DK Custom Products

Phone: 662.252.8828
Text: 662.420.4891
Email: [email protected]

Differences Between Outlaw HiFlow Air Cleaner Systems

425 - 587 - 606 - 636v - 828 - Velocity Stack


(See All The Dyno Charts Below)


a breath of fresh air

First, let's talk about what is the same about the Five of The Outlaw Model A/C Systems:

  • Made in The USA by DK Custom Products
  • All use a K&N Filter Element with a Million Mile Warranty
  • All Flow more air than the Sportster, Twin Cam & M8  Motors can breathe*
  • Unique low-profile backplate design make the 425, 587, 606 & 828 the lowest profile A/C’s on the market
  • Easy Installation
  • Street Developed & Tested -Dyno Proven

*Except the 425 on Twin Cams at high RPM, see more info below, does not fit the M8




The 425 filter element  is 4 ¼” in diameter and 2” deep, making it the second lowest profile air cleaner on the market.

There are 4 Different Cover Styles for the 425.

The Outlaw 425 flows more air than the Sportster can breathe, even a 1250.  

The Outlaw 425 is a bit too small for higher RPM riding on the Twin Cams.  It does great up until about 4500 rpm.  After 4500 rpm it does not flow enough air for the 96 & 103 Twin Cam for them to develop maximum power.  It still runs fine, just not quite as strong as it could.

Many still like it on the Twin Cam because of the low profile, and because many folks don't run up past 4500 rpm.




The 587 filter element is 5 ⅞” in diameter and 1 ⅞” deep, making The Outlaw 587 the lowest profile A/C on the market.

There are 23 different Cover Styles for the 587, plus many stock and aftermarket covers will fit on it.

The Outlaw 587 flows more air than the Sportster can breathe, even a built 1250 running up to 7000 RPM.

The 587 flows very well for the Twin Cam & M8.  There is no point that even a 110 Twin Cam or 114 M8 can breathe more air than the 587 will flow.  This is a favorite because of the excellent leg clearance and superior airflow. There is a huge selection of different looks for this air cleaner.





The 606 filter element is 6” in diameter at the back, 5 ½” diameter at the front,  and 2 ¼” deep, making The Outlaw 606  the third lowest profile A/C on the market.

The Outlaw 606 sticks out 3/8" further than the 587, but it is still quite a bit more tucked in than the stock air more than an inch.

There are 13 different Cover Styles for the 606, including running naked, with no cover.  Very Importantly, the 606 was designed to work with the Stock Rushmore Cover & the Stock Milwaukee-Eight Cover.  It bolts right on, as do many other stock and aftermarket covers.

It has very similar flow characteristics of the 587.  The 606 will flow more air than any Sportster, Twin Cam, or M8 can breathe.  

The 587 and the 606 dyno out almost exactly the same...the reason we came up with the 606 was for a different type of cover fitment, including the OEM Rushmore Cover & OEM M8 Cover.




The  636v is a forward facing Air Cleaner.  You have a choice of five different air filter elements.

All covers that fit on the Heavy Breather, including the SE designs, will fit on the 636v with the round style filter element.

The Outlaw 636v is effectively low profile also, since it puts the filter so far forward.  So even though it sticks out further than the 425, 587 and the 606 by a bit more, it does not interfere with the leg.  

The patented design generates a Venturi Effect that  gives the Outlaw HiFlow 636v Air Cleaner an Increase in Intake Velocity producing 3-6% more power than the 425, 587 or 606.  It will also flow enough air for even a fully built out 140 cubic inch engine. 




The Outlaw HiFlow 828 Filter Element is 6" tall, 9" front to back and only 1 7/8" deep.  This ties it with the 587 for the lowest profile Air Cleaner on the market.

It has a 6061 Billet backplate, designed for maximum flow.  This, combined with the extra large surface area of the element make it an air cleaner that will support air flow for up to a Stage IV build. 

There are 9 different Cover Styles for the 828, including running naked, with no cover.  The Ham Can Cover found on Many Sportster bolts right onto the 828.  Perfect for customized artwork on the cover.  Can also be run naked (no cover) or with the stock Ham Can Cover.

It Flows more air than even a 131 CI engine can eat, and especially shines at High RPM.




The Outlaw Velocity Stack is available in a 1.5" & a 3" Stack.  There is an optional Screen and an optional Screen with foam filter.  The 1.5" is very low profile, and even the 3" is lower profile than most Intakes on the market. 


We have many folks that Drag Race and use the Velocity Stack with no screen/filter.  As shown in the charts below, they are very good performers.  When everyday riding, it is suggested to use the screen and filter. 


 Available for all Sportsters, and for cable operated Twin Cams.  Available in Powder Black & Natural Aluminum finish.  The natural aluminum finish can be polished to a mirror finish.


Milwaukee-Eight Dyno Charts 

M8 587 Dyno Chart




Stock VS 606 M8


Stock vs 636v m8

Stock vs 828 M8

 Twin Cam Dyno Charts

Stock 103 vs 425 tc


 stock vs 606 tc


 stock vs 828 tc

 Velocity Stack vs Stock

Stock Rushmore vs 636 TC


Bonus Chart - Showing what a Monster the 636v Air Cleaner is!

636 Monster




Sportster Dyno Charts

Stock VS 425 SPT


stock vs 587 spt

Stock vs 606 spt


Stock 48 vs 636 spt