Smog:ok to eliminate?

ttt

This one's been beaten to death. Some people are fine with it (me), some people aren't (Michael). Search will net loads of good info.

I searched and stumbled across his unanswered post...

I have seen the different sides about pro-environment vs. pro-max power...

But what the heck does it do?

it sends air to the heads (when motor is cold) and to the cats (motor warm) to further oxidize HC's for emissions.

This one's been beaten to death. Some people are fine with it (me), some people aren't (Michael). Search will net loads of good info. Look for air pump or emissions.

HISSIN50 said:

it sends air to the heads (when motor is cold) and to the cats (motor warm) to further oxidize HC's for emissions.

Click to expand...

I took my smog pipes off before work today. The pump had been bypassed when I got it, but everything was still there. I needed the pump for my other car. I just took off the hoses up to the point where they split (one going to the exhaust, the other going into the head. Then I just capped the two check valves with vacuum caps. I noticed when I first started driving that the car ran a little rough and lacked a little power. When I left work, I let the car warm up to operating temperature before leaving. That time it ran fine. Could this be because of the cap on the pipe going to the heads? If so, should I remove the cap? I don't want anything flying into the head. I hadn't driven the car in a week and I also smelled a stronger presence of fumes.

Dont get the silly pulley thing: If you are going to remove things then celebrate in the cleanliness of a simpler enginebay, thats what I say.

The smog pump blows a light pressure stream of air into the back of the heads or to the catalytic converters. This is becuase unburned exhaust gases require oxygen to burn later on in the catylitic converters. If you have a _very_ well tuned car, then you will probably do better anyways but you will have less gasses to burn in your exhaust system since they burned in the chamber.

The factory system diverts air to the back of the heads or to the back cats as controlled by a mountain of stupid vacuum switches and wires and cables and tubes. To heck with that. All you need to do is cut all that out and hack off the one way pressure fitting (the bulb on the tube that goes to the back of the heads) and slip a hose from the airpump to the this tube. Now you are pumping air to the back of the heads 100% of the time. Pumping air to the heads is also pumping air to the cats but it's much much better because the gas combustion starts in the exhaust ports, then in the pre-cats (which arent fed air usually) and then finally in the cats themselves = much better emissions.

In the short run, pull all this crap off and get a shorter belt. This saves weight and cleans the enginebay (30 lbs). Remove the tab/tad solenoids and the field of tubes and hoses for that system. Remove the crossover in the back of the heads and plug the back of the heads with two bolts of the right thickness gooped in RTV. Dont get the official airport plugs or you will never ever be able to get them out.

When emissions rolls around, reattach the air pump and replace the crossover tube and run the hose as described above. The computer might complain that the tab/tad solenoids arent responding (since you took them out) so remove the check engine light's bulb.

Note that if your engine doesnt really run clean, your cats will be totally carboned up and useless exhaust restrictions so an offroad tube is a must in the longrun.

If you still fail emissions, replace the airpump pulley with an alternator pulley. It will sound like a cessna but it will pump loads of air into the exhaust (a supercharger for the emissions system). I did this and passed the sniffer with a carb. Dont drive it like that or the air pump will seize within minutes.

good luck man

Crazypete

US californians don't have the benefit of removing all that smog stuff. I need to move!

Are they really that bad in CA? I am planning on moving to San Fran within 5 years and taking my very "grey area" emissions mustang with me. Do they really pop the hood and look for the stock crap? Do they leave any area for modifications or do you need a CARB # for everything?

crazypete said:

If you still fail emissions, replace the airpump pulley with an alternator pulley. It will sound like a cessna but it will pump loads of air into the exhaust (a supercharger for the emissions system). I did this and passed the sniffer with a carb. Dont drive it like that or the air pump will seize within minutes.

Click to expand...

Interesting idea -- one I've never heard of before. But I've also never had a problem passing without an air pump at all, even on my carbed car.

i took mine off cause in canada we don't need to do any of that emissions stuff......, they're so easy here that to pass a vheicle inspection when you buy a used car you don't even need mufflers, as long as its sealed from front to back all is good...... any way here is a diagram that i drew out for myself so i remember how to route the belt........i don't have A/C and i have under drive pullies on, with this size belt you can still use the auto tension gauge to tell you when the belt is worn... so this may help you or not

Crazypete,

They'll look under your hood for the emmisions label to make sure the car is certified for use in California and they'll also check to see if the VIN #'s are good(meaning, they're not missing or scrathed off.) Just make sure your smog pump is still good and your cats are working properly.

