I have made all this mods in my 997 4s cab 08 tipt. model and my last mod was the awe cats and before i put them my Consumption in the bord computer was 16,5 liters per 100km(62 ml) or 350 km with full tank.and now with the awe cats it go to 19,5-20 liters per 100 km (60 miles) or 280 km with full tank.I saw very big defferens in power but the consunption is very very big!!
You now whats happening?
What is your consumption with the same mods?

 

You are driving it around a lot harder then before!

 

Yes i think you have a point because the sound with the PSE on is crazy!!LOUD and PORSCHE.I wish to be this reason but i am not sure i think the program saw the free flow from the cats and give fuel...i am not sure yet.

 

It is your throttle foot that gives more fuel. Happy driving.

 

When I was curious about fuel consumption I found that driving strictly below 3K would keep me at 19mpg, going 6th gear 70mph on highway with AC off would do 23mpg.

Pushing it properly to sustained 4.5K rpm with regular redlining on same stretch of road would keep me at 12-13mpg. I bet it is what you do now as you got used to your car power and if you keep it above 3.5K rpm so it could breath properly it simply burns more fuel and it is perfectly normal.

 

Glad you are happy with the performance, but as with everything there's a cost. You could "match" your car's previous performance and in theory get better economy. But when you are pushing the car, you are going to be burning more gas.

My 09 C2S is pretty amazing. I think my overall 7000 mile average is around 20 MPG city / highway (about 50/50) and on the highway I get in the 30s. But on the track, I'm getting about 9, which is much better than the 6 I got with my 2007. The DFI is that good.