I just got my cat gutted and i have an exhaust cut out on it that i got a long time ago but im afraid that opening the cutout and running the headers open. will the open headders screw up my car?????? any help would be great.
Thanx,
Ross

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keep the stang's far behind u and the cops even farther

 

Hell NO! Jet that baby up a little richer and pick up a couple tenths at the track!

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84 Camaro ZZ4 with HOT cam. 1.88 60' (12.98 @ 105MPH E.T.)
Other Mods: You name it and I have probably changed it.

91 Firebird 5.0L TBI

ASE Certified CHEVY DEALER Auto Tech
LIVE AND DIE BY THE ALMIGHTY BOWTIE!

 

no......but it will sure **** off the neighbors...

 

Neighbors--------Ha Ha Ha Ha Ha Ha Ha! ROTFLMAO!!!!

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84 Camaro ZZ4 with HOT cam. 1.88 60' (12.98 @ 105MPH E.T.)
Other Mods: You name it and I have probably changed it.

91 Firebird 5.0L TBI

ASE Certified CHEVY DEALER Auto Tech
LIVE AND DIE BY THE ALMIGHTY BOWTIE!

 

Thanx aolt guys! im going out to take the cut out off right now and listen to my neighbors yell like sons of bitches.
Later,
Ross

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keep the stang's far behind u and the cops even farther

 

While running open headers may not hurt your engine, you could actually end up losing a little bit of torque and gaining horespower. Naturally aspirated engines require some exhaust back pressure to function properly. But then again, you won't notice a large difference, and it sure would be fun pissin off people like that!!!!

 

ok i want a cutout too..but where to install?? does it go before the cat or after it..before muffler ??? where?? thanks rick

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Rick
90 Camaro RS 305 TBI
400 small block, Hooker 1 3/4 super comp long tubes, Random Tech Cat, Hooker aero chamber cat back on the way!!
TH700-R4 with Trans-Go shift kit
MacEwen Motorsports White Gauge Overlays
K&N Filter Charger (wooohooo)
GTS Headlight and Taillight covers
5% Limo Tint all around
Classic White Chevy Bowtie sticker on rear window

Man if my camaro were a rice-rocket all those mods would give me what...easily 50-60 hp!!!

 

i put it right after my y pipe comes together i gain 3 tenths in 1/4 mile i highly recommend it motor revs so much quicker with cutout in i crossed the 1/4 at 4800 rpms with it out i crossed 1/4 at 5200 rpms love it man get one

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1992 camaro RS
373 10 bolt rearend
ssm sfc's
87 350 TPI
bored 30 over
compucam 2032 with 1.6
482-495 LIFT 214-220 duration full roller rockers
msd6AL
1 5/8 headman headers
2 `1/2 flowmaster exuast
k&n filters gutter air box gutted maf
3 pc under drive pulleys
no emissions no egr etc
custom ED Wright chip
eddelbroc intake base and runners ported plenum
midly ported and polished stock heads
Taylor 8mm wires
B&M mega shifter
gutted maf/airbox
hotchkis lower control arms
3" exhuast cutout
homemade cold air intake
2000 tci stall
700R4 with B&M shift kit
new best ET 13.5 @104.66

 

Mine is after the cats. Here is a pic of it: http://24.1.139.249/images/101400/DCP_0018.JPG

I just open it up at that flange and it sounds awesome! On the previous engine I had, I gained 13 HP and 12 TQ on the dyno after opening it up. I havent dynoed it open with this engine.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

dont start with that backpressure bull****, thats a MYTH. Less backpressure is better. thats it.

 

Backpressure is only good for your low end. The less the better in the high end.

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1989 Pontiac Firebird Formula W6S LO3 TBI 305.

1985 Camaro IROC-Z LB9.

 

Im not gonna get started into this back pressure crap, jet right and youll always like less backpressure

 

kevin...i couldnt see yours...is it a flowtech?? do you think the best position would be b4 or after the cat...i think before. i have a random tech hi flow cat. thnaks...rick

 

It does'nt have **** to do with back pressure. Smaller pipes help certain cars because of EXHAUST VELOCITY!!!!!!!! A smaller pipe will produce LOW END TOURQE because of, thats right, EXHAUST VELOCITY! Stupid backpressure BS!

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84 Camaro ZZ4 with HOT cam. 1.88 60' (12.98 @ 105MPH E.T.)
Other Mods: You name it and I have probably changed it.

91 Firebird 5.0L TBI

ASE Certified CHEVY DEALER Auto Tech
LIVE AND DIE BY THE ALMIGHTY BOWTIE!

 

If you really want to make it flow, put one in after each header collector, I'm thinking of doing that on mine...

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1992 RS
327, Modded TBI, Rebuilt WC T-5 5-speed, PRO 4 15" rims, Nitto's, 3.73's, SLP 1 5/8" headers, and a few other things.

 

No, its custom by my dad. Best would be before the cats, but easiest is after the cats.

 

What if you can't "jet" your car? Or you want to still get good mileage?

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1985 Camaro IROC-Z LB9

1989 Pontiac Firebird
Formula W6S LO3 TBI 305
-180 degree stat
-Hooker Cat-Back

 

bump up your fuel pressure

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91 RS W/carbed 350, Vortec heads, performer rpm, Comp cams Xtreme energy 280 grind. BFG Drag radials. 3.42 posi,Corvette servoed 700r4, ****ty stock converter
13.24@104

 

Cool.

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1985 Camaro IROC-Z LB9

1989 Pontiac Firebird
Formula W6S LO3 TBI 305
-180 degree stat
-Hooker Cat-Back