Custom velocity stack intake-no welding

[brs2c]

First, a shoutout to Saxon for my inspiration found in this thread http://www.audizine.com/forum/showth...velocity+stack

I wanted to create the optimal setup. Here were my requirements:
-As a student a former student of fluid dynamics I loved the incorporation of a velocity stack.
-No/minimal diameter transitions. Maintain 3.5" diameter from the bellmouth velocity stack, to the TB (which will be 3.5" in the future).
-Filter as far away from the engine/heat as possible
-aFe filter
-No welding (I never learned)
-Under $200

Here are the pics:




Throttle response is noticeably improved. The SC whine is definitely there, and louder than my friend's ECS intake.

In case this inspires someone, here is the part list with links:
https://www.amazon.com/gp/product/B002TUNY6G/ (fit recessed inside the filter, on the 4th and 5th grip lines, to optimize bellmouth design)
https://www.amazon.com/gp/product/B001ABMMW2/
https://www.amazon.com/gp/product/B01K96L9ZO/ (used a hack saw to cut 4" off, so a total of 8" in length)
https://www.amazon.com/gp/product/B01ITYD0DM/
https://www.amazon.com/gp/product/B00TGP7PW6/
https://www.amazon.com/gp/product/B073V6VBP1/
https://www.amazon.com/gp/product/B00JPZEKOS/

Also bought a pack of vacuum elbows from Advanced Auto, for the TB vacuum line, that contained several like this (NOT sure of the size I used, but it was close to stock) https://shop.advanceautoparts.com/p/...m=vacuum+elbow I cut the part on the outside of the flange off with a razor blade, so that it would not stick out into the air path. I was going to use plastic epoxy to secure this into the silicone TB connector. However, after drilling small hole in the silicone connector, and testing the fit- I found it was so tight after the trimmed flange popped through, to the inside, that I just left it alone. It is very tight, and doesn't budge when pulled on.

When the new TB is available, all I have to do is buy an 3.5" to 3.5" 45 degree coupler for $12 bucks, and I am good to go.

Heat shield is next to fab up. Sorry about the dirty intake and engine bay, and poor hose clamp positioning in the pics (probably remedy that tonight). If anyone has any questions, let me know.

[saxon]

Looks great!

[brs2c]

Looks great!

Thanks man! You inspired it!

[The Machine]

Nice work!

[Oloung1]

in! for the heatshield action

[Jezza]

I like it. Be sure to take some logs and share them.

Sent from my SM-G930VL using Audizine mobile app

[CollecTTor]

Velocity stack always = winning.

[durfA4]

I would bet could use the same parts for my A7. I also wonder if I could fit that in the stock air box.


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[brs2c]

I would bet could use the same parts for my A7. I also wonder if I could fit that in the stock air box.


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The two 45 degree silicone connectors give you surprisingly good flexibility for placing the filter where you want it. You also have 6-8 inches of distance leway, due to how shallow or deep the aluminum pipe is inserted into the silicone connectors.

I say all that, to agree that you can probably make it fit in your car. The velocity stack could probably fit in the stock air box, but the filter I used is too large. aFe, is great, so you may be able to call them and give them dimensions and let them guide you to a filter that could possibly work.

Also, Vibrant Performance, who makes the velocity stack has some shorter filters made for their stacks, and cost less than aFe... I just think aFe has the best filters on the market with the progressive densities in the layers of their filters, and I saw a compelling flow study on high HP V8's where aFe handily beat the other big names.

[mattro]

I would bet could use the same parts for my A7. I also wonder if I could fit that in the stock air box.

The configuration on the A7 seems really similar to ours so I'd say you should be able to.

I did a similar thing, but without velocity stack, and connected it to the stock airbox.
3.5" to 3" silicone elbow for the throttle body, and 3.5" connection on the stock airbox.
here's my post: http://www.audizine.com/forum/showth...=custom+intake

[durfA4]

Looks good.


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[Ford Prefect]

The configuration on the A7 seems really similar to ours so I'd say you should be able to.

I did a similar thing, but without velocity stack, and connected it to the stock airbox.
3.5" to 3" silicone elbow for the throttle body, and 3.5" connection on the stock airbox.
here's my post: http://www.audizine.com/forum/showth...=custom+intake

I want one of your modified airbox tops, please, thanks!

