So I've read a lot here about doing the downpipe swap for u-bend delete and I'm thinking about tackling it. I've got an L67 from an '04 MC in my '03, so I think this is applicable to my situation. My biggest concern is with emissions. Being in NJ, I have to pass an emissions test. Any one run into issues with passing inspection after this change?

 

I say keep your stock one and swap it back on for testing.

 

You'll likely be fine, as long as you still have the cat.

 

I'm assuming that since you did an L67 swap you have a tuned PCM, and that you might have the P0420 code already deleted??

 

What he said. If you do a downpipe with a high flow cat your car will throw the P0420 code, if it has not already been programed out.

 

What you could do is, get the offroad DP and either:
1>> Save your stock DP and swap out when you need to go in for inspections or,
2>> (This may not apply) Some states will pass your car as long as you CEL isnt on. Like, if the PCM is saying the car is killing emmision (which your car is doing due to the tuned PCM you have) that is all some check for they dont actually check the exhaust gasses from the mufflers, like I said, they just make sure the PCM is saying its all good.
Either way, you could always keep the stock to swap out and you still wouldnt have to worry about nothing. Just a couple suggestions though, Ill tell you though, the PCM is somthing that I really enjoyed. Not just cause of the added performance, but cause the nice sound it gave my exhaust, not to mention the great smell people have to breath when they're behind me LOL. Have fun with whatever you do though

 

I had the L67 swapped in with the PCM from the donor car - no special tuning done at all, it's as it was when it left the factory. NJ does a full scan of all of the sensors and they all need to be reading "ok" to pass. I've been caught with a few in a "not ready" state and I've had to drive around for hours to get everything to reset so I could get rid of my "failed" sticker. I'm not sure what the delete from the PCM would do to that report. Would love to hear from someone in NJ that has gone through the process. Thanks for all the tips so far - much appreciated!

 

If you went as far as to do the engine swap then you probably aren't done modding yet. The hooks are in now. Your going to have to do something with the u-bend sooner or later. Its the right place to start modding. Downpipe or headers

 

That PCM needs to get a tune to delete the code: P0420

It's a very common thing, if you hit up zzperformance.com and look at PCMs under Grand Prix you'll see.

 

Id say, take a look at milzy to see if he could delete the code... But uh... Yeah.