do i need a smog pump for my cats to work?

jaidedeye

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Apr 4, 2004

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Goldsboro nc

Dec 20, 2004

#1

• Dec 20, 2004

• #1

on my car and all other foxbodys for that matter if you have cats you need a smog pump right? what if you run cats and no smog pump? what happens?

and why dont newer stangs run smog pumps? are the cats different?

 

hllon4whls

BANNED

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Covington

Dec 20, 2004

#2

• Dec 20, 2004

• #2

The smog pump adds oxygen to complete the chemical transformation. Michael is sure to post here and wow use with his stoichiometric analysis.

 

HISSIN50

"How long does it take to get help in here?

15 Year Member

Nov 29, 1999

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Dec 20, 2004

#3

• Dec 20, 2004

• #3

sure you can run w/o smog pump and with cats, but i would bet the cats dont last as long or work as effectively. do you have stock H-pipe and cats?

good luck.

 

jaidedeye

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Apr 4, 2004

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Goldsboro nc

Dec 20, 2004

#4

• Dec 20, 2004

• #4

well i have a bassani catted x pipe but im running an off road x right now

 

5.0 Nostalgia

10 Year Member

Feb 28, 2003

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CT

Dec 20, 2004

#5

• Dec 20, 2004

• #5

From what I hear, today's converters are much better and don't need the smog pump to provide extra air.

 

quiksilver9531

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Oct 9, 2001

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New Jersey

Dec 20, 2004

#6

• Dec 20, 2004

• #6

well the smog pumps adds air to the cats with help with the converting or whatever and from i've been told they wont last long or be as effective without the air pump

 

Michael Yount

Mustang Master

Apr 10, 2002

9,039

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79

Charlotte, NC

Dec 20, 2004

#7

• Dec 20, 2004

• #7

Today's fuel injection systems, chamber design/fuel-air mixing, and ecu's do a much better job of delivering an even cleaner mixture to the cats - so they don't have to work as hard as they used to.

Many people post and indicate that their cats clog more quickly without the air pump -- don't know how scientific that is, but it seems to be true.

 

B

BaXTeR3221

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Jan 12, 2004

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Orange County, NY

Dec 21, 2004

#8

• Dec 21, 2004

• #8

Damn, this is like the 5th post about smog pumps/cats i have read tonight. Weird.

 

HISSIN50

"How long does it take to get help in here?

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Nov 29, 1999

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Dec 21, 2004

#9

• Dec 21, 2004

• #9

intrcptrstng said:

Damn, this is like the 5th post about smog pumps/cats i have read tonight. Weird.

Click to expand...

most of the country is frozen (not me - it was 70* and sunny today!). i think people are bored and doing some winter projects.

 

H

Hydrocarbon

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Nov 18, 2003

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Medford Oregon

Dec 21, 2004

#10

• Dec 21, 2004

• #10

I believe the main reason the smog pump was used, was to help the cats with the rich mixture during warm up, which was when most vehicles failed testing.

 

HISSIN50

"How long does it take to get help in here?

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#11

• Dec 21, 2004

• #11

Hydrocarbon said:

I believe the main reason the smog pump was used, was to help the cats with the rich mixture during warm up, which was when most vehicles failed testing.

Click to expand...

not sure about things in Medford, but testing is generally not done on anything but a hot motor. the smog pump sends air to the exhaust upstream of the cats during warm up, as i recall.

 

H

Hydrocarbon

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Nov 18, 2003

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Medford Oregon

Dec 21, 2004

#12

• Dec 21, 2004

• #12

Actually I was referring to tests the EPA made Ford do during engine development.

 

HISSIN50

"How long does it take to get help in here?

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Dec 21, 2004

#13

• Dec 21, 2004

• #13

Hydrocarbon said:

Actually I was referring to tests the EPA made Ford do during engine development.

Click to expand...

ahhhh-so. i did not read enough into what you wrote. my bad.

with your username, i expect excellence from you, especially on emissons threads.

 

Michael Yount

Mustang Master

Apr 10, 2002

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Charlotte, NC

Dec 21, 2004

#14

• Dec 21, 2004

• #14

The cats aren't hot enough during initial warm up to help as they don't light off - that's why the air pump output is shifted to the heads on cold starts - so the cold air from it doesn't slow down cat warm up and light off. What helped control emissions to lower levels immensely during cold start up was heated O2 sensors. Instead of the 90-120 seconds needed to get the non-heated ones to operating temp (they have to get to 570F before they generate a stable signal), the heated O2's can be ready to go in 15-30 seconds, allowing the car to go into closed loop MUCH sooner on cold starts. Not only improved drivability, but allowed for better mixture control when cold - until the cats get hot enough to help. Air pump output gets switched to the cats once they're hot enough to light off.

 

H

Hydrocarbon

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Nov 18, 2003

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Medford Oregon

Dec 21, 2004

#15

• Dec 21, 2004

• #15

Mr. Probst says:

The extra air from the Thermactor (smog pump) helps burn leftover HC and CO from the fuel-air mixture. The hot exhaust gasses resulting from the burning fuel-air mixtures in the exhaust manifolds help to heat the cats quicker.

 

Michael Yount

Mustang Master

Apr 10, 2002

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79

Charlotte, NC

Dec 21, 2004

#16

• Dec 21, 2004

• #16

They certainly do - and the reason the gases are still oxidizing (exothermic) in that part of the system (the cat) is because the air was injected at the back of the head when the engine was cold. Once the cats are warm enough to operate, the (cold) air is shifted from the head to be injected directly into the cat where the precious metals on the cat's ceramic matrix catalyze the very same reaction -which begins to take place in the cat, and continue oxidizing downstream of the cat.

 

8

87'GTstang

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Feb 16, 2004

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Dec 21, 2004

#17

• Dec 21, 2004

• #17

Hydrocarbon said:

Mr. Probst says:

The extra air from the Thermactor (smog pump) helps burn leftover HC and CO from the fuel-air mixture. The hot exhaust gasses resulting from the burning fuel-air mixtures in the exhaust manifolds help to heat the cats quicker.

Click to expand...

Also in addition, to deleting the thermactor, you continue to heat the cats up without the addition of the cooler air from the pump near closed loop. So while you drive around with no thermactor, you are actually defeating full-efficiency of the converters and they have been tested to run much hotter than designed to. This extra heat (and we are talking about a definite measureable amount) is what casues premature failure.

If you want to take it further the air pump moves oxygen of course. So one of the problems with vehicles equipped with a downstream O2 sensor (post converter) is that it will not read the extra oxygen that the computer automatically takes into account when figuring how much fuel to send for the correct stoich. air/fuel ratio. So the oxygen sensor doesn't see this and in turn tells the computer that the exhaust is either too rich and the engine needs to run leaner, or in reference to the upstream O2 sensor (which it relates to for cat. converter efficiency), it relates it as just that - a defective converter.

 

H

Hydrocarbon

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Dec 21, 2004

#18

• Dec 21, 2004

• #18

We are thinking the same things.