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2011-2016 LML Duramax 4" Intake Kit with Air Box

- 37% Improvement in Air Flow Over Stock
- 4" Intake Pipe
- Air Box & Lid Constructed of 10G Aluminum Sheet
- Dry Air Filter
- Outerwear's Pre-Filter Cover
- Includes Installation Hardware
- Silicone Boot & Stainless Steel T-Bolt Clamps
- 14g Aluminum Construction
- Installs Easily with Basic Hand tools
- No Tuning Required, Bolt On!
- Custom Powder Coat Finish
- Made in USA
Availability: WCFab Red, WCFab Grey, Candy Teal, Gloss White, and Gloss Black in stock and ships in 3-5 business days. 10-15 business day lead time on other colors.
Shipping: This product Cannot Ship to the State of California
Pricing: $519.00
4 5 1

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- Powder Coating -
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- Spare 4" Air Filter -
 * required


WCFab 2011-2016 GM LML 6.6L Duramax 4" Intake Kit with Air Box.

This high flow, fabricated aluminum intake pipe and air box enclosure with dry filter assembly replaces the restrictive plastic factory parts on your diesel for improved engine performance.

All new design significantly increases air flow to your turbo producing improved horsepower and torque, quicker throttle response, and cooler intake temperatures by drawing cold air through the inner fender. All aluminum construction features large diameter 4" piping with smooth aerodynamic bends to improve intake air velocity, volume, and provide more aggressive engine and turbo sound during acceleration. High quality hardware, silicone boot, seals, and stainless steel t-bolt clamps ensure optimum durability and ease of installation.

Removable air box lid element allows for easy visual inspection and maintenance of your WCFab filter with included hydrophobic pre-filter cover, to help keep your MAF sensor, turbo, and engine airways contaminant free. Full assembly finished in your choice of WCFab's signature custom powder coat colors for a look as unique as your truck.

Supersedes WCF100337. This intake is not compatible with discontinued models WCF100641, WCF100691, or WCF100716 unless you have a compatible aftermarket intake horn.

Air box is NOT compatible with intake pipe from kits WCF100337, WCF100689, or WCF100691.

Replaces the following GM Part Numbers: 23467660, 20917396, 15819728, 25881207, 20847795, 23210121, 22870902



Today, we have our 2011 to 16 LML Duramax High Flow intake kit.

So here we have our high-flow intake kit for the 11 to 16 LML Duramax. This is a product that we've offered for many years for the LML, and we decided to go back to the drawing board about a year and a half ago and make some improvements to it. When we moved into our new facility about two years ago, we brought some new processes in-house that gave us many new capabilities and allowed us to redesign many of our products for the better. So we used to previously offer these kits as just a four inch intake pipe with an air filter on the end, and a lot of people like those designs, they look cool, but there is a big benefit to having an air box around that air filter. So we went back to the drawing board, and we designed a nice fabricated aluminum box that fits right into the OEM location.

All done in-house here on our laser and press break; we've got a nice heavy-duty 0.1" aluminum fabricated airbox, a little bit heavier construction than some other designs on the market. Gives you a much sturdier piece that doesn't rattle and lead to cracking and braking the brackets or the lids, we've got a full three-sided box as well as covered on the engine side. We are fully open to the fender for increased airflow to the intake and the bottom to the fender well, all for additional airflow over the factory box, which just has one small port to the fender. The lid has our logo riveted to the top, allowing us to do custom colors on that logo. If you choose, the lid is fastened to the rest of the box with four stainless steel allen head bolts. When you remove the lid, that opens up the slot for the intake pipe.

Instead of sliding that pipe through a hole and scratching it when the lid is removed, it opens up half of that circle so that the pipe drops into place. Nice. It makes for a simple install and removal of the intake pipe, or if you're servicing your air filter, it makes it much easier than pulling a pipe in and out of the hole.

So, as we mentioned on this opening here where the pipe sits, we've got a nice rubber grommet that sits right in place, both on the bottom and the top, with locating tabs on either end, which keep that grommet from wanting to spin or rotate out of that groove and fall off of the box. Those nice little tabs hold that grommet in place for a solid, long-lasting fit. That rubber rests against the four-inch pipe, so you don't have metal-on-metal contact.

