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Old 10-27-2012, 11:42 AM   #1651
spyrule
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maybe it's just me, but I would think that the hard angles would cause as much impeded airflow as the stock tubing... I'm probably wrong though.
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Old 10-27-2012, 11:43 AM   #1652
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Obviously not as ideal as a mandrel band but I'm sure it's better than the stock corrugation.
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Old 10-29-2012, 01:11 AM   #1653
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Quote:
Originally Posted by Soul Shinobi View Post
Oh you fancy huh?

Nice, thanks for sharing.

Looks good, so long as those couplers have enough flex (have someone start it and tweak the throttle aggressively while you watch). Don't want to put too much stress on the plastic MAF housing, if in doubt cut the pipe shorter there and use a longer coupler.

EDIT: Can you estimate the total angle of the bend?
There's definately enough flex in the couplers. My brother and I got bored during the summer one day, found some extra 304 in his garage, and thought "hey let's make an intake for the RS" - Quick run to summit later for the couplers and gold wrap and there you have it.

Angle of the bend - No idea, we just copied as closely to the OE as possible with what we had to work with.

Quote:
Originally Posted by spyrule View Post
maybe it's just me, but I would think that the hard angles would cause as much impeded airflow as the stock tubing... I'm probably wrong though.

Quote:
Originally Posted by Soul Shinobi View Post
Obviously not as ideal as a mandrel band but I'm sure it's better than the stock corrugation.
Well what you can't see is inside the pipe. All edges were beveled before welding so they're as smooth as can be. Also, the trick with pie cuts is after your first cut, your next cut has to be backwards from the first (probably not explaining it right but I could show you) - it's actually very straight, it just looks like it isnt.
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Old 10-29-2012, 01:46 PM   #1654
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Quote:
Originally Posted by Soul Shinobi View Post

EDIT: Can you estimate the total angle of the bend?
I measured up my engine bay recently actually, I believe a single bend like BloB's is ~125 degrees

BUT this is on a 98 2.2 impreza L, so yours may be different depending on car/engine.

Here's a rough sketch of my 2.2L :


bay measurements by distanceman89, on Flickr

Red are obstacles and firewall, Blue is the MAF and green is the Throttle body, everything +/- .5 inches for a safety cushion.

Here's a conceptual design I have, based on what I've seen here:


intake drawing by distanceman89, on Flickr

The major differences are that I ran the Largest radius curve I felt was reasonable to stuff into the engine bay, and instead of using a restrictive reducer it's a constant super gradual decrease from 3" dia. at the MAF to 2.5" at the Throttle body. Both of these help reduce the pressure/head loss in the pipe, and the lack of transitions will help as well. It's a tiny difference for the work i know, but this is serving as my independent research project in a fluid mechanics course at university, so killing two birds with one stone.

I plan on cutting a foam blank, laminating it in carbon fiber, attaching the vacuum line hookups, removing the foam with acetone and elbow grease and voila!

The only downside I can think of right now is that the epoxy used may yellow if heated too much, but since I'm taking cold air from the fender, this may be a non-issue.

I might be persuaded into making more if mine works out nicely
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Old 10-29-2012, 01:55 PM   #1655
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I love you.
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Old 10-29-2012, 01:55 PM   #1656
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Quote:
Originally Posted by tru1shot View Post
I might be persuaded into making more if mine works out nicely
DIBS!

I have the most ghetto intake ever made on there now. It's some exhaust pipe and plumbing fixtures. It's the prototype I made back when I was discovering all this for you guys. I never got around to making an actual intake.
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Old 10-31-2012, 10:50 AM   #1657
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Quote:
Originally Posted by williaty
DIBS!

I have the most ghetto intake ever made on there now. It's some exhaust pipe and plumbing fixtures. It's the prototype I made back when I was discovering all this for you guys. I never got around to making an actual intake.
Does anyone where I can get a cold air intake for my 2.5i?
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Old 10-31-2012, 09:19 PM   #1658
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Originally Posted by PrezaDriver2011 View Post
Does anyone where I can get a cold air intake for my 2.5i?
No, i've never heard of Cosmo Racing eleventy billion times on these forums.

