Today i had my cat removed, it was a newer low restriction catco cat, i just wanted to experiement and see how the tone changed. well, after it was all done at the muffler shop, i noticed a few things. first off, there was gas fumes, which dont really bother me, but it was different. second, i noticed a better midrange pull, which was much needed. the exhaust note was almost the same, but maybe a little deeper. when i get on it however, it howls. since i still have the exhaust manifolds on the car, im sure the tone has room for improvement. now im wondering, with the air tube that goes to the cat now doing nothing, what will that hurt in my car? will my gas milegae suffer?

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1987 LG4 Camaro z28
Mods- 80 series flowmaster, k&n filtercharger, open air element, high flow cat, 180* stat, edelbrock performer intake, msd blaster coil, ascd big block hood, panasonic cd player, rockford everything else.


[This message has been edited by z28onTweenkies (edited November 26, 2001).]

I've had my cats both on an off as well.. and I can't say much for the power (I just kept telling myself that it was all in my head).

But as for the exhaust note, I definately noticed that the car was A LOT quieter with the cats on. However, when I stood outside my car and had my gf rev the motor, I couldn't tell the diff.

The only thing that having that A.I.R pipe off will do, is effect your emissions, which are already being severely impacted by the lack of catalytic converter entirely. Your mileage will not be affected. Now is a good time to get rid of the A.I.R system completely, lose a couple more pounds and free up another pony or two...

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1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

If anything your gas mileage will improve, due to a less restrictive exhaust system

guys, need more info, like, if i was gonna get a catco cat down the line, like in a bit, should i leave the AIR tube utnil then, i should i chop it off???


ANY info you can give is appreciated, all i know is my cat is clogged.....


THANX!

ps. i just learned mig welding, so im ready to go..... i think,.,,,, ????

please help asap, ive never felt the true power of my car..

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91 FireBird 305 V-8
Edelbrock Catback, Custom Alarm. Fourth Gen Console. i have six cupholders. all for starbucks!
Go|)Created The Earth, And Then Turned Up The Bass.
Here's My Audio Install!

"Honda's FOR ME TO POOP ON!" -Triumph...

I replaced mine with a 3" Straight pipe when I did my headers. So I can't really tell u if there was a differnce in the cat vs. no cat battle. i am thinking of putting a high flow cat on there to see what happens though. Someone on here said it helped bring back some low end torque when they did it. Same setup as me. Full 3" all the way back with Edelbrock TES Headers (3" collector)

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Eric Natzke
91 Firebird 305 TBI
"It Ain't Stock"
http://members.aol.com/j007golden/91firebird.html
For info on certain parts or mods go to the site below
http://members.aol.com/j007golden/modeval.html

Removing your cat is a federal offense, punishable by a $10,000 fine, and jail time. Blah blah blah.... Go get it dynoed before and after the cat and tell me the difference.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
317 RWHP, 418 RWTQ
13.23 @ 107.62 MPH (2.10 60')
Southern California
Member: SoCal 3rd Gen F-Bodies
Member: SoCal F-Bodies
-=ICON Motorsports=-

Wow, wonder what the Federal fine is for not having a muffler at all. I am driving mine daily without one. Wanting to hold out till Christmas, so someone else will pay for a new one. Also, I only noticed minor differences with no cat. Sounds a little different, but that might be in my head.

Running without a muffler is a local offense, but its up to your city/county/state. Some enforce it, some dont. Usually its a noise thing rather than a no-muffler thing.

Hey, Tweenk, did you have an LG4 replacement cat on that you removed for your "comparison"?

If so, small wonder not having it seemed to produce an improvement. Put on a "real" 3" y-pipe, cat & catback, and you'll see a SOTP improvement over your current no-cat.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R4, 2300 stall TC. Ported World 305 heads, Crane PowerMax 2050 cam. ZZ3/4 intake, oil pump, pan & baffle. Accel HEI SuperCoil & module. Hooker 2055 headers, 3" Catco cat & 3" catback w/dual-opposite Flowmaster 80. 2.93 limited slip. Spohn SFCs waiting to be installed. AMSOIL syn lubes bumper-to-bumper. Daily year-round driver. Best ET, speed TBD...
57 Bel Air, my 1st car. '66 396, 9.7:1 forged TRWs, Weiand Action+, Holley 750VS w/4150 conversion, GK 270 cam, Magnum rockers, Jacobs Omnipack, 1-3/4" Hedders & 3" Warlocks, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, MegaShifter, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Idles smooth @ 700 RPM in D. Best 15.02/95.06 @ 5800' Bandimere (corrected 13.93/102.4 @ sea level).

Come and get me coppers.

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Eric Natzke
91 Firebird 305 TBI
"It Ain't Stock"
http://members.aol.com/j007golden/91firebird.html
For info on certain parts or mods go to the site below
http://members.aol.com/j007golden/modeval.html

yes i had replaced my cat with a 2 and a quarter inch catco converter a few months before i took it off. i didnt notice a difference, maybe a little better midrange pull, but the tone was certainly a bit louder. im going to install headers and bigger pipes all the way back probably around next spring, or whenever it needs to be re smogged. i just hope that a cop doesnt bust me for the no cat, however im not too worried. how many people have gotten caught? probably not too many. would they really give me a 10,000 fine and hit me with a federal offense? thats a rediculous law.......

so what happened with smog???


that air pipe thing that goes into the cat??

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91 FireBird 305 V-8
Edelbrock Catback, Custom Alarm. Fourth Gen Console. i have six cupholders. all for starbucks!
Go|)Created The Earth, And Then Turned Up The Bass.
Here's My Audio Install!

"Honda's FOR ME TO POOP ON!" -Triumph...