So I am removing the dual snorkel on my 81 to clean up the engine compartment and get some more air flow after doin some reading it didn't seem to make much of a difference and j like the look of the open better.

There's 2 hoses coming off of the snorkel housing hat I am not sure what they are and if I should just plug them after i remove or if it will cause problems.

1 is on the drivers side it is connected to a big black rubber tube looks like it was some type of sensor for when the charcoals filter was there. Can I just cut that tube off and plug it?

The second one is on the passenger side. The small black tubes running from the auto therm ac to the front of the carb. Can I cut that and plug it as well or will it cause error.

Also I am replacing the valve covers and on the drive side one the tube coming off in front of the oil cap and going to the front of the carb can that be delegated it has a t junction on it.














They are all vacume lines, at idle i started the engine and plugged them and un plugged and did not see a difference.
I just dont know if at higher rpms something will be effected.

the small tube is what controlled the flaps inside the ducts to open and close.

the big one that was connected to the underneath of the charcole filter goes down to the canister.

the other one with a T that goes in side the valve cover and then to the carb not sure what that does.


The valve covers i bought on one it has 2 holes for a breether to be installed and the oil cap

the other just has a single hole.

so not really sure how to hook everything up with the open air cleaner and the new valve covers. Thanks!

 

A photo of the underside of your valve covers would be great to see if they have a special part in them. Like the ones in your current valve covers.

DUB

 

just took these

 

Any advice on how to get this to work without messsing up the vacume system would be greatly appreciated. Really looking forward to getting the cleaner on and fixing the oil seeps from the old covers

 

Those valve covers you bought are a huge downgrade to the stock magnesium covers that are on there already. Also by removing the stock air box you are going to lose the benefit of the cold air intake setup GM designed for the car.

 

I am going to home make manufacture something to direct cold air to the filter area. The stock box is very limiting in the amount of air it actually lets in.

So does anyone know what vacume lines are not needed?

 

you can eliminate both vacuum lines and plug them. sounds like your Evap canister in missing anyways. there's no sensor hooked to that line.

 

Really? Got any flow bench data to back that up, or just making wild guesses. The stock set up is more than adequate for any reasonable engine you may want to install.

Given your other post admitting you know little about engines, you're getting off to a bad start.

 

I am in the process of converting to a dual snorkel air cleaner. That is to say, my 78 came with a single snorkel and I have a dual snorkel mounted along with the radiator scoop. I have the two ducts that from the passenger side of the radiator to the air cleaner, but have not installed them yet as they require a different AC line with a 2 90* bends rather than the 45-ish bend the single snorkel cars have.

At any rate, I decided to go down this by taking a few throttle blades that I have and the inside area of a single snorkel box covers about 75% of the area of the throttle bodies. Now, the throttle body is going to have different pressure than the snorkels, but if I were to double that I can easily see the box flowing more than the engine requires.

All of that said, running with the dual snorkel air cleaner vs the single, I can hardly tell a difference. I'm at the point that I think the 10HP they claimed in the late 70's was a marketing ploy. At some point, I intend to dyno these boxes back to back and see what the numbers say.

My engine has a bit more of an airflow requirement than the stock 78 L-48 (or L-82) does, though.

 

SHARK RACER///go back in your last post and correct it. It is NOT a dual snorkel intake...but a 'dual snorkel air cleaner'. I know what you meant but others may get confused on how an intake can have a single or dual snorkels.

I have to agree...that using the dual snorkel factory air clearer and all pats will provide fresh air from IN FRONT OF THE RADIATOR to get in the engine versus an open element design.

And if you want to get kinda technical and comparing 'things'....look at the air intake at the throttle body of a high HP new Corvette and see actually how big it is....and then when you figure the surface area of this circumferences of the dual snorkels...I am sure they would be really close if not MORE.

I also would stick with the stock valve covers....BUT the ones that you show in your photos are OK because they at least have the oil baffles in them and a way to still keep you PCV system intact....which still needs to be plumbed to the valve cover ...in my opinion....and then TEST/CHECK to make sure the engine is GOOD by verifying that the PCV system is able to pull in fresh filtered air and not FIGHTING to keep up with an engine that has so much 'blow-by'...that the PCV is worthless....and the engine needs to be rebuilt. BUT this is AFTER ....REPEAT AFTER...a qualified person has confirmed that ALL GASKETS that seal of the crankcase area are intact. BECAUSE a PCV system that is NOT pulling in air from the opposite valve cover DOES NOT MEAN that the engine is bad....because you can have no sealer at the front and/or rear china walls of the block and this will make it so there would be NO air coming in at the valve cover where your fresh air breather goes as designed.

DUB

 

After I went to the trouble of replacing all of the thermal actuators, sensors, hoses, fittings and such on the top of the engine..., I got to studying the network of hoses and sensors and realized that they could only serve one purpose... degrade performance. As I had made a number of changes to the engine toward greater performance, I didn't want all of that 'stuff' negating it.

So, I studied the hose diagrams in my shop manual and realized I could bypass 95% of the connections. What I did:

I 'FIXED' the actuators in the air cleaner so they are always 100% open. Hoses are run to them but they go nowhere... they are there to imply 'connections made'. I found the passenger side snorkel's actuator never was fully open; even after warm-up. That HAD to hurt airflow. Now, both are open 100% all of the time (even during warmup). I do not drive in winter so icing is not an issue.

I removed/bypassed all of the (NEW) thermal sensors (I think there were three) in the intake and installed threaded plugs where they were.

I removed the EGR.

I kept the vacuum advance but run it off the carb port recommended by Lars

I kept the EVAP lines routing as it is an effective means for capturing gas fumes and running them back to the gas tank. I also had a new charcoal canister and hoses running to the 'y' splitter at PCV.

I kept the PCV hoses and PCV.

I kept the filtered pipe that exits passenger side of air cleaner and enters right rear of valve cover.

I kept the check valves/filter that are fed off the intake fitting that drives brakes and headlights.

After all was finished, the top of the engine is cleaner AND I have the snappy performance that is not hampered by all of the emissions junk that was added to contribute to a very poor performing L48.

NOTE: My engine is an L48 in name only (block, crank and rods). Also, since I had all-new hoses and fittings (spliced/cut and reduced), I was assured that I didn't have any lingering leaks from rotted hoses/fittings. It is a (newer) setup and has 0% issues.

 

Done - plenty of "cold air intakes" out there, but I understand what you mean. Air cleaner is more correct.

 

Thank you everyone for your input, I was able to finish today and it does look a lot better. I will post pics of it finished tomorrow, everything that needs to be working is still working and I plugged the things that didn't seem to make a difference.