MarcD147

Quote from that series:

Technically in GT3, you can turn up with your wife's VW Golf and if it's homologated, they'll give you enough weight reductions and increase the power so much that it can produce the same lap times as the other cars out there"

It's gonna take a bit of work to get a GTI to go around Sebring or Daytona to create competitive times.

CRex

Sorry that just isn't true.

GT3 runs to SRO spec. It's very tightly homologated to the point of requiring each competitor to conform to the current-year homologation.

Example: the 991.1 GT3Rs in my avatar fell out of homologation in 2019. And during its life cycle it had an evo upgrade (hood strakes, etc.) that was mandatory spec in 2018.

There's zero chance for any team to run GT3 with anything less than perfectly in-spec hardware. That is one of the key reason why GT3 racing has gone to crazy budgets.

IMSA GTD is almost entirely based on the SRO GT3 homologation save for different BOPs.

Back to OP's question. Whatever you budget for IMSA GT4, multiply that by 1.5x to come up to a Porsche GT3 Cup Challenge rough budget. I'm extrapolating a bit here based on the global Carrera Cup operating model, which requires you to replace consumables on a tight schedule, either for competitive or safety reasons. Furthermore parts sales must be from the official series supplier...

Official Porsche one-make series are run partly as marketing but they ultimately need to balance their own P&L from vehicle and parts sales. That mission statement guides their actions.

From my own experience, cost per hour of seat time, at the sharp end of the grid:

SRO GT4 * 1.5x = Carrera/SuperCup
Carrera/SuperCup * 1.2x = SRO GT3
SRO GT3 * 1.7 to 2.0 = FIA GTE

Note SRO GT3 is typically a shared budget between two drivers. Assume two bronzes (i.e. each driver carrying half budget). GTE has a wide spread coz the bronze typically carries more than 1/3rd budget.

Finally: teams do their math on a mileage basis. You as a driver is after the experience; calc yours in terms of seat time.

MSR Racer

Math for weekend cost is bit simpler I think based on my experience in GT4 class. Typically, you need 6-8 sets of tires whether you are testing or racing. So that is like 15-20k. Then you have the track support costs approximately 15-25k+ But can vary with the team. I think you are looking at 40 k+ per every track event. In addition, there is spare parts, crash damage and the cost of the car and all other additional equipment and paraphernalia that you need to buy.

Nizer

Fairly accurate estimate. If you think it'll be cheaper you're fooling yourself.