Can you get away with a modified exhuast?

[Darktide]

Here is an interesting question. I know a lot of you modify your exhausts. I have a california emissions vehicle so I have the stupid precats. I'm getting a stupid sound that almost sounds like bees in a tin can when I accelerate and I know it's coming from my cats. Here's the question.If I change my exhaust over to headers and a y-pipe and get a new primary cat. Do you think a garage would be likely to fail me for the inspection? How many of you have had any problems with this? I live in NH and I normally take my car to Meineke to have my inspection done.

I'm just trying to weigh out my options since I'd prefer to not have to buy the whole front manifold to replace the pre-cat. If I have to replace anything like that I'd like to get some performance gains from it. Thanks in advance for any help.

Jay

[the converted]

They would plug in the OBD connector and not even bother looking for anything else. I doubt that they would even know to look for pre-cats.

[Darktide]

I've been in the car field for quite a few years and delivered parts to quite a few mechanics (sadly I'm not in the same area as I used to work), so I know that most of them don't know the specifics like that. I just am not sure whether I should count on it or not. It's not like I'm trying to do away with the cats altogether. Thanks for the input.

[Sentientbydesign]

You sure it's the pre-cat that's making that sound?

Most of the time, the bees in a can comes from the muffler, or so I've heard. Never heard a Max/I30 with that sound.

[Darktide]

I know its not the muffler as it was just replaced 4 months ago. And it certainly is coming from up front. I'm not sure if it's one of the pre-cats or the normal cat making the noise.

[Sentientbydesign]

hmmm interesting. Did it sound that way prior to the muffler install? Did you go with factory muffler or aftermarket?

I would take it to an exhaust shop and have them take a look at it.

[Darktide]

pretty ironic.

I didn't really get to find out what it sounded like before. I bought the car from a used car dealership and they failed their own inspection. So they let me take it to a repair shop of my choice to have the exhaust fixed. I chose Meineke. They repaired the flex pipe and then replaced the muffler with OEM. And they are the only exhaust shop in the area so I've only got them to go to. Well not including Midas but they charge twice as much (Meineke fixed the flex pipe for $185, Midas wanted $600... and that was just to weld in a generic flex section)

At the moment the car is sitting in the Meineke parking lot to have an inner tie rod replaced and the alignment done. I think I might make a quick call over there in the morning and ask them to listen for the noise and find out where it's coming from. They are kind enough to do free diagnostics so I'll probably find out what it is and get back to you tomorrow night.

If it is my pre-cats, I'm thinking of doing a headers/y-pipe to fix it. Though I'm going to have to do something with the O2's, I'd like to have them hooked up to the exhaust any way in case someone did check. Then nothing would appear out of the ordinary. I dunno, we'll see

[Sentientbydesign]

Good luck on that. Out here in Cali, exhaust shops are a dime a dozen.

I don't know why, but headers never appealed to me on the Max/I30. The y-pipe always did, but I didn't want to pollute more than I already was.

[blackmax23]

That tin can sound is NOT coming from your mufflers or your pre-cats. That's the notorious sound of maxima's with a bad flex section in your y-pipe. You might have a leak. In some aftermarket y-pipes, the manufacturer makes a good quality pipe, but awful flex section and you get that sound. If you go with a new y, go with one with a lined flex section so you stay away from the "bees"!

Also, even though you have a CA spec emissions max, meaning it's at least a 1999, doesn't mean you have to pass a CA emissions test. I don't believe where you're at, in New Hampshire, has any emissions tests. Even if they did, you would still pass with an aftermarket y-pipe, as long as you let your car warm up to operating temperature. What the pre-cats do is heat up the exhaust when the engine is cold so the cat can do it's job. But the cat can't do its job if the temp's aren't high, so the pre-cats heat it up. I have never heard of any SES or CEL coming on because of the y install. I have a Warpspeed ss y on mine and I love it. Amazing sound and great power from 2500-redline.

If you get just the y-pipe, you're only replacing bank 2's pre-cat, not bank 1. If you got the full header and y-pipe, then you'd be replacing both banks. Not really sure what the real gains are if you go with the headers, I've heard another 5-10 at the crank, but don't quote me on that. I would recommend you get an o2 simulator and stick them on the y where the pre-cats would've been once you get your new y, just as insurance that you won't trip a code. Good luck, let us know if you have any more questions!

[Darktide]

Thats basically what i'm looking at. The inspections are mostly visual but they require the car to be hooked up to the computer to check for codes. The flex pipe was repaired by Meineke when I first got the car about 4 months ago. They couldn't get it to recreate the sound though. Kind of irritated me because I always get the sound when I start it up. What brand would you recommend for headers and a y-pipe. I'm working on a kind of tight budget. Thanks for all the help. I've also got to get something that can withstand a New England winter/salt. thanks for the help

[blackmax23]

I have Warpspeed's Stainless Steel Y-pipe, it's a little more expensive than the aluminized, but I def. think it's worth it cuz I'm now driving my car in the winter and in central NY, the roads are awful. I'm sure you can relate!

They say aluminized will last at least 10 years. That's what the stock y's are...aluminized. However, I don't think manufacturers really know what winters are like in the northeast, so I went with the Stainless just to make sure.

As far as headers, I'm not really sure what to recommend to you. OBX headers had some quality stainless ones back in the day, but I'm not sure if they do anymore. I was looking into headers, but A) was worried about the gaskets withstanding extra heat, and B) didn't feel like it was worth the extra $500-$800 for stainless headers to get a few extra hp. But if I had the money, I can't say I wouldn't do it!