Today's GT3 to GT4 performance difference


Original poster
Nov 23, 2016
I went over Porsche's published data for their customer race cars for this thread:

Another thing that was standing out to me: the Cayman GT4 Club has pretty good specs except for the simple suspension front and rear.

But when I was e.g. the 24 hours of Nuernbergring there is a massive difference between the GT3 cars and the class that this Cayman is in. There must be more to it. Any ideas? Maybe tires? Is everybody allowed to run whatever tires they want? Is there a particularly low power limit for the GT4 class in that race?

Reference URL:

Current GT4, a 2019 Cayman.

911 GT3 R, this is probably what was used in the 24h nuern, unless they ran older models:

911 RSR:

Wayne Kerr

Jan 18, 2017
for an amateur driver, unless they've had a ton of seat time in various cars, hopping into the R they're in for a steep learning curve.

It's not just the tires, it's the aero, it's the dynamics, it's the car's system. And we haven't even touched on the budget side of things.


Oct 7, 2016
Just hop into the gt4 cayman vs the 911 gt3 on any sim that got both and you'll know why.
It's not really in the specs, more about the whole car being a different thing. Stiffer, optimized aero, optimized weight distribution, the chassis flex, how the suspension works in the details, anti roll bar setups, engine mapping.
Tyres are different afaik (gt3 tyres are a lot more "on the edge", less flex etc).

I sadly don't know more details but driving them in a sim that got both is eye opening.
The gt4 will be all wonky, sluggish, drifty and pushing easily into understeer whereas the gt3 is on rails.
Nov 3, 2015
They are both reigned in by BoP - you don't think an unfettered Cayman GT4 is going to be pushed hard by a TCR car like they are in a race? Nearly all today's GT cars are way underperforming because of BoP restrictions. I wonder how much GT4 racing hurts sales, honestly - if you've got cash & not so much sense you might wonder why you'd buy a Mclaren 570s when you could get an equally performing M4...

Additionally GT3 allows much more modification than GT4.