mikew968

Those that race your Cayman S...how many miles per gal of fuel are you getting. I calculated between 5.2 and 5.7 yesterday at Mid Ohio. I expected between 6 and 7 with a DI engine.

Krokodil

About 5.6 at Willow Springs (high speed, sweeping) and 5.8 at Spring Mountain (lower speed, tighter) - 3.8 M97 non-DFI (344 RWHP)

I doubt the DI does much to aid efficiency on the race track where you are asking for full power for a high percentage of the time. Your mileage is probably much more closely related to HP-seconds (assuming both ECUs are managing A/F properly).

Cheers,

Frank 993 C4S

Between 5.9 and 6.5 mpg depending on the track.

mikew968

My fuel gauge is always on the fritz. If I run the fuel low it takes nearly a full tank to get it working again. I am wondering if a pump out like on the cup cars would be worth doing.

usctrojanGT3

I get about 5-6mpg depending on the track on my 987.2 CS.

Krokodil

Do you use a data system? My gauge in the dash would go on the fritz quite often, but when we installed the AiM the readout on the MXL dash always worked. So, the signal was right in the ECU, but for some reason it did not properly trigger the stock gauge proper through system power down/up. Yours may be a different issue of course.

We installed a pump off system to deal with the fuel gauge issue (and lack of fuel use caused by of a cut short session before qual, etc.) and have never used it.

Cheers,

Frank 993 C4S

Couple of things I learnt:

1) Don't fuel the car with the power off, otherwise the fuel gauge will freak out
2) check your fuel consumption accurately by weighing the car on the scales before and after a session
3) putting in a couple of extra gallons for a race doesn't make a difference in performance
4) Not putting in enough will really ruin your day

mikew968

I have a new MXL2 in the car. Can I get fuel level from the CAN?

Krokodil

I can with my 987.1 and MXL Pista - BOSCH_FUEL_LEV. I assume you can do the same with the 987.2 and MXL2.

Cheers,

BGB Motorsports

A DFI car runs around 5.5mph to 6mpg and it varies somewhat by track. If you start making over 400rwhp, then you're going to head towards 5ish MPG. Killing the battery will cause the fuel level sending unit to wait a full tank's worth before it gives you a good number. Motec uses the flow rate on the rail to determine a fuel used amount and the fuel remaining amount.

When we run enduros at Sebring we usually get 1 hour's worth of running time with the PDK Cayman R that makes about 385rwhp. It's a 16.5 gallong tank but if you don't put any auxiliary lift pumps in the tank you're not going to get the last 1.5 gallons. If you could, the car might do 70 minutes but typically 1 hour's worth at a horsepower track.