This article appeared in Racecar Engineering, The International Journal of Motorsport Technology (RCE V19 N12).

As a computer scientist, I find it hard to comprehend that you cannot always quantify engineering. Computers represent, in many respects, a form of perfect engineering, free from the burdens of materials, tolerances and the infinite physics of an environment. In theory, a given operation is entirely predictable whether it is invoked once, twice or a thousand times.

The same cannot be said for most forms of motorsport engineering. Despite absolutely every possible effort being taken to minimise variance, there is no guarantee that two engines, two chassis or two sets of tyres, for example, will ever perform equally – despite being manufactured to an identical specification. And so, I was wondering, if you cannot quantify the manufacturing itself, is it possible to at least quantify the performance gain between different engines?

Formula Ford and the legend of Patch

Ever since the hey day of Formula Ford, there have been stories of engines that have dominated the formula. And the legend that is Patch demonstrates this well.

Patch was a Kent engine with remarkable pedigree. It is most well-known for powering four different drivers to successive Formula Ford Festival wins - Roberto Moreno (1980), Tommy Byrne (1981), Julian Bailey (1982) and Andrew Gilbert-Scott (1983). Additionally in 1981, it also believed to have powered a young 21-year old Ayrton Senna to the RAC and Townsend-Thoreson championships, in the same works-run Van Diemen that Tommy Byrne piloted to victory in the Festival.

However, the origins of Patch are rooted earlier with a young South African driver called Trevor Van Rooyen.  In 1977, Van Rooyen piloted a semi-works run Royale RP24 with a self-built (but Minister badged) engine. That year, Van Rooyen won the RAC championship and in the process won a staggering 33 races. However, the following year (1978), Van Rooyen’s engine was destroyed in a test session and the South African returned to his native land. For the record, Van Rooyen went on to enjoy a distinguished career which included winning the 1985 South African Formula Two championship.

Leading Engine builder Graham Fuller (Minister International) subsequently repaired the broken block, welding a ‘patch’ of aluminium where the block was damaged. The engine then returned to racing during the 1980s and to claim its place in history.

Whilst many would argue that much of the latter successes of ‘Patch’ was due to powering a works Van Diemen chassis, the dominance of which would invariably attract the fastest drivers anyway, the legend of ‘Patch’ continues to be known as the greatest advantage a Formula Ford driver could possibly have.

Formula Ford engine power and torque curves

The following is the dynamometer chart from my Formula Ford (1600 Kent) engine when it is was rebuilt in January 2009.

The vital statistics are that at the time of the rebuilt, this engine produced 105.8 BHP at 5800 RPM and 148.8 NM/torque at 4400 RPM.

The problem is that with only data from a single engine, who is to say whether or not this is a strong engine? What’s more, any comparison would only be valid if it were also from the same dynamometer. However, after a year of racing in Formula Ford I would suggest that immediately after being rebuilt, this engine was average. It was not poor but it was also not great and as the season progressed and the engine ran hotter, it became an obvious disadvantage.

But my question is, what did this disadvantage really do to my laptime?

rFactor for real world simulation

Image Space Incorporated have been producing world class simulations for over a decade and the latest incarnation of which is rFactor. Consumer distribution is almost exclusively online and the success of which is demonstrated by the large, dedicated and vibrant community of contributors it has amassed. GMotor2, the 3D and physics engine behind rFactor is utilised and licensed in many other popular sim racing titles including GTR2, ARCA Sim Racing and RACE – The Official WTCC Game. What’s more, Formula One teams including Williams F1, Red Bull and Ferrari use a (albeit customised) version of rFactor (and gMotor2) for their in-house simulators.

I could have approached this problem using a headless simulation such as Bosch’s LapSim. However, as a driver, the benefits of using an interactive simulation are too attractive. None the less, in the future, I might still do this and it would be interesting to further validate the results.

A more accurate Formula Ford for rFactor

In an attempt to answer this question, I have modelled the physics of a Formula Ford 1600 that is as close to my Swift SC94 Formula Ford as possible. In the process, I have accurately modelled the suspension geometry, imported the power and torque data from my engine and re-profiled the tyre slip curve to one that resembles the Avon ACB10.

