We undertake a tried and tested procedure in remapping the CSL’s, firstly the car undergoes a thorough check to ensure the car and engine are both running well with complete diagnostic download of the cars DME to ensure everything is running well, then we strap the car to the dyno and test the car is fuelling correctly and performing as we would expect. Most standard CSL’s are between 350-360bhp in standard form (power as measured at the flywheel).

BMW M3 CSL
on our Rolling Road.

BMW M3 CSL
on our Rolling Road.

We then download the cars standard ECU map, store it and upload a new ECU file to the car all via the cars OBD port under the dash, we then repeat the runs on the dyno adjusting the DME map to ensure it is perfect for the engine. Power gains range from 10-15bhp which doesn’t sound much but is very good for a normally aspirated engine and very noticeable, it feels very much like another sport button on the dash.

The CSL does have a different exhaust to the M3 but its hardly an improvement, the only difference is thinner wall tubing so a drop in weight by about 4 KGs, and it still sounds crap so adding a full Thorney Motorsport exhaust system makes a tremendous difference.

The full system comprises of a pair of 100 cell HJS race cats, a centre section   and sports rear silencer. On their own they generate over 12bhp but combine with an ECU remap the stage 2 adds 25-30bhp to the car. The full system complies fully with the MOT and has our usual 100% guarantee. It also saves over 10kg's in weight over the OEM system and obviously sounds fantastic, keeping the characteristic rasp from the car but ridding it of all the tininess - perfect. We actually spent some time tuning the exhaust to replicate the sound from the CSL air box; they really do sound stunning especially at full chat!

We do a complete diagnostic run on the car ensuring all is fine before we begin any work and then repeat this process afterwards to ensure the car leaves us in a perfect condition.

This is our new stage 3 upgrade, after many months of development (including a trip in our own CSL down to Italy) we have finally released our new Supersprint high performance manifold. A huge amount of effort has gone into developing this manifold to maximise power but also generate as much low down torque as possible, as a result we have both widened the of the standard system but tapered the interior bore to maximise airflow.

We also lengthened the primary pipes to give as much low down torque as possible to suit the free revving nature of the S54 engine. Just bolting the manifold onto the car on its own adds a clear 8-10bhp without any ECU adjustment, however when coupled with custom mapping and the TMS full race system with race cats we gain 30-35bhp over standard – thats a huge gain and will bring a massive smile to your face. Best bit of course is that all of this is simply allowing the engine to breath easier to generate more power and torque so no further stress is placed anywhere, the engine is working less hard to get more power – perfect.

The Thorney Motorsport Stage 3 is the same specification as the 2009 CSL Cup Standard Class Cars.

This is the daddy, the 400bhp, normally aspirated CSL. We’ve run one as our own demo car for four years now all with no issues or problems whatsoever – try saying that about some supercharger conversions! The stage 4 takes the full Thorney Motorsport exhaust, the TMS race manifold by Supersprint and adds our own specification Schrick racing camshafts and uprated rockers to the mix, the power delivery is nothing short of astounding.

The manifold gives you excellent low and midrange torque, the race cats and wider bore Thorney Motorsport exhaust give you freeer breathing in the rev range and the TMS/Schrick cams generate massive upper RPM power – the car pulls harder from 6500rpm than it does at 4k – its addictive. As part of the custom mapping we raise the rev limit as there is so much power it is still pulling strongly right through the red line.

Stage 4 conversions take at least a week such is the level of work undertaken (its three days alone to do the cams) and all are custom mapped as with all our work. This is by far the fastest cars we build and the basis of our CSL Cup Cars for 2010.