Help with header/single CAT setup

[SeanC]

Hey guys,

I've been wanting to get headers for my car since I first bought it, but was always afraid of not being able to pass emissions...well I know technically it will be illegal if I move the cats at all, but I think i've decided to go ahead and do it (almost everyone I know who lives in NJ with an f-body runs headers and never has much of a problem).

I'm a little unsure of how to set it up...I figured I would change my car over to a single CAT system. I was going to get a set of coated pacesetter longtubes (with AIR and EGR). If I buy a y-pipe and a high flow cat will it work, or do the aftermarket Y-pipes (ORY) eliminate any room for a CAT? Also, would I be okay if I just used 1 O2 sensor if I got a mail order tune? If so, where would I have to locate it?

Sorry for not knowing too much about it, i'm just really confused on the whole two CAT thing...Thanks in advance!

[darkhorsecustoms]

From what I understand, ORY's are off-road only, which means they don't have a place for a cat. I would go with the y-pipe and the high flow cats for a car that has to pass emissions.

[SeanC]

Thats what I thought...but do they make a certain y-pipe that lets you put a cat in?

[Trash man]

im not sure how jersey runs their inspection/emissions but i know in CT when i had my 88 trans am emission checked, when they typed in the vin, it told em everything bout the emssions system on the car,( i.e. single cat, smog, egr, etc) id get a set of shorties and a ypipe with the dual cats.

[Al 96 Ram Air T/A]

NJ is a pain in the a$$! We are "technically" not supposed to move the CATs, but like you've seen, people do. The trick is getting the monkeys at the MVC to not look under the car...that's hit or miss.

You're best bet is to ditch the long-tube idea. First off, ground clearance suffers, and with pot holes and all...you're bound to damage the pipes and put a gash in them. Second - unless you're going to buy an inspection sticker, passing the MVC check is nearly impossible.

I decided on Mid-length headers from AS&M/RK-Sport. They allowed me to keep two O2 sensors, run all emission controls under hood, and utilize a single cat car Y-pipe into a high flow single cat. I'll pass a "sniff" test now, and appear legal looking under hood since the AIR and EGR system is intact.

I discovered a NJ loophole that allows me to register the car as a Collector, so I won't have to worry about an in depth inspection any longer.

If you want headers and no issues, stick with shorties and twin cats. You won't be giving up huge power unless you've done major engine mods anyway. Long tubes are overkill unless you're planning head, cam, and even 383+ engine changes.

If shorties aren't what you're after, then Mid-lengths are up next. At least you can keep your emission controls and appear legal.

I wish I had a better answer for you. But in my research, everyone I talked to who claimed they ran no cats and long tubes in NJ weren't being totally honest. Most bought inspection stickers, and frequently had issues (with the law and ground clearance). One last thing to consider - you'll never sell the car if it won't pass. The best you can hope is to sell it out of state, which is a royal pain.

[Injuneer]

Going to a single cat system is illegal - a violation of Federal law, which prohibits changing the number of cats. NJ enforces that law - if they notice. Ditto with relocating the cats - it is a violation of Federal law. NJ enforces that part of the law as well - if they notice.

The only truly legal setup for your 96 in NJ is the CARB-EO certified dual cat headers. SLP made them, not sure if they still do. I believe JBA makes a set. But the CARB-legal dual cat headers are terrible. Keeping the drivers side cat in the original position requires twisting the primaries up over the valve cover, which causes outrageous heat in the engine compartment, and hurts gas flow.

If you opt to go the "single cat" route, when you buy a set of single cat headers, they come with the required Y-pipe. (Make sure they are CARB certifiec and have the tag welded to the headers, in case they look for it). Then you would need a single cat to attach to the end of the Y-pipe. In order to mate up with your stock IM pipe, I believe you need an additional component called an "S-pipe". That offsets the single cat outlet to meet the factory IM pipe. Not sure of the details on that.

Reality - I seriously doubt a NJ state-operated inspection station is going to pick up on the fact that you have altered the cats, as long as you still have two. I think thats the way to go. Go to Mufflex in Trenton. Ask for "Denny". Tell him "Fred with the green Firebird Formula" sent you. He will tell you what you can do, and how much it will cost. He built my custom 3" Y-pipe, with dual 3" CarSound cats, flanged so they could be dropped out for the track (I have to run leaded fuel with the 300-shot of nitrous), and Borla XR1 shorty mufflers installed in place of the cats. Then he installed a Mufflex 4" catback. Same system supported over 1,000HP on George Baxter's record-holding LT1.

Going dual cats eliminates any question of changing the number of cats, which is an easy data point for them to check. However, they aren't going to be too sharp on the location of the cats. You do run the risk of getting caught, it you draw too much attention to the car - excessively loud exhaust, obvious race setup, etc.

When I built my 800HP setup back in 1999-2000, it was capable of passing NJ emissions. But if they popped the hood an actually looked at the engine, they might have started looking a bit closer. I passed once and never went back. Back then, they were setting up the roadside emissions checks, with a mobile emissions dyno, and people who had the "books" for all the cars, and knew exactly what they were looking for. That's when I took the car off the street. The don't run the roadside emissions checks any more that I have seen. Rarely, they will set them up to check only diesel trucks.

Good luck.

And remember, in a couple years, NJ is scheduled to adapt the full California emissions system, so it will only get tougher to pass.

