What am I looking at?

[WFO]

I think I'd only put it on for inspections, and leave it off the rest of the time.

 

[SquareRoot]

Let me get this straight, it runs fine the way it is but you want to mess with it?

Maybe he wants to improve his gas mileage? You know every squarebody owner has to ask at least once.

 

[K5ride]

OPs getting a lot of **** for asking a basic question LOL. trying to get more air into the intake is like the most common “upgrade” made. It’s not unreasonable for him to ask if removing it would help. Engineers engineered **** for smog reasons a lot and not for efficiency. And sometimes for efficiency but suffered a few mpg. Also they would sacrifice both power and efficiency for cost cuts.

It doesn't go all the way to the top of the air cleaner lid. It is glued to the air cleaner bottom and stops a couple inches short of the lid. It should not affect air flow or volume. Also, air flows through the charcoal particles. It is not a solid chunk that would block flow. This system was set up for maximun engine effieciency and air flow while controling the hydrocarbons from escaping into the atmosphere.

 

[Paladin]

I think I'd only put it on for inspections, and leave it off the rest of the time.

Great minds think alike!! Such an easy way to keep something so simple from turning into rocket surgery!!! LOL

 

[Turbo4whl]

Maybe he wants to improve his gas mileage? You know every squarebody owner has to ask at least once.

Yeah, now that's funny! Good fuel mileage in a Square.

Fun Facts:

The GM Square trucks, dubbed as the "Rounded Line" were designed when gasoline was between 30 and 40 cents a gallon. No one was thinking about fuel economy.

Sure, through the Square years attempts to lighten the truck took place. The 12 bolt rear axles in the 10 and 1500 series was replaced with the lighter 10 bolt. The heavy transfer cases were gone along with the turbo 400, base automatic. Did you know that a turbo 400 shares some of the same size clutches and steels as an Allison AT540 MD trans?

Most of you know the glass got thinner but many little items went from diecast metal to plastic. Window cranks, Heater control brackets, and even the speedo gear box on the gauge to name a few.

You want better fuel mileage, rip out the power seat, power windows, power locks and the complete AC system to name some stuff you don't need. Put skinny high pressure tires on. This will get you a few miles per gallon.

 

[Snoots]

Dear God, What have I done?

 

[shiftpro]

Yeah, now that's funny! Good fuel mileage in a Square.

Fun Facts:

The GM Square trucks, dubbed as the "Rounded Line" were designed when gasoline was between 30 and 40 cents a gallon. No one was thinking about fuel economy.

Sure, through the Square years attempts to lighten the truck took place. The 12 bolt rear axles in the 10 and 1500 series was replaced with the lighter 10 bolt. The heavy transfer cases were gone along with the turbo 400, base automatic. Did you know that a turbo 400 shares some of the same size clutches and steels as an Allison AT540 MD trans?

Most of you know the glass got thinner but many little items went from diecast metal to plastic. Window cranks, Heater control brackets, and even the speedo gear box on the gauge to name a few.

You want better fuel mileage, rip out the power seat, power windows, power locks and the complete AC system to name some stuff you don't need. Put skinny high pressure tires on. This will get you a few miles per gallon.

Run propane with 10.5 - 11/1 compression. Anything bigger than a 350 will need 2 mixers (propane carb, Impco 425). The second mixer and regulator
(evaporator) can be on an electric solenoid gas valve. You can run on one carb but power will be low. Hit the Mad Max switch for the second carb and ROAR!

 

[Snoots]

Run propane with 10.5 - 11/1 compression. Anything bigger than a 350 will need 2 mixers (propane carb, Impco 425). The second mixer and regulator
(evaporator) can be on an electric solenoid gas valve. You can run on one carb but power will be low. Hit the Mad Max switch for the second carb and ROAR!

I'd hot wire it! Forget the switch!

 

[Kevin James]

OPs getting a lot of **** for asking a basic question LOL. trying to get more air into the intake is like the most common “upgrade” made. It’s not unreasonable for him to ask if removing it would help. Engineers engineered **** for smog reasons a lot and not for efficiency. And sometimes for efficiency but suffered a few mpg. Also they would sacrifice both power and efficiency for cost cuts.

lol I appreciate all the answers. I just wanted to know what it was and I guess I could’ve asked a less vague question. For example, is this piece OEM? Lol it’s all good though. I really appreciate every ones input. Thanks y’all.

 

[Raider L]

@Turbo4whl
Are those things like real fine screens? I've never seen anything like that either. Is that the paper filter in between? So there's one on the outside and one on the inside? Flame arrester? Flames from where, a carb backfire or something? Is it so prone to having flames coming from the carb that GM had to go to this extreme? I think it might be for flames on the outside?

@K5ride, It had to have been for something else otherwise those filter things wouldn't be one there. And since so many of you have them on your trucks and have seen them on other trucks than under what circumstances are they installed, and sold like that to whom? For what purpose? Like, aux. firetrucks out in Calif.??

 

[Turbo4whl]

@Raider L

If you check this vacuum diagram for the decel valve and the charcoal evap can, they each share a larger vacuum port to the PCV hose. That hose draws vacuum below the throttle plate. They also share a hose to the breather filter in the air cleaner.

You must be registered for see images attach

Somehow the engine could backfire on deceleration. Maybe because of the extra advance with the ESC system? Or sparks entering through the EGR valve? GM would not have added the decel valve if it wasn't necessary.

My though is the spark arrestor is a failsafe in case some other engine control, like the decel system, fails.

 

[Rusty Nail]

Maybe he wants to improve his gas mileage? You know every squarebody owner has to ask at least once.

Got ne tips?



I have a squarebody..or two maybe...
Maybe I need two tips huh? Whatchugot on better mpg?? I need some.


Need some?

 

[K5ride]

@Raider L
Like I said, it's part of the fuel evap system. It is filled with charcoal particles. I see these all the time while performing smog inspections here in California. If you remove it, you will fail the visual portion of the inspection. There is also a fuel vent hose that connects to it through the bottom of the air cleaner. Simple and effective system that got used for years with carburetors.

 

[K5ride]

A decel valve has nothing to do with backfiring through the carb. It opens the throttle plate a little to let air flow into the engine and exhaust to burn the unburned fuel / rich mixture caused by the rapid throttle closure at higher rpms.

 

[Raider L]

@Kevin James,

Welcome to the forum from Louisiana.