jeff

I am getting my catalytic converter taken out tomorrow and was wondering if it will make my exhaust gassy. First of all, the cars exhaust already stinks. So does cutting off the cat, and replacing it with a straight pipe, make the exhaust "gassier"? That smell is just nasty.

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http://www.angelfire.com/indie/jeff

1992Pontiac Firebird.
305 TBI
Metallic green/grey
T-tops
Still researching to find kick *** 350 for it.

Chuck

If the smell you don't like is a "rotten
egg" type smell, it will be gone when the
cat is. If "gassier" is unburned fuel
smell, it won't be gone - but is probably
messing up your cat right now.

jobryan26

I agree with chuck. I just removed my cat today. Hint if you're doing this yourself: mine is the single cat. The pipe to replace the cat was 3"in(slip over) and 2 1/2" out(slip in) and 23" long. I found out the hard way. This is my only vehicle and wife was at work. I had went and got a 3" in 3" out 22" long pipe the day before. Only to discover after cutting the cat off my rear exhaust was 2 1/2" behind the cat. Damn! Was Sat. and 2:00p.m. had to be at work at 3:00p.m. luckily was able to use a friends car. Just got it done and noticed big difference in sound(alittle louder and not as bellow), More power in the mid to upper end. Good Luck!

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'87 Trans Am:
(Engine)
305 TPI
160 Degree Thermostat
TB Bypass
Accel 300+ 8.8 Racing Wires
Accel Super Coil
Bosch Platinium Plugs
Custom Ram Air with K&N
Removed Emissions Equipment
(Stereo)
Kenwood Excelon

jobryan26

Oh and I noticed no difference in smell.

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'87 Trans Am:
(Engine)
305 TPI
160 Degree Thermostat
TB Bypass
Accel 300+ 8.8 Racing Wires
Accel Super Coil
Bosch Platinium Plugs
Custom Ram Air with K&N
Removed Emissions Equipment
(Stereo)
Kenwood Excelon

superz

when i bought my car someone had already gutted the cat. my exhaust smells thought. it smells just like my dads 84 Monte SS did when he had his cat gutted. it smells kinda rich, the best way i know to describe the smell is like most older muscle cars you see at car shows. it doesn't smoke, gets decent mileage (about 16mpg) and has great power for a 305 (6.6-6.4 sec. 0-60). it is TPI and i know that rich mixtures will kill cats. someone once said " cats don't die, they are murdered" i have a question for you guys, is it really running rich or is it just gonna smell that way cause the pollutants aren't burnt out?

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86 IROC-Z
40,000 miles!!
305 TPI
gutted maf/airbox
k&n filters
manual cooling fan switch
headers, no cat, cat back flowmaster
700R4 tranny
shift kit
manual converter switch
BF Goodrich radial TAs
3.23 gears
georgous car repainted by my dad and assembled by me

FASTER THAN YOU THINK FOR A "STOCK" 305 hehe.

TomP

When I put my high-flow cat on, I pulled the old one down and found out it was already gutted! (That probably explains why the front pipe on it had rusted out.) My exhaust never had the rotten egg smell, and it had passed NJ emissions through the state inspection centers (pre dyno-testing) every time.


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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!

jobryan26

I agree with chuck on this. I'm not a Mechanic but if your exhaust smells rich than it problably is. What mods have you done other than what's in your sig.? Like relocating MAT, 160 thermostat, TB bypass, and etc. I suggest getting a meter to check your air/fuel ratio. If you have made any mods like these I just stated will cause your car to run rich without a mod chip that will compensate for the changes. Your gas milage and performance will not be at it's best.

------------------
'87 Trans Am:
(Engine)
305 TPI
160 Degree Thermostat
TB Bypass
Accel 300+ 8.8 Racing Wires
Accel Super Coil
Bosch Platinium Plugs
Custom Ram Air with K&N
Removed Emissions Equipment & Cat.
(Stereo)
Kenwood Excelon

raging86

yeah i guess i'm not ASE certified but i have worked in a garage part time for a friend. it does smell rich, but i haven't done any of the mods you were talkin about cuz they don't do anything on a stock motor, the factory put the sensors where they did for a reason and they are meant to match the readings of the stock PROM. so moving them(while ratiaining my stock PROM) is just asking for a rich condition as u said. all the major mods i have done are in my sig. i only get about 14-16mpg last i checked, i should get better than that. the car runs like a dream and it is strong, i just don't know why it is running rich. maybe i should check my timing? that wouldn't cause it to run rich but it may help the mileage. why else would a basically stock motor run rich? the TPS is new, and i'm runnin a 180 thermostat. the MAF is good and i just cleaned and "rebuilt" my throttle body to get rid of all the carbon inside. maybe i should check the voltage in my CTS and O2 sensors? any other suggestions?

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86 IROCZ
T-Tops
700R4
305 TPI
3.23 gears
shift kit, manual TC switch, manual fan switch, flowmaster exhaust with edelbrock TES headers& hollow cat, gutted MAF.

[This message has been edited by raging86 (edited April 04, 2001).]

junkyarddog

16 miles to the gallon is awful!! you should get at least 20 hwy.