Intake insulation and other questions.

Snorkus, filters, throttle bodies and intake manifolds.

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coffeeman885
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Intake insulation and other questions.

Post by coffeeman885 »

So I think I have decided to change the intake pipe upstream of the MAF to a piece of seamlessly bent ABS. I am assuming that getting rid of any place to cause turbulence will give me something. I am going to insulate it somehow as well. I have ideas ranging from a radiant wrap option (more legit-ish) to foam pipe insulation wrapped with aluminum foil and duct tape (super ghetto-ish). I think that I will wrap the air box too. It has to help.

The radiant wrap I am thinking about.
http://www.homedepot.com/Building-Mater ... reId=10051

Another question I have is whether taking out the snorkus and replacing it with a piece of pipe or something else will yield the same adverse results as removing it all together. I can't afford to loose any low end anything but I would like get any gains that I can.

I am looking for any hps that are hiding out in my car. Last event my evening runs were all with a fraction of a second of each other. Even a hand full of hps would help me out. That damn STI **Shakes fist toward the sky**!
Speed limits are like herpes - once you get them you will never be rid of them. - Jeremy Clarkson

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coffeeman885
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Re: Intake insulation and other questions.

Post by coffeeman885 »

Just found this too. I wonder if I wrapped everything in aluminum foil first if that would bring up the R value.

http://www.homedepot.com/Plumbing-Pipe- ... reId=10051
Speed limits are like herpes - once you get them you will never be rid of them. - Jeremy Clarkson

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jefferson
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Re: Intake insulation and other questions.

Post by jefferson »

45 degree airbox mod would be good and it would be easier to do on a non turbo car I think. You could also bypass the throttle body coolant flow to remove some heat from the intake charge.
I like the idea you have of insulating the intake tract. It should help. Another thing to do would be to smooth the outside of the intake manifold. Less surface area to absorb the underhood heat. Much more involved though, or you could insulate the manifold which would help alot, but be a pain to do.

Jeff
91 Black SS 5spd. Edm lights, wrx gauges in dash, 45 degree airbox, cryoed drilled and slotted brakes. Invidia divorced downpipe with custom stainless exhaust. To be installed, aluminum a-arms, manual belts, awic.
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Re: Intake insulation and other questions.

Post by ciper »

If you are being cheap buy some emergency blankets from the camping store. They are essentially the same as the adhesive Mylar used for intercoolers.
coffeeman885
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Re: Intake insulation and other questions.

Post by coffeeman885 »

jefferson wrote:45 degree airbox mod would be good and it would be easier to do on a non turbo car I think.
Jeff
Ok I'll bite. What the hell is a 45 degree airbox mod?

I am doing the tb bypass this weekend.

I didn't think about space blankets.
Speed limits are like herpes - once you get them you will never be rid of them. - Jeremy Clarkson

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Re: Intake insulation and other questions.

Post by jefferson »

I would do a search and you will find pictures. The airbox is off an Impreza or later Legacy and the maf is angled in toward the engine. It will unshroud the entrance to the maf, get rid of a 90 degree bend, and it is also a larger airbox.

Jeff
91 Black SS 5spd. Edm lights, wrx gauges in dash, 45 degree airbox, cryoed drilled and slotted brakes. Invidia divorced downpipe with custom stainless exhaust. To be installed, aluminum a-arms, manual belts, awic.
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Re: Intake insulation and other questions.

Post by Legacy777 »

Honestly....by modifying the intake piping at all from the air box to the TB, you will likely see a reduction in low end torque. Those polished aluminum intake tubes that were used years back on the 2.5 RS helped top end, but didn't necessarily help low end. The Cobb intake with the inline filter setup was about the only one that probably helped both.

Honestly....what I would do if I were you is do the tb coolant bypass mod, remove the snorkus from the fender and use mylar tape/wrap on the intake piping and airbox. If you want to go further, you could do the phenolic spacers between the intake manifold & heads. Beyond that, the amount of money/time/effort vs. potential gains is very lopsided.

I'd start with the TB coolant bypass & snorkus removal. Those things cost nothing. Drive the car after those mods, then do the heat wrap. You'll be able to determine whether the heat wrap actually did you any good. I have my doubts you'll see any measurable gains.

The only other thing I'd suggest is putting a velocity stack at the inlet of the filter box in the fender. Something like this. You'll have to see what diameter you need.

http://www.google.com/products/catalog? ... YQ8wIwAQ#p
Josh

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Re: Intake insulation and other questions.

Post by jefferson »

You could also make your own velocity stack with the Volvo part I have written about and a heat gun. The hard part is finding the right Volvo in the pick and pull.

While you have the tb off to do the coolant bypass mod you might blend the leading edge of the tb to reduce turbulence.

Jeff
91 Black SS 5spd. Edm lights, wrx gauges in dash, 45 degree airbox, cryoed drilled and slotted brakes. Invidia divorced downpipe with custom stainless exhaust. To be installed, aluminum a-arms, manual belts, awic.
coffeeman885
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Re: Intake insulation and other questions.

