Performance Review - Performance Intercooler Kit R&D, Part 2 - Production Sample

Posted: July 28, 2021

Categories: Chevrolet/GMC 6.6L L5P Duramax Performance Intercooler, 2017-2019

After piloting any performance machine, the same question always arises, "How can I squeeze more performance out of this engine?" Whether it's a low-slung sports car, hot-hatch, or diesel powerhouse, the sentiment remains. The L5P 6.6L Duramax powering the 2017-2019 HD Silverados and Sierras are no exception. They're not destined for corner carving, but they perform in their own right. The Duramax holds a payload of power potential, with the intercooler being the key to it all.

In our last post, we installed our prototype to double-check clearances before starting production. Now, our production-level unit is here in the R&D facility and ready for a close examination.

The mighty Duramax demands tons of cooling, and we fully intend to deliver. Typically, we would have the ability to expand the intercooler in all directions, but that task is easier said than done with the L5P. Even being a towering machine, available space in the front of the truck is still at a premium, but we have other plans in mind for enhancing performance.

We started with the core. Even though space is hard to come by, our engineer, Dan, still found voids to fill and maximize the core's dimensions. We pushed out the core's thickness from 1.5" to 2.7", equating to a 70% bump in core thickness. Dan also made adjustments to the overall core size, which, combined with the additional thickness, increased the core volume by 72% over the stock core.

Core size wasn't our only revision to this intercooler; we also updated the construction from the ground up. The original, lightweight tube-and-fin core is out and in its place is a more robust bar-and-plate style core. This construction might add some extra heft to the front of your truck, but the benefits greatly outweigh the additional ballast. For one, bar-and-plate cores are much more durable and are less susceptible to damage from road debris damage or succumbing to chassis flex. The heavy-duty design is also conducive to heat dissipation.

Aside from the intercooler's core, the end tanks also received plenty of attention. We corrected the mix-matched makeup of materials in the stock unit and opted for a pair of cast-aluminum tanks that will be TIG-welded to the core. These end tanks are tougher than the stock units and are also designed to optimize flow through the core.

We made sure to revamp every mounting point on our new end tanks to ensure a solid connection to your truck

There's a little more to these end tanks than meets the eye, specifically regarding the inlet and outlet. One of the primary means to increase the performance of your Duramax is removing flow restrictions. With intercoolers, the inlet and outlet sizes play a huge role in determining the limits of the entire unit. So, we opted to increase both the inlet and outlet diameters to promote airflow and raise the bar for your Duramax's performance.

By stretching our intercooler's outlet to 77mm, we surpassed the fitment limits of the factory intercooler boot. Not to worry though, we'll include an adapter with this intercooler which slips right into the factory boot. Our outlet adapter also includes two ready-to-drill NPT bungs, perfect for additional sensors or methanol injection

After comparing both intercooler designs on our flow bench, we found that all our improvements had quite an effect. By opening up the inlet and outlet, reworking the end tank shapes, and improving the core, we reduced flow restriction by 64%.

The term "performance vehicle" isn't limited to only two-seaters and sports coupes; it's all-inclusive. Every vehicle performs in its own way, including the L5P powered Silverado and Sierra. So, make sure to unlock the potential of your Duramax today with a Mishimoto performance intercooler: