Has anyone installed a front y-pipe without the converters? And, if you have, what do you think of it? I think a better (modern) main cat would work just as good as the two pre-cats and the old, original main cat together.

 

 

I had one on my car for a few years, prior to installing headers, but I can't really comment on a modern main cat as I gutted mine when the y-pipe went on.

 

I have done this act of greatness! I have a 87 convertible. 95% stock. The car has 2:73 gears, stainless targa mufflers, a cut air lid with a regular filter, MAF screens removed and 11 inch zr-1's in the back. I went to the muffler shop and had them cut out the pre-cats and replace them with straight pipe. I replaced the main cat with the magnaflow stock replacement unit (part #94111? or something like that) and replaced the original o2 sensor with a Bosch sensor. The car before this work would barely spin the tires. The car now will spin the tires straight though first, and chirp second. Even on a roll now if I am accelerating and put the pedal down the tires break loose, start skating sideways looking for traction. This is on a dunlop 315/35/17 tire. The only modification I have ever felt do more work at one time to a car, was putting a vortech supercharger on my 5.0 mustang. This was the best two hundred dollars I have ever spent looking for performance gain. The sound was great. Sounds much like a newer corvette with an exhaust on it. I needed a little more sound so I ripped the packing out of the targa mufflers and can not be happier. I now feel like I am driving a CORVETTE!

 

Glad to hear cutting out the pre-cats has worked for you in all aspects. I may order the new y-pipe but will also look into getting them cut out of the current one.

 

Yes, a good modern single CAT does the job on Ga. emissions.

I fact the numbers improved.

Sounded better, too.

Why not just spring for headers?

TJM

 

Headers are A) much more expensive and, 2) harder to install. I like the idea of the y-pipe minus pre-cats and a modern main cat. I called one exhaust shop that said they wouldn't touch it - they don't want to remove cats. I'm not going to eliminate the catalytic, though, and a new and better main cat may improve the overall emissions.

 

I have a 1986 that had the precats on the y. Bought a y from a forum member w/o cats and a new catco main. It really feels as if the car has more power. Plus I like the sound

 

Dont tell them you want to cut out the converters. Tell them you want to cut out the warmers and put a sleeve in their place and replace the worn out converter with a new unit that you will supply. They all start to panic when you tell them you want to cut out converters. Word it differently and I bet they will do it...

 

I kinda got the feeling that if I asked the guy at the shop in person that he might do it. Over the phone, he may have felt like he was being suckered by the Cat Removal Cops.

 

does anyone make a y-pipe with nice mandrel bends? most of the ones i've seen either narrow down or have "wrinkle" bends. does it really make a difference - ??? as of right now, ive decided on the magnaflow hi-flow main cat, and the corsa cat back system.. the front y-pipe is still up in the air. if i go pre-cat, it will be the magnaflow assembly, or if i go catless, either from ecklers, mid america, or ??? assembly.

for those that bought an after market catless y-pipe, who did you get it from? quality - ???? comments... TIA -

 

Removing the pre-cats will increase the exhaust note slightly. With a modern high-flow cat, you should see some performance increase along with some good performance mufflers.

The reason the muffler shop guy refused to do the work is because there is a substantial (5-figure) fine for removal of cats that are in working order. He can't even legally replace a working cat with a high-flow version.

 

Bought my front y (no precats on it) and a free flow main cat from MAM.
Very happy with the fit. Slid in quite easily. Sounds MUCH better now.

 

I opted for the 2.5"

 

What about 2 Carsound spun metallic cats off the manifolds/headers, into the y without the cat and a test pipe instead. It'd keep the cats close to the engine so they'd heat up quick. I used Heddman elites, 2 2.5 cats clost to the collectors, and an X to stock type mufflers but you could Y them together instead. Resonance isn't bad at all but is there.