To demonstrate its potential, the following is a comparison of two similar laps (within one tenth of a second) of the Silverstone National circuit. The blue trace is the actual speed (mph) sampled from my Swift SC94 on 27 June 2009 whilst the red line is the same speed sampled from a simulated lap of the same circuit.

It would be unrealistic to assume that the two traces would perfectly overlap. This particular lap of data was sampled during race conditions and at the time I was dicing closely with two other competitors. There is also a degree of precision lost in comparing data sampled from two different loggers (one of which being virtual) as there is a small variation in actual sample frequencies. Finally and inevitably, there are small inaccuracies in both the Formula Ford physics and indeed the ISI model of the Silverstone circuit (Formula One teams will have access to much more accurate surface data, for example).

However, for the purposes of answering my question, it is sufficient and accurate somewhere in the region of about 2-5% at terminal speed (comparing speed and RPM).

The following video is two sample laps of Silverstone National circuit using the simulator (one of which produced the simulated data shown above).

Click here to view the embedded video.

One final note before I move on. Whilst I would love to contribute this work to the rFactor community and make it available for download, I can only take credit for remodelling the physics of the car. The artwork and 3D model itself originates from the impressive netkar PRO and doing so would be a violation of their copyright and intellectual property. The original conversion of the car encountered similar problems and for those reasons I will continue to respect the rights of these parties but thank them for their hard work.

Building three more powerful engines – artificially, that is

I have remodelled the engine power and torque curves three times – with two, five and ten more horse power. This is obviously theoretical; a real engine producing more peak power would do so with a entirely different power curve. If anybody has dynamometer data from their own Formula Ford engine please drop me an e-mail.

Running the experiment

I have run four separate 20-minute simulations of Silverstone. In order to minimise driver inconsistency I will be using the worlds best test driver – the computer. This enables me to run four near identical sessions. Internally the rFactor AI uses predefined way-points on the circuit to drive each lap.

A summary of each session is shown in the table below.

The following chart shows the individual lap times for each session run.

Finally, the following two charts show the speed and RPM traces respectively, for the fastest lap in each session.

Making sense of it all

I don’t think there is any particular surprises in the results. The fastest overall lap time was set using the most powerful engine. Ten extra horse power yielded a lap time of 62.626 seconds or 1.105 seconds faster than the best lap time set with the standard engine. Similarly, the average lap time was slightly faster still at 1.113 seconds.

An extra five horse power produced a fastest lap time of 63.298 seconds, 0.433 seconds faster than the standard. On average, it was 0.463 seconds faster.

With just two more horse power, the best lap time was 0.183 seconds faster than standard and on average 0.202 seconds faster.

Broadly speaking in this experiment, one horse power equates to roughly a 0.1 second per lap performance. Obviously, this will vary from circuit to circuit.

Back to reality

During the National Formula Ford race weekend in June I qualified in 7th position with a best time of 63.986. This was 1.216 seconds off the pole position time of 62.770, set by Rory Butcher. For the record, I did not test before this weekend and this qualifying session was the first time I had driven a Formula Ford 1600 around the Silverstone National circuit. I was also driving with a left-rear slow puncture caused by a broken tyre valve core.

If we assume that there was a couple of tenths to be found through familiarisation with the circuit, that brings us close to the fastest simulated time of 63.731. Likewise, Butcher’s pole position time of 62.770 is equally close to the best simulated lap time of 62.626, set with ten extra horse power. However, I would suggest this is probably more coincidence than it is scientific fact. An interesting coincidence, none the less.

Concluding with the caveats

Ultimately, there are many caveats to the conclusions drawn from this experiment. I will reiterate that the remodelled power curves are artificial and in many ways, unrealistic.

There is no allowance for engine wear – at the Silverstone race weekend my engine had run for around 400 miles and probably no longer produced 105.8 BHP at 5800 RPM. However, this works both ways and it could actually mean a horse power differential closer to ten, after all.

