96_Z28

I have a 1996 Z28 with 3.5 inch Borla Cat Back, what Headers and Y Pipe (going catless and O2 less) should I consider or avoid? It has an automatic Jasper tranny don't know if that would limit the space in there at all.

I have seen how narrow the Y-Pipe gets going under the firewall area, so don't want to get into a whole bunch of bending/tweaking, but also would like to do this rather cheaply and not go for some of the $1000+ dollar kits.

It does have an Eibach Pro spring kit which dropped it 1.4 inches. I am a little concerned about clearance under there as I have seen some setups where they y pipe is almost dragging on the ground.

So looking for suggestions on headers and y pipe to use, and then and I found the O2 simulators, also saw the EGR block off plate I could use as well.

and, since I am 3.5" cat back, wondering what I need to look for in Y pipe dimensions.

Thanks!

Injuneer

You have to decide if you want shorties, mid-length or long tube headers. The long tubes generally produce the best results for a street car, and the Pacesetter long tubes are relatively inexpensive... not the best, but then they don't cost $1,000. When buying, consider spending the extra cost for the cera-metallic coating. That will keep more of the heat in the headers, which reduces under hood temperatures/burnt wires, reduces corrosion and thermal cycle cracking of mild steel, and gives you a couple extra HP due to improved scavenging.

The down side of the long tubes:

-they will not meet emissions where there is strict enforcement of Federal law, which does not allow relocation or elimination of the cats. Appears you don't have an issue with that.

-ground clearance is tight, particularly on the driver side, particularly when the car has been lowered.

Shorties generally give somewhat limited gains, but mid-lengths, like the AS&M headers can provide substantial gains. Since you have decided to delete the cats, you would buy a set of "single-cat" headers (94/95). Shorties and mids come with a dedicated Y-pipe.

Whether that Y-pipe will interface with your 3.5" Borla (never saw anything but a 3" Borla cat-back???) needs to be determined. I believe the termination of the Y-pipe was different between the single-cat and dual-cat systems. An adapter (S-pipe) may be required. The advantage of the dedicated Y-pipe, that follows the path of the stock Y-pipe, is that there is no loss of ground clearance. The Y-pipe that comes with a set of single-cat headers will typically be a 3" diameter, but it should be easy to adapt to your cat-back.

96_Z28

You know what they are probably three inch, I was doing it off memory and I had them installed 1997 actually and couldn't find the receipt. So that is a big help, I have seen Y pipes at 3".

I was wondering about long tubes, I will rule them out because it is too low.

So 94/95 Y pipes went to a single cat so I can just not get the cat then is what I think you are saying?

So following the original path, one of the things that concerned me on the stock Y pipe is there is a huge kink it seems when it dips under the firewall area to go under the car. I guess there is really no way to get around that without:
1) let it hand low and have really low ground clearance.
2) Somehow cut a notch and add add some connectors for stability?

I will have to get under it again but I think I had a cat in each piece of the Y pipe. I was thinking of just going with an off road Y pipe.

Thanks so much! Finally have a house again with a garage so I can start working on it again.

Injuneer

The single-cat Y-pipe merges in front of the cat, and terminates at the inlet to the cat. It does not include a new cat. Factory system was welded at that point, so I had to cut the cat off the stock Y-pipe, and have the new Y-pipe welded to the stock cat.

The dual-cat cars have one cat bolted directly to the stock cast iron manifold on the driver side, and the second cat in the passenger side branch of the Y-pipe, directly under the passenger seat floor. That is the same location as the single cat converter.

The Y-pipe for the single-cat setup is not as restrictive as the one use for the dual-cat setup. I had a set of JBA shorties, and the Y-pipe had no problem fitting with the full diameter of the pipe (no flat spots or crimps as I recall). Maybe my memory is bad (I had the JBA's 15 years ago) so if you could post a photo of the area where you feel there is inadequate room for the Y-pipe it would help me understand your concerns. I've never seen anyone with headers have an issue with the clearance on a Y-pipe that follows the stock routing.

96_Z28

Your memory is better than mine, I just got under it looks like a tiny crimp going around the oil pan. That is it though, looks like if I follow that stock y pipe route there is plenty of room.

I don't know what car I was looking at I just remember a big kink in the line, thought it was my friends 95 and they were all talking about how stock Y pipes are no good, while the guy at the speed shop was saying they are fine. Guess I listened to the wrong person!

Thanks for the help with this, I figure this is first before the whole head and cam thing I need to figure out which I will be much more questions on my part.

I think I will skip the long tubes, think I will go with mid size tubes and find a 95 setup Y pipe to accompany them, then probably need to clamp in a piece of straight pipe where the single cat would have been unless they account for that.

Nice thing now is this is not my only car so leaving it on the jack stands to order and get parts is not a problem. I have an 08 vette but I don't really want to mess with that, in case I have to sell it, I don't see getting any money back on modifications. Only thing I have just ordered is that mild to wild piece for the dual mode exhaust.

Thanks again!