right? I know our stock, at least on the GS, is roughly 2.1... I have seen rumor that there's 2.25 out there somewhere too, maybe Injen?

[pat_08GT_Spyder]

yes, most catback's are 2.5" or 3"
stock GS piping is 2.25", GT is 2.38". and an exhaust shop should have 2.25,2.5 and 3" so that you can get a custom catback at whatever size you want.

RRE's webiste says that the GT piping is a "decent diameter", not 100%ideal with headers, but it's not like you HAVE to have a catback either...

[mwaterous]

I suppose I could go out and measure it, but is there any way to make the stock GS piping size official? I've seen people say everything on here from 2.129" to 2.25", but nobody ever pulled out the final word on it.

If 2.25" is restrictive enough to cause the bank 2 o2 sensors problems then that would be my reason for getting a larger diameter cat back. No sense in getting headers that are going to back up right when they hit the stock pipe, even if its only a little. If that's a debunked guess as to why they're throwing codes, then I'd rather save the few bucks and pick up the axel back and leave the stock pipe in place... see why I'm curious about specifics? Specifics cost money!

One way or another, I will be getting the whole exhaust system in place at the same time instead of piecemealing it. Whether that's headers+muffler, or headers+pipe+muffler (aka headers+axelback, or headers+catback before somebody gives me a lesson in terminology)... who knows yet.

[Ballfade]

TECH: Exhaust System FAQs