Hard to explain...

[boesewicht]

...but I'll try it.

Today, I had a ride in a 2004 Subaru Impreza WRX STI and you all know the big scoop on the hood.

Most of you also know, that the car sucks his air from this scoop to a filter (or is it a IC?) under the scoop.

So my question is, (and please don't say anything about how it would look) if I can get a big scoop like the one from the impreza, is it possible to mount an air filter on the top of the engine, directly under the scoop with a short tubing (it would have only one or two curves) to the original mount? Would that bring something more than a classic CAI? The way the air has to go is shorter and it has no time to heat up because of the direct way...that's correct, isn't it? And could I locate the MAS about 6 inches away from the end of the tubing?
What about water from the rain (germany has enough rain...) , would it destroy anything in my engine?

Hope you have some answers for me. :)

Alex.

[Renn 208]

better yet, here's a picture:

http://www.jrentech.net/benz/fb23c081.jpg

a w203...but same idea

http://www.jrentech.net/benz/fb23bff4.jpg

and as a random aside, hood scoops/cowl induction and similar ideas have been around since the early days of muscle cars...

As for how well it would work on your car, I think only you would be able to find out, since I am un-aware of any street MBs with a similar system. Also, another thing to look into would be to find out if that location of the hood really would create a higher pressure zone than the tested "bumper intake" a la speedybenz.

On the sti, the scoop is for the intercooler, as the air intake is much further forward in the engine bay

[boesewicht]

Thank you very much Renn.

I'm "affraid" of the bumper intake because we have lots of rainy days here...and sometimes very hard rain. At present, we had nearly constant rain for the last few days.

What problems could I get with that fuckin' water...? (with an normal CAI AND bumper CAI?)

What would you say, I should do? I want to gain some horses... :D

Alex.

[Pagz]

hey Alex,
Back in the day,I did this mod to my lancer 2L Diesel turbo :dont laugh:....it was fast for a diesel lol...
I constructed an oblong funnel under an STI bonnet scoop then mounted a panel filter in it,so air was forced through the filter...
ran must have poured in there,but the turbo made vapour out of it i guess....,i just had to avoid parking facing up hill on a rainy day!!!!
but if you have an NA car things could be alittle different.....

heres the beast:D
http://memimage.cardomain.net/member_images/3/web/735000-735999/735658_36_full.jpg

[Renn 208]

perhaps speedy will chime in with his own experience...but I'd guess that the rain risk would actually be lower with the bumper setup vs the hood scoop setup. (based on water having to travel up a pipe from the bumper vs. falling right into a cone filter facing upward)

[Linh]

I'm "affraid" of the bumper intake because we have lots of rainy days here...and sometimes very hard rain.

That's why you need to install one of thise "air bypass valve". It come in many difference sizes. Just search ebay for the right size.


http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=38634&item=7970170637&rd=1

[Renn 208]

if I understand that product...it will basically turn your CAI from a Straw into a straw with holes (really 1 way valves activated when cone sucks up water, causing a vacuum)?

Is there really a need for this? I would think that if your cone filter's wet enough to get plugged (i.e. submerged) You've got bigger fish to fry than getting air in from an alternate source?

[J Irwan]

just FYI


In Subaru WRX STi the hood scoop IS NOT for intake..

that's right..


The Subaru STi turbo is different than most car.
The turbo is water cooled instead of air cooled, that the reason that car doesn't need a turbo timer.

to get back on the subject the hood scope is used for intercooler..

so in answering to your question not it can't be done on street car..
hood scoop most likely can be done on a race car just like Renn's pic.. however keep in mind that race car only serve its purpose only for specific time (race time, i.e when not raining).

When you putting similar on street car I don't think its going to work.



in 23K case it might be different since I do not exactly know how the turbo diesel works, but since the principal is probably the same (force induction), the route between the intake opening to the intake manifold will be a lot longer than NA car.

Since the intake route is a lot longer and If the car doesn't have any intercooler, I am positive that any water that get ingested from the intake opening probably evaporated due the temp on the turbo unit ( I am guessing 23K' 2.L turbo diesel doesn't have any intercooler).
At the end the water is gone by the time it reach the intake manifold..

just my $0.02


Regardz,

[Pagz]

Originally posted by J Irwan


Since the intake route is a lot longer and If the car doesn't have any intercooler, I am positive that any water that get ingested from the intake opening probably evaporated due the temp on the turbo unit ( I am guessing 23K' 2.L turbo diesel doesn't have any intercooler).
At the end the water is gone by the time it reach the intake manifold..

just my $0.02


Regardz,

i installed a front mount from a VR4 lol...modified the mechanical fuel injection and ran 15psi from the very small turbo heh...
i had always worried heavy rain might have cause problems,but it never did,it ran alot better when it rained actually!....
but as you said without a turbo,there will be alot more chance of water in liquid form making it to the chambers...

as J irwan said,it is probley wise to avoid using the bonnet CAI fed idea,and maybe go with the bumper or custom filter box in the engine bay with a cool air feed from the front etc...

