I've got an AAM intake (similar to JWT in design) on a '05 Enthusaist...I was planning to remove the filter for an upcoming autoX event.

I'm worried that w/ the MAF being so close to the inlet, that removing the filter may cause the airlfow to change around the MAF and augment it's readings - anyone w/ practical expeirence in this area??

(There's a good deal of people that run w/ out filters for these events, so I think it's a low possibility of ingesting something that would hurt the engine)

Thanks!
Peter

 

I wonder what would happen if a pebble flew in there at WOT?

 

Why, at most you may gain 1/4 Hp, just not worth the risk.

 

driving without a filter is stupid and will damage your engine

 

don't do it.

 

naw, let him do it then when he starts a thread about how bad his car is running, that can be used as an example of what not to do. though anyone with half a brain can figure out that running a car with out a filter is just plain stupid.


good luck OP

 

I've never understood this fascination. How about no fuel filter either...that silly thing just slows the fuel down...Oh, another good trick is to take the oil out, and put in something thin and slick, yup, you know its Olive oil. its lighter and your pistons will go up and down w/ less resistance. Do it!

 

hummm...I was asking about air flow and how it may effect the MAF readings - anyone have a comment on that?

(I know the risks of running w/out a filter - I wasn't asking input on that portion)

 

I would not only remove the filter, but the hood, engine, and transmission as well. With the 1500+ lbs weight savings, you'll be faster than ever.

Of course, you'll need an autocross course set up on ice, down a glacier, with a massive tailwind.

Don't forget to take video!!!

 

I recommend dismounting the tires to autox. Always yielded me better times.

 

Sure, run it without a filter... That filter only restricts the air flow anyway.

 

bunch jerks just dont know how to answer the question he asked. I remember my filter came off my intake and it felt as if the car almost wanted to stall when comming to a stop.

 

^I've heard the same.

First350,
The only way to know is to try.

 

There's one reason you haven't gotten an answer...no one here is "gutsy" enough to try. we have fears of motors blowing up and stuff like that.

So if you want to find out, try it. nothing permanent will happen to the MAF (unless a rock, sparrow, or some other debris takes it out.)...car may not run w/o it, or you may get a CEL....but put it back, reset ECU and its fixed.

We're all commenting b/c your taking a huge risk for no gain.

Even if you could pull in a lot more air. The engine is a pump, what goes in much come out. not to mention this pump is controlled by a snobby computer.

 

thanks for the response guys - I doubt I'll have time to actually test this before the event, so I'll probably mess w/ this afterwards as a side project. (sounds like the filter may help to smooth the flow out so that the MAF gets an accurate reading...)

I've been searching to try to find the Delta P (pressure drop) across an air filter...I lucked out and found someone that had that data and also the delta P for no filter at all - assuming the Z's filter area to flow ratio is similar, the Delta P's should also be similar: http://www.bobistheoilguy.com/airfilter/airtest2.htm
*it's good to see real data showing that the actual gains from removing the air filter is minimal - at some point I'll have to run a similar test on my Z.

 

What is the reason behind wanting to do this?

 

While I agree that it is kind of foolish to run without an intake filter, I also think it's ignorant for people to answer a question that wasn't asked. If his initial post was "Is it stupid to run without a filter?" then most of the replies here would be appropriate.

Anyways, I can say from personal experience that a couple months after I installed my popcharger I noticed that the car was hesitating to start and bogging down a little bit when starting out in first gear. I let it go for a couple weeks then finally popped the hood open and found that the filter had fallen off and was just sitting in the heat shield. I must have undertightened the clamping collar, or positioned it in the wrong spot or something. At any rate I was running the car for at least a couple of weeks probably without any air filter, and I felt lucky that nothing got in there to damage the MAF sensor or make its way through the throttle body and plenum and into the intake manifold. I cleaned the MAF sensor and put the filter back on and everything seemed to go back to normal. So I wouldn't intentionally do this 'modification'.

 

power gains / throttle response (same reason ppl switch to other air filters...it's just taking it 1 step further).

*I've seen several people run w/out a filter in both AutoX and drag racing...and I'm not talking about random crazy drivers w/ 1/2 a brain.

 

thanks for your help - it's another confirmation that the airflow may do something funny around the MAF if there's no filter.

 

Seems to me that without the filter the air flow will have no "shape" if that makes any sense. It might not even be the geometry of the filter as much as the effect of the contoured plate that sits behind the filter, which creates the 'Venturi' effect in the flow, I believe. I'm not sure if this is accurate but I think that contoured plate helps the air flow to be more laminar (uniform) / less turbulent, which should result in the MAF sensor being able to sense the air flow most accurately.

I say that the shape of the filter may not be the main factor in performance because I can run a rectangular K&N filter in a stock airbox with Venturi plate, or I can run a popcharger cone filter with the JWT contoured mounting disc and I seem to get pretty much the same engine performance either way. But maybe the difference there is intake temp vs. filter shape, i.e. the panel filter in the plastic airbox will have decreased flow but lower temp. air charge, while the JWT cone filter has better flow characteristics but higher temp. air charge. Who knows...