Shopping Cart - $0.00

You have no items in your shopping cart.

Welcome, you can login or create an account
Set Descending Direction
  1. 1
  2. 2

Like many of our other products, this is a solution to a problem. I came across this many months ago, during turbo kit testing on our shop 2015 WRX. The engine had blown, but the violence was significantly more than just the bent rod we had hoped for. As you can see, debris went into th engine and made its way into the oil pump. I’m sure you can imagine the consequences of an instant oil pressure loss. A much more expensive repair!

Read More

Thoughts on 321 Stainless from an Industry Legend.

"Stainless and the Racer.

While the corrosion resistance and elevated temperature properties of the various stainless steels make them popular in the aerospace, food handling and chemical industries, we racers really don’t have much use for them.  For almost all of our applications, either steel or nonferrous alloys do the job as well if not better – and at a lower cost. The only stainless that I ever use is austenitic type 321, an alloy originally developed to stop the cracking of piston-engine aircraft exhaust systems. It makes truly outstanding race car exhaust systems, if the money is available. In my present case – ever since I made my decision not to work full time for the big teams – the money is usually not available and I use 1020 DOM. The stainless is lighter and more fatigue resistant, but except for turbocharged engines and long-distance racing (neither of which I do anymore, at least for now), the stainless is simply not cost effective. It does not sand bendable, so the exhaust system must be fabricated and welded from a section of mandrel bends and straight lengths. The bends are expensive because the material itself is expensive; there are no bends in stock anywhere; none of the tube benders want to know about it; and when you do find someone willing to bend it, you pay a giant setup charge. If you decide to make a stainless system (or to have one made) remember that, regardless of what the man who agrees to do the job may say, 321 is the ONLY stainless alloy suitable for the job. " - Carroll Smith's Engineer to Win, 1984.


The details to follow are specific to USDM (United States Domestic Models) part number and common names and descriptions. The models outlined here may not have the same descriptions and/or follow the same models. For example: A USDM Turbo EJ25 STi Oil Pan part number 11109AA131 may also be found on EUDM (European Domestic Market) or JDM (Japanese Domestic Market) Turbo EJ20 STi Spec-C (Twin Scroll). This information also ONLY covers WRX and STi models. While other models (Forester, Outback, Legacy, etc., and this overseas versions) may use the same engines/turbo configuration, the oil pan part numbers do not always follow the WRX and STi part numbers.



Subaru oiling systems have evolved over the time since the introduction of the EJ engine since its introduction in 1989. From a performance perspective, improvements have been made and a general statement can be made that more recent versions offer a performance advantage over older versions. This follows the performance progression over time as WRX and STi models have increased performance. As far as which oil pan will fit which engine, ALL EJ engines are the same from the bottom. They all share the same oil pan (and oil pickup) mating surface geometry, and bolt patterns. If changing to a newer version oil pan, you must always use the oil pickup made for that pan, not for that year engine. Same holds true for the dipstick and dipstick tube (if you want to retain OEM level accuracy; you an always scribe your new ‘full’ mark on an old dipstick). In other words, the oil pickup part number to be used needs to be for the oil pan it is made to be used with.



The Three most popular OEM oil pans and our own Killer B Motorsport performance oil pan are shown here. As can be seen, they all have the same flange bolt patter, same dipstick location and orientation. They all use an M20 drain plug and they all use liquid adhesive gaskets.

The Exterior Details

Here you can see that some pans have what’s commonly called a kicked-in, or tubbed, while the older versions have a flat bottom design. The flat bottom version generally holds a little more oil than the newer versions, it also does not control the oil as well. The flat bottom style allows the oil to move around the bottom of the pan a lot more vs the newer versions that keep the oil deeper and near the oil pickup. The flat bottom oil pans have more ground clearance. The other advantage to the newer tubbed versions is that they allow for the higher performance twin scroll equal length OEM manifold, or aftermarket equal length headers to be used.

