“I own a 1994 Porsche 964 Carrera with more than 250,000kms on the odometer. While it’s running well, I feel I would love to improve the power and response. I’m based in North America / Canada and want to know if you can help?”

This is a very common question, as the North American and Canadian air cooled Porsche scene is simply huge. Many owners are initially cautious at the prospect of being separated from their valuable air cooled engine by the Atlantic Ocean. In fact, the largest percentage of Ninemeister engines are destined for Porsches in Canada and North America.

Here’s Colin’s views on the best way to achieve the objective of improving a street Porsche 964, as there are several ways to improve the 964 engine, depending upon your specific objectives:

When it comes to performance enhancement of the 3.6 engines you have to use the Ninemeister philosophy of total engineering and consider the engine, intake, exhaust and engine management as a complete system, then decide a plan based around what you are willing (or legally allowed) to change.

Unfortunately unlike the 993, the 964 is saddled with a limited performance Motronic, so the first item to consider is whether to keep or replace the engine management system.

Option One

Keep it means that you have to enhance the engine around its limitations, hence my focus would be to use what we have to maximum effect by blueprinting (like the 964RS) whilst also reducing wasted power by lowering the inertia of the engine as much as possible – i.e. lightweight flywheel and lightweight engine internals. A nicely built 3.6 (or 3.75) using 993 (or 993RS) pistons & cylinders on 9m RSR connecting rods shaves 1000g from the reciprocating weight, 9m valves with flowed intake ports sort out the heads and with either stock or 993RS cams will achieve circa 300hp through the stock exhaust.

Option Two

Replace the management with Motec (or 993 Motronic or similar) with larger fuel injectors and the engine suddenly has the potential to give more. I would now consider 9m Sport camshafts with the low inertia 3.8 bottom end to be optimal for a stock looking installation. Run this through a straight pipe cat bypass & stock silencers and 350hp is possible. The final option on this package would be to consider a 993 Varioram intake conversion as well to add that mid-range torque which you are looking for. The photo attached is a 964 engine which we have converted to Varioram, installed in a 9m64RS which is destined for Oregon.

As a guide to likely costs, a premium top end rebuild with new pistons, cylinders & head studs would start at £10,000; the same engine to low inertia specification would be £15,000; add in the 3.8 litre upgrade on a full engine build and you are up to circa £20,000. The Varioram conversion largely depends on what parts that you can buy used and could be anywhere from £5,000 to £10,000.