Taken from the Norris Motorsport web site

www.norrismotorsport.co.uk

Stage 1

This conversion is a huge improvement over standard and involves the fitment of a new "chip" to the ECU and the fitment of a new wastegate actuator. I recommend a genuine Garret –31 item as these are superior in quality and operation to the usual alloy type. In addition I advise the fitment of a K&N type panel filter in the standard air box. The boost is then set to 16psi, the spark plugs either changed or gapped as appropriate and along with a general setup around 270bhp/270lbf ft can be expected.

Stage 1+

This is a recent development of the stage 1 conversion and takes the std engine to an even higher state of performance. This conversion however can only be performed on original engines in excellent health or those which have undergone a complete rebuild. Likewise the turbo must be in excellent condition and preferably be fitted with a 360degree thrust bearing. Again a new "chip" is fitted to the ECU along with a Garret -31 actuator, and suitable plugs fitted and gapped if required. For 2wd cars I advise the fitment of a 4X4 Sapphire Intercooler. Coupled with a full setup this chip allows the car to run in excess of 22psi between 2500rpm and 5000rpm, then dropping to 17psi by 6000rpm and finally tailing to 14psi at the 7000rpm limiter. This setup normally results in around 295bhp/320lbf ft.

Stage 2

This level of tune is now overlooked because the cost is so similar to the stage 3. It used to involve the fitment of Bosch 355 injectors and utilised the stage 1 chip. I no longer advise this route, unless looking for a replacement injector for old standard items. In this situation the power output can be regarded as the same as either Stage 1 or 1+.

Stage 3

This is the most common level of tune found on modified Cosworths. This involves a new "chip" fitted to the ECU calibrated for a 3 bar map sensor and a new set of Bosch 803 injectors. Coupled with a Garret –31 actuator and K&N panel filter the boost can now be set to 22psi and around 310bhp/310lbf ft is achievable. At this level I advise the fitment of a new breather system, though it isn't strictly necessary if the existing system and engine are in perfect condition.

Please note however that the standard 2WD turbo and intercooler are not suitable for this conversion, and I would advise the fitment of a 4X4 intercooler and suitably specified hybrid T3 turbo. It is also worth fitting a free flow 3inch bore exhaust at this stage, but sadly many off the shelf exhausts for Cosworth's feature restricted bore silencers which rather defeats the point of fitting the new exhaust. Again I can advise of suitable components.

Stage 3+

This conversion is becoming even more common as many owners choose to take their power outputs further. I now advise the fitment of 0.55 T34 supplied through Turbo Technics, and that the head gasket is changed for either a 611 or a multi layer steel item. (Results so far indicate the Cometics item seem to cope better than the 611). I insist on the use of GENUINE Cosworth std head bolts with either choice of gasket. At this level I advise the fitment of an RS500 style aftermarket intercooler such as the item made by Forge. Still utilising Bosch 803 injectors and 3bar map sensor, a new "chip" is fitted to the ECU, NGK 9 spark plugs are fitted and coupled with a full setup the boost is raised to 26psi and around 350bhp/340lbf ft can be expected.

Stage 4

This is the first level of tune where by the specification can vary dramatically from one tuner to the next. For this level I fit Bosch 403 injectors, a 3 bar map sensor, and suitable "chip". I also insist on the fitment of a WRC style multi layer steel gasket. (Preferably a Mountune item, otherwise Cometic). These must be fitted with GENUINE Cosworth head bolts, the head surface skimmed and block deck prepared correctly. It is still permissible to maintain the standard 8.0:1 compression ratio, but the turbo and intercooler must now be changed. I specify either a Garret T.O34 hybrid turbo built to my own specification or a T.04E and coupled with either an RS500 Genuine intercooler or a quality RS500 style unit. At this point the engine breather system must be uprated and a free flowing 3 inch exhaust fitted. All engine ancillaries such as boost hoses must also be suitable for the increased boost and it is essential the engine is in excellent condition. With the boost set to 28psi around 370bhp/360lbf ft can be achieved. (The main difference in turbo chargers will be the increased top end power band with the T4 as opposed to more midrange punch and response with the T34). In addition, with the T4 equipped conversion I use a set of cams which compliment the high rpm power band, and can be used in the std engine utilising a set of verniers without the need to pocket the pistons and allow bhp to exceed 400bhp.

Stage 5

For this level of tune, the specification is very fluid. Exact specifications can be discussed dependant on usage and power band required but ultimately comes down to cost and literally becomes a case of how fast can you afford to go! As a basic guide a typical stage 5 setup would consist of a complete engine rebuild utilising 7.2:1 compression ratio using Cosworth pistons, a fully reworked cylinder head, featuring suitable cams, 2wd exhaust manifold and TBO4E Garret turbocharger. Coupled with a custom or RS500 intercooler, 8 injector setup and a car and transmission to cope, up to 500bhp is attainable.