The same gear ratios were used for each run (2.40, 1.74, 1.43 and 1.17). These are also the same ratios used during the race weekend. With ten extra horse power, I would expect to run longer gear ratios and suggest this would see a further reduction in lap time. The flat line at the end of the straights on the RPM trace confirms that fourth gear is indeed too short.

Ideally, this experiment would need to be repeated a high number of times before the data is collated and analysed. Unfortunately, one reality of using a real-time simulator such as rFactor is that each 20-minute simulation takes 20-minutes to complete. A headless simulator, such as LapSim, would be able to repeat simulations at a much faster rate and as such produce more reliable results.

As far as I am concerned, this experiment has demonstrated that despite its caveats, a small horse power advantage offers a quantifiable and not insignificant reduction in lap time on the Silverstone National circuit. But even more, it has demonstrated what a brilliant and accurate simulation rFactor really is.

You can now read this article in print form online with Racecar Engineering for Zinio.

© David Galpin

Going into qualifying I was quietly optimistic that we would have a good session. Despite managing only 20-laps in testing on Wednesday after the clutch seals went, I have always enjoyed the Brands Hatch circuit and was looking forward to the first real weekend after winning at Mallory Park. However, my session was interrupted by a plug lead which had worked its way loose (creating a misfire) but after I rejoined I did a time good enough for sixth on the grid. This again was not quite what I had expected but considering it was another broken session, I was content none the less.

I was anticipating the races would be quite close – Brands Hatch is a difficult circuit on which to overtake for any category. After getting a decent start, I tucked in behind Cormac O’Neil in fifth place and followed him closely for the opening laps. I was slowly losing his tow but there was a breadth of air opening between myself and the following car of Adam Quartermaine. I felt faster through Paddock, Druids and Graham Hill but I wasn’t 100% sure where exactly I was losing out. Upon reflection, this suggests it was straight line speed.

At around lap seven, my engine temperature rose considerably to 100 degrees. Being conscious of possible serious damage I began short shifting gear changes to keep the revs low and generally driving slower. I was aware that if I was to DNF this weekend, my championship would be over. After a couple of laps at this speed, Quartermaine had closed up and was now looking to pass me. I held on for as long as I could, now with water temperature spiking at at almost 110 degrees but Quartermaine inevitably passed on the start and finish straight.

It was only two further laps before the race was stopped due to an accident at Clearways and I coasted my way back to the pits to finish seventh overall.

© David Galpin

After examining the car we were at a loss as to what had caused such severe overheating. This new Scholar engine has always run hot and has never delivered the power it promised. Since Anglesey we have been trying to cool it down having tried new radiators, holes in bodywork, water wetter and everything we could think of. The radiator cap seal was broken, perhaps this was causing the water system to de-pressurise (at which point water would boil at a lower temperature)? This was changed as a precaution before race two.

The grid for race two was determined by the finishing positions for race one and I would start on the fourth row. I made another decent start and formed the back of a seven car train to the lead, behind Quartermaine, O’Neil and Parr. After a couple of laps and a few failed opportunities to get past, Quartermaine ran wide on the entry to Paddock and I slipped up the inside to move up a place. There was now a brief gap up to O’Neil which I managed to close fairly quickly. Malvern was leading but appeared slower than those chasing and Butcher, Grady, Parr, O’Neil and myself were all nose to tail behind him. Whilst I felt faster than the cars ahead of me, I couldn’t see an opportunity to make a pass – I would lose ground between Clearways and Paddock but then catch back up before the exit of Graham Hill.

The next time around, O’Neil spun on fluid whilst turning into Graham Hill Bend and I moved up to fifth position. At this point it was clear that the overheating had returned. Once again, I backed off to try and let the engine cool for a couple of laps but before long I was shown the Black and Orange flag for a mechanical problem and forced to retire to the pits. The Clerks felt that the fluid on the circuit was from my car and whilst I do not know if this was the case (it felt more like oil on the track not water to me), if it was, I can only apologise to those it affected. Had I finished the race, there was an opportunity for at least a podium as championship contenders (and race leaders) Butcher and Malvern finally had their inevitable championship collision at Graham Hill Bend on the penultimate lap.

