Our Group Technical Director shares some insights into Daytona's approach to owning and preparing 250 race karts for our 100,000 drivers each year.
Against The Clock
During the long endurance races we hold at Daytona, one of the most important aspects from an engineering point of view is the regular maintenance stops. To make it fair, we have all teams stop for a minimum of five minutes at regular intervals throughout the race in order for the engineering teams to check over the kart thoroughly. Most of the time, it takes fewer than five minutes, but if we encounter a problem we can normally rectify it within the allotted time.
We check for the main safety and performance issues, for example: tyre wear, chain tension, brake pad wear, steering assembly, wheel bearings, throttle cable tension, clutches, electrical connections and much more.
With up to 40 karts to maintain every few hours, the engineering team is kept busy throughout the race. It’s time consuming and very hard work but ultimately it helps us to ensure that the karts perform well throughout the race and most importantly, that they are safe at all times.
Take a look at just two of the 164 maintenance stops during the 2016 Daytona 25hr race:
The Winning Mentality
Motor racing is no different to any other competitive sport; winning is all in the mind. Obviously talent and determination are also key factors but to get to the chequered flag first, it takes a large degree of mental acuity.
It’s no good turning up to a race already thinking you’re going to be beaten. Winners have only one thing on their mind: winning. It’s all in the head. Mind games are a part of racing and can take place on or off track, just don’t get caught being suckered into it. Keep a level head at all times and concentrate on your own job.
One of the most consistent things I see on track is leaders who chance a sneaky look behind them. Don’t do it. No seriously, don’t do it. Almost every single time someone looks behind them from the lead, they end up losing the race. You’ll know if someone is close – you can feel it, hear it, you just know it. Keep your head, keep looking forward and concentrate on your lines. Make the others do the work.
The first lap of a race is probably the most important. At the start, don’t do what everyone else is doing; take a different line, look for opportunities and take them. Make a decision and stick to it. Where people come unstuck is when they’re caught in two minds, the decisive drivers tend to always make it stick, the indecisive drivers tend to always spin off.
While driving a kart at the limit is physically demanding, the total concentration needed to sustain the performance for extended periods is just as, if not more draining. Only by practicing can you build up the mental strength required to focus for the time needed to win a race. Some use test sessions, some use simulators but whatever you use, be sure to maximise your time and keep your mind focussed on the mission and don’t allow your mind to wander. Build the session lengths up if you’re having trouble but the more you put into it, the more you’ll achieve.
Hitting the gym or pounding the pavements is great for keeping your physical fitness, but to neglect your mind is to hand others an advantage before you even take the green light. The winners seize every advantage.
Richard Brunning – Jan 2017
Adapting Your Driving To Different Karts
With the choice between various karts available at Daytona’s circuits, it won’t be a surprise to learn that it takes different driving styles to get the best out of each of them.
The Sodi RT8 is a very different animal to the DMAX kart. With the Sodi at our outdoor tracks, you’ve got a torquey 390cc single cylinder, 4-stroke engine that has a lot of low-down pull. Conversely, the DMAX have a high revving 2-stroke engine that needs to be revved hard to extract the best performance.
The ideal way to drive a Sodi kart is to be smooth with the controls. It’s essential that you brake in a straight line and turn the steering wheel after you’ve finished braking; it’s not ideal to trail-brake into the corners with these karts as the relatively narrow rear width means that if you do trail-brake, it can set up a ‘hop’ through the corners which can be quite uncomfortable.
Once you’ve turned in, stamp on the throttle and let the torque drag you through and off the corner. The light steering is quite precise on initial turn in, but then if you’ve carried a bit too much speed into the corner, it can turn to understeer in the middle phase of the turn. Be accurate and get on the power early to get the best from them.