[CollecTTor]

The two 45 degree silicone connectors give you surprisingly good flexibility for placing the filter where you want it. You also have 6-8 inches of distance leway

The more length and bends you add, the more you increase flow resistance. I know you have to make it fit with the real estate available, but a smoother transition 90 out of the throttle and no more bends would flow better if it fit. Just throwing ideas out there for discussion.

[saxon]

The more length and bends you add, the more you increase flow resistance. I know you have to make it fit with the real estate available, but a smoother transition 90 out of the throttle and no more bends would flow better if it fit. Just throwing ideas out there for discussion.

I'm not sure if agree with that.

Back in my Honda days you tune the hp curve with the length of the intake

[CollecTTor]

I'm not sure if agree with that.I

Back in my Honda days you tune the hp curve with the length of the intake

Are you taking about intake manifold runner length? Yes, that can be "tuned" to shift the powerband. Actual intake tube? Not really. If I remember correctly, Hondas usually had the option of short ram or longer "cold" air intakes for D/B series motors. That may be what you are thinking of.

[saxon]

Are you taking about intake manifold runner length? Yes, that can be "tuned" to shift the powerband. Actual intake tube? Not really. If I remember correctly, Hondas usually had the option of short ram or longer "cold" air intakes for D/B series motors. That may be what you are thinking of.

No, I'm talking about actual intake

I was never a fan of an out of the box intake so I would have the intake length adjusted to make leak power. You'd be surprised on a NA engine the difference in 12" of intake length for max power/tq

[brs2c]

The more length and bends you add, the more you increase flow resistance. I know you have to make it fit with the real estate available, but a smoother transition 90 out of the throttle and no more bends would flow better if it fit. Just throwing ideas out there for discussion.

The length does add a more surface area, and thus more drag resistance. However, I believe benefit of the reduced air temperature gained by not being above the headers (main heat source in engine bay), far outweighs the increased drag. Injen had some quality research papers on this, many years ago.

On the 45 degree versus 90 degree topic, what you are trying to avoid is abrupt/sharp changes in air direction. Two 45's are more gradual, so I think they are slightly better than one 90, but I don't think it is by much at all.

If you talk to anyone who does quality head porting, they will tell you that it is really about the smooth transition more so than the angle of transition (although it is still a factor). With this in mind, I actually think the important part of the couplers is how you position your hose clamps. I try to position on the far outer edge of the pipe (like half on, half off) snd tighten the crap out of it. It takes a little guess and check by looking inside the coupler at how flush the pipe edge is inside the coupler. If you get it just right, the hard edge of the pipe sinks a little into the silicone coupler- thus minimal turbulence introduced. If you aren't careful you can end up with almost a gap between the outside of the pipe and the coupler which is terrible for optimizing the flow.

I hope this all makes sense. Kinda tired.

[BG SQ5]

The more length and bends you add, the more you increase flow resistance. I know you have to make it fit with the real estate available, but a smoother transition 90 out of the throttle and no more bends would flow better if it fit. Just throwing ideas out there for discussion.

This is 100% correct. @saxon is thinking about resonant frequencies which are not something of concern with the s/c. We simply want the least amount of restriction so that the s/c can be as efficient as possible. If it was a n/a engine, then sure- designing the intake tract length for the pressure waves produced by the intake valves closing can play an important part in the volumetric efficiency at specific rpms.

I love all the weekend warrior engineering that goes on with our intakes. It's cool to see so many people get extra technical with them. Unfortunately, much of what we do is pretty negligible, and I've even seen some designs (long-tubed CAIs) that I'm sure do more harm than good for the 3.0T.

If we're over-engineering this, the inlet tube should be made out of one piece (so no internal shoulders) of material that has a low thermal conductivity (not metal) or insulated/cooled. Then, the filter should be fed ONLY by outside air. I think the next step for this intake is enclosing the filter in a box that is only fed by 'cold air'. Obviously the cold air feed tube(s) can't be restrictive either, and ideally they would have some kind of ram-air effect at higher speeds further reducing the pumping losses within the intake system.

Btw- why did I think the stock replacement aFe filter already has a velocity stack inside it?

[brs2c]

If we're over-engineering this, the inlet tube should be made out of one piece (so no internal shoulders) of material that has a low thermal conductivity (not metal) or insulated/cooled. Then, the filter should be fed ONLY by outside air. I think the next step for this intake is enclosing the filter in a box that is only fed by 'cold air'. Obviously the cold air feed tube(s) can't be restrictive either, and ideally they would have some kind of ram-air effect at higher speeds further reducing the pumping losses within the intake system.

