maspirito

I have a question with regards to fuel consumption and the need for a fuel cell. This is a pretty standard 3.4 car no engine upgrades. The car is stripped and caged. Has been used as a track\race car. Now , we will be using it for endurance series and the car is new to us so we don't really have a handle on fuel usage. What is the conventional wisdom as to the size of the fuel cell\tank that is needed to effectively compete in the series doing two hour stints.
The car currently has what I believe is the original fuel tank with a dry break fuel neck installed.
Thank you for your collective wisdom and time

Bill Lehman

Having tracked Caymans for many years, figure about 6 mpg.

Frank 993 C4S

The conventional wisdom is that you need to figure it out for a specific car for a specific race series. Each endurance race series will have its own rules and classing. What you need to figure out is your max stint length for a specific target lap time. In AER for example your competition will be BMWs with massive 20 gal aux fuel cells that can run way over 2 hours on a fuel load. That gives you a lot of flexibility to time your pit stops during double yellows. For a typical 987.2 Cayman you will need to figure out how to stretch your stint length to at least 80 minutes.

maspirito

Thanks for that we were hoping to get closer to the two hours and I suppose we may have to move into getting a fuel cell? And if that's the case Is there any insight on what size we might want to use 22 gallons? 26 gallons?

38D

For AER, get the largest size cell that fits, as it will give you more optionality on when you pit. For WRL, there is a spec/formula on how much fuel you can carry; for GP1, the likely class you'd been, you'd be limited to 17 gals.

Frank 993 C4S

^^^ This

zmon

yes and no... def check the rules of the series. people put big cells in the BMW to get rid of the sadle tank and the starvation issues it presents.

for our AER car we were using the stock 16gal saddle tank with and aux 8 gal wheel well cell for the trunk and depending on the track, driver and weather conditions got hour and a half to 2 hours to more. back to knowing the rules you dont need a massive cell as you are required to make 5 pit stops in a race.

in WRL for example there is a restriction to stock tank plus a factor... this didnt allow us to run a cell for this series so we run the stock tank and a tiny radium surge tank to ensure we basically get all of the 16 gallons. no mandatory number of pit stops in this series..

again check the rules and design for that. you can always go with what you have and modify as you go and see where you stack up and how/if it affects your race..

Jeff951NJ

There is a 987.2 Cayman that is actively campaigned in AER under the team name "Angry Croc Racing" that has been very reliable. You may want to try and reach out to them for details on there build. After looking at AER's website and the stint reviews it looks like the car can go around 1:45 - 2 hours before needing to stop for fuel. (I looked at there last two races at Mid-Ohio & VIR)

https://race.americanenduranceracing.com/car/670

RobT 394

As others have said, it depends on the series. In WRL you will be restricted to approx 20-21 gallons. Fuel efficiency is more important than fuel load for that series.

Tim the Engineer

Racing at Sebring I consume about 1 liter per minute of hot lap. there are 3.8 l/US Gallon. So you would need about 30 gallons to go 2 hours.

On the low side, on momentum tracks, I consume about 0.7 liter per minute of hot lap.

This is a 2010 987.2 Cayman 3.4 L. PDK. When it was a 6 speed, it consumed a bit less.