The DMAX karts are quite different. You can be much more aggressive with the kart. It is set-up much more like a pure racing kart and, to get the best from it, you have to be assertive. You can trail brake the DMAX karts without it hopping, so you can brake a little later than you might in a Sodi. The engine needs revs to stop it dropping out of the power curve, so your job is to keep your minimum RPM through a corner as high as possible. That means getting back on the throttle as early as you possibly can – squeezing the pedal smoothly to avoid bogging down – and keep the engine spinning over. Be aggressive with the initial turn in, getting the kart to pivot and then unwind the lock quickly as you apply the power. Don’t be afraid to chuck the kart about, it won’t bite you; the grip in the dry is very constant and predictable.
Both karts offer a challenge in different ways, so take your time to learn both styles and don’t be afraid to get it wrong from time to time! Extracting the best performance from the two types of kart is very satisfying, but not everyone can do it. Can you?
Richard Brunning December 2016
Understanding Kart Dynamics – Part Three
In the final part of this series on basic kart dynamics, we’re going to investigate chassis materials and stiffness.
Race karts come in many different shapes and sizes. Although the trend lately has seen most of the major manufacturers use a very similar chassis design, this wasn’t always the case. Generally speaking, a stiffer chassis generates more grip than a softer chassis. The innate stiffness of a kart can be affected by two means; first the actual layout of the rails and then also the rigidity of the tubing used. Most karts come in 28mm, 30mm, or 32mm tubing and are often made up of a combination of these sizes to achieve the desired rigidity.
You might think that more grip equals faster times but the truth is, once more, far more complicated. One of the most desired characteristics of a kart is for it to ‘release’ off the corners. A kart with too much grip will bind up and not allow the engine to accelerate as quickly as it should. This is especially noticeable with low-powered engines such as cadets. The type of tyre is also part of this equation.
For example, our DMAX karts have reasonable power, but a fairly hard tyre so a stiff chassis is needed to work the tyres hard enough to generate the grip needed. The Birel chassis we use has a unique 35mm diameter tube which allows the kart to have a relatively standard race kart chassis design but combines this with the strength needed to be as durable as we need and work the tyres hard enough to generate the grip.
Axle design has changed dramatically over the past twenty years or so; it wasn’t long ago that an axle was just a piece of 30mm steel bar. However, we’ve seen that develop now to a very lightweight 50mm hollow axle with a multitude of different stiffnesses.
A hollow tube is inherently stiffer and lighter than a solid bar so while originally the hollow axle was fitted for weight saving purposes, it wasn’t long before racers realised they could tune their karts handling by using different grades of axle. No self-respecting racer goes to a meeting without at least 2 or 3 different grades of axle now! Need more grip? Change to a stiffer axle. Bogging down out of corners? Change to a soft one.
Even seats have many different grades of stiffness now. It is not unusual to try multiple seats to fine tune the kart in the same way that you might change an axle.
Thankfully, when you come to race at Daytona, we’ve done the hard work, development and research for you so all you have to do is put your visor down and concentrate on the track ahead of you.
Understanding Kart Dynamics – Part Two
Part two of our series on the basics of kart dynamics concentrates on kart track width.
One of the easiest ways to affect the handling of the kart is by adjusting the overall distance across both the front and the rear wheels – the track width. As we aim for uniformity across our fleets, our karts at Daytona don’t have a huge amount of adjustability, but we can play with the track widths.
Each type of kart at each of our venues is tuned for the demands of that particular circuit. Milton Keynes for example, needs a slightly different set-up than Sandown Park due to the tighter nature of the MK track. Tamworth, with its sweeping corners and high-grip surface, needs a whole different set-up again.
We can adjust the rear track width on our karts fairly easily. The effect of this is to either increase or decrease the amount of grip on the rear end of the kart. If you decrease the track width – that is, move the wheels inward towards the chassis – you increase the amount of grip at the rear. The opposite is true – move them out and you decrease the grip available making the kart slide a bit more.
