What does the flap do on an air cleaner?

[Lorenzo]

This may sound like a dumb question but i have no clue what the flap is for on the air cleaner 😳 Today i looked at it while the car was running and it was open. I have headers so i dont have the manifold pipe going in so is that bad? Also what are the perks of switching to a different air cleaner with no snorkel?

 

[Dr. Rudy]

is it a flap in the snorkel? if its the one where the chimney pipe coming up from the manifold connects then as the car warms up it opens. its a fuel atomization mechanism i believe. changes the airflow as the engine warms up.

 

[Lorenzo]

is it a flap in the snorkel? if its the one where the chimney pipe coming up from the manifold connects then as the car warms up it opens. its a fuel atomization mechanism i believe. changes the airflow as the engine warms up.

Yes its that one, but like i said i no longer have manifolds so i dont have that heat pipe. Is it bad to have it like that?

 

[anakputa]

Are you running headers? you can actually by an aftermarket adapter that clamps to tube, if you have an aftermarket air cleaner then don't worry..

 

[Lorenzo]

Are you running headers? you can actually by an aftermarket adapter that clamps to tube, if you have an aftermarket air cleaner then don't worry..

Yes i am running headers. This is do you gain some performance and efficieny switching to an aftermarket aircleaner? Because ive been thinking of doing that...

 

[Bonnewagon]

It is called THERMAC, and what it does, is it feeds a constant incoming air temperature of approximately 100º to the carburetor. It does this by blending hot air from the exhaust manifold tube and cooler engine compartment air from the snorkel via a temperature sensor inside the air cleaner and the vacuum operated flap. The carburetor is calibrated to operate with the 100º air for good driveability, mileage, and emissions. Warm up time is shorter and smoother. On a stock motor if the hot air tube is missing or malfunctioning the motor runs crappy in cold weather, especially those cold wet nasty days. On a hot rod you don't need it, since you only drive it on nice sunny days and let it warm up for as long as it needs.

 

[Lorenzo]

It is called THERMAC, and what it does, is it feeds a constant incoming air temperature of approximately 100º to the carburetor. It does this by blending hot air from the exhaust manifold tube and cooler engine compartment air from the snorkel via a temperature sensor inside the air cleaner and the vacuum operated flap. The carburetor is calibrated to operate with the 100º air for good driveability, mileage, and emissions. Warm up time is shorter and smoother. On a stock motor if the hot air tube is missing or malfunctioning the motor runs crappy in cold weather, especially those cold wet nasty days. On a hot rod you don't need it, since you only drive it on nice sunny days and let it warm up for as long as it needs.

So If i only drive it when Spring comes around i dont require it? Also does an aftermarket air cleaner with no snorkel give you any noticiable difference in the way the car dives and mileage wise?

 

[Bonnewagon]

Definitely at WOT, but otherwise in normal driving, no. What I do is keep the THERMAC hooked up for Winter and disconnect it for Summer. But even in Spring and Fall we get some snotty weather and the motor runs crappy until it's thoroughly warmed up. Of course when it's 90º you want as cool air as you can get in there.

 

[rustyroger]

Keep a snorkel to feed cold air to your carb if you want maximum power, an aftermarket air cleaner looks cool but it will take in air at underhood temperatures, not good for hp.

Roger.