Open top stock airbox Vs. Cone Filter.
 

Well I have been messing with my stock airbox lately and I like what I have found. I first started off by trying to do a ram air effect with a 4" duct pipe running up to where the hood meets the stock air intake tube.

Then I took that off and was running a cutout top of the box, like icemark drilled his holes on his. But now I was thinking about a cone filter without a sealed engine box and how much it must heatsoak so I took the top off of my filter and attached rubber bands to hold the filter down. I know this isn't perfect, but I do seem to be getting more air, because I had to add fuel up top to compensate for the new air box mod. It "feels" like it has more acceleration on the low end, and it pulls hard to 8k still.

Ok to get to the question. Which would flow more, a cone filter or a topless stock box? Which do you think would heat soak more? To me it seems like a flat filter with more surface area would be able to suck in more air, rather than a smaller cone filter, is this true? Thanks for any input in advance.

Neither will flow very well... when you took the top off the snorkel isnt very effective anymore, and you are sucking in hot engine bay air. Even with a cone, assuming you make a good sealed box you need to duct in enough cool air for it to function properly. I think there is a thread in the archives about doing a CAI that you route outside the engine bay where the window washer bottle is, that's what I plan on doing.

i have a cone filter with aluminum box surrounding it. I took out the windshield washer resevior, and drilled another 3" opening. I plan to use the opening later on for fmic piping, but in the meantime, it lets in nice cold air for the filter

I dont know why people remove the top of the air box... It doesnt work, in theory. I was working on my 7 a minute ago and I decided to take it off for a minute and secure the filter with zip ties. Just a little experiment to see how people feel a "difference." Besides a little extra intake noise the only difference I noticed was.. well nothing. It might have been alittle slower actually.

i think this would also be a little easier if it wasnt for the afm
give us a couple more options anyway

Uh, how would it not work? And you're "theory"...I see no theory there. In theory, the top of the airbox being off would allow an entire realm of air to be used, rather then it being cut off from the atmosphere. Having the top off would be a huge un-restrictor..

In theory, it DOES work.

Even moreso if you seal off the side on the engine bay, and have a 3" duct coming from down at the windshield washer.

Well every car is different, but how would it not flow more? The opening on the snorkel at the hood closure, is about the size of a pack of cigs, while the top of the filter is roughly the size of a cereal box? And if heatsoak between a cone and open top are about the same then there should be no reason to go cone right. Come on let's get some technical answers here.

Did you test through all gears?

i just removed the top a couple minutes ago and it is definaltly faster. I do have a t2?

and i did end up getting to 70 on a block as opposed to 55 normally

Sweet. If I end up going to the dyno this next week, I will do a test with it on and with it off just to see for sure.

Yes, it could potentially flow more. But.. its hot air, and who cares how much it flows if it outflows your AFM??

It's definately not outflowing my AFM, because it never maxes out airflow on my SAFC II. I think with the proper ventilation of air coming into the filter this will work as well as a cone filter.

Did you ever think maybe your not getting enough fuel or something, and maybe your injectors are clogged some or something and thats why it doesn't work for you?

Stock filter 90 sq ins draw area, ambient air temp------- pod ??? sq ins draw area, underbonnet air temp, AFM-- same restrictive little sucker in both instances ----filter prob K&N or APEXI for both, shouldn't be to hard to work out from there, better air in box? put a pod on the air pump line, mount under OE airbox, blank of the airbox/pump out-take, I personaly couldn't care what air temp the pump has to ingest---- Ho Ho , Cheers all , AL .

Err...I'm not trying to be mean, as it seems you have something to honestly say, and I'd like to hear it. But..I seriously can't get a sentence of sense out of that...

A guess, would be you are saying that, whether the top is on or not, it is still having the same restriction, being the tiny little filter?

If this is the case, I disagree. The stock airbox, in my sense of looking at it...is like a vacuum seal. The only source of air, would be coming from the intake duct going over top the clutch fan.

Now, this means, the air is going into the (estimate) 1"x3" duct mouth, SLAM into the first wall, go down it's narrow path, go into the air box, SLAM into another wall, and finally reach the filter. All of this, in a 1x3 duct! The volume of this thing cannot be much at ALL. It's a giant restrictor.

Also, the placement of the duct is horrible. Sure, the air could easily go right into from the nose. BUT, the hood linkage..happens to be RIGHT there! Yay! Forget the idea of pressing in cold air, making this box more efficient, because this hood linkage is making it go around, and probably miss the duct all together.

Having the box open..this allows unrestricted air flow into the filter. Pretty good! :)

Can you guys post pics of how you have the filter secured? Thanks

just like a turbo, even though you are flowing more air, it is much hotter than that of what the snorkel is picking up, with that in mind, cold air being denser, you need MORE hot air than cold air to achieve the same ratio. so, it really isnt doing anything wether keeping the snorkel or taking the top off the air box.

I say just do a fenderwell CAI and call it finished

Yes very true, I will do the fenderwell when I can get a cone filter, I bought my K&N drop in filter like the first thing for my car so I didn't want to just throw it away ya know. I do have the snorkel in place still so some fresh air is still getting in.