It’s not always the case that more grip is better. If you have too much rear end grip, the kart can bog down on the exit of corners and destroy your acceleration out of the bend. It can also set up a ‘hop’ where the kart bounces around the corner which isn’t quick and can be uncomfortable to experience. Therefore, it is always a fine line between creating enough grip to corner as fast as possible without bogging the kart down. Getting the chassis to ‘release’ correctly is a fundamental part of chassis set-up.
The front end track width has more effect on the kart than the rear. In a full race kart on good rubber, we tend to set the rear width at maximum +/- 10mm and use the front end geometry to change the handling. Basically, the wider the front end, the more grip and turn in you get from the kart.
As I illustrated last week, the jacking effect of the front castor angles is very important to the turn-in characteristics – so it follows that increasing the front track width increases the jacking effect of the chassis allowing the inside rear tyre to come off the ground quicker and higher. This allows the kart to pivot faster.
However, there’s a point at which the kart becomes unstable and oversteers too much, so finding the sweet spot between having enough front grip to make apexes at speed and not having the kart oversteer is a tricky thing to achieve. Throw in different castor angles and Ackermann angles and the set-up variations are almost infinite! It’s very easy to get lost attempting to set a kart up correctly, so most manufacturers supply a base line set-up sheet for their karts. Start there and tweak only one thing at a time when testing. Write everything down so you can refer to your findings later.
Kart track widths are a powerful tool for achieving a good handling kart and it’s one of the areas that Daytona works hard on to make sure you have the best experience possible at our circuits.
Richard Brunning, October 2016
Understanding Kart Dynamics – Part One
This is the first in a series of articles that will hopefully demystify the rather arcane workings of a racing go-kart.
On the face of it, a go-kart is very simple; you have a tubular chassis, four wheels and an engine. The steering is as simple as it gets – no rack and pinion mechanism for karts – and a solid rear axle that drives both rear wheels with equal torque. Easy… However, this simplicity hides a much more complicated truth.
For the first part of this series on kart dynamics, I’m going to concentrate on something called castor. The castor angle is one of the most important parts of kart design. It has a fundamental effect on how a kart handles. The castor angle is the angle of inclination of the front king pins in the longitudinal plane. In other words, how far forward or backwards the king pin is angled in relation to the vertical:
A go-kart has no differential, or diff for short. In a car, the diff allows the driven wheels to rotate at different speeds around a corner. The outside wheel always needs to travel further than the inside wheel. Without a diff, turning becomes very difficult as the two driven wheels are always working against each other. This tends to result in horrific understeer.
In a kart, the solid rear axle with no diff means that understeer is a certainty. The castor angle however, goes a long way to combating this phenomenon. The way this works is that the castor angle means that every time you turn the steering wheel, you ‘jack’ the inside rear wheel of the kart up. This momentarily picks the inside rear wheel off the floor allowing the outside rear wheel to rotate the necessary further distance. When you turn the steering wheel, you are literally physically picking the rear wheel off the ground. You can see this happening if you watch the really fast drivers closely. The wheel can come off the ground a long way!
The way to make this work for you is to turn the steering wheel very quickly, with controlled aggression and then immediately bring the steering wheel back to centre. You’ve picked the inside rear wheel up, the kart has pivoted around that wheel, then both rear wheels are back on the ground and you’ve got your foot hard on the loud pedal driving it through and off the corner. It’s a technique that takes some practice to master, but that’s how you get the most from the way the kart is designed to work.
In the next article, I’m going to explain go-kart track widths which work hand in hand with the castor angle.
Richard Brunning – September 2016
The Centre of Gravity
We’ve been busy commissioning brand new fleets of Sodi RT8 karts across the group this month. All of them feature both adjustable seat and adjustable pedal positions so that we can welcome drivers of almost any height. But what a lot of people don’t realise is that, whilst comfort and ease of driving are very important factors, the seating position is one of the most important factors when it comes to lap times.