And so that signalled the end to a very difficult, frustrating day. It is hard to imagine that there isn’t now lasting damage to the engine (piston rings and head gasket) and so if it was bad before, it is now worse. Our first Scholar engine lasted just 50 miles before the crankshaft broke and destroyed the block and now this one has been down on power and overheating right from day one. It really is heartbreaking considering Rory Butcher also runs with a Scholar that even Alan Wardropper admits is “exceptional” when it comes to horsepower.

For me, it is a shame for we are now no longer able to win the Midland South Championship. I have to admit, whilst I realise that in some ways it is due to circumstances (the Pembrey National rounds were cancelled and replaced by the Brands Hatch Midland South rounds becoming National, plus the Donington Park race being cancelled) it is a shame that in the Midland South Championship there are fewer non-National rounds than there are National (5:4). Effectively, that has unintentionally put bias towards competitors who score well at National meetings but don’t enter stand alone Midland South rounds.

We have persevered with our Swift SC94 and its engine all year and on reflection I think we have done well to achieve what we have. However, is it worth entering the Formula Ford Festival and Walter Hayes Trophy with the car in its present state? As it stands, it is hard to imagine achieving anything more than a top ten in either. I cannot afford an engine rebuild and our lack of testing this season has meant we never have fully addressed the cars handling characteristics. It’s frustrating because I feel I am driving well, better even than in 2007 but without the platform to show it.

Thanks again to everyone who helped me this weekend and those who came to support and spectate! Thanks also to David Galpin for the photographs!

© David Galpin

I think this would be a good opportunity to reiterate a previous post - the 2010 British Grand Prix isn’t going to happen.

Even before the circuit became unsafe, it very quickly became a bad day for us and a far cry from the euphoria of one weekend ago. We were served a technical infringement during scrutineering based on Formula Ford regulation 4.1, reading “Any device designed to augment aerodynamically the downthrust on the vehicle is prohibited, as are aerofoils, nose fins or spoilers of any type.”.  This was in relation to the one inch peice of floor forward of the sidepods (it can be seen in this photo). I do not intend to write much about this because in any case it was rectified, however, what I will say is that this floor has been on the car since 2004 and in that time has been raced by at least three different drivers. No competitor has ever protested the eligability of the floor and for these reasons I feel that is was unreasonable to prevent me from qualifying until it was removed. So, Nick Brown and Neil went to work on the floor with an Angle Grinder generously donated by Paul Mason. Thanks to everyone for their help with this.

We eventually made it out to qualify after the session had started and I managed five laps before the session ended. To makes matters worse, during this time I had no clutch for what turned out to be leaking clutch seals. And having never been around the Grand Prix circuit before and under the circumstances, qualifying fifth was not a bad result.

However, it was very wet and we had a lot of work to do to make it on the pace. Over the next couple of hours it continued to rain – sometimes hard, occasionally drizzling. At one point it even dried. However, before the main event Superleague Formula qualification had finished, the activities on track were suspended due to flooding on the track between McLean’s and Coppice. With our race scheduled late in the day (at 1745), we were told that a decision would be reached by 1700. Indeed it was and we were informed that Superkart qualification would be the first session to resume on track, followed by our race. We arrived in the collecting area, lined up on a dummy grid and waited to be released to the circuit. We waited for half an hour before we were told the day was cancelled. So here are my questions:

• After this exact same problem occurred during June at our previous Donington Park round, what steps were taken to rectify the issue and prevent it from occurring again?
• Assuming any were taken, why is it that these steps proved insufficient?
• What steps will be taken to reimburse the BRSCC for a second cancelled meeting?
• In turn, what steps will be taken to see that all competitors will be reimbursed for the significant costs incurred (not simply our lost entry fee) in attending a second meeting with no racing?
• What steps will the MSA/FIA take in ensuring that safety standards, in all weather conditions, are sufficient to justify their permit?

Ever since Formula Vee I have been looking forward to racing in the Edwina Overend Trophy. I wasn’t able to do so in 2008 after my brief appearance at Cadwell Park and so I was pleased that this year it also included a round of the Midland South Formula Ford Championship.

