Rain+Cone Airfilter question

[dylokjai]

I am already having issue the first i washed my car forgetting to cover it up what happen when it rains? beside customing a plexiglass type cover as i saw in another thread.

[traintech86]

my car came with that setup and the PO cut out a piece of sheet metal to cover it. i am going back to the stock intake tho so i won't have to worry! GL

[mr3]

Get some magnets and put it over the vent. I'm going to move the battery to the frunk then put a 45 of the intake manifold and then the filter by the battery tray to keep it dry. I'm not even sure if I'm keeping the cars though so progress has slowed down pretty good and that hasent been done.

[Oteck]

whats wrong with a little free water injection

[ToyotaTechGeek]

i've seen these devices that work with the clamp to secure the air filter. they cost like $20 at Auto Don't.

[ToyotaTechGeek]

Originally Posted by traintech86

my car came with that setup and the PO cut out a piece of sheet metal to cover it. i am going back to the stock intake tho so i won't have to worry! GL

why? does it work?

[traintech86]

remember? i told you the PO had a cone and you advised me that the stock intake is worth keeping. well this morning after i get outa work i will be putting the stock one back on.

[LokiRx7]

AIR FILTER HEAT SHIELD BMW E36 E46 318/323/325/328/330:eBay Motors (item 400084032253 end time Nov-14-09 17:06:40 PST)


Cheap, EASY, works great, Ive had one on my car for over a year.

I also have one on my girlfriends 2, it rubbed the bottom of the engine lid on my car, but not her's. Never hurt the paint on the engine lid.

You can paint stainless so you could easily change the color. I posted a thread on this before it really needs stickied or something.

Just go to eBay and type in "Air Filter Heat Shield" you'll find them, they are universal so dont worry about the make and model in the title.

Reference pic from before I installed this part....

[ToyotaTechGeek]

^ yeah that is the same thing they sell at Auto Zone.

btw: that air filter appears to be too small. i'd be curious to know what sort of CFM numbers you get with that thing.

[hellbillylarry]

Put an elbow on it and point it down. You'll get better intake temps and won't have to worry about rain at all.

[LokiRx7]

Originally Posted by ToyotaTechGeek

^ yeah that is the same thing they sell at Auto Zone.

btw: that air filter appears to be too small. i'd be curious to know what sort of CFM numbers you get with that thing.

....Its a daily driver, not a race car. I dont particularly care about performance, although I get high 30's and occasionally low 40's whenever I average fuel economy.

If it somehow is affecting performance, which I doubt it is, I would say it is possibly restricting 1/3 to 2 horsepower.... So I dont care enough to change it out. When I do auto-x it it does fine, I can post times as fast or faster than our local STi.

Sorry if I sound like an ass, just the average CFM an air filter pulls just seems so trivial to me. But then again I am not looking for every last hp I can find.

EDIT ::

We did do a test on Rx7Club years ago to find the average CFM a 12a could swallow. It wasnt much, considering I have stock injectors, stock intake manifold and the stock throttle body, I can promise you it is receiving all the air it needs. Adding an Air filter that far outflows the stock airbox doesnt add much power because the car will breath in only as much as it needs, and with the stock intake, afm, and injectors... It doesnt use much, if any more than the stock airbox would provide. Really? Do any of you honestly think Toyota would have put such a restrictive airbox on the car that a cone filter would magically free up a ton of power?

That said, I have a cone filter simply because my stock airbox was full of rust and the rubber intake pipes were dryrotted and cracked. The cone filter was a cheap and simple fix. And it frees up alot of room to work in.

[toyotaspeed90]

there won't be any damage to the engine from the small amounts of water that will come through the filter there.... you could probably even spray a hose on it and it would be fine...

hydrolocking only occurs when the filter is completely submerged in water.... in that there is no air to pull through... air is lighter than water and will be pulled through before water.... If small amounts of water gets through.... all you'll do is create some steam in the cylinder and probably wash some carbon off.

Funny how people on here are more than willing to dump seafoam through their engine and then are concerned about a little rain

[LokiRx7]

Originally Posted by toyotaspeed90

there won't be any damage to the engine from the small amounts of water that will come through the filter there.... you could probably even spray a hose on it and it would be fine...

hydrolocking only occurs when the filter is completely submerged in water.... in that there is no air to pull through... air is lighter than water and will be pulled through before water.... If small amounts of water gets through.... all you'll do is create some steam in the cylinder and probably wash some carbon off.

