Rally Round / #Saxon-Motorsport
The team’s engineers take on a technical challenge. As well as prepping its own race cars for the VLN and a trip to Spa, Saxon Motorsport has been busy fettling a BMW diesel for a Polish rally raid team. #BMW
On Cotswold Saxon’s return from round seven of the #VLN-Endurance
series at the Nürburgring, the team set about preparing for round eight with its V10 #BMW-150
race cars. The 120d was again to be driven by Ellis Hadley, Martin Gibson and Tom Barrow as they completed their qualification process to compete in the #2017
24-Hour race around the infamous Nordschleife circuit. The V10 would once again be driven by team owner Nick Barrow and Miami-based regular driver Jamie Morrow.
However, before preparation of the race cars could begin Saxon had another project to attend to. As Bosch Motorsport dealers with vast experience of competition diesel powerplants, various competition outfits come into contact with the team and become aware of its expertise. One such company, encouraged by Bosch, is Polish rally raid specialist, Neoraid. Based to the south-east of Krakow, the rally raid racing team competes in cross-country rallies worldwide, completing the Paris Dakar rally in two of its three entries since 2014 in #BMW-X3-CC
s. The team had recently taken delivery of a #BMW-X5-CC
with a very special early #M57
3.0-litre diesel engine developed in conjunction with #BMW-Motorsport
. This is a similar unit to that used by Saxon until it switched to the current #N57
late last year. Being fitted with a Bosch Motorsport competition ECU by the engine’s previous rally raid owners, Neoraid found itself lacking the experience and data to exploit the engine’s potential and was directed towards Saxon to look for assistance. Items of note fitted to the powerplant included a bespoke CNC-machined dry sump installation with associated oil pump, a CNCmachined rocker cover replacing the standard moulded composite item, and bespoke twin-turbos with associated manifolds and actuators.
The twin-turbo system had been developed to maintain maximum power output despite the fitting of an FIA-spec inlet restrictor, mandatory for Dakartype rally events for turbo vehicles in any fuel class. This meant additional complications for chief engineer Jon Taylor as he needed to synchronise the small VGT (Variable Geometry Turbo) with the larger unit cutting in at higher engine speeds together with the various wastegate and diverter actuators.
Having agreed to take on the project, an understanding was reached with Neoraid that the engine would be fitted in a test rig and delivered to the team’s Hereford base by the Neoraid team manager and one of its engineers. The engine, ECU, and all components would be fully wired and ready to map. Three days were allowed for the task. However, as is often the case in motor racing, the project was a little behind schedule. Upon arrival, as can be seen from the accompanying photographs, the wiring loom was still a long way from being completed! Undaunted, Jon and the attendant engineer set about sorting out the various connections and inter-connections between components and recording all the wiring pin details so that a more suitable wiring loom could be produced later. During this phase a two-stage intake air cooling feature was discovered; this consisted of an initial air-to-water chargecooler followed by a conventional air-to-air cooler for the secondary stage. A lightweight 180A McLaren TAG alternator was fitted.
The Bosch Competition ECU had been installed, calibrated and mapped by Bosch with bespoke Bosch-manufactured, BMW-assembled injectors, for which no data was available…
After some head scratching – and discovering the astronomical cost of having the injectors dismantled and interrogated by Bosch – Saxon and Neoraid decided that standard BMW injectors should be fitted instead. Saxon’s experience with the M57 engine came into play here as the team’s development of the early engine resulted in it knowing which injector gives the best spray pattern and distribution characteristics for this type of endurance engine. As delivered to Hereford, the engine was also fitted with larger valves – necessitating piston cut-outs – a ported and polished cylinder head and a #Bosch-Motorsport
‘Fuel Hydraulic System’ delivering up to 2100bar of fuel line pressure!
One problem experienced and effectively managed by Saxon whilst using this engine was a tendency for the crankcase breather to allow oil to escape. The problem has been resolved on the latest standard N57 engine and so the team’s catch tank was no longer required. This engine, however, was fitted with a bespoke oil separator pump to address the problem.
Despite the slow start to rewire various sections and the time it took to become acquainted with several components new to Saxon, the team of Saxon and Neoraid engineers completed the task in the allotted three days in the team’s tuning bay. By the time the two engineers departed for their base in Poland they had a running engine with all components integrated and working together on a base map.
The engine will now be removed from its test rig in Poland and installed in Neoraid’s X5-based rally raid car for the necessary wiring and supply systems to be installed around it. As the vehicle is all-wheel drive and Saxon’s rolling road is a single roller installation, Jon Taylor will then fly to Krakow and work at a local twin-roller road to fine-tune his map for the performance required by the team.
To date, the project has been an interesting variation on the work carried out on the team’s own race cars but on a vehicle being built to a completely different design brief but with significant similarities in the propulsion unit. Saxon was very interested to be part of the development of the powerplant and Neoraid has gained enormous experience with the M57 engine through this collaboration so far.
Meanwhile, as the Neoraid team returned to Poland, Saxon’s attention returned once again to its own cars. Whilst the 120d was left in a similar setup as used last time out (in order for Martin and Ellis to continue assessment of the Giti tyres), the Chinese company had been unable to produce the next development tyre specifically for the ‘Ring in time for round eight. The drivers therefore continued to collect data and experiment with the setup using the existing rubber. Further improvements to the V10 were, however, planned following the last outing.
