Air filters or no?

[Milwaukee Midget]

Mark flowbenched my 45 DCOE Weber both with and without a K&N Filter.  I don't recall the numbers, but the numbers were insignificant enough to warrant retaining the filter.

 




Conversely, when we put foam filters on the air horns, at 28 inches of water, it darn near sucked the filter into the carb.

[Esslinger Eng]

It's super common for the higher hp turbo engines to gain 50-100hp by removing the air filter from the turbo inlet.

From my experience, your "plenum" right on the turbo inlet is actually worse than having nothing at all on there...

How concerned would you be about running an air filter at all ?

I'm not all that worried about it, but my father is.

I would run a filter at least untill you're to the point where you're usilizing all the power you can get.  It'd be better to up the boost 3-4psi and run a filter in my mind!


Maybe Rick Mc Inroy will chime in here with what he saw in the intake manifold plenum?  His car has a forward facing hood scoop that ingested salt last year.  He says that he could see the salt coming up off the front left tireand crossing the hood due to the crosswind...

[wobblywalrus]

There are too things to worry about with air filters.  One is having them large enough to not cause a restriction.  The other is having them big enough to filter correctly.  My experience says it i good to discuss both of these aspects with the filter manufacturer.

 

[wobblywalrus]

Today I looked at my notes.  First I ran open intakes and there was a lot of scratching on the piston skirts.  Next, oiled gauze pod filters were tried for the second build.  They were pretty small and they did not filter very good.   After that oiled foam filters were tried.  Vizard's 3.5 square inch filter surface area was used to calculate the horsepower they would support.  It was 250 HP per filter and the bike made 46 per cyl.  Scratching was reduced on the skirts.  Finally, some big oiled foam filters were installed.  They support 322 HP each according to Vizard's flow value to not cause restriction.   The skirts have no scratching and the wear surfaces and nice and shiny and polished.  This equates to about 1.8 engine HP per square inch filter area.

Bikes have short and open intake tracts compared to cars and there is pulsating flow at the bell mouth inlet.  My guess is the big filters are needed to compensate for this.  I really do not know why, but the big filters are needed to keep the salt out of the engine.     

[Dynoroom]

I think it depends on where the inlet air is located on the car......

None of these cars use air filters........

Many others I can show but the point is..... it depends on the car & where the inlet is. YMMV

[Bob Drury]

  About ten years ago Gary Vail spun the Geisler, Vail and Hizer Studebaker and afterwards found salt in the combustion chambers.  They were running a v6 Buick with spril dominators and they were running a low snout scoop on the hood which followed the contour of the hood.
  Apparently the spin kicked up enough salt that it was at least 30" +or- high.
  Why was the motor still running?  You will realize why the first time you spin.........................
                                                                    One Run................

[Buickguy3]

  The scoop on our car in my avitar picks up Salt thrown up by the front tires. We built some Salt deflectors to direct the Salt higher up and away from the inlet but we were told that they couldn't be used because the car is running as a lakester. Another problem was on a damp track they throw up a Salt mist that drys instantly on the canopy and makes seeing the mile markers impossible. [ask me how I know that] 
    Doug 

[JR529]

I always thought of an air filter as a life extending product. Kind of like eating healthy and not smoking. But since race engines run hard and fast, and almost always get rebuilt at ridiculously short mileage intervals, then why not let them enjoy a bacon cheeseburger and smoke a few while they are doing their business?

So, on my street cars and push truck, definitely. On my race engines? no, I just make sure the scoops are pulling clean air and no salt or dust gets in under normal operation. I also try to make sure no big chunks of stuff can get into the turbo impeller. So far I have never had to replace a turbo because of compressor damage. I always ruin them long before they get to that point by ejecting hot valve parts through the exhaust side first.  

Also, keep in mind that we run alone, never in packs and never directly behind another vehicle. That is the condition where lots of crap gets kicked up and ingested by the trailing car. I would definitely run a filter on any engine where you may be following another vehicle.

Also, I run a turbocharged, inter cooled engine. My complete intake tract is a convoluted set of passages and tanks and what not. It would be very difficult for a solid mass of any size to make it to the engine. N/A guys have a different set of conditions. 

Just my opinion, YMMV  

[Seldom Seen Slim]

I guess it's time to offer this information.  It's about our motorcycles - and the proclivity of salt to get into the air intakes.

And the intakes on both the 12 and 14 are mounted above the front tire and just behind a vertical plane of the front of the front tire.  In other words, the salt has to get thrown forward as well as up to be in the right place for ingestion by the time the scoop is at that point.

Another way to say that is the salt manages to get to the vehicle - the scoop - far sooner than the scoop mounted as on Doug's car, for instance.  Just 'cause your air intake is just about even with the front tires won't protect it from getting salt in it.

[Hot Rod Lincoln]

I have a couple of good ideas I'm working on that should work without having to rebuild the front of the car. It's amazing to run out of space after putting a 4 banger where a v-8 used to sit. 

[Hot Rod Lincoln]

 I wish K&N had a CFM rating on their filters.

Thinking about building the air box we need then rearranging water line, radiator brackets, and (the big thing ) moving the intake manifold plenum. It will be some work, but shouldn't limit ourselves to what's there to work around. build the air intake system to what we need and then make the other parts work.

Would have our fab guy build a mounting base then sandwich 2 of these 5"x9" filters then either use a solid lid to hold them together or one of the K&N XStream air flow tops the 9" diameter one.
 http://www.knfilters.com/search/product.aspx?prod=E-3650&pkid=1618190&rw=1

I'd think allowing the turbo to feed air from all sides ( filters will be horizontal mounted to the compressor) it wouldn't lose much and having basically 10" long by 9" dia should allow all the cfm needs it would have.  

it will mount just like the screen

[Buickguy3]

   After K&N told us we should have more filter area than the 10X12 filter that we were using we built this box. One 10X12, two 4X12's, and two 4X10's. Seems to work and keeps the Salt out.
      Doug 

[Hot Rod Lincoln]

  After K&N told us we should have more filter area than the 10X12 filter that we were using we built this box. One 10X12, two 4X12's, and two 4X10's. Seems to work and keeps the Salt out.
      Doug  

how many cubic inches are you feeding and hp level?

the other option is something like you did with 4 8x10's and an end cap

[Sumner]

   After K&N told us we should have more filter area than the 10X12 filter that we were using we built this box. One 10X12, two 4X12's, and two 4X10's. Seems to work and keeps the Salt out.
      Doug 

Nice  



Do you have any more pictures of the other side and such.  I'd like to see how that is connected to the compressor.  Thanks,

Sum

[Buickguy3]

 I don't, but it's not totally sealed up underneath. On the compressor we have a 4" by 90% elbow that just sticks through a 4" hole in the bottom under the filter pac. Probably could have put a little stub on the bottom and slid it over it but it is kind of a pain to get on any way and we were just trying to stop the big pieces of Salt from getting in. It seems to work as the Salt just lays on the top filter now.
   Doug