The Baffles

There are some stark differences in the baffles with these oil pans. Older versions use two horizontal baffles and newer versions use a more direct flow-thru path. The horizontal baffles help with oil control a lower cornering speeds and allow for increased ground clearance, but they have performance downsides. Under more severe cornering and accelerating, the oil can pool on the horizontal baffles preventing good flow to the bottom of the pan and in oil pickup inlet. Conversely, the tubbed pan designs allow for more direct oil flow to the bottom of the oil pan. This is why early generation WRXs tended to have more oiling related issues, especially on track.

Splitting Hairs

The 11109AA131 and 11109AA151 (newer) are very similar in design. The tub section on the 151 version does not have a step, a portion of the baffle is integrated into the tub side and some other subtle changes in the baffle profile. The drain port also does not have a baffle; allowing more oil to be drained at oil changes. These changes should not provide any better performance, but are very likely done to reduce material, part count and manufacturing times; cost.





At some level of performance, the OEM pan will not be able to provide adequate oil supply to the engine. A Killer B Motorsport oil pan will provide a reliable supply of oil under the most severe track conditions. The additional +30% helps keep oil temps in check and maintain good oil condition. The second NPT drain port can be used for oil temperature monitoring or a quick change oil valve. The Killer B Motorsport Performance Oil Pan is welded aluminum providing a stronger and lighter part than OEM, and completely Made in the U.S.A.


Killer B Motorsport J-Pipe – Not really a pipe, but a gateway drug for more power.


Before divulging into why our J-Pipe is so great, let’s dissect the OEM component it replaces. It’s made from stamped and formed metal. These are great cost effective manufacturing processes for high volume parts. The design itself contains an O2 port and a catalytic converter. From a flow and performance perspective, it’s horrid. With modern emissions standards, placing a cat as close to the heat source as possible improves light-off times (how long it takes for a cat to start altering the emissions), so it’s easy to see why that design choice was made. Removing this front cat increases the time for light-off, since the second cat is much further downstream, and increases cold starting emissions.



From a power creation standpoint, the factory J-Pipe is restrictive. The cat placement at the turbine exit reduces the turbines efficiency. Consider the gas flow as it exits the turbine, and remember… It’s spinning. Air, having mass, flows similarly to water. This is any easier way to visualize flow when you think about it as water. The spinning gasses need to change direction to make their way through the cat, and in doing so create turbulence. Additionally, this is done at the worse possible spot, in a bend. A straight transition into a cat is ALWAYS the best approach as it assures even distribution across the cat, maximizing flow potential through it.


The obvious performance advantage of the Killer B Motorsport J-Pipe, is the removal of the factory cat. This alone frees up substantial flow capacity. Additionally, smooth free flowing tubing is used, as well as turbine port matched flange, with the markets smoothest flowing transition. What’s all that mean? It means the Killer B Motorsport J-Pipe in a great bang for the buck power enhancement. By only swapping out the J-Pipe you’ve made a significant flow capacity increase while still maintaining some of the factory emissions system and exhaust. Quieter, and cleaner than going all-out. Improving power a good bit, and taking less out of your pocket than any other exhaust upgrade… Bang for the buck.



How does our product compare to the competition? Without dragging anyone through the mud, here are the things to look for when forming an opinion on a J-Pipe… Is the transition from turbine housing to J-Pipe flange smooth with no step? Is the transition from flange to 3” long and smooth (over several inches), but before the bend starts? Is the bend radius as large as it can be, or a ‘standard’ an inexpensive tight bend? Is the bend formed over an internal mandrel? If the answer to any of these is no, the product has not been designed for optimum performance and efficiency. The same design philosophy holds true with the Killer B Motorsport I-Pipe. The subtle differences may not seem significant, but as power levels increase every little difference that improves the exhaust efficiency adds up to making a bigger difference (as in more power) over the competitor’s product.


As time rolls by, and power wants increase, the Killer B Motorsport J-Pipe is upgradable, by adding to it the Killer B Motorsport I-Pipe (available catted or cat-less). This eases the financial impact and can help with putting together a plan over time, to build the setup you want.


There’s a lot of debate on the forums about what makes a great intercooler; core size, cross-section, fin density, length…? So what’s important? It depends on budget and what you’re doing with your car.