Check out this site for all the good info:

www.dmv.org

Interesting, I have a carb instead of FI with a spacer plate with provisions for PCV, EGR and a tube for the Charcoal canister. My airpump runs directly to the x-over behind the heads without switching. I have longtubes so I sawed off the precats and rearranged and welded/clamped the stock hpipe to be a little snubby 4 cat pipe.

In other words, it's all there but its all been rearranged, messed with, replumbed. They're gonna gimme crap about that arent they? The emissions sticker? That factory ugly thing they stick to the fanshroud? I peeled that off years ago.

Not to hijack this homie's thread so I'll comment about removing emissions and my experiences:

Definatley sabotage your EGR. You're pumping hot contaminated air into your intake and filling your intakes with carbon! Remove your upper and look inside, it's black! It's only supposed to be an air tube. On top of this, you need to run coolant to the TB to remove the heat from the exhaust gasses running to the TB. Bypassing the coolant and the egr will cool your intake greatly (especially with a spacer plate inbetween the upper and lower intakes. ). People spend lots of $$$ trying to cool their intake charge and ford heats our intakes! I think removing the vacuum hose to the little drum on the TB will keep the EGR peg in the closed position.

Now the PCV also pumps vaporized oil smoke from your hot oilpan through your intake as well for recombustion. Definatley sabotage this too. Disconnect the hose from the filler neck and the back of the intake and run these hoses to the back of the car and dump it behind. This smokes a lot on a high mileage engine so dont dump it to the enginebay or there will be smoke everywhere. I learned this the hard way.

Now you have a clean, cold intake air charge heading into your chambers. No dilution. I know the exhaust gasses supposedly help the motor warm up faster but I've lived without them with a carb for 2 years now and driving this in the new england winters too.

The charcoal system is useless but harmless to leave in. Cap its tube and remove the cannister to clean up the enginebay a bit if you want. On the hottest hottest day of summer , the cap might pop off due to pressure from the gastank. Then you'll vent a bit of gas vapor to the enginebay while standing. No biggie. Just smells a bit like gas. I love the smell of gas

Good luck!

Crazypete

crazypete said:

Definatley sabotage your EGR. You're pumping hot contaminated air into your intake and filling your intakes with carbon! Remove your upper and look inside, it's black! It's only supposed to be an air tube. On top of this, you need to run coolant to the TB to remove the heat from the exhaust gasses running to the TB. Bypassing the coolant and the egr will cool your intake greatly (especially with a spacer plate inbetween the upper and lower intakes. ). People spend lots of $$$ trying to cool their intake charge and ford heats our intakes! I think removing the vacuum hose to the little drum on the TB will keep the EGR peg in the closed position.

Now the PCV also pumps vaporized oil smoke from your hot oilpan through your intake as well for recombustion. Definatley sabotage this too. Disconnect the hose from the filler neck and the back of the intake and run these hoses to the back of the car and dump it behind. This smokes a lot on a high mileage engine so dont dump it to the enginebay or there will be smoke everywhere. I learned this the hard way.

Now you have a clean, cold intake air charge heading into your chambers. No dilution. I know the exhaust gasses supposedly help the motor warm up faster but I've lived without them with a carb for 2 years now and driving this in the new england winters too.

The charcoal system is useless but harmless to leave in. Cap its tube and remove the cannister to clean up the enginebay a bit if you want. On the hottest hottest day of summer , the cap might pop off due to pressure from the gastank. Then you'll vent a bit of gas vapor to the enginebay while standing. No biggie. Just smells a bit like gas. I love the smell of gas

Good luck!

Crazypete

Click to expand...

i beg to differ a bit. the EGR passes spent gasses at cruise/part throttle, which improves economy and helps to cool the chambers. the puter dials in a lot of timing with the diluted mixture; delete it w/o telling the puter and you can see some good detonation. this might not be such an issue on a carb converted car, but something to consider on an EFI set up.

i would also run breathers on the PCV, as flow is bi-directional. with a MAF set up, you will be running unmetered air (also not an issue with no carb). a catch can and filter are a better solution on a N/A EFI set up, IMHO.

Pete - which emissions test did you pass - what state?

EGR is a win-win. It doesn't open at idle or full throttle, so there's no performance benefit to removing it. At part throttle, it cools the combustion chamber allowing the computer to add more timing, and to remove fuel for a leaner burn. This reduces NOx and increases fuel mileage. The only upside to removing a properly functioning egr system is cosmetic.

"I think removing the vacuum hose to the little drum on the TB will keep the EGR peg in the closed position." ??? That hose has nothing to do with the EGR system. It's there to provide metered make up air to the crankcase when there's intake vacuum; and to help vent the crankcase when there's little intake vacuum.

