My intake theory/design

[Legacy777]

The two key factors I was sorta thinking about, which would essentually steer the rest of the design, would be sucking cool air from the fender & utilizing some form of velocity stack right before the MAF.

Probably the one to model after would be Cobb's intake http://imprezars.com/images/cobbtuningcai.jpg

A buddy of mine has a modified version of this on his 99 RS with the MAF sensor, so I know it can be done.

Ideally if I were to set it up. I would star out with the intake tube going into the fender, maybe even slightly flare the end all the way around the tube. Have that for about 3-4" (something like that), then put the PRM inline style filter. http://imprezars.com/images/prmfilter.jpg

Then I'd probably run another 3" or so of tubing, then have a velocity stack. Scoobysports made a pretty damn nice one, but their site seems to be non-existant, so they may have gone belly up. I have no pictures of theirs. Best pic I can show you is of the stock airbox on my car http://www.main.experiencetherave.com:8 ... ystack.jpg

It's not a huge one, but I think it does help a little to smooth out & speed up the air flow as it goes into the MAF. The only trick to building the intake, I would think you would want to have the diameter of the velocity stack be wider then the MAF opening so you can shrink it down slightly, but still retain the max opening going into the MAF....so that would make the piping coming from the filter be larger.....or so one would assume.

After the MAF, you would have your standard tube going to the TB, with the appropriate tubes goin to the breathers and such.


So to recap, you would have tubing in the fender, which would go into the PRM in-line filter setup, which would go into some more tubing, which would then go into some sort of velocity stack right before the MAF, and then would go into the TB.

What do you think? Am I off my rocker.....or might I be onto something?

Everyone I've talked to, or the general consensus is that the cobb intake is the best one out there. It retains low end torque, while giving you free flowing top end.

I wouldn't be objected to buying one used and modifying it to fit. But I don't really want to spend the money to buy a new one and hack it all up.

Personally.....if I were to make one....or have something made.....I could care less if it were made out of shiny polished aluminum. Hell if some sort of plastic could be used or setup in a mold, i'd go for that.....however most plastic stuff has a very high initial cost.

let me know what you think of my crazy lack of sleep induced idea.

[rallysam]

Sounds interesting.

What's a velocity stack and what's it's purpose?

[eastbaysubaru]

Larry Ganz makes pretty nice intakes for various NA cars. I got one for my g/f's '00 RS and my brother recently got one for his '01 Legacy GT. The nice thing about these is that they retain the factory airbox for a large volume of air at any given time. Obviously there'd be a major difference for our cars due to the location of the factory airbox, but it's good if you're just looking for other ideas.

http://www.imprezars.com/images/legacyintake2000up.jpg

and here's his page for ordering:

http://www.subaruplanet.com/legacy_forester_intake.htm

-Brian

[Legacy777]

Sounds interesting.

What's a velocity stack and what's it's purpose?

Check out the last post by me in this thread http://www.bbs.legacycentral.org/viewtopic.php?t=212

I explain it a little better.

[ciper]

velocity stack examples

[Legacy777]

Thanks ciper for the pics.......that last one is definitely a little on the extreme side

[rallysam]

Very cool. Thanks for the fluid dynamics lesson!

[ciper]

Somewhat on topic, Ill post my idea for an intake.

This is easy for those of you who have no ABS. I was looking at the average cone filters and realized that they have equal or LESS surface area than the panel replacement K&N that Im using!!

My idea is to leave the stock air box but cut a large hole at the bottom front side of the box and run a tube from this hole.

The hole will be on the dirty side of the filter and the tube will run to a point that will get plenty of cool air. You get the benefit of using the tuned airbox with velocity stack, use of standard filters and cool air.

BTW, what happened to the word wrapping?

[entirelyturbo]

I'm about ready to put my stock airbox back on. I will really miss the noise, but I just don't think the cone-filter is designed for warmer weather like here in FL.

The word wrapping is gone b/c of the big pic...

[Legacy777]

You mean something similar to this



I know you were meaning something bigger.....but I was limited with room due to the alarm siren & MSD.

[boostjunkie]

If anyone's interested, my roommate has a PRM filter that he used on his Jetta. He got it from www.imprezars.com and doesn't need it now that he turboed his car. I think it only had like 7000 miles on it . . .

[Legacy777]

How much he want for it?

I might be interested.

[boostjunkie]

I'll ask him this weekend
*adding to the list of to dos for the weekend*
1. PRM intake price for Legacy777
2. 90-94 Legacy dash pocket and radio antenna for Eastbaysubaru
3. Send off intercooler
4. Wire in S-AFC

Anyone else have any requests? lol!

[Legacy777]

Jason,

I was parusing your site......do you still have the bends and such that were on your car with the PRM.......or did that go with the car when you sold it to adam?

Also, may want to change the dark blue font for the links.....

[boostjunkie]

Nope, the whole intake went with the car . . .

The PRM filter was used for a Jetta, so it doesn't have an intake pipe.

You could try and fabricate something from mandrel bent stainless . . . I think JC Whitney has U-bends that can be cut to the appropriate lengths.

Thanks for the advice on the site . . . thing is, I'm VERY new to this website thing and I don't know how to change the link colors

Jason *non-techie kinda guy*

[boostjunkie]

If you do decide to buy that PRM, I've got the old torque box from my GT. I'm not sure if you have one or not on your legacy, but I can throw that in the deal too, if you want.

Just tryin to clear out my basement.

[ciper]

Legacy777: Your not allowed to steal my idea! Thats exactly what I meant. Unfortunatly for me I have ABS in the way.

[Legacy777]

If you do decide to buy that PRM, I've got the old torque box from my GT. I'm not sure if you have one or not on your legacy, but I can throw that in the deal too, if you want.

Just tryin to clear out my basement.

Yeah I don't have the torque box......but if you wanna throw it in....I could possibly play with it.....Lord knows I need more car parts in my living room Lemme know what your roomy says on price.

Legacy777: Your not allowed to steal my idea! Thats exactly what I meant. Unfortunatly for me I have ABS in the way.

I had thought of this idea for quite some time.....and when I finally decided to put the stock air box back on, I wanted to put the idea into action....I did this, this past summer.

If I had more room, place & time to fab something up, I think it'd be cool to remove that whole side and fab something up........

[ciper]

My thoughts differed in that I planned to run the new inlet pipe down next to the valve covers. Anything noticable with that pipe in place?

[Legacy777]

Yeah I do notice a little bit better pull through the higher rpms. However it's still not the same as the cone filter.

If I could remove one half of the bottom of the air box I think it would be better......however at that point, I'm not sure if it's worth it. You are still going to have a restriction in the box.

If I could do a custom jobber.......I think I could get the best of both worlds.......can't say it'd be the cheapest though