Funny how people on here are more than willing to dump seafoam through their engine and then are concerned about a little rain

Have you ever tried starting a car with a sopping wet air filter? Apparently not, even on the seafoam container it tells you to fully warm up the engine, and warns you not to let the car die while you are adding the seafoam. Its the same with carb cleaner, Ive had a car sputter and die when I was cleaning the carb. Its a BITCH to start it even when its hot, its worse when its cold.

Before I had this piece of stainless over my air filter I came out one day after it had been raining all night and my car wouldnt start. I had to take off the air filter and pull all the spark plugs and turn it over a few times to clear out the cylinders. Even after that I barely got it started.

[toyotaspeed90]

Yeah... I live in a pretty wet climate here in WA.....

if you had to pull your spark plugs to clear out the cylinders because of rain water hitting your filter then...

your filter seems to be pointing so water can travel downward into the TB.

your TB must have a decent sized leak in it

you must have filled your intake manifold, as it is chambered to 8 runners

your intake valves must have some nasty leaks on them


if all is the case... then a wet air filter isn't the only problem.

a wet air filter will still have webbing that is open to the air.... plus you should have more than enough compression to pull air through any thin layer of water that may build up on the filter.

[LokiRx7]

Originally Posted by toyotaspeed90

Yeah... I live in a pretty wet climate here in WA.....

if you had to pull your spark plugs to clear out the cylinders because of rain water hitting your filter then...

your filter seems to be pointing so water can travel downward into the TB.

your TB must have a decent sized leak in it

you must have filled your intake manifold, as it is chambered to 8 runners

your intake valves must have some nasty leaks on them


if all is the case... then a wet air filter isn't the only problem.

a wet air filter will still have webbing that is open to the air.... plus you should have more than enough compression to pull air through any thin layer of water that may build up on the filter.

Wow your amazing, go soak a sponge until its sopping wet. Put your lips on it, suck in, see how much air you get....

My air filter was SOPPING WET,

In order for a car to start it needs fuel, air, and fuel. WATER even trace amounts in the fuel makes it difficult to start the car,

Again, pour some gas on the ground put some water in it, stir it around, try to light it....

Put some seafoam in your car, while its not running, try to start it....

See here is the thing, the car draws air THROUGH THE AIR FILTER, if there is water in the air filter the car will INHALE IT! The same way as if your lips are smack dab up against a sponge. I dont know how I can break it down anymore than that....

You must be right, a wet air filter cant be a big deal, because NOBODY ever talks about covering it up and keeping it dry right?? Because the only reason I want mine dry is because I want a ton of carbon build up, not because I have problems starting my car...

Yeah my intake valve leak like crazy also when I crank the car, because they suck in all kinds of air, matter of fact now that you say that my throttle body has a HUGE hole in it, Im gonna go patch all that up...

[ToyotaTechGeek]

Originally Posted by LokiRx7

....Its a daily driver, not a race car. I dont particularly care about performance, although I get high 30's and occasionally low 40's whenever I average fuel economy.

If it somehow is affecting performance, which I doubt it is, I would say it is possibly restricting 1/3 to 2 horsepower.... So I dont care enough to change it out. When I do auto-x it it does fine, I can post times as fast or faster than our local STi.

Sorry if I sound like an ass, just the average CFM an air filter pulls just seems so trivial to me. But then again I am not looking for every last hp I can find.

EDIT ::

We did do a test on Rx7Club years ago to find the average CFM a 12a could swallow. It wasnt much, considering I have stock injectors, stock intake manifold and the stock throttle body, I can promise you it is receiving all the air it needs. Adding an Air filter that far outflows the stock airbox doesnt add much power because the car will breath in only as much as it needs, and with the stock intake, afm, and injectors... It doesnt use much, if any more than the stock airbox would provide. Really? Do any of you honestly think Toyota would have put such a restrictive airbox on the car that a cone filter would magically free up a ton of power?

That said, I have a cone filter simply because my stock airbox was full of rust and the rubber intake pipes were dryrotted and cracked. The cone filter was a cheap and simple fix. And it frees up alot of room to work in.

funny, i don't look at trying to supercede CFM values; just to optimize. it doesn't matter if it's a daily driver or a racecar. one way or another putting an airfilter that could support a lawnmower on a car that is rev-happy and uses something like TVIS isn't a smart idea.
obviously your 12A isn't a fire-breathing monster like those i've witnessed. i have video of a 12A built by a SERIOUS rotary guy...12' flames fed by a HUGE holley double pumper...

furthermore Toyota engineered/built the 4AG-E when? yeah and as a manufacturer, a main concern would be EPA standards and what-not outside of reliability and good mechanical function.

