Round to square air filter mod

[cober]

 

[joney]

"I don't want to use this crap anymore!" And you toss it! Makes sense to me. It appears the flat filters MAY have more filtering surface (SOHC here). Oddly though I've seen a lot of people on this forum make the opposite change - don't know if the filters they are using are some advanced type rather than stock.

 

[Mbrooks420]

A round filter would have more surface area.

 

[cober]

"I don't want to use this crap anymore!" And you toss it! Makes sense to me. It appears the flat filters MAY have more filtering surface (SOHC here). Oddly though I've seen a lot of people on this forum make the opposite change - don't know if the filters they are using are some advanced type rather than stock.

people are strange

 

[Josh P]

"I don't want to use this crap anymore!" And you toss it! Makes sense to me. It appears the flat filters MAY have more filtering surface (SOHC here). Oddly though I've seen a lot of people on this forum make the opposite change - don't know if the filters they are using are some advanced type rather than stock.

I swap my cars to the round type filter, sucking hot air from the engine bay. I see 1-2 mpg increase.

 

[cober]

ahaha

 

[joney]

I swap my cars to the round type filter, sucking hot air from the engine bay. I see 1-2 mpg increase.

So you're getting cooler air in? Sounds good for summer I think.

 

[Josh P]

So you're getting cooler air in? Sounds good for summer I think.

No, warmer air for better mpg. I have not noticed any loss of power, even on the 120 degree days.

 

[cober]

What makes you think that air will be warmer with round filter?

 

[Mbrooks420]

He’s taking about a “cold air” intake, I assume.

 

[cober]

go figure

 

[Josh P]

What makes you think that air will be warmer with round filter?

Not the shape, it is where I located the filter. The square filter works fine. When I buy a used car I'll run the stock filter till it needs to be replaced, then throw out the filter box and put a round filter on the end of the intake tube.

 

[donalds]

My Functional cold air intake if you look you can see this box seals on the hood and gets air from inside the front fender

 

[cober]

Not the shape, it is where I located the filter. The square filter works fine. When I buy a used car I'll run the stock filter till it needs to be replaced, then throw out the filter box and put a round filter on the end of the intake tube.

but why?

 

[Josh P]

but why?

Because better fuel economy.

 

[joney]

Always heard you want colder air coming in, but maybe just if you have a turbo or supercharger. Getting air from inside the front fender - then not the hot air under the hood? Never heard of wanting hotter air coming into the intake, but Josh, you're already in Phoenix, so you must be getting some really hot air into your intake. And it improves fuel economy? I've the stock square filter, assumed it was getting air under the hood but no idea really.
You all know I'm a noob about most auto repair/mods so it's interesting finding out here!

 

[Josh P]

Always heard you want colder air coming in, but maybe just if you have a turbo or supercharger. Getting air from inside the front fender - then not the hot air under the hood? Never heard of wanting hotter air coming into the intake, but Josh, you're already in Phoenix, so you must be getting some really hot air into your intake. And it improves fuel economy? I've the stock square filter, assumed it was getting air under the hood but no idea really.
You all know I'm a noob about most auto repair/mods so it's interesting finding out here!

Same principle as when people change their thermostat, cooler for performance and warmer for fuel economy. My van logged 500 to 800 miles a week for years working for the cable company. I gained a consistent 2 mpg with the air filter sucking the air from under the hood. A4LD to manual transmission swap was another 2 mpg gain. The fuel tank is 21 gallons and I can go 550 miles before I start looking for fuel. I also ran it on E85 while working in Oklahoma city for 3 months in the winter and it somehow got .6 mpg better economy than the ethanol free gas sold there.

 

[Mbrooks420]

Exactly. Cold air is more dense so the car can add more fuel for the same volume of air. With warmer air it runs slightly less fuel. Since the density of the air is changing it doesn’t run richer, or leaner, just a different volume of fuel mix.

 

[cober]

In a flat filter air comes from behind the headlight and in a round one - from inside of the fender. And why do you think that it's different?

 

[donalds]

In a flat filter air comes from behind the headlight and in a round one - from inside of the fender. And why do you think that it's different?

Its no different you are correct