The best advice for someone shopping for an intercooler, is knowing what you’re going to use the car for 95% of the time, budget, what turbocharger you’re using and the power goals.

Knowing the application and budget are the biggest driving factors. Getting a HUGE intercooler capable of making 2,000hp is going to be a detriment to performance on a 450hp application. Why? Because boost is made by filling and pressurizing the volume between the turbocharger and intake manifold. The smaller this volume, the quicker it fills. Conversely a huge volume between the two takes longer to fill. A little headroom isn’t a bad thing, but a lot is. Ideally, an intercooler is precisely sized to how many lbs/min the turbocharger can flow. Both turbocharger and intercooler core manufacturers, provide efficiency and flow rates that can be matched. The problem with this, is that a lot of marketing information is under specific ‘ideal’ conditions, or a different pressure than what will be used, and so on. Add to that, model specific manufacturers do not provide off the shelf intercoolers in MANY different sizes. Regarding budget, like many things in life, the quality of a heat exchanger (intercooler core) is proportional to price. You can’t buy a new Ferrari for $20K and a $20K car will not be as fast as the Ferrari. This analogy can be used for MANY things in life and holds true for intercoolers as well as they are bound by the laws of physics and manufacturing processes used. If there were exceptions to this rule, we’d all be using that magical product.

So you’ve decided on size and have a budget. Now What? This is where the detective work begins. Resources available include forums, shops, friends, tuners, etc. Be wary of the bias and less than informed sources. Bias you say? It comes from higher margin products, and manufacturers. It doesn’t take a rocket scientist to understand shops need and desire profit, and a more profitable product is more enticing than one that is not as profitable. Exception to this rule are reputable shops that demand top quality and performing products for their customers and their own reputation. Manufacturers on the other hand tout their products as ‘best performing’, displaying graphs and charts showing magnificent results. This is not independent, comparative or unbiased. We ourselves prefer to share the data we get from shops, not our own, to minimize this effect. When asked how our Aftercooler performs (or any of our products) I will often refer the inquisitor to reach out to a local shop or any local social groups that may have someone running our product. Essentially, I also believe in never trusting the guy ‘selling’ the stuff. Forums are a great resource for information. Unfortunately, there is almost as much miss-information as there is good information. If forums are your preference, read a LOT. Learn who the players are that have no dog in the fight and are respected for their knowledge and capabilities for sharing and relaying useful data.

So you have a power goal, a budget, and feedback from others. Now what? It’s time to form your own thoughts and opinions on what you see when you look at an intercooler. End tanks are fairly easy once you think about how air flows best, and that is to imagine it as water. It doesn’t like to go around corners, it slows down when the cross section gets bigger and speeds up when the cross section is small. For example an intercoolers inlet port is sometimes smaller than the outlet, being the smallest means air is traveling fastest through this area, and with this speed, will want to change direction the least. Knowing this, look for inlet end tanks with smooth flowing features, and a tapered ends and corners. Avoid sheetmetal end tanks as they have corners that produce turbulence. If the engineer who designed it is worth a salt, under full flow, the airflow is forced across the majority of the cores surface area, with minimal turbulence. This ‘best design practice’ assures the core is being utilized to its maximum.

Moving onto the core, a designer takes several things into consideration. These include capacity, available ambient airflow, size, fitment constraints, etc.  Then engineering principles are applied. Ambient airflow is less effective the thicker the intercooler core is. This can be compounded by location; an indirect path (top mounted) has lower ambient airflow capacity than a more direct path (front mounted). Using a thicker core in a direct airflow location, like the front, will have more effective ambient airflow. Core turbulence and pressure drop function hand in hand. Turbulence are what cause the transmission of heat from charge air to the core. The less turbulence the less effective the core is at absorbing and transferring heat. Conversely, the higher turbulence increases pressure drop. It becomes a balancing act, but when done properly, a core is used that is as efficient as can be, with the lowest possible pressure drop. What determines these factors is core design. Ambient vs charge path sizes (bars and plates) and ratio to each other. Fin design can be coarse and simple making it inexpensive to manufacture. On the other side of the coin it can be much more advanced with higher fin density and advanced precise attachment to the bars that promotes ideal transfer from charge to ambient fins. The fin designs themselves can be offset, staggered, and/or louvered to add turbulence for better thermal transfer from air to metal, and back to air. A great core with good engineering behind it, will often have different fin design and features on the ambient flow path and charge flow path, taking advantage of the best characteristics for both conditions to maximize efficiency. The downside is that all these advantages in efficiency comes at a cost, due to the higher manufacturing costs involved.