The Sodi karts weigh 150kg. Our drivers may weight anything between 50 and 150kgs. With the average driver making up about one third of the combined weight of the driver and kart, the positioning of that third of the weight is important as the driver’s position within the kart fundamentally affects the handling of the vehicle.
Owner drivers set the seating position as per the chassis manufacturer’s instructions and then adjust the pedal positions to suit the individual driver. This gives the kart the best handling characteristics possible and is fixed. A number of other factors can affect the kart and can be changed; for example seat design, seat stiffness, the addition of metal seat stays etc.
In one of our Sodi RT8 karts, moving the centre of mass longitudinally along the kart by adjusting the seat position can have a huge effect on the handling. If you are struggling with the kart understeering for example, by moving the seat forward you move the weight towards the front and therefore more load is going into the front tyres. This will decrease the understeer, but move it too far forward and you’ll end up with the opposite problem of too much oversteer!
If you’ve got too much oversteer, move the seat backwards a little to plant more weight over the rear axle and thereby reduce the amount of oversteer you are suffering with. As the pedals are independently adjustable to the seat, almost everyone can find that happy balance. Don’t assume that the most comfortable position is the fastest because it may not be.
Why not take the opportunity in an arrive and drive session to come into the pits, adjust the seat and the pedals and try to find a position that suits your driving style and that reduces your lap time. Our marshals will be happy to assist and offer advice.
Richard Brunning – August 2016
F1 Technology on board karts
Back when I started in karts, the only thing kart racers had at their disposal to keep an eye on their engine was a very expensive digital rev-counter. If you were lucky, the tachometer would display peak revs after a run so you could set your gearing. Things have moved on somewhat in the last thirty years…
We can now use the same sort of technology that that used to be the preserve of Formula One teams.
We can fit the latest, state-of-the-art data-loggers to our karts. They have integral GPS chips that uses both the American GPS system and the Russian GLONASS system with unparalleled accuracy – and are able to update your current lap against your best lap every ten metres or so! These are fantastic tools for trying different racing lines and getting instant feedback as to whether your new line into or out of a corner has worked or not.
They also combine RPM and GPS speed measurement with an additional array of sensors like steering angle, throttle position and brake position so that we can see exactly what the kart and driver are doing every millisecond of every lap. When you add all this up, they make for the most powerful tools available for improving your lap times.
Our instructors are very experienced and when you are looking to improve by a few seconds a lap, it’s quite easy for them to see what you’re doing wrong. However, when you’re looking for improvements measured in tenths or hundredths of a second, the data-logging comes into its own when we can overlay your data traces on a graph against an instructor’s data. This gives us an in-depth view of what the differences in driving style and lines are and suggest improvements based on the empirical data.
We can also use this level of technology to ensure the competitiveness of our fleets of karts. If we identify that a kart’s lap-times are not within our acceptable range, then we can use the data-logging equipment to identify where the kart is losing time and thus deliver even fleets at our venues.
If you would like to sample just how F1-style technology can improve your racing, why not try one of our One-to-One Tuition sessions?
Richard Brunning, July 2016
Kart Engines – Two-Stroke or Four-Stroke?
Daytona is in a unique position to offer drivers a choice of either our Sodi RT8 390cc Four-Stroke Karts or our DMAX 125cc Two-Stroke Karts. Despite the former having over 3 times the “cc”, the latter are actually more powerful and thus faster. In this tech talk, I hope to explain in layman’s terms how the smaller engine DMAX fleet are faster.
Kart engines are not that different to car engines. They both use the internal combustion model to mix air and petrol to create an explosion that pushes a piston down which, in turn, turns a crank that provides drive. The key difference between our senior fleets of karts is the different way that the engines work.
