P.Williams

iTrader: (1)

Okay, I own a 2002 IS300 5-spd which is still under warranty, and I'd like it to stay that way. Also, I live in St. Louis and Missouri law requires an emissions test every two years. That being said, am I completely out of luck in my quest to find a header? From what I understand, no one offers a header that is emissions compliant, nor one that will not trip the check engine light (and in-turn potentially cause me some problems when I bring the car in for scheduled service.) Is this all true, or have I just not come across the right header yet? Looking at the stock exhaust manifolds, I see that each cluster leads into a pre-cat. There are two O2 sensors, one before the first pre-cat, and the second just after. I'm guessing that the second O2 sensor is what is causing the check engine light with a header installed, when it realizes that the pre-cat is missing. So, it seems that I should be able to put on a header with the first O2 sensor in the stock location, then install a new pre-cat just beyond the header in the midpipe. Lastly, mount the second O2 sensor just past the new pre-cat. Am I forgetting anything here? Does anyone have a setup like this that they can comment on? If so, is there an aftermarket header available that will bolt to the stock midsection, so I can have a muffler shop install a new pre-cat and sensor fitting? I realize that this won't give me the greatest preformance gain, but it's a start.
One last thing, I was reading through the "extractors" section of Julian Edgar's "21st Century Performance," I noticed a picture of a GS300 engine bay on page 146. They comment on the "large diameter, beautifully bent primary tubes" of the stock exhaust manifold. Now that is not the same as what is on my IS. Does the US-spec GS300 have a different exhaust manifold than the IS, or is this photo only indicative of those sold overseas? If so, do their GS300's have comparable emission controls, and therefore be swappable? If anyone has any information they could provide in my quest to find a street legal, emissions compliant, warranty friendly header it would be greatly appreciated.

scottc25

I will try to catch all of your questions:

[B]Okay, I own a 2002 IS300 5-spd which is still under warranty, and I'd like it to stay that way. Also, I live in St. Louis and Missouri law requires an emissions test every two years. That being said, am I completely out of luck in my quest to find a header?

Yes, you are. I don't believe a header will pass emissions in any state. Plus, headers are sold for off road use only and are illegal in all 50 states. But if you live in a state like me (FL) there are no tests whatsoever and you can pollute all you want.



From what I understand, no one offers a header that is emissions compliant, nor one that will not trip the check engine light (and in-turn potentially cause me some problems when I bring the car in for scheduled service.) Is this all true, or have I just not come across the right header yet?

All headers will give you a CEL without an O2 sim. You can get a generic O2 sim from o2simulator.com or companies like Toyomoto give you them with the header.



Looking at the stock exhaust manifolds, I see that each cluster leads into a pre-cat. There are two O2 sensors, one before the first pre-cat, and the second just after. I'm guessing that the second O2 sensor is what is causing the check engine light with a header installed, when it realizes that the pre-cat is missing. So, it seems that I should be able to put on a header with the first O2 sensor in the stock location, then install a new pre-cat just beyond the header in the midpipe.

I'm not an expert here but our cars have three O2 sensors, all before the cat. As to where they are, I will leave that up to someone else here.



Lastly, mount the second O2 sensor just past the new pre-cat. Am I forgetting anything here? Does anyone have a setup like this that they can comment on? If so, is there an aftermarket header available that will bolt to the stock midsection, so I can have a muffler shop install a new pre-cat and sensor fitting?

What you are talking about here is the Y-Pipe I assume. The same people who sell the headers also sell Y-Pipes (Toyomoto, Xerd)



That's all I can help you with. I know there is someone out there that can add to my response. Good luck.

rominl

iTrader: (4)

that's what i believe too, no headers for the is3 are street legal

AndrewG13

So far there are no engine mods for the IS that are CARB exempt. .
Here in CA we have to be careful. Any traffic stop can get you sent to
the Ref.

flipside909

That's true but there are a few intakes out there with CARB E.O. numbers like the Injen intake.

rominl

iTrader: (4)

and most of the cat back exhaust are no problem too, unless they are stupidly loud