Ignore me, i'm tired.....
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Old 11-12-2012, 08:47 AM   #1659
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Hey guys...so I've found this thread a while ago and def decided to do a hybrid intake. I don't want to have any issues with my car. I was just checking my air filter recently and decided it needs to be changed. I then got an idea.

What about adding a funnel filter before the snorkel and then taking out the stock filter from inside the box. The funnel filter is a little more free flowing. Now that filter mixed with the hybrid intake should be a nice touch. So it just so happened I had an extra funnel filter laying around. After a few min I ended up with my mini hybrid intake.(this is what happens when your bored)

My question is would this make any changes at all? As long as its not something bad I don't mind it. Though I don't think it should cause a problem since the snorkel is not taken out.
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Old 11-12-2012, 09:08 AM   #1660
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Truth is those aftermarket filters don't filter as well, and the stock filter creates a seal between the two halves of the airbox (but I suppose you could just cut the center of the filter out). Still sounds doable in theory, so long as everything is sealed well.
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Old 11-12-2012, 03:19 PM   #1661
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Leave the stock filter alone, it's good at its job and doesn't cost you any power.
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Old 11-12-2012, 09:45 PM   #1662
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My intention is to make the intake as free flowing as possible as a CAI or even short ram...

I was thinking of connecting a straight pipe from the snorkel where it connects to the air box to the manifold. So that would eliminate the air box, the stock accordion like pipe, and the box at the manifold. The filter would be connected before the snorkel. There were proven gains with the hybrid intake so this wouldn't really be much different. If anything it should be a little more free flowing since the filter box would be removed....


I would add a diagram to make it easier to understand but I don't know how to add a pic here( can someone help)
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Old 11-12-2012, 09:52 PM   #1663
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Quote:
Originally Posted by Jb2.5rstst View Post
My intention is to make the intake as free flowing as possible as a CAI or even short ram...

I was thinking of connecting a straight pipe from the snorkel where it connects to the air box to the manifold. So that would eliminate the air box, the stock accordion like pipe, and the box at the manifold. The filter would be connected before the snorkel. There were proven gains with the hybrid intake so this wouldn't really be much different. If anything it should be a little more free flowing since the filter box would be removed....


I would add a diagram to make it easier to understand but I don't know how to add a pic here( can someone help)
Jesus christ, did you even read the first post in this thread?

It shows that what you want to do will fail and that the hybrid as described is so close to flowing as much as a SRI that it's not going to make any difference in the real world.
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Old 11-13-2012, 01:10 PM   #1664
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Originally Posted by williaty View Post
Jesus christ, did you even read the first post in this thread?

It shows that what you want to do will fail and that the hybrid as described is so close to flowing as much as a SRI that it's not going to make any difference in the real world.
Engine load compensation tables.


Those are the key to tuning out the maf voltage spike at the resonant RPM's.


Why hasn't this been attempted here? Why are we still running "hybrid" intakes and stock airboxes?
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Old 11-13-2012, 01:57 PM   #1665
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Originally Posted by gdoggmoney View Post
Engine load compensation tables.


Those are the key to tuning out the maf voltage spike at the resonant RPM's.


Why hasn't this been attempted here? Why are we still running "hybrid" intakes and stock airboxes?
Try it and post your results. We'd all be extremely interested to see your well documented and clearly explained research on the topic.

The other question you'll have to answer, if you can even make it work, is what did you gain from the difficulty of doing it? What I mean is, after you've gone through the development of your idea, found out that it has to be custom tuned to every individual install, and then written it all up for us, what's the benefit to running a different intake vs a hybrid?
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Old 11-13-2012, 02:22 PM   #1666
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Quote:
Originally Posted by gdoggmoney
Why hasn't this been attempted here? Why are we still running "hybrid" intakes and stock airboxes?
Because this thread is about HYBRIDS. it's a thread to inform the community about a cheap alternative to spending a lot more money on an intake PLUS the cost to get it tuned to make it effective.
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Old 11-13-2012, 02:32 PM   #1667
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Originally Posted by Bubakanush View Post
Because this thread is about HYBRIDS. it's a thread to inform the community about a cheap alternative to spending a lot more money on an intake PLUS the cost to get it tuned to make it effective.
A tactrix cable, and romraider or ECUflash?