I wasn’t too sure what to expect when we arrived as I was not able to test before hand. In actual fact, the last pre-race weekend test day I did was back in Anglesey. Anyway, I did a 10 lap shakedown in 2007 in the car (albeit with Brands Hatch ratios) and I was reasonably confident I could be on the pace within a few laps. We also had two qualifying sessions – the first for the Midland South race and the second for the Trophy race.

Qualifying

First qualifying was exploratory, refreshing myself of the circuit and working out where we were on setup. The consensus was: we were too soft, struggling for traction at the hairpin and the brake pedal was a bit too long. Anyway, I set a time good enough for 2nd on the grid, two tenths off Ed Moore.

For second qualifying I went out with a brand new set of brake pads (thank you Nick Brown!) and these took six or seven laps to bed in. For the remainder of the session I didn’t get a particularly clean lap and I wasn’t able to get within 2 tenths of my previous time. However, I qualified third, behind Quartermaine and Moore.

Race 1 – Championship race

Just as we were preparing to leave for the assembly area for race one it started to rain – much like it did at Silverstone. It was enough to unsettle your nerves about staying on dry settings but not enough to justify a change to wet. We decided to stay on dry settings even if the circuit was damp at the start of the race.

I made a good start and was able to go to the outside of Moore into Gerrards for the first time and gain the lead. Conditions were damp and it was very difficult to tell at this point how hard to push, how the braking zones would be and where the grip was. I told myself that the circuit wasn’t wet, driving as close to normal as I could and I was consecutively over a second per lap quicker than anyone else at the start. On around lap five the conditions were improving and I think I was a little slower to react to the change than the chasing cars. I lost a bit of time passing a back marker and by the half way point of the race Moore had caught me, with Quartermaine and others in close succession.

At this point I knew that for what ever reason I wasn’t as quick as Moore but could hold on if I defended correctly. I decided to go to the inside at Gerrards, the Esses and the Hairpin and forget about lap times. As Moore became closer, the chasing pack behind caught him making it a close, four car train. Moore got alongside me on every straight, at times his wheels were actually in front but as I had the inside line I could just run deeper into the corner and hold the position.

With only a few laps to run Quartermaine got past Moore at the Esses and I had a few car lengths gap. Quickly after, I saw Moore spin on the exit of the Hairpin and I knew at this point the race was mine and I was elated at taking my first lights to flag victory in Formula Ford.

Before I had even unbuckled my belts in park ferme Ed Moore had lifted my visor and promptly told me that in the next race, he would put me into the wall and break my legs. He then continued for some time with an onslaught of similar profanities until I left back to the paddock. All I will say on the matter is that to me, for a driver of Ed’s calibre, experience and maturity to feel he has to act in this manner is somewhat pathetic and the respect I had for his achievements is sadly lost.

Race 2 – Edwina Overend Trophy

After a short break, it was time for the Edwina Overend Trophy race. By this time the circuit was dry but it remained overcast and dim.

Starting from third position I made a decent start but had nowhere to go in order to make a pass and I slotted in behind for the run around Gerrards. I stayed very close to the second place car of Quartermaine. I struggled to get alongside him on the straights but felt I was probably stronger on the brakes. Conscious that Moore was getting away at the front I dived down the inside at the Hairpin on lap two and made the move up into second position. At this point Moore had a two second gap and I set about trying to reduce it.

For the next fifteen laps I pushed as hard as I could to try and catch Moore. We exchanged lap times and I reduced his lead to just over a second before I lost time behind a number of back markers. Unfortunately, I could never make up the time I lost at the start and I finished 2nd but did take fastest lap in the process.

So, I got my first win – not the trophy race I wanted but a good result none the less. The entry was not great but to beat Ed Moore at Mallory Park in race one and then later to be faster than him to take fastest lap is a good indication of our improving pace. I think that despite the win, Mallory Park has proved to me without doubt that we are very short on engine power (and I will blog on this more over the next few weeks). I think that Moore had about 5 car lengths on me on every straight and it is costing me between 5 tenths and 1 second per lap. I think this also accounts for our relative performance in National races.

