smog removal still not a thing?

mostsmooth · Jan 8, 2021

Hi all,
i am bringing my 95 gt out of a long hibernation (like, 17 years of not moving much at all, like, maybe 3 times up and down my driveway total).
the other day (a month or so ago) i replaced the belt, and because im a genius i said hey, let me buy a shorter belt and bypass the smog pump, and i did.
the car has an off road x-pipe on it so the pump is doing nothing as far as i know (unless it has a dual purpose?)
i was thinking about removing the pump altogether and the plumbing that goes with it.
so i started reading some threads here, and it seems there's more people suggesting to keep the pump on rather than remove it as theres not much benefit to removing it.

the car is over 25 years old now and does not require any inspection in my state.

the goal for the car is getting it running well again (which is surprisingly close) and then maybe slowly replace/add parts to get it to a respectable 1/4 time. maybe even put the supercharger back on it.
right now it has the usual bits and pieces, a cam, ported GT40 heads, gt40 upper and lower intake, roller rockers (and maybe a missing ground wire...)

so, i should just leave the smog pump on at least until it becomes a dedicated track car perhaps?

Thanks

nickyb · Jan 8, 2021

You should be fine removing the smog pump, but keep it and all the parts that go with it.These parts have been or will be soon discontinued,meaning big money for good stock ones. My smog stuff is all in place because I have yearly inspections,and I keep the cats on to not smell like a refinery.

Mustang5L5 · Jan 8, 2021

If you have an off-road pipe, you can remove it. You’ll free up 8lb or so and 1/2HP

keep it though. Those parts are getting harder to find.

HemiRick · Jan 8, 2021

No benefit to it being there it doesn't actually reduce pollution in any measurable way, it just dilutes it.

jozsefsz · Jan 9, 2021

Well its theoretical purpose was to inject air into the exhaust stream (first into the back of the heads while the car is warming up to heat up the converter more quickly, and then switching over to the converter itself to get it hot enough to burn more unburned fuel and to prevent the converter from fouling). If you have the stock catalytic converters, you could theoretically shorten their lives removing the air pump, though it's doubtful (and by how much - if your car burns a lot of oil it may be considerable) as they eventually heat up all on their own.

If you've deleted cats or installed moderns cats that don't require air injection, there is very little benefit. They also contribute to overheating tubular exhaust headers (even the stock ones) and shortening their lives, so pick your poison. Air pumps are also prone to failure and lock-up when the bearings go bad, as well as a little parasitic drag, and removal will very likely have no impact on tailpipe emissions (though visual inspections may get you a fail), so again pick your poison.

Now the EGR (completely separate) does have significant impact on your NOx emissions and will cause a tailpipe emissions fail (unless you retard your timing a bit). It'll also trigger OBD codes that need to be addressed. The ECU doesn't complain much about their air pump removal.

7991LXnSHO · Jan 9, 2021

So the SN95 ECU does not check out AIR valves like the Fox 302 ECU? I rarely see them, the hoses and crossover pipe usually go away if the pump does.

mostsmooth · Jan 9, 2021

7991LXnSHO said:
So the SN95 ECU does not check out AIR valves like the Fox 302 ECU? I rarely see them, the hoses and crossover pipe usually go away if the pump does.

I don't know, but now I'm interested in knowing more about what you're talking about because I have a computer in my car from a 93.

revhead347 · Jan 13, 2021

7991LXnSHO said:
So the SN95 ECU does not check out AIR valves like the Fox 302 ECU? I rarely see them, the hoses and crossover pipe usually go away if the pump does.

It's virtually identical to the Fox. You just cap the vacuum lines that control the valves. It doesn't throw a code or anything.

Ditching the smog pump is actually a good idea. If you have ever taken one of those smog pumps apart, the reason becomes immediately obvious. Whatever designed these things needs to use a smog pump as a butt plug as far as I'm concerned. These smog pumps regularly seize up instantly, which is going to melt your engine belt, and leave you on the side of the road. You have to get a shorter belt, and then route it opposite around the water pump and crank pulley. Basically you want the belt to run straight from the bottom of the crank pulley to the alternator, so that the tensioner has some leverage on it. I think mine is an 89.5" belt, part number 895k6, or 5060895, depending on the manufacturer. I have a smaller crank pulley though, but that's a good ball park number to start with.

Kurt

mostsmooth · Jan 13, 2021

revhead347 said:
It's virtually identical to the Fox. You just cap the vacuum lines that control the valves. It doesn't throw a code or anything.