The thread is about a problem with intakes and an alternative, from the 40+ pages I have read.


Engine load compensation seems like a solution. Looking at my tables it seems subaru implements it at 3k where the resonance is on all of these motors.

Looks like adjusting the load compensation and or rescaling some tables to apply to that area if needed will deal with the voltage spike from the resonance effectively.
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Old 11-13-2012, 02:33 PM   #1668
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Originally Posted by gdoggmoney View Post
Why hasn't this been attempted here? Why are we still running "hybrid" intakes and stock airboxes?
Or, to put it another way, what's bad about the stock airbox?
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Old 11-13-2012, 02:34 PM   #1669
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Try it and post your results. We'd all be extremely interested to see your well documented and clearly explained research on the topic.

The other question you'll have to answer, if you can even make it work, is what did you gain from the difficulty of doing it? What I mean is, after you've gone through the development of your idea, found out that it has to be custom tuned to every individual install, and then written it all up for us, what's the benefit to running a different intake vs a hybrid?
I am going to be trying different things. This is one of them.

I'll have gained the ability to get rid of the airbox, plastic maf housing, and all of that for a nice slick looking intake that pulls air through a velocity stack and filter inside the fender. Win win win.

Why the hate?

Think you are the only one capable of figuring the "solution" out ?
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Old 11-13-2012, 02:42 PM   #1670
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Originally Posted by gdoggmoney View Post
I'll have gained the ability to get rid of the airbox, plastic maf housing, and all of that for a nice slick looking intake that pulls air through a velocity stack and filter inside the fender. Win win win.
Measure it. Properly, on a load-holding dyno under controlled environmental conditions, and keeping the engine's thermal conditions stable. You'll find out that you didn't gain anything meaningful over keeping the airbox. That's precisely what I did, at pretty significant cost (thankfully to someone else, not me) and I confirmed that the stock airbox and snorkus are not a meaningful restriction so there's no power gain from eliminating them.

Quote:
Why the hate? Think you are the only one capable of figuring the "solution" out ?
This whole thread has had nothing but people popping up thinking they've managed to find magic new physics that somehow allows them to do special things. They've all been wrong. Therefore, I'm tried of people claiming **** without providing well documented proof.

As far as what you want to do with tuning, yeah, I beat you to that by about 3 years. Go back in this thread and the announcement one and you'll see me post about being able to do it. I've been sitting here waiting for someone else to think about doing it. There's a bunch of tables in the ECU that look like they ought to be able to help combat this. All but one of them look right but turn out to really screw things up when you mess with them. One of them will allow you to do what needs done. However, a mis-step with it and you'll blow the engine up. In the end, the average person would end up paying a tuner 2-3 hours at $100-$150/hr just to dial in the intake tuning. At the end of which you'd have a system that made no extra power, just more noise and let more dirt into the engine than stock.
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Old 11-13-2012, 03:21 PM   #1671
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Originally Posted by williaty View Post
Measure it. Properly, on a load-holding dyno under controlled environmental conditions, and keeping the engine's thermal conditions stable. You'll find out that you didn't gain anything meaningful over keeping the airbox. That's precisely what I did, at pretty significant cost (thankfully to someone else, not me) and I confirmed that the stock airbox and snorkus are not a meaningful restriction so there's no power gain from eliminating them.


This whole thread has had nothing but people popping up thinking they've managed to find magic new physics that somehow allows them to do special things. They've all been wrong. Therefore, I'm tried of people claiming **** without providing well documented proof.