My next outing is this Saturday at Donington Park for the rescheduled Midland South race from earlier in the year. It will be another tough meeting with no testing, having never been around the Grand Prix circuit before qualifying. Finally, thanks in advance to Nick Brown for the brake pads for the coming weekend!

This was the fourth straight race weekend I would not be testing the day before. As such, qualifying was my first opportunity to drive a Formula Ford 1600 on the National circuit and in regards to set up and gear ratios, we were running the same as at Donington Park (which ultimately didn’t actually happen).

Click here to view the embedded video.

Both Saturday and Sunday would be run as independent races – the Saturday had qualifying and a race for the North West Formula Ford championship whilst Sunday had qualifying and a race for the Midland South Formula Ford championship.

First qualifying on Saturday was marked by a slow puncture (caused by a faulty valve core). I qualified on row four, 7th on the grid.

When it was time to race, we were absolutely baking in the heat on what was the hottest day of the year. After making a decent start, I was quickly engaged in a race long battle with Matthew Parr and Neil Pattern for 5th position. I have to admit, this was the most enthralling duel I have had since 2007 and Formula Vee. We continually changed positions, twice or even three times per lap. The racing was hard, but fair. However, with about 4 laps to go, I started to be unable to shift into third gear and gradually lost touch with Parr and Pattern. I eventually retired to the pits on the last lap (unknowingly), crossing the line as I made my way to my pit garage.

Whist investigating the gear selection problem, we noticed we had a different and much more serious problem. It quickly became obvious that the clutch itself was slipping to the point it was no longer possible to pull away from static. Interestingly, there was no clutch slip during the race.

I was able to purchase a new clutch from Medina Motorsport and we all worked hard into the night to change the clutch. A really huge thank you to both Neil Paxton and my Dad who worked tirelessly to get the car ready in time for Sunday and to Justin Dawkins who helped us with the gearbox and initial diagnosis.

For Sunday’s race we again lined up 7th and on row four. This time I was a bit disappointed to have not qualified higher but after everything that had happened on Saturday, I was just glad to be racing. I had gone about 4 tenths slower in qualifying than I had during the previous race but I think that most of this I can be attributed to not really getting a clean lap. Of course, I cannot blame anyone but myself for this!

It is hard to believe but as we were sitting in the collecting area waiting to go to the grid, it started raining. It rained hard enough to warrant a change to wet settings but with barely two minutes before we were released to the grid, we opted to stay on dry settings.

The circuit was very greasy and as the rain fell it brought the previous weekends Formula One rubber to the surface. The wettest portion of the track was at Becketts whilst Copse, on the other hand, was just damp.

Off the line I made a good start and was up to fourth position on the first lap going into Brooklands. However, more bad luck presented itself as my gear linkage broke again (this time in a different place to Saturday!) and the linkage sat idle in my lap. It took me a lap or two in order to learn the technique but I realised that I could continue to drive but needed to physically hold and line up the gear linkage as I approached a braking area. Likewise, going up to the gears, I would have to pick the linkage up from my lap and move the rod forward and back in the hope I would correctly move the selector forks! I can think of one moment, driving through a wet Woodcote corner with one hand holding the linkage off of my lap and the other correcting lock as slid sideways through the turn.

I brought the car home in a respectable 6th, disappointed and frustrated with not being able to push to the maximum in conditions I enjoy. But none the less, it was a good result considering the circumstances, the bad luck of the weekend and how hard everybody had worked.

It is now time to leave the National Formula Ford 1600 championship as the next two rounds at Oulton Park and Knockhill, together with the final meeting at Mondello Park (Ireland) will be too expensive for me to compete. I will instead consolidate where we are in the Midland South Formula Ford 1600 championship (currently leading Class B) and concentrate on improving the car for the end of season trophy events. After contemplating the weekend, I think I can draw parallels between this season and 2006 when I had a difficult (and unreliable) year in my GAC Formula Vee. I kept my head and the following year I went on to win the championship.

My next race will be on July 26 at Mallory Park for the next round of the Midland South Formula Ford championship and the coveted Edwina Overend Trophy.