Custom Cold (?) Air Intake Build

[iso100]

I decided to try my hand at building my own intake instead of purchasing an Injen or one of the other offerings currently on the market. The one thing that did turn me off is the use of a metal pipe for the long run from the MAF to the turbo inlet. I didn't like the fact that heat soak would turn this into an air charge heater (even if it's just a small amount radiated into the intake charge when at speed).

I started my build by ordering a silicone Mountune style induction hose from JS Performance. It looks identical to what Mountune sells and I received it from the UK including shipping and VAT for ?92.46.

I also ordered a MAF adapter from J1 Automotive also in the UK. This was 30 GBP to my door.

I wanted lots of surface area to reduce suction losses so I went with a large K&N filter at 6" ⌀ (long end) 4" ⌀ (short end) by 5" tall. This has a 70mm or 2.75" inlet ID to match the rest of the system. K&N part number RU-4870 is what I used. It was expensive at $46.99 from Amazon.

I also ordered a 45? elbow to use but it turned out not to work as the filter I selected was WAY too large. I ended up ordering a 90? silicone elbow from Amazon for $10 to aim the filter straight down in the hole where the airbox used to be.

I finally received everything and then realized I needed a way to connect the 90? elbow to the K&N. Of course 2.75" pipe is nearly impossible to find locally. I finally found a 2.75" OD (not ID) exhaust pipe and had to make it work.

Below is the nearly finished product. I still need to use my ABS sheets and a heat gun to build a heat shield and potentially a bracket to keep it secure.

The sound is great. Pretty loud actually. It definitely feels more responsive. I want to think it's a butt-dyno miscalibration due to the $ spent and time involved but I believe it's a real thing. After my test drive I started to get worried about how low the filter is to the ground, hydro locking, etc... but after looking at it again the bottom of the filter is a full 5" above the top of that lower IC charge pipe. The filter is also nestled behind the headlight and off to the side of the radiator so I bet it's fairly safe from water. I think the first time it rains I'll rubber band some paper towels to the side of it to see how wet they get.

For those following along, I definitely didn't save money. I'm at $254 including the induction hose, the MAF adapter, the elbow and the filter. I'm hoping that the position of the filter down low as well as some well placed heat shielding will be a net win. I know for sure this is a larger filter (surface area) than anyone else is using.

As long as the COBB filter isn't a restriction in and of itself due to small size, the plastic induction tube they're supposedly using is a win over other offerings right now.

 

[dyn085]

Big filter is big.

 

[iso100]

Way.

 

[_RED_]

That is a nice set up for sure.

 

[envyist]

Looks good op, repped ya just for being different

 

[Harvick]

Very professional DIY intake. Really great job.

 

[me32]

it looks really nice. in fact it looks better than any CAI on the market today. the bigger filter is a much smarter move, the aftermarket kits use too small of a cone filter which doesn't really have more surface area than the stock air box filter. would be nice to see some dyno numbers on this

 

[iso100]

Thanks everyone. I need to replace the clamps, build a heat shield, build a 3D printed bracket and hopefully adapt the ducting outlet.

 

[iso100]

I calculated that the drop in filter surface area is about 52 square inches while my cone filter is 80.

 

[me32]

I calculated that the drop in filter surface area is about 52 square inches while my cone filter is 80.

Huge improvement

 

[razorlab]

Very cool. I'm interested in seeing what the heat shielding is going to look like.

As an FYI, you can log intake filter air pressure via Accessport. It's the monitor labeled "Air Filter Press." and I believe it's measured at the MAF. This would be handy data whenever you are changing the intake. You would see a drop in intake filter air pressure whenever you remove a restriction.

 

[iso100]

As an FYI, you can log intake filter air pressure via Accessport. It's the monitor labeled "Air Filter Press." and I believe it's measured at the MAF. This would be handy data whenever you are changing the intake. You would see a drop in intake filter air pressure whenever you remove a restriction.

Nice! I didn't know that one existed. I should have run a log before and after.

 

[razorlab]

Nice! I didn't know that one existed. I should have run a log before and after.

Well you can log it now and I can log my stock setup and we can at least get sort of an idea.

 

[iso100]

Well you can log it now and I can log my stock setup and we can at least get sort of an idea.

Sounds like a plan. 3rd gear to stay out of jail?

 

[razorlab]

3rd gear to stay out of jail?

Yup!

 

[dyn085]

Ryst also has a log with the OEM filter in the datalog threads. He's showing 8-10 lbs/min more than my Cobb drop-in, iirc.

Definitely interested in what you get with this setup.

 

[iso100]

Does the AP log everything by default or do I need to set the gauges up for the bits of data I want logged?

 

[dyn085]

It doesn't log everything, but I'm pretty sure it logs air pressure by default. I'll look in a second.

Edit: It logs airflow mass by default, you have to select air filter pressure.

Edit to the edit: Here are my numbers after a full third-gear pull-

 

[iso100]

I logged the car this morning. Everything was looking awesome at first while the car was warming up. I was literally getting intake air temps exactly at or slightly below the temperature indicated in the gauge cluster: 68?.

I should have logged speed as well as the rest of the data points but I was in a bit of a rush.

All of that went to hell once the thermostat opened and the radiator was hot. The output of the fan shroud is literally .5" from the side of the K&N so once the radiator was hot, I get HOTTER intake temperatures the faster I drove. When at a stop, the intake temps would plummet. It's pretty much the opposite of most CAI's right now.

Here's a log showing my air filter pressure on a 3rd gear pull:
http://datazap.me/u/iso100/new-intake-3rd-gear-pull?log=0&data=3

Starts at 14.62 and peaks at 13.9 at 6650 RPM. I'm not sure what these values are though. Seems to be PSI so atmospheric at sea level should be 14.7. If I'm showing 13.9 that means it's pulling .8psi of vacuum meaning there's some kind of restriction. I find it hard to believe that this huge filter and large induction hose is more restrictive than the stock filter and box, etc.

Thoughts?

My airflow mass peak was 21.89. A prior log I have shows a peak of 20.95.

Also, unrelated... any idea why my ETC angle actual took a dip when I had my foot to the floor?
http://datazap.me/u/iso100/new-intake-3rd-gear-pull?log=0&data=4-5-8

 

[iso100]

Also, unrelated... any idea why my ETC angle actual took a dip when I had my foot to the floor?
http://datazap.me/u/iso100/new-intake-3rd-gear-pull?log=0&data=4-5-8

I see what was going on now. As soon as the boost spiked over 20psi the computer yanked throttle angle in an attempt to regulate it. I had a spike to 21.23psi.