Post by coffeeman885 »

Taking out the accordion section of the intake tube would kill low end torque? Since I can't seem to find ABS pipe anywhere (back when I was making potato guns you could buy it anywhere) I was thinking of just wrapping the stock stuff. The heat wrap is for rallycross - I don't care about everyday so much. Running lap after lap at WOT with little airflow due to how technical the course is, the engine bay gets crazy hot. A lot of us will usually prop the hood up if we get any long breaks in our run group.

So taking out the snorkus won't mess with the MAF? I thought that it made it bog a low RPMs because it causes some weird thing to happen to the MAF. Was that just taking the airbox out all together?

Do you think that the velocity stack will help with flow? I was just going to throw a piece of pipe in there if I was able to change the snorkus without problems.
Speed limits are like herpes - once you get them you will never be rid of them. - Jeremy Clarkson

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Re: Intake insulation and other questions.

Post by evolutionmovement »

I never had any negative effect from removing the snorkus. I replaced mine with a hose attached to a NACA duct in the lower side bumper. The only time it would bog was when I rammed a snow bank and clogged the duct.
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Re: Intake insulation and other questions.

Post by jefferson »

The velocity stack will help the flow. Long tubes don't flow as well as short ones. The Volvo tube is quite a bit bigger in diameter too.

Jeff
91 Black SS 5spd. Edm lights, wrx gauges in dash, 45 degree airbox, cryoed drilled and slotted brakes. Invidia divorced downpipe with custom stainless exhaust. To be installed, aluminum a-arms, manual belts, awic.
coffeeman885
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Re: Intake insulation and other questions.

Post by coffeeman885 »

I think if I did the NACA duct I would clog my filter at RXs.

I will yank the snorkus tomorrow then.
Speed limits are like herpes - once you get them you will never be rid of them. - Jeremy Clarkson

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Re: Intake insulation and other questions.

Post by Legacy777 »

coffeeman885 wrote:Taking out the accordion section of the intake tube would kill low end torque?
Are you talking about the entire stock black plastic piece with the accordian piece in it? If so, then yes it can. There can be pressure waves in the intake tubing, which depending on length, size, etc can affect how air flow goes through. You'll see on some of the newer cars that have the odd shaped plastic pieces off the stock intake tube. These are called helmholtz resonators. So modifying the intake can cause some negative effects, especially on non-turbo charged engines.

The link below has some more info on helmholtz resonators

http://blog.autospeed.com/2003/11/30/th ... o-intakes/


Also, regarding the velocity stack, as mentioned it can help improve air flow. They do this by allowing for a smoother transition of air flow into the airbox.
Josh

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1990 Legacy (AWD, 6MT, & EJ22T Swap)
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dillonr92
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Re: Intake insulation and other questions.

Post by dillonr92 »

Legacy777 wrote:Honestly....by modifying the intake piping at all from the air box to the TB, you will likely see a reduction in low end torque. Those polished aluminum intake tubes that were used years back on the 2.5 RS helped top end, but didn't necessarily help low end. The Cobb intake with the inline filter setup was about the only one that probably helped both.

Honestly....what I would do if I were you is do the tb coolant bypass mod, remove the snorkus from the fender and use mylar tape/wrap on the intake piping and airbox. If you want to go further, you could do the phenolic spacers between the intake manifold & heads. Beyond that, the amount of money/time/effort vs. potential gains is very lopsided.

I'd start with the TB coolant bypass & snorkus removal. Those things cost nothing. Drive the car after those mods, then do the heat wrap. You'll be able to determine whether the heat wrap actually did you any good. I have my doubts you'll see any measurable gains.

The only other thing I'd suggest is putting a velocity stack at the inlet of the filter box in the fender. Something like this. You'll have to see what diameter you need.

http://www.google.com/products/catalog? ... YQ8wIwAQ#p


josh, the link at the end of this post will not work anymore i am interested in the volocity stack mod thing. if you could explain some more or hook me with another link so i know what it looks like thatd be awesome.
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Re: Intake insulation and other questions.

Post by Legacy777 »

Josh

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dillonr92
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Re: Intake insulation and other questions.

Post by dillonr92 »

how would i attach the V stack? to the bottom of the airbox or attach to the fender well hole some how?
92 SS winestone red. td04 - FMIC. RWD 5 spd swap/LSD.dead...
94 LEGACY GT RAISED ROOF WAGON, fozzy lift hydro clutch/91SS 5speed/VLSD..#5.NEW FuLL DRiFT SLuT 93SS winestone,RS 5speed RWD. Welded rear, td04, fmic, 17x9 +20
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Re: Intake insulation and other questions.

Post by Legacy777 »

You'd have to use something to attach it to the intakae tube in the fender. You could try making a bracket, use tape, or whatever else you can find.
Josh

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1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
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