Ditching the smog pump is actually a good idea. If you have ever taken one of those smog pumps apart, the reason becomes immediately obvious. Whatever designed these things needs to use a smog pump as a butt plug as far as I'm concerned. These smog pumps regularly seize up instantly, which is going to melt your engine belt, and leave you on the side of the road. You have to get a shorter belt, and then route it opposite around the water pump and crank pulley. Basically you want the belt to run straight from the bottom of the crank pulley to the alternator, so that the tensioner has some leverage on it. I think mine is an 89.5" belt, part number 895k6, or 5060895, depending on the manufacturer. I have a smaller crank pulley though, but that's a good ball park number to start with.

Kurt

yeah, im already bypassing the smog pump, just debating on taking the pump off or not

revhead347 · Jan 13, 2021

mostsmooth said:
yeah, im already bypassing the smog pump, just debating on taking the pump off or not

Oh yeah, that's totally up to you. It's not hurting anything just sitting there bypassed, and it doesn't hurt to take it off either. Makes no difference.

Kurt

Cheapskate207 · Jan 13, 2021

If you’re not using it I would take it off and meep
It in a safe place. Doing so would clean up the engine bay and reduce weight.

Mustang5L5 · Jan 13, 2021

If you have no cats, pull it off along with all the solenoids. Just make sure to cap the vac ports

mattys91gt · May 29, 2022

jozsefsz said:
Well its theoretical purpose was to inject air into the exhaust stream (first into the back of the heads while the car is warming up to heat up the converter more quickly, and then switching over to the converter itself to get it hot enough to burn more unburned fuel and to prevent the converter from fouling). If you have the stock catalytic converters, you could theoretically shorten their lives removing the air pump, though it's doubtful (and by how much - if your car burns a lot of oil it may be considerable) as they eventually heat up all on their own.

If you've deleted cats or installed moderns cats that don't require air injection, there is very little benefit. They also contribute to overheating tubular exhaust headers (even the stock ones) and shortening their lives, so pick your poison. Air pumps are also prone to failure and lock-up when the bearings go bad, as well as a little parasitic drag, and removal will very likely have no impact on tailpipe emissions (though visual inspections may get you a fail), so again pick your poison.

Now the EGR (completely separate) does have significant impact on your NOx emissions and will cause a tailpipe emissions fail (unless you retard your timing a bit). It'll also trigger OBD codes that need to be addressed. The ECU doesn't complain much about their air pump removal.

sorry it's a old post I'm having a issue with my EGR I keep getting code 84 and all the parts are new but the smog is gone so my vacuum lines aren't correct any tips

jozsefsz · May 30, 2022

mattys91gt said:
sorry it's a old post I'm having a issue with my EGR I keep getting code 84 and all the parts are new but the smog is gone so my vacuum lines aren't correct any tips

This is a good post on code 84 - it's geared towards the Fox but pretty sure it's the same setup on the SN95. https://www.stangnet.com/mustang-forums/threads/help-with-code-84-please.821845/

Labora · Jun 2, 2022

You can easily delete it on a GT.

If you have a Cobra the oil cooler water lines are in the way for a short belt so takes some other modifications.

mattys91gt · Jun 2, 2022

Labora said:
You can easily delete it on a GT.

If you have a Cobra the oil cooler water lines are in the way for a short belt so takes some other modifications.

it's just a stock 91 gt and I have a EGR block off plate but I got a new EGR idk if the lines I plugged are right and coming out of the fender / strut tower

smog removal still not a thing?

mostsmooth

Active Member

nickyb

I gotta say i never painted my nuts, Never Ever

Mustang5L5

That is…until I whipped out my Bissell

HemiRick

I'd be looking at jacking under the house

jozsefsz

7991LXnSHO

wanna catch the space herp

mostsmooth

Active Member

revhead347

Apparently my ex-husband made that mistake.

mostsmooth

Active Member

revhead347

Apparently my ex-husband made that mistake.

Cheapskate207

The left one hangs a little lower

Mustang5L5

That is…until I whipped out my Bissell

mattys91gt

Active Member

jozsefsz

Labora

mattys91gt

Active Member

Similar threads

smog removal still not a thing?

Active Member

I gotta say i never painted my nuts, Never Ever

That is…until I whipped out my Bissell

I'd be looking at jacking under the house

wanna catch the space herp

Active Member

Apparently my ex-husband made that mistake.

Active Member

Apparently my ex-husband made that mistake.

The left one hangs a little lower

That is…until I whipped out my Bissell

Active Member

Active Member

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