Regards,
Paul

[jnenad16]

Originally posted by Linh
That's why you need to install one of thise "air bypass valve". It come in many difference sizes. Just search ebay for the right size.


http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=38634&item=7970170637&rd=1 :werd:

[boesewicht]

Okay, so I wil go the classic way.

Should I remove the original filter box and put a cone filter with a heat shield and a short tube enlargement / tube replacement at that place or should I customize a tube down to the front bumper and place a cone filter there? But the second method is illegal in germany, guaranteed...hm.

I think the first method is the best.

What about a closed cone filter, like the ones from Green? Twister is it called, I think...does that bring an advantage compared to an open cone filter?

What about this idea:

- Enlarging of the tubing (perhaps replacement, samco hose or something) that the cone filter is located ahead as possible

- Installing that Green Twister Filter with it's housing

- Putting a hose (a tube) from the front opening of that filter housing to the grille or to the openings in the bumper


Or does anybody have a better solution? Thank you all.

Alex.

[VIP_MBZ]

Originally posted by J Irwan
just FYI

The Subaru STi turbo is different than most car.
The turbo is water cooled instead of air cooled, that the reason that car doesn't need a turbo timer.



Almost every turbo car I've been around has been water cooled from the factory. Even old ones (Mitsu Starion, 87-92 Supra MA70, etc). Subaru just started toting this as a "feature" to negate the need for turbo timing, when actually I still would recommend idling an STi just like any other turbo car. It's not the turbo we're worried about, it's the oil in the turbo, which if not circulated, becomes coked.

Just as a side note, the reason for the Subaru top mount intercooler is to maintain proper air flow even when driving through dirt and mud. The front mount intercooler is still a better street design, no ifs ands or buts. Otherwise Subaru owners wouldn't spend $2000+ on intercooler kits relocating it to the front. Only advantage of having it on top is that there's less piping, so there will be better response.

-Ray

[boesewicht]

Thanks for the infos VIP_MBZ BUT could you guys reply to my last post please...

Thank you. :D

Alex.

[VIP_MBZ]

Originally posted by boesewicht
Okay, so I wil go the classic way.

Should I remove the original filter box and put a cone filter with a heat shield and a short tube enlargement / tube replacement at that place

- Enlarging of the tubing (perhaps replacement, samco hose or something) that the cone filter is located ahead as possible

- Putting a hose (a tube) from the front opening of that filter housing to the grille or to the openings in the bumper




It has always produced good results to have an open element filter like the K&N FIPK, and then heat shielding the area away from air from the radiator and other engine bay heat sources. You can relocate the filter further down into the bumper, but not only is it as you said illegal in Germany, but it also doesn't produce a significant gain over the previous setup. Routing a hose from the grill area up to where you have your filter mounted is also a good idea, to sort of "pressurize" the area sealed off by whatever head shielding you've fabricated.

Either way, the difference between the best setup and completely stock is still probably not going to be more than 10 hp, so I wouldn't waste time splitting hairs over it. With that in mind, don't do anything irreversable, and don't do anything that will make it ugly.

-Ray

[boesewicht]

Thanks for the reply.

So I will make a big heat shield around the whole area where the original box was.

I will route a tube from behind the grille to the cone filter.

I will take a normal K&N cone filter or I will take a Green Twister with that housing around?

Is it necessary to replace the stock tube with a steel tube? Like on the following picture? Up to the MAS? Is there any better solution than the steel tube? samco hoses?

I hope somebody can answer my questions and say if I'm correct with that plans.

http://memimage.cardomain.net/member_images/3/web/819000-819999/819788_11_full.jpg

[VIP_MBZ]

Originally posted by boesewicht


I will take a normal K&N cone filter or I will take a Green Twister with that housing around?

Is it necessary to replace the stock tube with a steel tube? Like on the following picture? Up to the MAS? Is there any better solution than the steel tube? samco hoses?


I would definitely go with the K&N filter. Most likely it is a better filter to begin with, and with redundant heat shielding the Twister is only going to impede air flow. Stick with what works, K&N has been around forever and a day.

The advantages of a metal pipe is that it may have less turbulence than stock due to a smooth inside, but the disadvantage is that it doesn't reject heat like plastic/rubber does. You can have it ceramic coated, which will help. I think Samco hoses, however cool looking, may just end up being a more expensive version of the stock setup (outside of being able to last longer than the rest of the car).

-Ray

[Josh R]

I was thinking of putting a scoop on my roof so in the morning it would dry the hair gel in my hair faster. Or ala central air conditioning.

[speedybenz]

You should fab a Ram Air system similar to mine and then where the the pipe comes up through the frame you have a simple connector so that when you get heavy rain days you just open the hood and pull the connection apart and this will eliminate the problems on rain as the air will be pulled from behind the bumper and not connected to the Ram Air system. Works for me very well.

Jeff