Headers for a V6

**Grieverr** · 07-15-2011, 07:41 PM

Was wondering if anyone has or knows if these headers are worth anything?
http://cgi.ebay.com/ebaymotors/MITSU...item4aabe6e8b2

I keep getting SES light for code PO431, warm-up catalyst efficiency below threshold, and am assuming that it is the front precat dying on me. I replaced the o2 sensors awhile back with the same code popping up and it didnt make it go away.

I am frustrated because I live in dumbass Cali and nothing is legal here, I want flow, but I can't get HFCs and be legal here, not to mention the cost. I figure I could put on these headers, they should fit, and get the most flow for the least hurt to my checkbook. Swap them out when smog comes along and swap back after. Looked for and couldn't find a test pipe for the precats, and headers should be better than just tossing on a test pipe, good headers at least.

If the headers I linked are crap is there any others that aren't that could be had for a decent price?

I assume that if I fashion a test pipe for the front precat and leave the rear precat as is that might create an issue with it being unbalanced? Free flow on one side and lots of back pressure on the other, please correct me if I am wrong that it would be stupid to do that.

Lastly, sorry I know I have already written a lot, is there anyway to clean a cat that is becoming plugged? I tried seafoam years ago with no change and before I read about the seafoam debate. Also I don't want to hollow the cats out, heard that it sounds like trash not to mention turbulence.

All help is appreciated, thanks guys.

**foxbrand** · 07-15-2011, 08:07 PM

unless you have soot in your cats, there is no cleaning them from what I've heard and learned in chemistry, once a catalyst is used up, you can't reverse it

the headers are probably not as crappy as most I have seen for sale, the fact they are including the diameters of the pipes does say something about the seller though. BUT, these are probably still generic knock offs, they won't give that high a gain (if you had a FED spec car), however, yes, they will flow better over the Cali spec exhaust

you probably can't run the stock manifold/pre cat on one side and then a header on the other as the y pip (to me really an F pipe in my opionion in regards to the shape), good thinking though, but it won't work

gutting out a cat (the catalyst, not the animal) won't sound like trash, it will put more rasp into the exhaust note as well as increasing noise, turbulance will only be a problem if you don't smooth out where the honey comb used to be attached

I do applaud your thinking on switching out the exhaust when it comes time for emmissions, just be weary of the police when you are driving
another option that is NOT legal but will allow you to pass smog if they don't use an exhaust probe is to use o2 sensor simulators, they will eliminate a CEL and will trick the ecu into thinking that you have functional catalysts

hope this helps

**foxbrand** · 07-16-2011, 05:18 PM

bump, I would like to hear what everyone else thinks of this conundrum he's having

**oakrdrs187** · 07-16-2011, 08:03 PM

1. If HFC stands for High Flow Cat there is no such thing.
2.That header will be just as good as gutting the cat, there's no way to clean it.

You might as well replace the cat so you rid yourself of the CEL.

**Grieverr** · 07-17-2011, 12:10 AM

oakrdrs187 I have seen many posts in forums and sites not linked to any cat manufacturer that shows before and after dyno results with stock, high flow cats HFC, and test pipes. From what I have read it seems that there are HFCs. I read your reply post last week with the cut and paste from www.catalyticconverter.org that claims HFCs do not exist, for others reading here is the link post #4

https://www.thegalantcenter.org/showthread.php?p=687993

Other than that site, do you have any other reference, dyno proven perhaps, that backs that claim. I am not trying to be an ass, I have an open mind and am willing to concede a point if it is proven to me, but that site doesn't do much to convince me.

Also oak you said that the headers would be just as good as a gutted cat, does that mean that those particular headers are lousy or that headers in general do not have as large an impact as I have been lead to believe? bout 4-10hp on a federal spec car.

foxbrand you mentioned that unless there is soot the catalysts can't be recovered. This had me thinking, as I had an oil leak for along time from the front valve cover, if there might have been a way for that leaked oil to have gotten down to the cat and helped clog it. Also had a random misfire years ago until I did a tuneup which may have helped soot it, but if it is just soot then maybe I can clean it and get a few more years.

Not worried about the CEL light, I made my truck into a truck dual, full flow all the way through, and used the anti-fouler trick, works great. I know it will be louder with headers but I am not changing the exhaust catback so the resonator and muffler will still be there. No matter what it wont be as loud as my truck exhaust, and I haven't been caught with that, just don't drive like an idiot around cops and they wont have a reason to pull you over.

I appreciate your input on the headers foxbrand, almost bought them but I try not to be hasty, like to do my research and get advice from those that have more experience than myself. Does anyone else have an opinion on the ebay headers?

**oakrdrs187** · 07-17-2011, 04:02 AM

If you read the post, it mentions that Cats with higher flow are those with less cells within the substrate. A bit more flow yes. On a race car gains may be as high as 20hp. Our V6 and I4 grocery getters 1-2 hp, and an O2 with whacked readings giving you poor Gas Milage and a CEL. Worth it? No.

