Not all ports - just flared ones. For a long time most (if not all) ports had just straight cuts. I guess it's the same idea as a velocity stack: the radius of the flare reduces turbulence, which in the vented loudspeaker world can sound like chuffing. I've never experienced this personally, with any of my designs - but then again, I've never really found my car wanting for a "velocity stack"! Apparently, though, that's what the end of my fancy new K&N filter is supposed to be:



I like that it looks like a turbine (hidden inside a black plastic box), but I can't really tell that it does anything special.

As for flared ports, here's a whole bunch of options - all for a lot less than the $30 eBay wants for something specifically billed as a "velocity stack"! The only thing I would caution against is having something too rigid (i.e., ABS plastic) in a fixed position between the firewall shroud and the airbox. The airbox is effectively "hinged" in several spots against the movement of the motor, but I'd still be wary of something brittle that might start to rattle... Hence I went with rubber in my design.

 

True, but it also uses a metal box as opposed to the plastic stock box. And doesn't the Alta remove the front air collector from the bumper?

- Andrew

 

I don't know for sure, but I think that's the best source of actually cold air you could ask for.

 

Yeah that would suck if true.

 

Ha! It would ONLY suck. I think the best thing about the grille feed is that it's pushing air into the airbox, rather than just allowing the filter to suck what it needs from the firewall shroud (or take advantage to whatever extent of the "high pressure zone" at the base of the windshield).

I haven't run any tests (and don't intend to, and am not smart enough anyway), but I feel like air courses into the grille and through my box, and the air filter just takes what it needs from the fresh air that's passing by. Granted, that fresh air might be a bit hindered by the three water traps on the airbox inlet, but once pressure builds up (i.e., at whatever minimum speed is required to maintain a given constant, minimum pressure) it will stay built up, regardless of the water traps.

 

Agreed. I think the opening through the cowl is mostly good news for getting cooler fresh air when you're at a stop light or something (or on a dyno). The front collector is what does most of it when you're actually moving.

- Andrew

 

Well lets set the record straight shall we..........

The Alta does indeed have a metal surround, but it really never heats up much.
It does indeed keep the grill inlet in addition to the open cowl area.
And it does get plenty of air from the cowl area at speed. It has been tested and proven. Just look at the many, many cowl induction systems on cars through out the years.

You are welcome.......

 

The little weatherstrip on Alta's intake will never seal as well as an enclosed box.

Not that it really matters much. The most you'll gain from an intake system is from an induction pipe. Otherwise, you're in it for the sound (and I don't blame you for that).

Has anyone just tried enlarging the hole at the bottom of the airbox? Methinks an ALTA panel filter and enlarging that hole would yield similar gains with a little less work.

 

I really like the Voltage intake. Seems to be the best of both worlds, i.e., composite, foam filter, velocity stack, and fully open in the cowl area. I know, a velocity stack that far away from the engine is probably not doing anything, but this intake seems to have it all.

http://www.voltageproductsonline.com/intakes.html

 

"ventury effect"

 

Hey, at least you got Captain Haddock involved! (And shouldn't that be "Venturi effect"?) Those guys at Voltage, at least, are trying to sell a product. Here we're just trying to prove our own awesomeness... Sometimes I forget what a comedy of anonymous self-righteousness is the Internet, and then a get a reminder so poignant it just reads, "You are welcome" followed by a whole buncha periods.

I had a whole buncha fun making my cold air intake, and am more pleased with it than I was with the K&N that cost three times the price. But I come from a number of different DIY backgrounds, and work as a mechanic, so making my own mods, as it were, and reaping the benefits, pays dividends far beyond what I could achieve just bolting on someone else's (and then adding it prominently to my signature line, so everyone else on the board can confirm my awesomeness). I would encourage others to give a bit of mild fabrication a try! It was tons of fun, and I'm quite pleased with the results.

 

It most certainly does........just look at the indentation on the bonnet insulation to see.

Just ask one of the guys at Alta on why they came out with the box top. Because it looked nice....

That Voltage intake is one of the better ones, but still expensive.

to applesauce for the DIY intake, that is a great way to improve the intake (all you need is the foam filter!!!.....LOL)

 

What if you use the A/C vent gauge mount that blocks off one of the A/C outlets.... Port that outlet into the air box--- WOO HOO, you have a variable cold air intake. ;-}

 

Lmao !

 

My apologies, I was incorrect on the Alta. Maybe I saw some fool disconnect his front grill inlet on his own.

 

First post ever. This mainly picture of my version of Dave's F. intake

Guess I'll try agian later on my laptop instead of my phone.

 

The Voltage intake is nice looking but their service Blows.
you can do what the Dave F dose for a ton less money. its nice but over priced
Guess its alright if you never want to take your hands out of your pockets.

 

Do you know the part # of k&n filter in the dave f airbox setup it would be greatly appreciated .

 

filter is RX 5090
I used a 2in 22.5deg street fitting. It pushed into the oem upper hole. It wasn't easy but its in there. Then I used a 3in rubber pipe boot to bring air in on the lower part of the box.

 

Thanks

 

Nice touch Hillis24! When I first learned of the Dave F mod, I had wondered why nobody simply enlarged the original inlet. Seemed practical. I like that you not only did this, but you also found a fitting component to bridge the gap between the cowl and the air box.

I'm going to complete the mod myself in a couple of weeks while following Applesauce's tutorial. I, however, am going to use the K&N SN-2560 filter, not the RX-5090 or the more popular RU-3190, because I found one at a great price. I know it's classified as a snow mobile filter, but, from what I understand, there is no difference in material, construction, etc, just dimensions. If anyone learns otherwise, please let me know.

Thanks to everybody for their input.

 

Anybody looking to do this mod on their own I have several OEM Intake boxes for sale. PM for a price.

 

Hillis24, I have a question for you. I found the 3" rubber pipe boot at the hardware store, but wondered if you were able to get the sound that everybody else has reported; how does it sound?

Also, I'm having a difficult time finding a pipe to fit the outlet of the air box (air box/filter adapter) because I don't want to stick a 2" pipe with 2 3/8" OD into the 2 3/8" ID outlet. I feel that reducing the diameter of the outlet to 2" would restrict the airflow going into the throttle body. Am I correct to assume this, or will it do nothing more than create the questionable "venturi effect?" Sorry, had to throw that in there!

 

The sc whine is. Very noticeable and also has a bit of growl like a subaru. The pipe will restrict some, but it's not enough to hamper the amount of air flowing

 

SC whine + growl, I like the sound of that! Well, if I don't get the additional 1-4 hp expected from a cone filter I'll at least have the gratification of listening to the sound and of having done the job myself. Thanks for the input!

One more question, can anybody who has a Dave.f intake tell me what filter brand and product # he uses for his mod?