Briefly, a 4-stroke engine uses valves that open and close to suck in the air and fuel mixture on the first downward stroke of the piston, close to compress it on the next upward stroke where it’s ignited at the top of the stroke, The resulting explosion forces the piston down on the power stroke and then the exhaust valves open to allow the burnt gases to be expelled on the last of the 4 strokes. Suck-squeeze-bang-blow…
A 2-stroke engine has no need of conventional valves to open and close for the inlet and exhaust, it combines the intake, exhaust and power in the same downward stroke and the power stroke happens every single complete turn of the crankshaft.
The Two-Stoke engine produces much more power as a result meaning that the engines can be lighter and smaller. Our DMAX 125cc engines are about half the weight and size of our Honda 390cc engines. The former produces 22bhp whereas the latter outputs 13bhp.
The main disadvantage of a 2-stroke engine is wear. They need much higher RPM than a 4-stroke engine to produce the power. The Honda GX390 engines in our Sodi karts revs at a maximum of around 4400rpm, whereas the DMAX engines rev to over 12,500rpm. These extra revs combined with the fact there’s no dedicated lubrication system – all the oil is pre-mixed into the petrol – mean they wear out much quicker than their 4-stroke brethren, therefore, they’re more expensive to run – requiring a major engine rebuild quite often.
But even though they cost more to buy and cost more to run, pound for pound, a 2-stroke produces more power for much less weight, that’s why we like them and that’s why we use them on our DMAX fleet which are the fastest arrive and drive karts in the UK!
Richard Brunning – June 2016
Tech Blog – April
During the course of a normal week, our fleets of karts get driven hard in all conditions by our customers and I think it’s fair to say that not everyone treats them as carefully as we would like. Consequently, they often get driven across the grass, the kerbs, binned into tyre walls and occasionally other karts. This takes its toll on the cleanliness of the karts.
Amongst our armoury, we have various different products to tackle the inevitable build-up of grime, dirt, grass and tyre marks. We recently entered into a partnership with Power Maxed for the supply of all of the chemicals and kart maintenance products we use on a day-to-day basis. This wasn’t entered into without quite a lot of testing. Despite many different suppliers offering a similar sounding product, there are huge differences between the respective qualities. We’ve found the Power Maxed range to be very good indeed; more than a match for our previous products.
When you’ve got 100 karts at a venue to clean and maintain, it takes time to jet wash and polish all of them, so what you don’t need is a chemical that requires multiple applications to achieve the finish you’re after. With the Power Maxed TFR and their engine degreaser, once is enough and the kart is clean.
We get through literally tonnes of chain lube every year but with chains and sprockets being critical components, you need a very high quality lube to cut down wear and maintain reliability. This product is probably the most critical when it comes to kart reliability so we wouldn’t compromise on the quality. Thankfully, Power Maxed produces a superb chain lube.
And you thought running a go-kart business was just all petrol and burning rubber…
Tyres – they’re black and round and connect you to the track right?
Well yes, but there’s far more to it than that. With a range of different karts and four different tracks to content with, there’s no ‘one size fits all’ solution.
At any one time, there are approximately one thousand two hundred tyres on karts in the Daytona group. Each track has its own particular needs when it comes to tyre selection. For example, Sandown and Tamworth are very sensitive to noise so a tyre that doesn’t squeal so much is ideal. Manchester has the bridge so a higher sidewall for more ground clearance is ideal.
The track surfaces are all very different too and that has a huge impact on tyre wear. Replacing tyres is the number one biggest cost of running our karts and during the summer months, we can be changing tyres on a bi-weekly basis.
Therefore, choosing the right tyre for the track has a massive impact on our business. The very long corners of the new section at Tamworth put a lot of load into the front tyres and they wear out quickly on the new, very grippy surface. At Milton Keynes, the stop-start nature of the layout combined with a relatively low grip surface mean that a different compound can be used to maximise performance.
At Sandown Park, the corner known as Vale wears out the left front tyre very quickly, so the front tyres get swapped from side to side to even out the wear.
