i had my cat cut off the past weekend. gives it a great sound and a noticible take off differce. can any one tell me how much hp this adds? also does it affect your gas mileage in any way?

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a*jones (bandit II)
'92 Firebird MFI 3.1 V6
Vortex Muffler,
k&n filtercharger,
rapidfires,
B&M shift kit
'79 T/A graphics,
bushing less tranny mounts,
open element
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According to CamaroVroom, 40-60 hp!

Seriously, depending upon how stopped up your cat was and how restrictive it was, you could gain up to 15 hp (flywheel). I'm not sure how big your exhaust is or if you have an aftermarket. Congrats on the mod, and have fun.
Cheers!

Chris

 

well cutting the cat out is an old trick. though I hope you have no big bad mean emissions guy or he'll take your car and chew it up..LOL J/K you'll fail pathetically however.

 

Are 15hp are really gained from !cats???

These cats must have been pretty restrictive because doing the same thing on my 99 does nothing but 5-8hp...

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1999 30th anniv. TransAm #877
** BESTS:60ft=1.935 1/4 ET=13.08 MPH=111.8 ** (Only 3.5K miles)
T-TOP,6M-Hurst,12cd, TCS
!EGR * !MAF Screen * ported and polished MAF * !silencer baffles * ! lid baffles * ported and polished TB * removed primary and secundary baffles * sealed ram-air * 9.4k timing-tricker * !CAGS * Mobil 1 * Lou's short stick * BMR panhard rod * BMR poly/poly LCAs * !DRL * Polished SLP resonator catback * 2 Ractive mufflers * 3x3 'fernco' mod * K&N * TB stop grind * Grotyohann headers * offroad Y-pipe* Power pedals * 19+ coats Zaino * WHITE gauges cluster * blue door TA badges * pontiac windshield decal * Polished momo shift **** * 4.5" brosal exhaust tips
Ordered:
Kenny Brown DD SFC
Polished: Calipers * Hood struts * Air tubes * Valve covers,Heat shields , etc.
Later:Cam + spring + pushrods swap + stage II heads
2000 Black Z-71 K1500 5.3l
ext.cab * !intake baffle * !MAF screen * !EGR mod

 

Why cant you gues go spend 80 bucks get a high flow cat and make it so i can breath and in 10 years when i have kids they can breathe come here to LA and you can see the wonderful cloud of smog that we get to breath in.

 

The subject made me remember another exhaust mod (the "Borla Wannabe") if anyone is interested. On the rear passenger side, you'll notice you have the exhaust pipe (going into the muffler), and the tail pipe (going out of the muffler) running close together. Take a tubular cutting bit (whatever thay're called, made to cut circular holes in pipes using a power drill) and cut a 1 inch or so hole in each of them at angles nearly facing eachother. Now, use a few 45* elbows and a few inches (or not even) of straight pipe in between, some JB weld or actually welding to attach it in a leak proof fashion, and boom! Instant better flow, better sound (from what I've heard), but not a total bypass at all. I've seen it a few times on 4th gen LT1's. LEt me know what you guys think.

-Reno

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89 Formula

 

2 1/2" in n out HI FLOW Cat Convtr
$60
I got one on my S-10 Blazer back in 1990.
Still passes emissions.
Go get one & no HP loss!
You will discover it's the exact same one as the more costly ones!
From Don's Hot Rod Shop, Phoenix AZ
800-888-8892

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

 

Reno, yeah, I saw a webpage on that poor-man's Borla mod! I have no idea where it is, though.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

Reno, that's actually a pretty nifty idea.. I might have to look into that. =P

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'86 Camaro SC, black /w silver racing stripes
2.8l MPFI/700r4 /w special 2nd gear delete option
In search of new v8 engine & transmission, now contemplating t5 swap to get me out of this mess.
Misc Mods: Cut air box, '83 Firebird spoiler.
Performance Parts: MSD coil, Accel 8mm wires, SplitFire plugs, Gabriel hijackers.
Audio Mods: Pioneer DEH-P3000, two 12" Optimus Pro Audio subs in hand-made enclosure each powered by a 260 watt Optimus amp. Working on shaving the box for weight.
My Homepage, with pics.

 

Fast RS, great thinking, your brain is not clocked like some catalytic converters
Horst

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www.marion-becker-nidda.de
91 Firebird 3.1
Modsynomax ultra flow stainless steel