The Borg Warner S300 SX-E: An Inside Look

2nd Nov 2015

SEMA 2014 provided the turbocharger arena a new look on some Borg Warner products. The popular S300sx turbos received a welcomed face lift and brought together a few high tech aerodynamics borrowed from Borg Warner’s elite EFR product line. Forged Milled Wheels (FMW) are standard on all SX-E turbos and these compressors work in conjunction with the new Enhanced covers that feature an integrated speed sensor port and pre-machined boost port. Turbine options have the familiar carry-over 68mm/76mm from the S300sx line, however a new 73mm/80mm turbine wheel has entered the field. One of the key features exclusive to the S300 SX-E line is a 6 pad 360 degree thrust bearing that replaces the standard 3 pad 270 bearing from yesteryear. Now that Borg Warner has filled the market with these competitively priced Enhanced turbos, let’s see them going on your new gasoline or diesel powered machines.

Compressor Wheel

On the left you see the standard S300sx cast wheel. Although these wheels perform very well in today’s gasoline and diesel powered markets, there is always room for improvement. New aerodynamics that utilize forged blanks with final machining operations creates a much stronger wheel able to sustain higher pressure ratios, extended choke flow, and overall faster response under all driving conditions. Even though the Forged Milled Wheel on the right may look similar, the only things it shares with its older, crustier, distant great uncle is the fact it came from the same company, the bore is the same, and the blade count is the same. Borg Warner has simplified the market by offering out of the box superiorly Enhanced FMWs and now there is no need for the dealers to offer those shiny billet wheels as upgrade options.

Turbine Wheel

The original 73mm/80mm wheel, common on the “S366,” has been ditched in favor of the new non-clipped version. The clipped turbine wheel on the left was an old OE design that made its way into the Airwerks product line simply because it was already in production. It worked great, however response was hindered due to its design. Since the SX-E line was developed from the ground up as a performance oriented product line, the new and more responsive wheel was chosen as you can see on the right. Overall turbine flow supports the 950+ horsepower that the largest SX-E produces while larger blade surface area allows for quicker initial shaft speed resulting in a turbo that “spools up” faster.

Thrust Bearing

On the left, we see the standard 270 degree 3 pad thrust bearing that the S300sx line has used since the beginning. Because of the high demands in the performance gasoline and diesel markets, we have always needed to upgrade to a 6 pad or 360 degree severe duty thrust bearing to get these turbos to live in our environments. Borg Warner decided to take the guess work out the equation and equip all S300SX-E turbos with the 6 pad 360 degree bearing shown on the right. From the factory, these turbos have the best bearing option, period.

Turbine Housing Options

Just as before with the S300sx lineup, a slew of factory Borg Warner turbine housings are available in open T4 and Divided T4 ranging in .88, .91, and 1.00. Additionally, AGP Turbo offers some custom machined Borg Warner housings in .83 divided and 1.10 divided both in T4 with the 3.5” commonly called the 4.21 marmon outlet and AGP can machine these outlets to accept the industry standard 3” V Band as well. Opening up even more options, AGP casts their own T3 open and T3 divided housings, along with 5.9 Cummins specific housings with both HE341 or HX40 outlets, and AGP recently released the backwards compatible .68, .81, and .96 A/R open T4 housings to replace your old tired “T” series turbo with a new SX-E. Below is the chart for all the available turbine housing offerings from AGP Turbo on the for the SX-E.

Compressor Housing Options

The standard SX-E compressor housing has a 4” inlet ported shroud and a 2.5” hose style compressor outlet. The integrated speed sensor and pre-machined boost ports come standard. However, these ports are not fully machined and Borg Warner does not force you to use them. If you want to use them, simply drill and deburr a ¼” hole through those features. Simply put, these features are NOT boost leaks if you decide not to use them. From AGP Turbo, you can add the option of a 2.5”, 2.75”, or 3” elbow welded to the outlet in any direction. For the 2nd Generation Ram Cummins customers, we can machine the v band outlet to fit your factory charge pipe elbow. For the 3rd Generation Ram Cummins customers, we can weld the 2.75” elbow facing forward on the truck to match your factory charge pipe.

This is a simple and informative comparison between the older S300sx line and the Enhanced S300SX-E. Even though the name is very similar, the product is quite different and definitely improved with new aerodynamics and stronger bearing structure directly from the factory. Combine these new features with AGP Turbo’s exclusive turbine housing offerings and you have the most versatile series of aftermarket turbos at a very affordable price. Make certain to consider the S300SX-E when making your next purchase.

Check out these turbos.