So, moving on from our airbox to the intake pipe itself, we manufacture this intake pipe from 14 gauge mandrel bent four-inch aluminum. Many other fabricated metal intakes are made from 16 gauge, which is notorious for getting crushed. If you tighten your clamps too much, which can lead to a leak point at your boot connection or your air filter, typically, you can clamp down a T bolt clamp, and you'll likely break that clamp before you have to worry about crushing the pipe. Another thing that we did when we redesigned this intake kit was to spend some additional time on the flow bench and vehicle testing before and after the OEM intake to get us a mass airflow sensor location that mimics OEM so that you do not throw check engine lights or have to deal with mass airflow sensor codes with the installation of this intake.

With that being said, this is emissions tested 49 state compliant bolt-on component, meaning there's no tuning required. This works on a factory stock application. Don't have to worry about check engine lights or any custom tuning to make the intake system work.

Now with that being said, there is a big benefit with custom tuning the four inch intake system installed on a stock truck. You're not going to see massive 20 to 25 horsepower gains like some people claim when you're trying to mimic the location of that factory mass airflow sensor so that you don't throw check engine lights. You can't get that mass airflow sensor to do additional fueling when you're trying to replicate those OEM airflow readings. So on a bone stock truck, you're going to feel increased turbo spool up and throttle response. You're going to have some additional turbo noise and some in-cab engine noise because you're replacing those factory parts with aluminum pieces.

So those are some benefits that you will get aside from the great looks on a stock truck where these high flow intake systems really shine is in a tuned application. If your truck has performance tuning, whether it be custom tuning or if it's just a plugin style plug and play type tuner, the stock airbox and a tuned application is a major airflow restriction and you will see horsepower gains with these intake systems in max effort tuned applications on the flow bench. As far as numbers go, the intake system here when compared to factory is a 37% increase over the OEM components giving you 250 CFM more airflow at its peak flow. So it's a massive increase over the OEM unit and big gains can be had on an application that has other performance upgrades. So the four inch intake pipe connects to in this application because it's just our basic stage one kit, we supply a silicone boot and T bolt clamp to connect to your OEM style intake horn.

We do offer and we touch on in a separate video is our stage two intake system, which is this kit with the addition of our high flow 4.8 inch cast aluminum intake horn, which you can powder coat to match the rest of your intake system and fully complete the air track from air filter to turbo. Last I will touch on our air filter. All of our intake systems use a dry replacement style air filter. We've never been a big fan of oil filters. We've always supplied dry filters with our kit. It's much less problematic. They're easy to oil improperly or over oil leading in poor performance as far as catching debris or ending up getting excessive oil onto your mass airflow sensor and causing performance and drivability issues. So we're a big fan of using dry air filters and that's what comes standard in all of our kits.

Another item that we include standard with all of our intake kits that a lot of other companies charge extra for is our Outer Wears pre-filter cover. So these outer wears covers are a nice addition as they prolong, they extend the service life of your air filter. This cover on here helps keep the pleats of the filter from clogging with debris and allows you to service the filter with compressed air a handful of times from the inside and blow out just the fine dust that it's trapping while any large debris can't make its way in. Another benefit to the filter cover is its water repellent properties. So in driving in rain, any sort of situation where you're getting potential water through that fender well or in the fender helps keep that air filter from getting saturated with water and causing poor performance or drivability issues. So one of the last things we'll touch on for our intake kit on the LML here is our powder coat finish.

We take great pride in our powder coat process here at WCFAB State-of-the-Art Powder Coat facility here in-House. And this color here is one of our in-stock. Quick to ship options WC Fab Red, as well as black and white. So if you're in a hurry for a kit, your trucks tore apart or you're looking to get something in time for the weekend, we have a handful of colors in stock that are ready to ship quick. Otherwise, we've got many colors to choose from with just a little bit of extended lead time on those custom color choices. If you've got any other questions about your LML, we offer several other high performance bolt on upgraded components for the LML, from intercooler pipes, exhaust manifolds and up pipes and high flow crossover, and very soon a high flow y bridge. Feel free to leave a comment below or reach out to our sales team if you've got any questions on this kit or anything else that we offer for the LML and thanks a lot for watching.



Shipping Information

  • Item Requires Shipping
  • 13.0 lbs.
  • W24.0000” x H16.0000” x L16.0000”
  • This item ships in its own box.
  • This product Cannot Ship to the State of California

Customer Reviews

Comment Total Reviews (1)

Great but…
  • Currently 4/5 Stars

Reviewed by:

Product ownership: Less than 3 months

Purchased from: Wehrli Custom Fabrication - WCFab

Love the kit, looks awsome. Only complaint is the boot that comes with it is incredibly tight like took me over an hour just on the boot.

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