Y-pipe question
Thread Starter
Pro
Joined: Jul 2006
Posts: 570
Likes: 1
From: Huntsville AL
Y-pipe question
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.
Racer
Joined: Apr 2007
Posts: 305
Likes: 0
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!
Drifting
Joined: Sep 2002
Posts: 1,642
Likes: 0
From: Suwanee,Ga
I fact the numbers improved.
Sounded better, too.
Why not just spring for headers?
TJM
Thread Starter
Pro
Joined: Jul 2006
Posts: 570
Likes: 1
From: Huntsville AL
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.
Melting Slicks
Joined: Jun 2007
Posts: 3,389
Likes: 0
From: Poocakes loves teh sausage! N.E. Ohio
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 
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Racer
Joined: Apr 2007
Posts: 305
Likes: 0
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...
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 764
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 -
for those that bought an after market catless y-pipe, who did you get it from? quality - ???? comments... TIA -
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
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.
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.
Pro
Joined: Jan 2008
Posts: 657
Likes: 1
From: Sykesville Maryland
I opted for the 2.5"
Pro
Joined: Oct 2005
Posts: 721
Likes: 1
From: Charlotte NC, behind someone going 10 under the speed limit
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.