Pulling all the smog stuff

[Ricko1966]

Removing the emissions stuff isn't legal in any state,it's federal law,not state law,not local law Some states aren't serious about enforcement. That could change,you never know. But most of the emissions equipment is part of the total package and you will hurt mpg. Before you start believing taking this off or that off is going g to be an improvement. Remember the engineers at GM are way smarter than us. P.S. in Texas it's a 25,000.00 fine to sell a car with the Cats removed. Chances of getting caught meh but I wouldn't want to get caught.

 

[Joe Voter]

Don't do it! That's a fool's errand.

You have to breathe that air too, duh.

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[fast 99]

Really some of you who want to remove parts in an attempt to clean up the engine compartment should go look at a late 80's dual air pump carbed Ford 351 or GM 454. You have no idea.

When TBI units came out it became much easier to work on them. Actually, I can't think of an engine compartment that was cleaner after 71 or 72 until TBI came out.

 

[Redfish]

Really some of you who want to remove parts in an attempt to clean up the engine compartment should go look at a late 80's dual air pump carbed Ford 351 or GM 454. You have no idea.

When TBI units came out it became much easier to work on them. Actually, I can't think of an engine compartment that was cleaner after 71 or 72 until TBI came out.

Every single time I open the hood of my '87 I am grateful that it is not the '84 my Mom owned.

I am slowly doing what I can to restore mine to all of the original components. I want to get it back to what it was originally. But we do not all want the same thing.

I have seriously considered installing some high flow cats as a couple of you suggested. If I do that I will absolutely be installing a new belt on that smog pump.

 

[PhotonFanatic]

I guess I have two thoughts... I've reached an age where I don't want to get out of my car smelling like unburnt 93 anymore.

At age 40 I'm the same way. I've had my fill of noisy exhaust and now I value peace and quiet. When I changed out the giant factory cat because it apparently stopped working, the smaller replacement added noise. A downgrade imo.

So how do you get good flow without the noise? I think flowmaster has some mufflers called "Hushpower". They claim they flow as well as straight pipe but are as quiet as the stock muffler. Maybe the other brands offer a competing muffler. But I don't think you'll get away with not having a cat if you want it to be "quiet" like stock. Maybe you'd have to run 2 mufflers lol

 

[Ricko1966]

At age 40 I'm the same way. I've had my fill of noisy exhaust and now I value peace and quiet. When I changed out the giant factory cat because it apparently stopped working, the smaller replacement added noise. A downgrade imo.

So how do you get good flow without the noise? I think flowmaster has some mufflers called "Hushpower". They claim they flow as well as straight pipe but are as quiet as the stock muffler. Maybe the other brands offer a competing muffler. But I don't think you'll get away with not having a cat if you want it to be "quiet" like stock. Maybe you'd have to run 2 mufflers lol

Before cats they used to run two mufflers,they were called resonators. Then in the 80s the way to be smog legal was just run the cat as the muffler.

 

[Bextreme04]

On my 2011 to support the 6.2L upgrade, I ran long tube headers to 3" high flow cats that then merge into a single 3.5" pipe with a resonator then into a single Flowmaster 50 series big block muffler. It is very free flowing, still has the cats to kill the smell and be marginally legal, and is actually very quiet at highway speeds. The stock 6.2L exhaust on the GMT900 trucks is also dual 3" merged to a single 3.5".

I had a similar setup on a 2005 Neon SRT-4 with a custom turbo setup and computer. It dyno'd at 471whp. I had full 3" exhaust with an electronic dump valve right after the downpipe. The cutout went to right behind the front wheel. With the cutout closed it ran through a 3.5x24" resonator and then to a flowmaster delta 44 series single in to dual out muffler. It was much quieter than the stock exhaust and very free flowing and had zero resonation at highway speeds. When I went racing or just wanted to hear the turbo scream I could open the dump and go to town.

 

[SquareRoot]

Something I learned going thru this exercise is the location of the cat is very important. The cat is only as effective as the temp it heats up too. You want it as close to the manifolds as possible. Long tube headers are lousy for cats, they cool the exhaust stream and render the cat ineffective. On a K series, space becomes a premium when you try stuffing a Y-pipe and cat(s) under there without interfering with the trans/t-case and front driveshaft. Just a FYI. Moving my cat FWD 1 foot closer to the Y-pipe made a difference in smell, e.g., performance. Using 2 1/2" tubing for the Y-pipe was also a mistake. But after all the trial and error, it is very satisfying now.

 

[SirRobyn0]

I'll give my opinion on this. The OP will be in regular print I'll be in italics
1. They said the trucks would run better after that. Is this true?
No. I don't know what else to say that is simply false.

