Whilst we may have been busy with GT-Rs recently, we have also been quietly testing and developing our 991.2 Carrera T and the results have been amazing.
The 3.0 litre twin turbo engine was introduced to the 991.2 facelift back in 2016. It can be found in all models from the base 365 bhp (370 PS) Carrera up to the 444 bhp (450 PS) GTS with the only hardware changes being the turbo size.
Following time on our dyno and on the road, we have settled on a recalibration of the ECU that produces a comfortable 450 bhp (460 PS) at the top of the rev range and a smooth 400 lbft throughout the mid-range. This car feels much more urgent and where the power would drop away around 5,500-6,000 rpm, it now pulls cleanly all the way to the red line.
As we observed in a previous blog post, it was clear from our testing that the exhaust design of all the 3.0T models was restrictive. We knew decent gains could be had from changing just the rear silencer. The Porsche Sports Exhaust fitted to the Carrera T has an active exhaust valve so we have chosen to use the Akrapovic and Remus rear silencers as both of them feature internal valves.
Combined with the new rear silencer we have fabricated our own high flow sports catalytic converters to further improve the exhaust flow and sound. With the ECU recalibrated to suit the engine, it now produces power of around 465-470 bhp and torque of 430-440 lbft.
One part we had earmarked as a major restriction in the exhaust layout was the original Porsche exhaust manifolds. These use a pressed and cast log design that combines the three cylinders on each bank before exiting into one small 30mm pipe at either end. Internally these manifolds have large supports to strengthen the oval shape, but these would cause a significant flow restriction, coupled to the very small outlet.
We have set about producing our own tubular headers in conjunction with one of our exhaust partners, Nortech, in Yorkshire. Nortech are experts in turbo manifold design and the available shape under the 3.0T engine gave us plenty of room for our new CAD designed 3-into-1 manifold with equal length headers. The new design smoothly merges each port into the free flowing collector just prior to the turbo entry. This helps reduce the exhaust pulse interference and drastically changes the way the turbo responds. The turbos spool much faster, providing almost immediate throttle response even from very low in the rev range. The engine pulls more urgently higher up the rev range and the exhaust note has a cleaner and crisper note to it.
We’re extremely happy with the developments we’ve been able to make to an already outstanding car. Overall the new exhaust system and ECU calibration increases power to 480 bhp and 450 lbft, which is a healthy increase (+115bhp & 116lbft) over the original Carrera’s power of 365 bhp and 334 lbft .
These upgrades can be applied to all of the 3.0 T Carrera range with higher power figures available from the Carrera S, which has a larger turbo compressor wheel, and also for the GTS which has both larger turbine and compressor wheels within its turbo.
For those wanting to know more about how the car drives please take a look at our 5 star reviews from Car Magazine and Autocar.
For more information please visit our upgrades page or give us a call.
