Question about intake modification.

[nextse7en]

I'm thinking of doing a ram air setup.

functional small scoop on the hood that feeds directly into the stock filter box?

I would move the filter box upstream, placing the maf just a few inches upstream from the TB. Invert the filter box, cut a hole in the bottom, and allow the plumbing built into the hood running to the scoop to seal with it when the hood closes.


I know that there are proven gains by going with some sort of ram air setup. One member reported some level of success by simply cutting a hole under the fender where the intake resonator resides. My logic is that I could get higher pressure in the manifold with a scoop. And possibly a quicker throttle response with a dramatically shortened intake length.


Thoughts, suggestions? put downs?



Thanks, Patrick

[ensteele]

That sounds like an interesting project. Keep us informed if you do it. Many here have modified the intake box, but I don't think any one has done what you describe. Good luck. :)

[DarknessofDeath]

if i am understanding it correctly, it does sound like a good setup

[ItsPeteReally]

I'm thinking of doing a ram air setup.

functional small scoop on the hood that feeds directly into the stock filter box?

I know that there are proven gains by going with some sort of ram air setup.

One member reported some level of success by simply cutting a hole under the fender where the intake resonator resides. My logic is that I could get higher pressure in the manifold with a scoop. And possibly a quicker throttle response with a dramatically shortened intake length.


It's distinctly possible that you might see some gains at high speed, while running at high revs, and with wide-open throttle, although even this is not a cast-iron certainty.

At low speed there will be little or no ram effect, and at less than wide-open throttle any ram air-flow effect that you do achieve will be reduced. Which is, of course, what throttles are supposed to do.

The price you pay is one of altering the resonant behaviour of the entire inlet tract. By making it shorter you raise the resonant frequency, which might possibly help at high engine revs, except for the fact that the IRIS valve in the inlet manifold is set up to work with the original system.

Subaru claim that the IRIS valve contributes to a volumetric efficiency of over 100% for certain portions of the rev range. Once you change the inlet tract the IRIS valve will not open at the optimum time any more.

Its anyone's guess whether such a change will be for the better or worse overall - but if I had to bet, I know where I'd put my money;)

Pete.

p.s. If you want higher airflow at all speeds, just take the air filter out!!!

[Trevor]

Hi Patrick,

On the face of it I agree that the prospects may appear rosy, but apart from a possible placebo affect, you could be very unhappy at having hacked your car about.

Do some reading and you will understand why. Google will find you loads of factual data. A ram charge system as coined by Chrysler, involves a different set up. The SVX is already set up so that air is drawn from a high pressure area, which is in effect what you are trying to achieve.

If you would like the visual affects of a bonnet scoop, that is another aspect entirely.

[curly2k3]

well after a large amount of time tinkering with this stuff myself i would honestly say only modify with filters, once you start in with the intake system all hell breaks loose. as has been stated earlier in here the IRIS valve will basically cancel out and decrease the good of anything you do, beyond that... the frequencies of the resonation can REALLY suck, with mine we got the intake set up exactly where we wanted it and we saw gains, however we are now having some not so fun problems with interfiernce with the MAF and its putting the car into a limp mode and killing it all. initial curve with the IRIS off and closed we hit bigger numbers at the wheels then when it opened and drop us into a limp mode.

simply put, only go filters, possibly the inverted intake set up, but DONT move the MAF and dont change the length of the set up. that would be the personal advice i would give you in regaurds to this project. however, put a nice K&N or better pannel filter on your inverted scoop set up and i do believe you would see a reasonable and noticible gain across the board. good luck and best wishes! i hope to see some sound results and pics along the way!

Chris

[SVXRide]

Yes, ram air works...
No, it won't do anything below ~25 mph (confirmed with pressure gage measurements)
Yes, it will add ~5-10 hp above ~25 mph
Yes, you shouldn't move the MAF or airbox (I use a GREEN filter in the stock airbox)


http://www.subaru-svx.net/photos/files/SVXRide/24195.jpg

(in use for over a year with no issues...)

-Bill

[Myxalplyx]

Some good info in this thread. I am hoping to see how this pans out. What ItsPeteReally is saying about the IRIS valve is really interesting since I have been reading up on this the past two days.



simply put, only go filters, possibly the inverted intake set up, but DONT move the MAF and dont change the length of the set up. that would be the personal advice i would give you in regaurds to this project. however, put a nice K&N or better pannel filter on your inverted scoop set up and i do believe you would see a reasonable and noticible gain across the board. good luck and best wishes! i hope to see some sound results and pics along the way!

Chris

Chris,
Could you give me more information on your findings as far as maf placement and intake tubing lenghth? I will be looking for info from you by searching but this is the first time I am reading about this. I am REALLY interested in this information. We can talk in PM since this may be unrelated to this thread. Thanks!
BTW: Chris...are you referring to this intake-->
http://img516.imageshack.us/img516/4554/paintballgun011gl4.jpg

[curly2k3]

yes sir that one would be mine. shoot me an IM if you want to talk about it more, its just easier. curly2k32007