If you’re diving into the world of high-performance engines, you know that every part matters, and that’s where ACL Race Series Engine Bearings come into play. These aren't just any bearings; they’re a solid blend of smart design, tough metallurgy, and solid engineering that really delivers when you push your engine to its limits. Built for those higher RPM conditions, these bearings are a must-have for anyone running popular 4, 6, or 8-cylinder setups.

What sets these bearings apart? For starters, the high-strength overlay plate is thinner, which might sound minor, but it actually boosts fatigue resistance—so you can really lay into that throttle without worrying about wear and tear. Plus, all the rod bearings come with hardened steel backs. This isn’t just for show; it helps support the bearing lining and keeps everything snug in the housing.

Another thing I appreciate is the increased crush. It’s all about keeping the bearings firmly in place, especially when you’re pushing your engine hard. And if you’re worried about heat, ACL has got you covered by eliminating flash plating on the back of the bearings. This means better heat transfer and a tighter grip between the bearings and their housing. Trust me; when you’re running hot, every little bit helps.

These bearings also feature increased eccentricity, which is a fancy way of saying they compensate for bore distortion at high RPMs. This is crucial for forming those hydrodynamic oil films that keep everything lubricated and running smoothly. The 3/4 grooved main bearings optimize the load-carrying surface area and improve oil flow to the conrod bearings, which is exactly what you need for high-performance applications.

And if you’re someone who likes to keep things tight, the consistent wall tolerances help maintain the clearances you need. Plus, the enlarged ID chamfers on the bearing edges accommodate those larger fillet radii on performance crankshafts, making installation a breeze.

Now, let’s talk specs. You can get these bearings in sizes like STD, .025, .25, and .50, with standard oil clearance. They come as identical halves and are made from tri-metal with hardened steel backs. For the nitty-gritty, the minimum standard shaft size is 2.1636 inches (54.956 mm), and it tops out at 2.1646 inches (54.980 mm). The tunnel sizes range from 2.3206 inches (58.944 mm) to 2.3216 inches (58.968 mm), with a max wall at the crown of 0.0780 inches (1.980 mm) and an overall length of 0.752 inches (19.10 mm).

These bearings fit a range of models, including the Nissan Primera from 1991 to 2007 and the Nissan Pulsar from 1987 to 2005. Specifically, if you're working on a Nissan SR20DE/DET (2.0L), the 0.25mm oversized high-performance main bearing set is definitely worth considering.

In short, if you're serious about performance, these bearings are a solid investment that can handle the heat and keep your engine running strong.