I think if they made that much difference in performance, every truck would have them. If it were me and I wanted to do have dual outside air filters, I would find a truck that already had them rather than adding them on, after the fact. Those canisters are very expensive. According to everything I have read about wind resistance, those outside filters provide a lot of drag and take a lot away from your fuel economy. They do look cool, though. :wink:

 

I seem to remember reading somewhere that the outside filters pulled in cooler air and that helped some but not enough to offset the drag created by them.

But alas, I have no evidence to back any of this up. But this is the internet so I will just claim it as fact. :lol:

 

Without having a Phd in science or aerodynamics, I'd be willing to bet they wouldn't do you any good, then look cool. Not sure what the cost would be, but more then likely would cost you in the long run. What ever benefit of cooler, denser air would be thrown out the window with the extra drag you'd create, and the cost of buying, installing them. Just my thought.

 

Dual air cleaners are more efficient than a single and will stay cleaner longer. That being said it's a lot of work to put them on a truck that didn't have them to start with. Freightliners of that era did come with them so you could get all the pieces. Fuel mileage wouldn't be affected doing your kind of work. For my money I'd try to find a bigger one that fits under the hood. Usually you can't go too big on air filters. If your filter restriction gauge works you can use this to see how plugged your filters are. Every two weeks seems a little soon for it to be plugged.

 

They'll increase your mileage by 32% and prolong your engine life by 33% and you can double these figures if you put chicken lights inside them so they glow purty.

If I was you, I'd put on FOUR air cleaners.

 

:roll: :roll:

 

Here's where they got started http://www.vortox.com/

One thing they don't do is Rust.

I saw and old Pete that was in Calif. all it's life ( dry state ).
The 2nd owner said that the air filter ( outside mounted ) rusted on the inside dropping big flakes off that the Turbo sucked up.

The filter didn't pick them up because they were past the filter...inside.
He said it took out two turbos before they figured out what was happening.

 

the trucks are built for optimal performance, so I would say that it wont do any better by changing them, but it does make the truck look better
(in my opinion)

 

The cost alone might scare him off the idea, I bought two new ones for my kenworth and they were over $900 each. I would say if your truck didn't have two external mounted aircleaners already, I would just leave it as is.

 

Thanks everyone for your advice and input. After seeing what the initial cost would be, I will stay with what I have now. Man those are more expensive than I thought. I appreciate it very much.