So with this knowledge how does it apply our (your) own setup? The application of this knowledge is where it all comes together, but we’re not quite done. A thick long intercooler in a top location is a poor choice. You have a hood vent that is the limiting and restricting factor for ambient airflow. Having a shroud distribute air flow across a large core slows that air dramatically, and this is compounded when core thickness is also added. The reduction in efficiency is significantly. This is especially important when a load is going to be continuous like when going through several gears in a drag race or road course racing, and less important for a single gear pull when there is very little ‘load’ on the intercooler. Having no shroud directing air to the core is a bad idea in both top and front mount application. Moving to a front mounted location improves ambient airflow, and often times available space, but adds other challenges like additional intercooling tubing (volume), modifications required for mounting, managing airflow through the core, reduced airflow and adding heat to the ambient air now going to the radiator (reducing its capacity to cool) and possibly the deletion of safety components.

Continuing down the path of assuring best efficiency is maintained we are back at the ‘air flows like water’ premise, it takes the path of least resistance. Shrouding plays an important role here and I cringe every time I see a top mounted setup with no shroud, or a front setup with half the core behind the bumper. Doing this converts the heat exchange (core) into a heat sink. You have a chunk of metal that heat is transmitted to, but the forced active cooling from the ambient airflow has been removed. This example is easy to reproduce with a hose or a bucket of water. Pour it on and see what happens; less goes through the core. Want to get more Mr Wizard with it (if you know who this is, congrats you’re as old as me!) tape some yard on the top center of each side and blast it with blower (yard blower, blower port on a shop-vac, compressed air, etc.) and see what the yarn does. With a shroud in place, the air is forced through (yarn doesn’t move), without the air flows sideways (yarn pointing out) not through. On a more micro level when this happens it can create vacuum on the top outer area of the core as air goes across the open ambient area. This will pull with it hot engine bay are from below the core. This is bad. On the front setup, the same holds true and in some instances, can be worse and more difficult to manage. Shrouding from bumper to the front face of the core can be difficult due to limitations in available shroud mounting options. Worse, is putting any part of the core behind the bumper where it has no exposure to ambient airflow. Again, this puts us back to a heat sink vs active heat exchange. Changing from unexposed core to a thicker (same cross section) fully exposed core has a dramatic effect improving the efficiency.

In closing, the information provided here are based on engineering principles that have been proven and time tested in the professional motorsports industry. The more we as customers know, the more informed and smarter buying choices we make as customers. This is my goal for this post and I hope it serves you well.

Here at Killer B Motorsport, we are most popular for our Pickups. We make 2 different versions, one for the EJ20 and one for the EJ25. You might be wondering “What’s sooo special about the Killer B pickup over the OEM one?” Well, let me share a little bit of information....

Read More


 2015 FA20 WRX stage II+ (KBM full turbo-back, KBM Aftercooler, IAG TGV Deletes and Protune).


We've been getting this questions a LOT over the last several weeks and here's the last teaser. 2015 FA20 WRX stage II+ (KBM full turbo-back, KBM Aftercooler, IAG TGV Deletes and Protune). Repeat with the addition of a Killer B Motorsports Turbo Kit (GTX3067-R) and have yourself the same response with 100 more WHP. Who's ready for one?

You’ve asked, you’ve waited, and you’ve asked some more. Now - we answer.. It’s time we unleash Hell’s Fury with the new Killer B Motorsport Aftercooler.

Read More

Now Available!!! Dual Oil Sender Adaptor

Read More
Set Descending Direction
  1. 1
  2. 2
} .btn:hover { background-position:bottom; }