Each of the different tyres we use needs a different tyre pressure to perform at its best and this will change from day to day as the weather and ambient temperature changes. In the winter, we use a higher pressure than in the heat of the summer to make sure the tyre comes up to working temperature quickly. In a long race like the Daytona 25hr, we might drop the pressures by a couple of psi to keep the tyre from overheating during the long stints.
We all tend to take the rubber for granted, but there’s an awful lot of thought, testing and experience that go into making sure the tyres you drive on at Daytona are the best suited to giving you the best possible racing.
Daytona’s Rotax Max Evo Engine: Technology On Track
Why did we choose the Rotax engine for the DMAX fleet way back when we originally designed them? Well there were a number of factors that led us to this decision. We tested a range of direct drive, air-cooled, water cooled, different capacity engines before finally deciding on the Rotax FR125 engine. We have to balance performance with reliability, speed with noise and ease of use with racing kart feel.
The Rotax engine gives us the best blend of these attributes whilst retaining the characteristics of a proper racing kart. For example for the sheer visceral thrill, nothing beats a direct drive engine but the problem is they need bump starting and this is a huge issue if you spin off – the engine dies instantly and then you have to wait for someone to come along and start you again. Therefore, an on-board electric starter was absolutely essential.
Air cooled engines are much simpler to maintain and package as there’s no radiator or water hoses but they are noisier and the cooling isn’t as efficient. The Rotax has an integral water pump so it does not have to be driven from the rear axle like many other engines so it’s not vulnerable to off track excursions.
We balance the performance using different sized restrictors, so we are not using the maximum amount of RPM available therefore prolonging engine life and giving us the ability to fine tune the performance of each individual engine to ensure parity across the fleet.
Of course, we have made our own changes to the engine to adapt it to our needs – the radiator is on the left hand side of the kart inside the protection of the side pods; we’ve moved the switches up to the Nassau panel so it’s easy to get to; we’ve changed the exhaust so it’s easier to package and even quieter than the standard unit. It all adds up to what we think is the most technologically advanced arrive and drive kart anywhere. You just have to drive one to see what we mean…Rotax FR125 Engine
One Careful Owner
We don’t usually sell our used karts. If we did, then we could honestly describe them as having one careful owner – but we would probably have to advise any potential purchaser that each kart had probably had 50,000 drivers.
Our karts don’t have odometers, so we can’t watch the miles clock up, but our timing systems do log every lap that every kart does. In about ten seconds, we can look up the kart running hours, number of laps, average lap-time etc for each and every kart in the fleets.
Obviously we record every lap because drivers like to know their lap-times and their race positions – but we also log them so that we can measure each karts relative performance to ensure that they are as even as possible. We also log the laps so that we can use planned preventative maintenance to ensure that we replace worn parts in good time so that they don’t let the driver down in a race.
You could compare our karts to Trigger’s Broom in Only Fools and Horses. We replace so many different parts throughout the lifetime of each kart, its very rare for any orginal parts to still be on the kart when it reaches the end of its life – and that includes the chassis – which is also a replaceable part. The Rotax 2015 Evo Engines on our Dmax karts cost £2500 each so we cant afford to throw them away – but we can get them rebuilt and that’s what is happening this January – even thought that costs over £400 per engine!
We are very excited to partner with Power Maxed – our new technical partners and we are looking forward to measuring the life of kart parts that they will help us lubricate and protect over the coming years. We know they look forward to proving that their products will help maintain and present Daytona’s karts to an even higher standard in the future.
We looked at the stats for our fleet of Sodi RT8 200cc karts in Manchester recently and found that the fleet of 24 karts had done 1.84 million laps since they arrived 18 months ago. That’s nearly 24,000 miles per kart and well over 500,000 miles of hard racing. Whilst that doesn’t sound that many when compared to Tim Peake’s daily 472,000 miles travelled in International Space Station since he popped up there, its still a lot of miles of hard racing – and a lot of fun.