In Reference to the header, it is piping with out flow restriction. 2 wks ago or so I gutted the pre-cat on my I4, when I was done it was simply a foot long oval straight pipe. My car doesn't rumble more, backfire or is it any louder/faster. The only thing is, that you can smell my exhaust from 15 feet away at idle. Now I know why Cali is so strict :phew:

As far as swaping pipes for smog, I say go for it. Buy the header and swap for smog. I'm in Cali too and I have never been pulled over and had the officer check for catalytic converters. BTW: Soon as I can afford a new pre-cat I'm getting one, only gutted it because it was clogged to the point of bogging down as I hit the throttle.

**Grieverr** · 07-18-2011, 12:16 AM

Went ahead and bought the headers, after searching through the ebay sellers feedback for someone who bought the same thing and they seemed happy with it. When I get them I will post some pics for others interested in it.

**oakrdrs187** · 07-18-2011, 02:25 AM

Were gonna want DYNO sheets!!!

j/k!! LOL!!

**SPD_FRK** · 07-21-2011, 01:53 PM

Some crappy information being given here. Foxbrand, you should at least know enough about this particular item considering we covered it on GT a while back. These headers are nothing more than "knock-off" Megan short tube headers. Same pipe diameters, design...just without the name plate.

These will suffice for the average owner and will add some better performance over stock manifolds....regardless of stock Fed spec or Cali Spec manifolds. Compare the design...it's quite obvious these will flow better.

Another thing to point out is the reason you smell fuel from removing the cat, it's because if the car isn't tuned you WILL smell fuel. These vehicles run very rich from factory for emissions standards during those production years. Tune the vehicle and the excessive fuel smell from the exhaust will be drastically reduced.

California will likely void your state inspection on these headers simply because they do not include any C.A.R.B. certifications or other documents you would need...even though they have the O2 bungs to re-install all 4 Cali spec O2 sensors....hard to get around that.

The kit is a bolt-on replacement from the header back to where the mid pipe connects, save the stock piping for future emissions testing. You should also note that these cheap headers have some issues with the exhaust stud flange holes not being 100% lined up. You can simply drill them out a little larger (maybe 1/8" or less honestly...don't remember for sure how much I did mine). They will fit just fine, and for the price...you really can't bitch too much about them

**foxbrand** · 07-21-2011, 02:00 PM

Some crappy information being given here. Foxbrand, you should at least know enough about this particular item considering we covered it on GT a while back. These headers are nothing more than "knock-off" Megan short tube headers. Same pipe diameters, design...just without the name plate.

really, not to get personal or off topic, I mentioned in my first post that the are probably knock offs

**SPD_FRK** · 07-21-2011, 02:16 PM

Originally Posted by foxbrand

they won't give that high a gain (if you had a FED spec car), however, yes, they will flow better over the Cali spec exhaust

Then explain the thinking behind this portion of your reply to the thread please?

Fed Spec and Cali Spec manifolds have two differences....Cali is Cast, Fed is Stamped. Both designs are highly restrictive, and any aftermarket header such as what the original posting showed, will make noticeable improvements regardless of what stock manifolds were on the vehicle....

**foxbrand** · 07-21-2011, 03:02 PM

Originally Posted by SPD_FRK

Then explain the thinking behind this portion of your reply to the thread please?

Fed Spec and Cali Spec manifolds have two differences....Cali is Cast, Fed is Stamped. Both designs are highly restrictive, and any aftermarket header such as what the original posting showed, will make noticeable improvements regardless of what stock manifolds were on the vehicle....

I'm not disagreeing with you, yes they flow better (hence more power most of the time) and there are gains but they aren't like the gains that happen from say a supercharger, maybe 10 whp at the absolute most is gained on a cali spec car, but with a shorty header, most of the gains are up top, there are some at the bottom end of the rpm range, but they aren't that much. In anycase, I can see some of the confusion you might have had from my first post, when I said 'they won't give you that high of a gain (if you had a FED spec car)', I should have clairify a bit more with the Cali spec manifolds, I have no actual hands on experence with them, but I should have given a bit more info on that they do flow even worse than the FED spec manifolds, so as I stated earlier, yes more gains are given on a cali spec car with headers

**Exhaust power** · 07-21-2011, 03:23 PM

To say a header/s wont give you a gain is out right foolish a header is a complimentary mod to many other modifications. You might start off at 5-15 whp gained then when you add modifications like intake, cams and such they benefit greatly because of that header/s.

Its funny how the other person automatically thinks that a high flow cat will throw a code. when they make them up to obII standards. You guys should speak from experience instead of speculation. Galants have to be tuned to maximize on bolt ons we dont have the smartest ecus out there like some others.

**oakrdrs187** · 07-21-2011, 03:24 PM

Originally Posted by SPD_FRK

Another thing to point out is the reason you smell fuel from removing the cat, it's because if the car isn't tuned you WILL smell fuel. These vehicles run very rich from factory for emissions standards during those production years. Tune the vehicle and the excessive fuel smell from the exhaust will be drastically reduced.

Can you tune a stock 4g64 with stock ECU?