2. What exactly do they mean by "run better"? Is it smoother, less noisy, or just have more power?
A smog pump, being belt driven does take some energy to turn, but if you take our belt off of it and go for a drive you'll realize it's insignificant.
3. Can I just cut the belt on the smog pump, or is that a bad idea?
Sure, you can do that, and if you want to try running without the smog pump please just try removing the belt first before you scrap the entire system
4. Will the truck smell terrible at idle if I remove all the smog stuff?
Probably. The main thing is that the smog pump helps the catalytic converter to work by introducing air / oxygen to help the catalytic converter to burn up the bad gases. Without the air pump it'll take the catalytic converter forever to get up to working temp, and in cooler weather it might not ever get up to temp when cruising. Even if you have already removed your cat, the air pump still helps to clean up the exhaust a bit. Have you ever heard of an exhaust gas called NOx? It's not as bad for the environment as other gases, so people don't talk about it as much, but it is REALLY good at destroying lung tissue in any animal that breaths enough of it. Any mechanic that has COPD is probably aware of this gas. Anyhow I'm not trying to be scary or anything like that, just trying to state the facts as I know them.
5. Will the check engine light come on? Any other considerations like that?
Maybe, but there is no downstream O2 sensor so I think it's unlikely.

 

[gmbellew]

I'll give my opinion on this. The OP will be in regular print I'll be in italics
1. They said the trucks would run better after that. Is this true?
No. I don't know what else to say that is simply false.

2. What exactly do they mean by "run better"? Is it smoother, less noisy, or just have more power?
A smog pump, being belt driven does take some energy to turn, but if you take our belt off of it and go for a drive you'll realize it's insignificant.
3. Can I just cut the belt on the smog pump, or is that a bad idea?
Sure, you can do that, and if you want to try running without the smog pump please just try removing the belt first before you scrap the entire system
4. Will the truck smell terrible at idle if I remove all the smog stuff?
Probably. The main thing is that the smog pump helps the catalytic converter to work by introducing air / oxygen to help the catalytic converter to burn up the bad gases. Without the air pump it'll take the catalytic converter forever to get up to working temp, and in cooler weather it might not ever get up to temp when cruising. Even if you have already removed your cat, the air pump still helps to clean up the exhaust a bit. Have you ever heard of an exhaust gas called NOx? It's not as bad for the environment as other gases, so people don't talk about it as much, but it is REALLY good at destroying lung tissue in any animal that breaths enough of it. Any mechanic that has COPD is probably aware of this gas. Anyhow I'm not trying to be scary or anything like that, just trying to state the facts as I know them.
5. Will the check engine light come on? Any other considerations like that?
Maybe, but there is no downstream O2 sensor so I think it's unlikely.

an 87 TBI will have a downstream O2 sensor.

 

[SirRobyn0]

an 87 TBI will have a downstream O2 sensor.

Oh, that's right. For some reason I was thinking it was in the manifold but your absolutely right it's in the Y-pipe or just after the Y isn't it. In that case pulling the air pump will very likely set off the check light.

 

[andybflo]

At age 40 I'm the same way. I've had my fill of noisy exhaust and now I value peace and quiet. When I changed out the giant factory cat because it apparently stopped working, the smaller replacement added noise. A downgrade imo.

So how do you get good flow without the noise? I think flowmaster has some mufflers called "Hushpower". They claim they flow as well as straight pipe but are as quiet as the stock muffler. Maybe the other brands offer a competing muffler. But I don't think you'll get away with not having a cat if you want it to be "quiet" like stock. Maybe you'd have to run 2 mufflers lol

So, for a good flowing "cruiser" muffler, I've become a fan of Solo Performance "Stealth" mufflers. They're quiet, all stainless, well made, last forever. Not exceptionally expensive, and come in a ton of sizes/shapes. They still have the tone, though.

They're good at killing the drone you frequently get from Performance mufflers. Look 'em up. I have them on the Square and the Impala; shipped them on many, many cars...

 

[gmbellew]

Oh, that's right. For some reason I was thinking it was in the manifold but your absolutely right it's in the Y-pipe or just after the Y isn't it. In that case pulling the air pump will very likely set off the check light.

i think TBI only sets a check engine code if the O2 is open (no sensor) or if it goes extremely lean or extremely rich, I believe.

but I think the moral of the story is that it is probably best to keep running it as GM intended.

 

[SirRobyn0]

i think TBI only sets a check engine code if the O2 is open (no sensor) or if it goes extremely lean or extremely rich, I believe.

but I think the moral of the story is that it is probably best to keep running it as GM intended.

I agree. Keep it as GM intended. By the time we got into the 80's any emissions controls were so integrated into the engines, it's hard to just chop stuff off... My thoughts anyway.

 

[sidschev]