[SeanC]

Thank you so much for the help guys. I really appreciate the time you spent on your detailed posts.

Al 96 Ram-As of right now, my engine is pretty much stock. The reason I wanted to go with long tubes is that I'm planning to either do heads/cam or build a 383 in the future (eventually), and honestly, they seem to be much more affordable than most mid-lengths. I feel like I want long tubes, or nothing at all. I would hate spending the money on mid-lengths and then just want long tubes soon after. Does AS&M make the ones you have anymore? I cant seem to find them anywhere. It also looks like AS&M is really expensive. If I was going to do this I wasn't planning on spending much more than $450 for a set of coated headers. As far as emissions goes....i'm not overly concerned about passing emissions to be honest. I know not all people will support making the car "illegal", but as of right now the car is a toy and is not my daily driver anymore. Not to mention, I won't be living in NJ when I eventually graduate college. I'm just concern about the problems with clearance. Do you really think I would have a problem? The last thing I want to do is rip apart my headers on a NJ pothole....I dont have a lot of money to begin with, I definitly dont want to ruin my brand new headers. Do you have a picture of your setup by any chance?

Injuneer-Like you said, I didnt even want to go with the certified dual cat headers because theyre not very good. It doesnt even seem worth spending the money at that point. To buy a set of single cat headers, would I have to opt for the 93-95 ones to get the necessary y-pipe? I see they sell two sets of pacesetter longtubes (93-95 and 96-97), but it doesn't say what the physical difference is.
Thank you for your suggestion on going to "Denny" at mufflex, i'm only concern about the price. I know I won't be able to afford a custom setup...If it comes down to that I'll just have to wait until I can. I may give him a call and see what he says. I dont know how long you drove your car for on the street with your headers on, but when you did, did you ever have clearance issues?

[FTA1995]

I dont live in new jersey (thank god according to the emissions restrictions) but in Illinois you can pass a visual inspection if you leave the cat bodies in place without any guts. Just an idea, I'm not sure how you guys have to handle thing out there.
Fred, are you saying they actually have literally roadside dynos for random inspections??!?! That's insane.

I'm glad in this state OBD1's dont even have testing anymore.

[Al 96 Ram Air T/A]

Gutting the cats in NJ --- very bad idea. First off, you can smell the exhaust from a gutted-cat car. It's hard not to. Second, they still have the ability to do an emissions check, regardless of what you dashboard is/is not showing. In essence, even if you don't have any check engine lights on, all they have to do is insert the "sniffer" into your exhaust.

Roadside emissions checks were being conducted, just as Fred said. Welcome to one of the most Liberal states in the nation.

[Injuneer]

Yes - portable dynos, typically set up in an abandoned gas station of parking lot, out of sight. Cops select from the cars driving by, pursuit cars available if you try to elude them. They are still used but mainly to check diesel trucks.

I never had ground clearance problems, because I don't run long tubes. I have a set of AS&M mid-lengths, with the dirvers side collector modified to that it points straight back, rather than toward the engine like it does for the single-cat Y-pipe. I have extensions from the collectors to the floorboards, and now run just the XR1 mufflers with 3" pipes toward the rear axle, and turndowns. All the work was done by Mufflex. The mandrel-bend up to 4" pipe. Really high quality work.

At one time, I did have the front end lowered 1.8", and that did cause the cats (or mufflers when I had them in) to drag on speed bumps, going over humper driveways, etc. But no problems at stock ride height.

Current setup:



Original setup:



The AS&M's were modified by my buddy for his 9-second 30th SS convertible. The actually produced more HP and torque in the range he ran at the track (5,000 - 7,500 RPM) than Hooker LT's. But once he went over 1,000HP, the Hookers made better power. So I got the AS&M's for $175.

[Al 96 Ram Air T/A]

Because of Fred...it was why I chose the same ceramic coated mid-length header. Mine were made by RK-Sport....but they are the same as the AS&M.

I had to do a bit of fab work to get the single cat setup to work with my dual cat Borla. But it came out great and sounds like a NASCAR Sprint Cup car when the cutout is opened up.





I was able to maintain a full 3" diameter all the way from the Y-pipe.





The only issue (besides moving the stock location of the cats and using a single hi-flow unit), I had to delete the post cat O2 sensors. But, I had the PCM reprogrammed and the sensors deleted. I've been assured that if the MVC hooks up to the computer they won't see the deleted sensors. Not that it'll matter once I register it as a collector.

[SeanC]

Thanks again for the great responses guys. I would absolutely go with the AS&Ms if they werent so expensive. Its just out of my price range. I wanted to see what you guys thought about this idea.....I was going to buy the pacesetter longtubes and their ORY. Once I get enough money, I'm going to buy two high flow cats, have a muffler shop cut the ORY, and weld the cats into place. I talked to someone who did this, and he seemed to like the setup. I feel like it is one of my best options. It allows me to have 2 cats, requires a minimal amount of custom fab., and I think it should flow pretty well. Here is a picture of what his system looked like:



What do you guys think? Are there any disadvantages to this type of setup? If you think its a good idea, do you have any suggestions on what CATs I should get? I'm hoping to be able to find 2 "bullet" style cats to keep my clearance problems to a minimum.

Thanks a ton guys. You have really been a great help