The hoped-for power steering improvement had failed to materialise last time out and so Jon Taylor set about fitting yet another larger capacity hydraulic pump, this time engine-driven rather than the previous electric version. This caused several packaging problems as space is at such a premium under the bonnet with the 5.0-litre engine installed and Jon resorted to purpose-made mounting brackets, belts, tensioners and idler pulleys in order to install the pump. Initial indications, however, suggested that the effort may well have been worthwhile with considerably less effort required on rapid lock-to-lock movements, whereas previously the hydraulic system failed to keep pace.
Further work will be carried out on the paddlechange software to smooth-out gear synchronisation on up-changes. Another possible reason for this roughness emerged whilst examining the data from the previous race as it became apparent that the engine was failing to lose sufficient rpm for the next ratio to engage smoothly. To try to address this, the team has ordered a lightweight double-plate racing clutch and corresponding flywheel to reduce the energy within the drivetrain; the inertia generated by the standard 15kg flywheel/clutch combination was too high to allow the engine revs to fall fast enough. Hopefully this will improve the situation and transfer less stress to the Drenth gearbox; however, this will not be available until after the car’s next planned outing at Spa on 9-10th October.
The team’s drivers were still anxious to dial-out some of the power-on understeer that the V10 experiences during the exit stage of a corner. Drivers reported that initial turn-in is good but despite this the car suffers with understeer as power is applied. To attempt to overcome this characteristic, the team fitted new ramps to the Drexler limited-slip diff to alter the limited-slip effect and also rebuild the spare diff with fewer active friction discs as an alternative. Both options were tested in the practice session at the ‘Ring, together with larger front tyres (now the same 285 width as fitted to the rear). In addition, a new more sophisticated traction control map was uploaded with additional feedback to make the most of the modified ramp characteristics.
The Saxon team was confident that these changes – together with the front tyre options and all the existing setup alterations available – would enable the car to remain neutral throughout all cornering phases. The team left for the Nürburgring on the Wednesday night prior to the next race on Saturday 24 September, hopeful of a class win with the 120d and at least a podium position with the V10 if the modifications were as effective as expected.
On arrival at Friday’s practice at the Nürburgring it soon became apparent that the reworked diff with fewer friction plates was definitely not the way to proceed and so the team quickly replaced this unit with the ‘re-ramped’ item. This, combined with the traction control upgrade and wider front tyres, immediately allowed Nick to set the V10’s fastest time around the GP circuit, cutting a full second off the car’s previous best. Meanwhile the three 120d drivers quietly set about improving the setup and doing everything possible to make sure they were in a good position to complete the following day’s race, as this alone would complete their qualification process.
Saturday qualifying gave Nick and Jamie their first chance to gauge the new setup’s effect on the Nordscheife lap time for the V10. First, however, in order to prepare for the race, new brake discs needed to be bedded-in and so the first opportunity for this fell to Jamie, driving the second qualifying stint. Jamie duly took his chance and set the team’s first ever subnine- minute lap, qualifying in 51st place with an 8:57! The 120d set a fast time in the Alternative Fuels class, giving the three drivers hope of a competitive fourhour race.
As the race got under way, Jamie started the first stint not knowing that the V10 was carrying an underlying gearbox problem. Having run with the aggressive upshift issue for the previous few outings, the stress had built up in the components and finally caused a failure on only the third lap of the race. As it was difficult to recover the car during the race, it was not possible to get the car back into a competitive race position and so the V10 was retired early, much to the disappointment and frustration of both drivers given the lap times being set. Meanwhile the 120d drivers were in the middle of a battle for class honours between themselves and both the 3.0-litre diesel Audi A4 and methanol/petrol hybrid Porsche Cayman with which the team had battled during the 24-Hour race in the Saxon 135d.
With half-an-hour to go, the 120d put up a valiant fight and actually led the class… until drama struck. Ellis found himself pushed from behind by an overtaking GT3 car, the resulting ‘off’ leaving him stranded on a raised curb until rescued by marshals, dropping the car from contention. As a car has to pass the chequered flag to classify as a finisher and drivers have to be classified in order to obtain their 24-Hour licence, what had been a fascinating battle for class honours now became a challenge just to finish the race! Ellis cautiously brought the car back to the pits for any damage to be assessed; there was just enough time to patch up the rear of the car and check for safety issues before returning to the track for one final lap to complete the race. There were sighs of relief all-round. Mission accomplished!
Further to the three drivers qualifying for their 24-Hour licences – and trusting that the V10 would return from Germany intact – Nick had hoped to forego round nine of the VLN Championship and travel to Holland for the 9 October Dutch Supercar round on the Circuit de Spa-Francorchamps. Nick and regular endurance driver Richard Corbett were keen to debut the 5.8-litre version of the V10 on the famous historic track. As we have previously stated, the V10 engine is restricted to 500hp at the ‘Ring but there are no such limits in Dutch Supercars so it is hoped to run in full 680hp mode for this two race (one 60-minute and one 90 minute) meeting.
Fortunately, Jon and his team will be able to fit the replacement Drenth gearbox and reprepare the car in time for an anticipated departure for Spa on Thursday 6 October, as Nick had intended.
The Cotswold Saxon team looks forward to reporting back on their eagerly anticipated visit to this iconic circuit after unleashing the full potential of the #V10
and further developments on the Neoraid project.