Next time you set off for a fast lap around one of our tracks, it may be one of 1000’s of laps that day but we know that every lap is important and we always aim to ensure that the kart is up to the job!
Gearing it up.
With six different types of karts running on four different home circuits plus away rounds for DMAX and special events, how on earth do you settle on a specific gearing for each of the karts?
Setting the gearing for a race kart is relatively simple. You arrive at a circuit and set the gearing to achieve your maximum RPM at the very end of the longest straight. You then fine tune a tooth here and a tooth there on the rear sprocket until you’re happy with the performance. Not so with a fleet of corporate karts, although the principle is similar.
At Sandown Park, it’s relatively easy and along the same lines as gearing a race kart as the circuit is flowing with few very tight hairpins. Milton Keynes however is quite different. The back straight at MK is really long and with the preceding turn eight being reasonably fast, you should be running a very tall gearing to achieve maximum RPM before turn nine. However, the tight right hand hairpin at turn ten is so tight; you need a very short gear to get good acceleration out of that corner. Therefore, the gearing at MK is a compromise between speed and acceleration. The nature of the circuit means if you geared it specifically for acceleration out of turn ten and turn four, you would run out of revs halfway up the straight, and the opposite means you’d have very poor acceleration, but loads of speed up the back straight! It’s never simple…
Tamworth has a comparable compromise to Milton Keynes with its very tight hairpin and flowing, fast first section. The compromise on all our karts also needs to take into account weights of drivers. What might suit a 50kg junior driver would not suit a 100kg senior driver so we have to test with different driver sizes too!
The juniors and cadets also need careful thought as for most of the time, they get used on the shorter club and north circuits, but once a month get let loose on the bigger full tracks at each of our outdoor circuits. As it takes a lot of work and time to change the gearing on a full fleet, the compromise is that they need to perform on all types of track layout. Thankfully, the Honda engines are very flexible and allow us to gear them accordingly without too much protest from them.
The DMAX fleet has gone through a number of different gearings over the past few years. Attempting to fix one ratio to suit all circuits is really difficult, but with the new Rotax Evo engines, the increased low down performance has meant we can make the gearing a little longer to cater for faster circuits without compromising performance at tracks with tight hairpins. That increased low down pull has meant the racing is closer than ever.
Like all aspects of kart performance, we constantly evaluate our decisions and change things when we feel it would have a beneficial effect. At Daytona, things never stand still we’re always gearing up for the next big challenge…
Tech blog – October 2015
It’s tempting to believe that we created the new 2015 DMAX karts out of a bunch of parts readily available off the shelf. That is not exactly the case though. We have been running the original DMAX karts since the middle of 2008 and in the years that followed we’ve learned a great deal about what goes wrong and what’s right on the karts.
We didn’t sit down with a fresh sheet of paper for the 2015 fleet, we knew that the chassis is fantastic, the tyres suit really well and that towards the end of 2014, Rotax were coming out with an updated FR125 MAX engine. Details about the engine were scarce, but the factory let us in to a few secrets early on. The carburettor has been completely redesigned internally, the piston and conrod had been changed to increase reliability and the ignition and wiring loom had been totally replaced with new parts. All very exciting of course, but what about the rest of the kart?
Drawing on more than six years of experience, we went about designing and making some custom parts to make the karts even better. The water hoses are now attractive three-ply red silicone units tooled up and made specifically for us. We designed a custom made exhaust manifold made out of billet steel that fits the special ELTO exhaust much better than the previous manifold. 2mm thick steel restrictor plates sized in 0.1mm increments have slots machined where the holes would be so we can quickly change a restrictor and fine tune the engine performance to ensure parity across the fleet.
The karts come with an updated brake caliper from Birel and this is married to a brake line made especially for us using -3 JIC stainless steel braided motorsport brake hose. The engine mount now has an additional red anodised aluminium spacer plate due to a design change late on in the process. The old wiring loom had push on, crimp fittings that occasionally came off during a race which was very frustrating for all concerned. The new loom has bolt on terminals at every point and the starter motor is fired through a relay so there’s no high amperage at the ignition switch.