[toyotaspeed90]

Originally Posted by LokiRx7

You must be right, a wet air filter cant be a big deal, because NOBODY ever talks about covering it up and keeping it dry right?? Because the only reason I want mine dry is because I want a ton of carbon build up, not because I have problems starting my car...

Yeah my intake valve leak like crazy also when I crank the car, because they suck in all kinds of air, matter of fact now that you say that my throttle body has a HUGE hole in it, Im gonna go patch all that up...

I've started many cars with soaking wet air filters.....

the problems with your statement are rediculous...

when the engine is off only 1 set of intake valves should be open.... there may be 2 sets partially open.... further, your TB plate should be closed 100% at off throttle -- the only air passage is through the channels built into the throttle body...

further, to reach all cylinders you would have to have a TON of water in your intake manifold, regardless of how wet your air filter is.... you obviously haven't ever pulled a bigport manifold off the motor and looked inside of it...

further, even if THAT much water poured through the engine lid vent.... then it will hit the top of the filter... if it gets all that wet it may penetrate through the filter element and drop onto the bottom, but unless you're in a monsoon it's probably dry on at least 25% of it's surface area.... thus allowing air through.

Next.... yes, if there is water in the filter (which the element, if you include the height peak to peak of the grooves, is maybe 1/4" on most aftermarket filters) you will pull a small amount of air through... if it stays airborn, it will enter the combustion chamber.... but when you are starting your car you have not only the standard injector pulsewidths but you also have the added fuel of the CSI, which is a constant spray.

[LokiRx7]

Originally Posted by toyotaspeed90

I've started many cars with soaking wet air filters.....

the problems with your statement are rediculous...

when the engine is off only 1 set of intake valves should be open.... there may be 2 sets partially open.... further, your TB plate should be closed 100% at off throttle -- the only air passage is through the channels built into the throttle body...

further, to reach all cylinders you would have to have a TON of water in your intake manifold, regardless of how wet your air filter is.... you obviously haven't ever pulled a bigport manifold off the motor and looked inside of it...

further, even if THAT much water poured through the engine lid vent.... then it will hit the top of the filter... if it gets all that wet it may penetrate through the filter element and drop onto the bottom, but unless you're in a monsoon it's probably dry on at least 25% of it's surface area.... thus allowing air through.

Next.... yes, if there is water in the filter (which the element, if you include the height peak to peak of the grooves, is maybe 1/4" on most aftermarket filters) you will pull a small amount of air through... if it stays airborn, it will enter the combustion chamber.... but when you are starting your car you have not only the standard injector pulsewidths but you also have the added fuel of the CSI, which is a constant spray.

No your right, atomized H2O pulled through a throttle body would HELP combustion.

Ive never worked on a 4A-GE in my life, Hell I dont even know what an MR2 is.

Explain to me WHY when my MR2 with a sopping wet filter wouldnt start, explain to me why my carb'd 12a doesnt want to start when there is carb cleaner spray in the combustion chamber?

Lasty no where am I saying it filled up the intake manifold, that is just assinine and YOUR the one who is saying it. I have a side draft carb on my Rx-7 the air filter and throttle body lay on their side.

The first time I EVER cleaned mt K&N years ago I used too much of the spray oil on the filter (It wasnt turning red, I was young so I kept adding... stupid mistake I learned from it)

So explain to me, WHY did the Rx-7 not start and WHY did I have to do a full carb rebuild and scrape oil out of all the air passages and some fuel passages in the carb? Why if air will just pass through DID IT PULL OIL THROUGH THE FILTER??? (And it didnt atomize it, it literally sucked liquid oil off of the filter and into the throat of the carb, thats how strong the intake pulses were)

I know for a FACT that if your engine is cold and it pulls water through the filter it will NOT aid combustion, that is an ignorant idea. If the engine were at operating temp it might not be a big deal but we are talking about a cold engine, something that has sat overnight. And these re-useables have oil in them as well so we arent JUST introducing water.

Apparently you start alot of cars with wet filters, thats wonderful. Me I would prefer to keep the filter dry, I have had a past bad experience with a bad airfilter, you are talking to a guy who does ALL of my own maintence and is in the process of welding in mounts for a V6 and splicing together a wiring harness for the car from SCRATCH. So no your right, I just am not qualifed to talk about my past experiences.