As far as what you want to do with tuning, yeah, I beat you to that by about 3 years. Go back in this thread and the announcement one and you'll see me post about being able to do it. I've been sitting here waiting for someone else to think about doing it. There's a bunch of tables in the ECU that look like they ought to be able to help combat this. All but one of them look right but turn out to really screw things up when you mess with them. One of them will allow you to do what needs done. However, a mis-step with it and you'll blow the engine up. In the end, the average person would end up paying a tuner 2-3 hours at $100-$150/hr just to dial in the intake tuning. At the end of which you'd have a system that made no extra power, just more noise and let more dirt into the engine than stock.


That's fine.... I'm glad you "beat me to it".

I also don't recall claiming anything.

So you mean to tell me, a velocity stack and free flowing filter with proper mandrel bent pipe will not be a gain? Silly me, I think I will work on this anyways. Noise is cool, so are velocity stacks.

We don't need to change physics, only need to make the ECU work with what is happening.
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Old 11-13-2012, 04:37 PM   #1672
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So you mean to tell me, a velocity stack and free flowing filter with proper mandrel bent pipe will not be a gain?
Yep, that's exactly what I mean. Those changes, while they do represent local improvements in efficiency, can't magically improve other parts of the total path from the outside world to the inside of the cylinders. The airbox and snorkus are effectively non-restrictive at the airflow levels achieved by the NA cars. There are other things further down the path that are definitely restrictions at the airflow levels achieved by the NA cars. Unless you're first going to fix those bigger problems, nothing you do by eliminating the airbox and snorkus are going to make any difference at all to the total massflow into the engine.

Quote:
Noise is cool, so are velocity stacks.
So you're saying that people should spend $300+ just for shiny bits and a really loud farting noise?
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Old 11-13-2012, 06:36 PM   #1673
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I'm 100% certain he was being sarcastic

Williaty - I get what you're saying, but I also get what he's saying, and you're both right in your own respects. We're all gonna do what we want if we feel like it, just let it go.
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Old 11-14-2012, 10:58 PM   #1674
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Oh man what did a start...lol...

Sorry guys didn't mean to start the arguments. The reason why I brought up my idea is because of the following:
1-if my idea actually makes a slight improvement or gives someone else an inspiration to come up with something better then in the end it will benefit all dealing with this problem.
2-if my idea had no gains but also no losses then it will at least look more pleasing than the stock setup. (This was my main question that I was looking for and answer to). Based on the research done already technically it should not affect anything as the main things are still the same(snorkus and maf are in the same location)

I plan on making my car look as good as possible and you would have to agree that having a nicely painted intake pipe would look a lot better than a box with an accordion like connector into another box. That's just my opinion at least.

Not sure who is willing to go through the hassle of tunning his rs for and aftermarket intake to work just for sound or the minimal gains it gives. Just buy a wrx or an sti and you'll get real performance out of it.

All in all I'm just looking to learn more about this whole situation as this is the first time I experience this problem with intakes.

Thanks for your help
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Old 11-15-2012, 09:38 AM   #1675
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Originally Posted by williaty View Post
Yep, that's exactly what I mean. Those changes, while they do represent local improvements in efficiency, can't magically improve other parts of the total path from the outside world to the inside of the cylinders. The airbox and snorkus are effectively non-restrictive at the airflow levels achieved by the NA cars. There are other things further down the path that are definitely restrictions at the airflow levels achieved by the NA cars. Unless you're first going to fix those bigger problems, nothing you do by eliminating the airbox and snorkus are going to make any difference at all to the total massflow into the engine.


So you're saying that people should spend $300+ just for shiny bits and a really loud farting noise?

You are right there, the accordion pipe and torque box are not that elegant. I have a mandrel bent piece of 409SS that I had swapped into place of the torque box and accordion tube which made a nice difference.

Ideally, i'd grab an injen kit with the MAF housing and etc, add a velocity stack to the end of it in the fender and a different cone filter. That is a complete system end to end, rids the torque box and accordion tube.

If that is what they want -- and they feel the price is ok, then so be it.
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