We love our 911 T but if there is one thing it’s missing is a little extra fire power and acoustic drama from its 3.0T engine.
All of the 991.2 Carrera range share the same engine but they vary in power output and turbo size. The standard Carrera and T produce a claimed 370 PS, the Carrera S features a slightly larger turbo compressor wheel and produce 420 PS, and the GTS variants use a larger turbine wheel and compressor wheel to lift power to 450 PS.
The T either uses the smallest turbos with the aim of producing a great throttle response (and it is very good) or they don’t want to tread on the toes of the other models. Either way whilst the power delivery is silky smooth, the chassis can clearly handle more, especially higher up the rev range where it begins to run out of punch.
We began with recalibrating the 3.0T engine to release much of this untapped potential.
Ross performing initial power runs on our Porsche Carrera 991.2 on our in-house dyno
However when spending time on the dyno we’re always looking for consistent and repeatable runs. It quickly became clear that the 3.0T engines biggest drawback was cooling of the charge air temperature. Even while logging on track you can monitor reasonably high charge air temps of 35-40°C
but on the dyno they would quickly become too high. More precisely the dyno’s cooling system was not able to get enough cool air down into the intercooler ducting, which has its feed just below the rear spoiler. With limited airflow over this area of the car, temperatures would increase to over 80°C
with multiple runs which isn’t remotely acceptable!
On the 911 Turbo models we would duct our extra fans onto the intercoolers which sit lower in the rear bumper and are fed from the side of the car. But the Carrera 3.0T engines even more tightly packaged with the air feed smaller and and being fed from above.
Porsche 991.2 cooling on dyno
Twin fans feeding rear intercoolers
We needed to think of a new solution so test 1 saw our in-house fabricator, Scott, build an impressive collapsible A-frame which allows us to try different options for getting cool air through the intercooler ducting.
With the frame in place we started by ducting two fans directly into the gap between the rear grill and spoiler. This was a partial success with the fans on full there was now a steady breeze from the bottom outlet holes. The charge temperatures were still too high at a maximum of 60°C
but would cool quickly after each run, and would perform consistently with multiple runs. We are now going to try different revisions of this layout to improve it further.
However the high temperatures gave us a good opportunity to test the safety settings in our calibration and gather data at different boost levels.
It also gave us a great way to see how improvements to the engines efficiency would reduce the overall temperatures.
Porsche 991.2 3.0T Twin fans feeding rear intercooler
The aim is to let the 3.0T engine breath more easily to release performance rather than forcing it. A turbo that has less back pressure to force against will generate less heat and therefore more power.
Akrapovic Slip-on Line exhaust install
These initial exhaust tests would see how the engine responded to each element before doing our full recalibration. We’ll have another blog post on the exhaust options we’re looking at but to begin with we have installed the Akrapovic slip-on system and diffuser that not only aid power but look and sounds brilliant! More on this to come soon…
On the road the new power is great fun and just what the car needed, and with many more revisions and refinements still to come we think this 3.0T engine is going to be something very special. Recently we got to drive the car back to back with the latest GT3 touring and the difference the turbo engines torque make during day to day performance is huge. The T’s newly released power makes for a very accessible performance car. Where you need to wait for the right road and conditions to open up the GT3 to its true potential, the T is always primed to instantly react.
We can’t wait to do more choice modifications to the 3.0T the let it breath and exhale more easily.