Yes, please...I'd even pay more than $200 for this ;)

[CollecTTor]

No, I'm talking about actual intake

I was never a fan of an out of the box intake so I would have the intake length adjusted to make leak power. You'd be surprised on a NA engine the difference in 12" of intake length for max power/tq

Yes, on an NA application, and depends on intake manifold design as well.

The length does add a more surface area, and thus more drag resistance. However, I believe benefit of the reduced air temperature gained by not being above the headers (main heat source in engine bay), far outweighs the increased drag. Injen had some quality research papers on this, many years ago.

On the 45 degree versus 90 degree topic, what you are trying to avoid is abrupt/sharp changes in air direction. Two 45's are more gradual, so I think they are slightly better than one 90, but I don't think it is by much at all. The temperature issue is going to be much more of a factor at idle or slow vehicle speeds. Airflow through the bay mitigates most of that. When dealing with forced induction, flow outweighs temperature when dealing with intakes.

If you talk to anyone who does quality head porting, they will tell you that it is really about the smooth transition more so than the angle of transition (although it is still a factor). With this in mind, I actually think the important part of the couplers is how you position your hose clamps. I try to position on the far outer edge of the pipe (like half on, half off) snd tighten the crap out of it. It takes a little guess and check by looking inside the coupler at how flush the pipe edge is inside the coupler. If you get it just right, the hard edge of the pipe sinks a little into the silicone coupler- thus minimal turbulence introduced. If you aren't careful you can end up with almost a gap between the outside of the pipe and the coupler which is terrible for optimizing the flow.

I hope this all makes sense. Kinda tired.

Head porting is all about velocity and usually is a factor of the tapering down of cross sectional area in the head port. Not exactly comparable to pre throttle intake design. That said, a lot of what you said applies. My point about 1 90 vs 2 45's was that if you could get one 90 you'd only have straight before that, hence my real estate comment as well. It has to go somewhere and still let the hood close.

This is 100% correct. @saxon is thinking about resonant frequencies which are not something of concern with the s/c. We simply want the least amount of restriction so that the s/c can be as efficient as possible. If it was a n/a engine, then sure- designing the intake tract length for the pressure waves produced by the intake valves closing can play an important part in the volumetric efficiency at specific rpms.

I love all the weekend warrior engineering that goes on with our intakes. It's cool to see so many people get extra technical with them. Unfortunately, much of what we do is pretty negligible, and I've even seen some designs (long-tubed CAIs) that I'm sure do more harm than good for the 3.0T.

If we're over-engineering this, the inlet tube should be made out of one piece (so no internal shoulders) of material that has a low thermal conductivity (not metal) or insulated/cooled. Then, the filter should be fed ONLY by outside air. I think the next step for this intake is enclosing the filter in a box that is only fed by 'cold air'. Obviously the cold air feed tube(s) can't be restrictive either, and ideally they would have some kind of ram-air effect at higher speeds further reducing the pumping losses within the intake system.

Btw- why did I think the stock replacement aFe filter already has a velocity stack inside it?

Agreed with all of this.

[brs2c]

I wanted to update this thread for anyone searching for DIY intakes and heatshields. I used this cardboard and tape to mock up the shape I wanted my heatshield to be.

I then flattened this cardboard template to trace an outline on some aluminum from Lowes. Cut it out with come tin snips, and added this trim to the bottom and front https://www.amazon.com/MATCC-Protect..._1519579052038
I used this on the top and rear edges to tighten fitment against the fender wall and the hood https://www.amazon.com/dp/B019RXHYVS...detail_5?psc=1

My theory was to try and seal it from the back side of the factory intake duct (which I left to keep cooler air flowing to my filter), to my intake pipe. I slightly angled the top of the aluminum heat shield, so the hood bends the shield just slightly towards the engine. I figured this, plus the form filling abilities of the bulb trim on the top would keep it as air tight as possible, over those headers. It definitely does make a difference in delaying high IAT's, but if you are in traffic on a hot day, or doing multiple pulls- IAT's still get hot.

Used 2 self tapping screws with 1 rubber and 1 metal washer each, to attach. Here is the finished product: