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).

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.

Related posts:

1. Formula Ford (Duratec): Snetterton testing
2. Formula Vee: Pole Position, Fastest Lap and 2nd at Silverstone
3. Articles

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).

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.

Related posts:

1. Race Report: Mallory Park (UK Formula Vee)
2. Formula Ford: Anglesey Review
3. Formula Ford: Brands Hatch Review

The decision to race this weekend was taken very late. Without being able to afford to test on the Friday preceding the race, our rationale for competing was to use the seat time as an extension to last weekend at Anglesey. And ironically, despite being a Silverstone ARDS instructor, I have never actually been around the International circuit. For these reasons, it was important to be circumspect about our prospects and concentrate on how the car and I perform, rather than an arbitrary result.

Sunday was a typically wet and greasy morning at Silverstone. The circuit has an unusually impermeable track surface which sees water remain for long periods even after rainfall has stopped. There is also a significant build up of rubber which rises to the top and leaves a greasy and challenging level of grip rivalled only by Donington Park in similar conditions.

Qualifying was an adventure to say the least. Conditions were at their worst for the day and I was heading into the unknown on a circuit I did not know. It was also the first time I had driven the car in anger under wet conditions. None the less, we qualified 5th and under these circumstances, this probably wasn’t a bad result.

Thanks to the Bookers for the use of their awning this weekend.

By the time of the race, it had stopped raining but with overcast skies and no wind the circuit remained wet. I made a decent start from the third row and was almost alongside the leaders heading into Copse corner for the first time. I lost out on the exit, getting very out of shape and rounded out the first lap in fourth position, narrowly missing an accident behind me into the Abbey hairpin for the first time.

After a few laps I worked out a way past Jim Morris for third position, getting a better exit from Luffield and going around the outside of the Van Diemen RF05 at Woodcote corner. From this point on, I pushed hard for a number of laps to put a gap between myself and the chasing cars and whilst I was able to keep a constant distance from the two leaders, I was not able to make any dent into their already substantial lead. At this point I decided to ease off a little bit, even though the conditions were improving, maintain the gap to the chasing cars and concentrate on bringing the car home. As the circuit began to dry in places, I realised I had no real reference points at all for braking, turning and cornering.

So after a long day, we ended with our first podium in Formula Ford and much more progress with the car. Every time we have been out on track, we have improved both the performance of the car and I am beginning to feel more comfortable in the category. Overall, both Ian Gough and Matt Shawyer were quicker this weekend but having tested on the Friday (in similar conditions) and having raced on the circuit before, I guess this is to be expected. Third doesn’t seem so bad.

You don’t find these at Monaco. Getting trophy from Peter Ritchie, Midland South Co-Ordinator.

The next race weekend is May 3rd at Snetterton for rounds three and four of the National Formula Ford 1600 championship. Personally, I am feeling confident for this weekend and I am optimistic that it will be first weekend we will be able to properly challenge at the front of the field and possibly even for a win.

Related posts:

1. Formula Ford: Silverstone Review
2. National Formula Ford 1600 at Cadwell Park: Review
3. Formula Vee: Pole Position, Fastest Lap and 2nd at Silverstone

Race Commentary

Friday testing suggested quite how close Saturday would have been. The full GAC team were out in strength, with ex-BTCC works Toyota driver Ian Flux testing Farmer’s car during the morning. Daniel Hands returned to the track after his Brands Hatch misfortune and to the best of my knowledge, Farmer, Hands and myself were separated by a matter of hundredths all day.

Come Saturday and the forecast of rain, qualification was neither wet nor dry. Damp patches covered the circuit but as I was in the second of two sessions conditions were invariably better for me. However, it was of little advantage as Martin Farmer, James Birch, John Hughes and Jake Oliveira all contested this session too.

As the session got underway, I settled in behind Birch, Hughes and Farmer and quickly worked up to the front, using each of them as a spring board forward. After four laps the session was stopped due to oil down between Brooklands and Copse. Whilst waiting for the session to be restarted I was told that I was fastest by eight tenths, ahead of Farmer. Knowing that Farmer would also be told this, he would certainly be pushing hard once we got going again.

By the time the session was resumed, circuit conditions had improved. However, the remnants of oil at Brooklands meant I couldn’t improve on my previous best lap. Never-the-less, neither could Farmer and it was good enough for my third consecutive pole position by little over four tenths of a second from Martin Farmer and James Birch.

The Clerk of the Course later deemed that the two sessions had different enough conditions to justify staggering the results and so joining me on the front row would be Sam Oliveira, with Ian Buxton and Martin Farmer making up row two.

So, an hour before the race the rain settled in, the full extent of which I did not know until we made the grid. Large puddles of standing water lined the circuit, at Copse, Beckets and Brooklands.

Getting off the line was a struggle in itself. Even the most extreme clutch finesse gave too much wheelspin. Sam made an equal start but by the time I made second gear, Ian Buxton had already jumped us for the lead.

Benefitting from an absolutely storming start, he moved to the inside and led into Copse for the first time. Feeling the need to make it back to the front I got to the outside of Buxton under braking for Brooklands and we ran side by side until I had the inside line for Luffield.

Now back in front I could start to think about running at my own pace. Unbeknown to me was that as entering Becketts on lap one Farmer had touched wheels with Birch, spun and was now trailing at the back of the field.

I started to push reasonably hard but it was short-lived. I stretched out a sizeable lead over Buxton on that lap but after making the apex at Brooklands, continued to aquaplane off towards the gravel. Realising the potential that I would get beached was high, I got back on the throttle fractionally before reaching the end of the track. This gave me just enough momentum to power through the gravel, over the grass, across the tighter, disused Luffield corner, over some more grass and to rejoin just behind Buxton in the middle of the corner.

I had lost a few seconds to Buxton but remained in second position. After regaining my composure, I decided that I needed to chase down Buxton for the win as I had no idea how Farmer was progressing.

Within two laps I had caught him and in the process set a new fastest lap, 1.2 seconds faster than his and a second faster than anybody else. Starting lap six and on the run down to Becketts I had a think about going down the inside of Buxton. We were millimeters apart and on the exit I was completely out of shape. I couldn’t hold it and spun. Keeping the engine running I had to wait for Birch, Lindsay and Oliveira to pass before I could rejoin. It was at that point that I realised Martin was no longer towards the front.

So I got lucky. Yes and I admit it. The red flags were thrown due to an incident between Alan Robinson and Ankit Love at Luffield, therefore on count back, I retained second place.

Martin struggled to make up positions and finished down in 18th position, scoring just three points. He will now drop that round, his worst finish of the season and with my 22 points for second place and the extra point for fastest lap, I have retaken the championship lead and have a ten point buffer heading into the final two rounds.

However, whilst the dynamics of the championship have changed (I can now finish second to him even if he wins and gets fastest lap), it is far from over. A DNF at Oulton Park or Snetterton would put me largely out of contention, albeit not mathematically, but practically. It may only be 30 minutes of racing but there is a long way still to go.

Overall, I can’t help but be slightly disappointed at myself for not winning. I was quickest in qualifying and in the race by a sizeable margin. The truth is, the conditions caught me out.

Congratulations to Ian Buxton on his first win of year. He may not have been the quickest but he did manage something I didn’t – he kept it on track.

Next up, Outlon Park.

Related posts:

1. Formula Vee: 3rd at Oulton makes me Champion (Video)
2. Preview: Next up, Snetterton
3. Preview: Castle Combe (UK Formula Vee)