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Old 07-02-2001, 12:19 AM   #1
adeck
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Default ram-air intake pic

Tittle says it all!
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Old 07-02-2001, 12:20 AM   #2
adeck
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Another pic
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Old 07-02-2001, 12:24 AM   #3
adeck
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one more
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Old 07-02-2001, 12:45 AM   #4
King Ding187
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how does she feel?
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Old 07-02-2001, 01:36 AM   #5
rpone605
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so what about all the low end torque your loosing?

how about the velocity measurements??? did you consider those?
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Old 07-02-2001, 04:15 AM   #6
bratmantlz
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lets not forget water ingestion(sp?) and objects like birds moths grasshoppers etc.
Brat
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Old 07-02-2001, 08:09 AM   #7
Peaty
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I'm sure you are getting cooler air and that's a good thing. But in order for ram air to actually ram any air you have to be going around 140 mph and even then the pressures are very low. Pat has the same setup. It sounds wild at the auto-X
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Old 07-02-2001, 08:47 AM   #8
adeck
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There is no torque loss, none. Believe it or not the filter stays 100% dry, I have been in some pretty heavy downpours. I have had this setup for about 1 month now and I have not had to clean it out at all.
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Old 07-02-2001, 09:49 AM   #9
adeck
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So far with my S-AFC I have reached very low and zero intake maifold pressure. I didn't really open it up yet, today I will to see if I can reach positive pressure.
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Old 07-02-2001, 10:12 AM   #10
Layman
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Hey Peaty, that 140mph notion about Ram Air is a myth. A proper ram air setup can provide gains at normal highway speeds. Go to some of the F-Body boards and ask if their Ram Airs are useless below 140mph.

Granted, on an impreza there may be a different story, but not for ALL ram air setups.
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Old 07-02-2001, 11:47 AM   #11
Peaty
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When I was on the contour board there was a guy that was really a "Rocket Scientist" and he went through some math that explained the whole thing. I saved the post but can't seem to find it. I'm just going by what he said. The scoop would have go be huge
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Old 07-02-2001, 11:53 AM   #12
Layman
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Well, if you look on the RamAir firebirds, the scoops ARE huge.

Anyhow, I, too, doubt it works on an Impreza, but I've been told that ramair can work on other cars.
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Old 07-02-2001, 12:41 PM   #13
adeck
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I agree that it's not a true "Ram Air", but the hood scoop is open and the box behind guides the air from the hood scoop into the intake. I drove around for a ahwile with my homemade box installed and not, it makes a huge diference. without the box you can feel a low RPM loss but high RPM gain. With the box you can feel gains throughout all the RPM's.
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Old 07-02-2001, 12:47 PM   #14
adeck
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One other thing if the ram-air on a F body works so well than why wouldn't it in ours? If you think of our car in a wind tunnel the air travels up the hood and the scoop catches the air.
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Old 07-02-2001, 12:56 PM   #15
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Look at the difference between the hoods on an F-Body and ours. Their scoops are much more prominent (believe it or not ) and cut into the air more. Because the front end of an Impreza is as aerodynamic as a brick, I'd be suprised is too much air actually forced it's way into the hood scoop.

Maybe somebody has a way to measure the wind velocity from underneath the open hood scoop. That would be helpful.

BTW, I'm not bashing your intake at all. I'm sure it works pretty well, just not as well as an F-Body's similar setup.
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Old 07-02-2001, 01:12 PM   #16
Peaty
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I've got 3 of these I use at work:

http://www.mesalabs.com/datatrace/pressure.htm



The base is a little bigger than a quarter to give some perspective. The pic is kind of big.

I'd be happy to put one in the intake and one beside it for a control to see if there is indeed some pressure. I can't send them out though I'd have to do it here as they cost around 3K each. These can be programmed to record at 1 sec intervals for up to 1000 readings. They also get temp. at the same time.

I did something similar with temp that I have to redo now that my scoop and vents are open. that info is here:

http://www.scoobymods.com/mods/impreza/thermal.php

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Old 07-02-2001, 01:16 PM   #17
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Peaty, that would be great, though I was thinking that mounting one inside the hoodscoop itself would give the greatest insight as to whether there is any real ramair effect.
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Old 07-02-2001, 01:30 PM   #18
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hey guys... if the scoop did not bring in a noticable amount of air, y do we put our intercoolers under it? don't those require air to be useful? and unlike the ram air intake shown above, they do not have anyhting pulling air into the scoop.

that brings me to points 2: you would still need to be moving fast enough to scoop more air than the engine is pulling, wich would require a lot of math that i dont understand to figure out.

and point 3: our engine has half the displacement of your "standard" big V8 engine... hence only uses half the air per revolution, hence only needs half the scoop "area" to get teh same effect, this is of course not taking into effect scoop placement in the airstream and many other factors of course.

so IMHO i think that there would be some gain in air pressure to be had by using hte hood scoop... wether it will make a real difference? only a lot of R&D $$ and a dyno will tell for sure. I am still a believer that short of a turbo or super, COBB has the best intake for the RS
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Old 07-02-2001, 01:48 PM   #19
dRu18
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Default "ram" air

i believe to get MORE gains from your "ram air" set up, it would be wise to turn your hood scoop backwards creating a sort of "pressure buildup pocket" between your scoop and windshield. i've learned this in automechanics taht you have less pressure buildup when the air is smashing into your scoop. one example would be the lancer style hood, it's built like that for a reason
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Old 07-02-2001, 01:51 PM   #20
Peaty
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In an ideal situation three datatrac units would be used. One on the dirty side of the air filter, another on the clean side to see the drop in pressure across the filter itself, but care must be taken to secure the datatrace, I don't think it will fit past the butterfly valve in the TB but I wouldn't want to find out the hard way. The last one should be secured under the hood somewhere by, but out of the airstream of the scoop for a baseline control. Maybe I can do this with Pat's intake (KC_TopDog) someday since his is very similar.

Peaty
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Old 07-02-2001, 01:56 PM   #21
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Hey Peaty find that post by the Rocket Scientist. I'm studying to be one and I have a 40+ page packet laying around on scoops from when I was on the aerodynamics group for the UofM formula team. I'd like to see his math.
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Old 07-02-2001, 02:04 PM   #22
adeck
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Is a S-afc an accurate meter for reading intake pressure, because it was reading at zero when I bleeped the throttle going through town today. I can almost guarantee that it will read positive pressure, when I open it up after work.
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