In most states that inspect Pete, your car wouldn't make it past the visual inspection to the sniffer -- for the simple reason of replacing the efi with the carb. The better inspectors would also bust you on the lack of charcoal cannister and no functioning pcv system. While you've been quite clever, you've also been lucky. By the way Pete - that open air filter up on top of the carb pulls in WAY MORE hot underhood air than having a functioning pcv or egr system.

My bad....

by the way, all of this commentary was for my old 87 5.0 lx stang that "passed away" a few years back <sheds a tear>

now,

I was operating under the assumption that the spent gasses are at exhaust temperatures: the same ones that burn 1500 degree ceramic paint off my headers. I cannot imagine that any byproduct of a combustion porcess would end up at less than atmospheric temperature (though there are strange laws of physics at work inside motors...like exhaust pulses that pull spent gasses OUT of the combustion chamber.). In my defence though, I was told the coolant is run to the TB to offset the extra temps from the egr so that led me to believe that the charge is hot.

I had blocked off the egr passage in my EFI with a cobra spacer that did not have the egr passage drilled. No negative effects. Maybe the EEC offset the appartent higher exhaust temps from the lean condition caused by extra air. It would be reported by the O2 sensor with an adjustment factor that richened the mixture a bit. Isnt that what the O2 is there for? Constant tuning? The EEC is supposed to adjust for the operating conditions and tune the engine as it ages and becomes less efficient. Even a speed density stang should be able to make such a basic adjustment I think.

I guess I was wrong about the little canister though. The passage behind it when removed looked _black_ with soot. Exactly the same as egr passage so the assumption was made.

Now the PCV definatley has no benefit to pump into the intake stream, of this I am sure. I have the pcv hose hooked to the pickup on the underside of the carb's dish aircleaner and you could see a brownish black streak from the hose's port torwards the carb as the vaporized oil reenters the engine. All this would do is gum up the intake, foul plugs and increase tailpipe emissions with the extra burning carbon.

At inspection time, I'm rolling with stock 4-cats, airpump to crossover , egr/pcv spacer plate hooked to hoses and charcoal cannister in stock location with tube run to aircleaner. Granted the last time I got it inspected, I had sneaky tubes dumping crankcase gasses into the fender, the h-pipe's airtube sneaked out the side, airpump with alternator pulley filling the exhaust pipes with fresh air and the carb crazy tuned to stoich, secondary side disconnected and a 3.5 power valve. When you go carb, you plan to do a little sneaky stuff at inspection time.

Maybe I should get a fake efi intake I could slide over the carb and some fake OEM wiring bundles I could toss on top of the engine and some hoses.

They dont strain themselves doing the visual inspection around here. As long as the tailpipe says what the machine wants to hear, everone's cool as long as your blinkers and wipers work and the wheels dont fall off while you're there.

Hmmm, would I gain anything by reintroducing the EGR spacer into the system? I have all the provisions necessary to reenable flow of EGR into the motor but I was operating under the assumptions that a fresh clean aircharge burns more fuel and makes more power.

I'm all for having everything in place in case someone makes a spot inspection.

I dont think manifold vacuum will operate that drum properly (or will it? You guys just turned my world upside down.). Would fulltime egr flow be devastating or beneficial?

I'll go get the 85 snorkel when next I see the junkyard

Thanks!

You're missing the fine points of egr Pete - combustion temps (before coolant removes any heat) are up in the 2000-2500F range. EXHAUST temps are what occur after the cooling system has removed a BUNCH of wasted heat from the process - because the metal can't stand up to it. Also, once that exhaust gas has passed through the head, intake manifold ports, and the cooled egr spacer it's at a MUCH lower temp than even the 1500F you referenced. But the bigger benefit of injecting it to reduce combustion temps is that it's inert - it won't support combustion. So the charge per unit volume doesn't have as much oxygen and fuel - and that reduces combustion temps.

So the simple answer is - Yes Pete, egr cools combustion temps. Engineers/engine designers have known for years that egr had the potential to be a win-win. It's just that it took the advent of electronic engine control to be able to control the amount and timing of the exhaust injection to take full advantage of it.

"They dont strain themselves doing the visual inspection around here." This is the main reason you've succeeded. Spend some time talking to folks in CA or some of the other tougher states, and that got a particularly anal inspector, and you'll see what they're up against. They'd NEVER get a carbed car to pass - especially if it was originally injected. They'd laugh you out of the inspection station.

Oh Pete - pick up an 85HO twin snorkel air cleaner for that motor and duct the air intake to the fenderwells or the front of the car (behind the grill). You're probably injesting 180F-200F degree air from the top of the motor and you LOSE 1/2%-1% HP for every 10F increase in intake air temp. It's why they run so much better when it's 30F outside.