Birel switched to a slightly different Ackerman angle on the steering column for the latest karts which makes the steering lighter and easier on the arms. All in all it comes together to make one of the most technologically advanced karts on the planet.
All this stuff doesn’t happen by accident, much of it isn’t readily noticeable by all but the few who really know what they’re looking at. We’re lucky to have a team at Daytona who put an awful lot of hard work into bringing our customers the best experience possible. We continue to develop the karts, trying new things behind closed doors, always innovating and improving the fleets. It’s no good standing still because sooner or later you’re going to get overtaken; we push the envelope so you can push the limits.
Fuelling The Fire
Petrol; you purchase thick end of 250,000 litres a year from the same supplier you put it in the karts and forget about it. Right? Wrong.
During the latter part of 2009, I kept getting reports from our Sandown Park circuit that karts were stalling too frequently, performance was down and there was a lot of carbon build up in the inlet tract of the engines. Now, we use EXACLTY the same fuel at Milton Keynes as we do at Sandown; it’s shipped from our huge tank at MK in large barrels down to Sandown. At MK, we saw few of the problems that SP were experiencing so it didn’t immediately flag up fuel as an issue. However, after considerable research, I found out some interesting stuff. My initial thoughts were that we were buying ‘clean’ fuel without any additives.
Without the small amount of detergents and other highly complicated chemicals present in all forecourt bought petrol, I thought this might be giving us all the carbon build up, dirty inlet valves etc. I was wrong.
As Brussels is wont to do, they issued a new EU directive a few years ago that stated that all pump gasoline should have at least 5% renewable fuel content by the end of 2010. This renewable fuel is Ethanol. Now, ethanol is lovely stuff, in fact, every time you have a beer or a glass of wine or a Bacardi Breezer, you are drinking an amount of ethanol.
However, ethanol is hygroscopic and when added to a fuel tank that has water present, it mixes with the water, forms a sludge and drops to the bottom of the tank. This would be bad enough except as the ethanol mixes with the water, it draws out some of the octane from the fuel. What you are left with is a water/ethanol sludge at the bottom of the tank and octane deficient fuel floating on top. Not the best for running any kind of engine on. This was the cause of the problems. Once I had established this as the issue, fixing it was actually really easy. A company came to our MK venue with a van and a load of intricate kit. They succeeded in sucking out dozens of litres of sludge and water from the bottom of the 22,000 litre underground tank and then proceeded to ‘polish’ the remaining fuel. This is basically an extreme filtering process which over the course of a few hours takes all the fuel from the tank and puts it through various filters, magnets and clever bits of kit to leave you with pristine, fresh, lovely fuel. The smallest filter the fuel goes through is just 3 microns!
I wanted to test the ‘new’ fuel immediately and on a back to back test found an improvement of half a second a lap straight away. Success!
Having been through this and scratched my head over the issue for some considerable time, it occurred to me that many of us must have water in our own cars fuel tanks and would be completely unaware of the problems it might cause. So I recommend the use of a fuel tank additive such as Wynns Dry Fuel that binds with the water molecules and allows it to be burnt through the engine. This only needs to be done once every 6 months or so and you might find it improves the performance of your vehicle.
And let’s be honest, who doesn’t want better performance? We at Daytona do, and that’s why we’re constantly striving to bring you the best karts on the best tracks at the best venues in Britain.
Richard Brunning, Group Technical Manager
DMAX Tech Blog
HND in Mechanical and Production Engineering
22 years of racing experience winning club and national titles in karts and cars
8 years as a rally navigator
4 years spent in the USA, racing cars and karts and also engineering with Formula Mazda team
3 years with the Zip Young Guns team
Numerous self built race and rally car projects