MHX-521 High-Efficiency Oil Cooler

Improved Racing's Motorsport Heat Exchanger (MHX) series oil coolers are the result of several years of development and testing to create a highly efficient oil cooler. These coolers were perfected through extensive testing on our in-house heat exchanger test system and wind tunnel.

The MHX-521 oil cooler is a dual-pass oil cooler that matches heat rejection rates to larger, heavier stacked-plate coolers made by brands such as Setrab, Mocal, and Earl's. Compared to a typical 34-row stacked plate cooler, this cooler is 21% smaller overall and 19% lighter, yet holds 39% more fluid volume. The core is 23% thinner and has a lower row and fin density, allowing more air to flow through the cooler to other heat exchangers (such as a radiator) behind it.

A major design focus was to minimize welds and brazings to make these coolers stronger, lighter, and less prone to leaks. All four end caps are single-piece CNC-machined billet aluminum. The rows consist of laser-welded, thin-gauge aluminum tubes stuffed with turbulators to maximize heat transfer while minimizing weight.  The dual-pass design also maximizes heat transfer efficiency.

There are four M8x1.25 mm mounting holes, one on each corner of the cooler. Improved Racing has designed lightweight aluminum brackets (sold separately) to make mounting your cooler as easy as possible. The brackets feature integrated rubber isolators that protect the cooler from excessive vibration and extend the life of the cooler.

The MHX 500-series coolers feature -10AN female O-ring boss ports on the same side of the end tank for convenient line routing. Optional fittings are available in -6AN, -8AN, -10AN, and -12AN JIC male flare threads.

All Improved Racing oil coolers are pressure tested to 175 PSI to ensure no leaks and are rated for continuous operation at 150 PSI. Our coolers are made in the USA and backed by our Lifetime Warranty.


CNC-machined billet aluminum tank end caps with machined mounting holes on all four corners

3/8" or 1/2'' hose barb fittings or AN fittings in -06AN, -08AN, -10AN, or -12AN are available with the purchase of a cooler

Vibration isolating mounting brackets available (sold separately)

Features and Benefits

• Compact, lightweight design is 21% smaller, 19% lighter, and has 39% more oil capacity than a 34-row stacked plate oil cooler.
• Similar heat rejection rates to larger 34-row stacked plate oil coolers.
• Dual-pass design.
• Lower air side pressure drop than stacked plate coolers.
• Female O-ring boss -10AN ports on same side of end tank.
• 4x flanged M8 mounting screws are included.
• Lifetime Warranty.
• Made in the USA.

Dimensions and Specifications