hepkat63

Hi all,
looking at EVO HighFlow FRESH Air Intake System, 911 on the Pelican site.

From the threads I have read on this forum, they don't make a whole lot of difference to simply drilling your airbox.

There are (as I am sure you are aware), pages and pages of comments, theories, tests etc and even in the couple of Porsche 964 books I have they state that anything you replace the standard airbox with makes no conceivable difference in performance, but gives a nice sound about 4k revs.

Yes, my airbox is drilled and yes, the sound is amazing above 4k revs - however, I am into cleaning up the engine bay and was looking at the EVO one for that purpose.

I don't race the car, it is just used for street/highway cruising.


I was wondering if anyone on this forum has this setup and can comment about it please?

The main arguments i saw for NOT using this type of setup is that not enough 'cool' air is forced into it as it sits too far back in the engine bay.

FOS373

You pretty much answered all your own questions

I have one. I haven't noticed any improvement from my drilled air box. Sound is similar. Cleaning the air filter is obviously easier and quicker. It does look better than the stock heap of plastic as you noted.

I have a similar setup on a diesel truck, however the cool air is forced in so it's not really comparable

vagluv

I considered that piece, mostly as a way to clean up the bay, as you say. Well, I considered the other style that doesn't have the elbow. To me, the elbow style really doesn't do much for the appearance of the bay bc it's pretty big and sticks out into the normally open space, but the filter that sticks straight out off of the MAF does. The problem with the straight option is that it actually hinders performance bc the air it's pulling in is hotter than it would be with a drilled box.

Vandit

My car came w/ this setup when I got it. It's alright, makes cool sounds, especially when you give the gas a sharp blip. and what not. I'm not sure about performance (probably a wash to airbox), or filtration (possibly deficient to airbox). I replaced the tired filter w/ an AEM dryflow piece and installed oversized washers at the AFM because it seemed like the plastic base was warping, possibly causing an air leak.

Vandit

GeorgeK

I fail to see how any intake would take "fresher" air in the maelstrom of wind that must be the engine bay at speed.
I question the filtering ability (permissivity) of the cone element, when compared to the factory air filters. Any values as to permeability?

hepkat63

actually, it got me thinking (always a dangerous thing....) that drilling an air box would make the tube scoop at the front of the air box basically useless.

I am comparing it to the vacuum cleaner at home (sorry...) where when complete, you suck up stuff from the end of the vacuum hose. If you get stuck on something (like kids toys), then you open the little sliding flap at the top of the vacuum hose to release the pressure.

So.... if the air is effectively sucked in through the Air Cleaner box, and the only opening is the tube, then that's where the air comes in - BUT, if you drill out the air box cover, then surely all the air comes in there (again, rending the tube pretty much useless).

That being the case, then a cone filter would be exactly the same filtering/capability as a drilled air box.

Ouch... my head hurts now

StanUK951

In the real world none of these theories about cool air, warm air, turbulent air, really make any difference... I found my drilled airbox had warped at the back meaning the element was no longer sealed properly and could allow unfiltered air into the intake. I bought a universal bolt on filter from ebay for much less.

Vandit

If you search eBay for "944 air filter" you'll find kits like Stan's above. You might have to fab up a small bracket to stabilize the AFM on the old airbox mounting point at the back of the plenum.

hepkat63

thanks guys - much, appreciated. Will check it out.

vagluv

Stan's is the version I was talking about. See how nice that looks with the heater bypass?! But the air back there is warmer according to some long thread I found at the time.

jpar

I bought the universal ebay flange a long time ago and this thread inspired me to finally do something with it. This weekend I did a little Home Depot Motorsport engineering and came up with this bracket, which also holds the vacuum tank. I'll probably end up powdercoating both pieces black. Total cost with a new K&N filter from amazon, $60. I'll post an updated pic when its all done.

g60pops

jpar, very nice work with the bracket.
Any dimensions for it so I can copy it?

hepkat63

great job Joe - will be doing mine this weekend too - parts arrived , the bracket you made is cool - I'll be shameless stealing that design - many thanks

jpar

Thanks, I'll get you the dimensions next time I take it out.

The air filter came today so I threw it on real quick.