I told you the REASON I am using this filter cover, and I havent had a problem since. But you are not going to call me a liar, I dont go around making up B.S. stories just to help people out and then use my B.S. story to justify buying a part. A question was asked, I answered it, you asked a question, AND I TOLD YOU WHY I AM USING ONE.

I dont have time for an internet pissing match, you can either take my information as it stands, or keep arguing by yourself.

[LokiRx7]

Originally Posted by ToyotaTechGeek

funny, i don't look at trying to supercede CFM values; just to optimize. it doesn't matter if it's a daily driver or a racecar. one way or another putting an airfilter that could support a lawnmower on a car that is rev-happy and uses something like TVIS isn't a smart idea.
obviously your 12A isn't a fire-breathing monster like those i've witnessed. i have video of a 12A built by a SERIOUS rotary guy...12' flames fed by a HUGE holley double pumper...

furthermore Toyota engineered/built the 4AG-E when? yeah and as a manufacturer, a main concern would be EPA standards and what-not outside of reliability and good mechanical function.

My Rx-7 is tastefully modified and mostly original... Am I not a serious rotary guy? Besides 12a's are like 4A-GE's they are lucky to reach 200 hp N/A without alot of help and you only see a handfull boosted making over 500 hp. And no mine doesnt shoot flames, Ive spent alot of time tuning to ensure it doesnt. Its fun when your a kid, but the tickets get old. And shooting flames is nothing special, if you buy a stock 7 and whack the cat(s) off and run a tad rich you can have four foot fireballs easy!

I dont know for whatever reason your comment annoyed me at the time lol. Maybe I felt like you were insulting my modest air filter. Its only half the overall length of the average cone filter, although it doesnt look like it I know. And the average cone filter doesnt have the opening at the top. Its less CFM I am sure, but it isnt noticably slower than any of the other 4A-GE cars we own, which includes another '86 MR2 an old beat up AE-86, and an '88 GT-S Corolla.

EDIT ::

The '88 GT-S is in the same state of tune, and uses a typical cone filter I should add. Seat of the pants reveals no difference, so I just dont worry about it. And the other '86 MR2 runs a stock airbox has 2/3's the mileage my car has and is stock other than an aftermarket chambered muffler and beats up on my MR2 like its no big deal. (Which is abit embarrasing since its my g/f's MR2... And its pretty much totally stock..)

[toyotaspeed90]

I'm not saying it will aid combustion.... never did I say that.

However... you state that it was so bad you had to pull your plugs (your words)... which would imply your starter was no longer spinning (if it was still spinning, then you're showing your ignorance in saying that you had to pull your plugs to spray the water out)... implying that you had so much water in your combustion chamber that you were hydrolocked and requiring you to pull your plugs.

Sorry if I actually read what you said and know what I am talking about.

Friends 89 came with one of those stupid covers... he has a cotton k&n style filter like most, and it gets rained on through the vent. It rains enough here that his car is gutted due to the interior being destroyed. However, he has no problems starting it (well, before the rod knock) when the filter is/was wet... I know this for fact because he would have called me. Further, I know it was outside because for over a year his st165 was in the garage being worked on.

So maybe you should be asking why your car wouldn't start when the filter was wet. Maybe it's time for a compression test? Maybe time for a tune up or plugs that aren't so fouled a mist of water will keep them from sparking?

Your information is pretty bad, to be quite honest.

Oil is pulled through the "filter" when your pcv splashes oil... you must have too much crankcase pressure in your 12A that is enough for oil to get through the PCV. Further, at a starting cranking speed there isn't enough vacuum to pull the oil through, this probably occurred at high RPM. If you really think you can refute this, I would like you to include the actual math. Physics don't lie in that lighter particles will move through the path of least resistance. If the oil was getting pulled through, then the area that had been oil soaked was large enough or your air filter was too small to accomodate for the required amount of air for that given RPM.

And you building a wiring harness from "SCRATCH" makes you special how? I've done it several times, for mine and others.

Personally owned 9 MK1 mr2's in a rainy state.... owned a plethora of other 4a and 7a powered cars... worked on probably 1/2 of the MR2's in town (and many out of town)ASE certified, worked parts for 3 years and a shop for one.... but you MUST be smart because you can get your cars to defy the laws of physics