International sports car racing is unbelievably confusing, with a half dozen classes that all look the same and have nearly the same names. Here's a simple guide that unravels the whole tangled mess.

GT racing started out many years back with GT1. It was simple. It was one class of top-flight race cars derived from road-going sports cars. Corvettes raced the European marques and everything made sense. Then someone cut the head of GT1 and, like a super Hydra, a half-dozen new classes sprouted in its place. We're here to explain them all.


This article was put together by Jalopnik reader and motorsports expert porsche9146. If you have any questions for him, drop them in Kinja below.

Here's what you need to know:

GT1 was designed by the ACO as high tech production based racing for factories. It saw the Corvette C6.R, the Aston Martin DBR9 and the Saleen S7R race for wins all over the world.

Photo Credits (top and above): Getty Images

GT2 was designed by the ACO as professionals only production based racing for privateers (mostly in customer cars). It saw 911 GT3 RSRs, 430GTCs and M3 GTs race for wins all over the world.

Photo Credit: Getty Images

GT3 was designed by SRO as pro-am production based racing for privateers (mostly in customer cars). It saw Z4 GT3s, 911 GT3 Rs and SLS AMG GT3s race for win in regional series all over the world

Photo Credit: Getty Images

GT4 was designed by SRO as am-am, low tech (barely modified) production-based racing for privateers (mostly in team built cars). It saw Lotus 2-Elevens and Maserati MC GT4s fighting for wins in regional series mostly in Europe.

Photo Credit: Mark Braithwaite/Flickr

GT1 died in 2009 when the ALMS got rid of the class. However, SRO decided they wanted the class to live longer, so they took their FIA GT championship and split it into two parts: GT1 World, a series for old GT1 cars on the world stage with pro-pro drivers, and GT3 Europe, a series for current GT3 cars on the European stage with pro-am drivers.

Photo Credit: Andreas Reiffer/Flickr

GT1 lasted two years with moderate success before the grids started thinning out and, in 2011, it was disbanded. The name was still used in 2012 for a new series intended for pro-am AND pro-pro GT3 teams that raced all around the world. For some reason, this was still called GT1 world. All of its dates outside of Europe and Asia were cancelled, so it became GT3 Eurasia most of the time, and paired up with GT3 Europe.

Photo Credit: hkedwardtong/Flickr

GT1 world and GT3 Europe are now both dead, leaving the real GT1 cars dead for good, but the GT3 class is still being run on a big European stage in the Blancpain endurance series, which allows for pro-pro AND pro-am pairings in separate sub classes. Add to that the many regional GT3 series (such as British GT, Grand Am GT and SUPER GT GT300) still running the cars and it's one of the strongest classes in the world.

Photo Credit: Getty Images

GT4 is also a part of the Blancpain Endurance Series and many other GT3 classes around the world because it is much cheaper and slower than GT3, allowing for it to be a decent am-am feeder class into GT3.

Photo Credit: jez B

GT2 has been massively successful on the pro-pro stage, to the point that all the GT1 teams left GT1 to enter GT2 (they joined in through a loophole that allowed factories to race in the series), leading to the end of GT1 in 2010 (this was of course followed by the aforementioned two years of real GT1 world). GT2 then was renamed GTE (for GT Endurance) by the ACO in 2011, and along with the re-branding came a new sub class: GTE Am. this was for GTE teams that had an amateur driver and a car a year or more older. GTE-Pro and GTE-Am use the same cars and race on the same weekends.

Photo Credit: Getty Images

Japan's national SUPER GT brings another GT class to the table with its smaller GT300 series, which was originally intended for super low power, super high downforce local creations, but a few years back they started allowing in GT3 cars and they've over-run the series. The Z4 GT3, 911 GT3 R and SLS AMG are displacing the quirky likes of the GT300 CRZs, BRZs and Prii. Yes, as in the plural of Prius. Its GT500 class, meanwhile, is completely independent and local, but is more of a super touring car series (like DTM, NASCAR or V8 Supercars) than it is a GT series.

Photo Credit: Takayuki Suzuki

Grand-Am has only one GT class, one that's GT3 based, but it's fundamentally different from the others in that it's actually only half GT3 and the rest are tube framed cars. Next year the only tube framed cars will be one team's BMWs M3s and a few Camaros.

Photo Credit: Trevor Andrusko / Track 9, Halston Pitman

The American Le Mans Series also has a spec class called GTC, which is for Porsche 911 GT3 (named after the road car, not the class) cup cars only. A certain cancellation will come in 2014 since ALMS merged with Grand-Am.

Any questions?

Photo Credit: Halston Pitman

This article was republished with permission of Porsche914yr74. Follow him on Twitter @porsche914yr74 and in Kinja.