MotoGP technology in BSB, surely not! Well that’s what seems to be going on. We heard about the Fuel Cell bikes that Rizla Suzuki has been using in BSB. There seem to be many benefits to using Fuel Cell, from weight distribution, better handling, confining the components to a more centralised smaller space, holding more fuel to just saving money. Intrigued by the concept behind it, we went to Croft Circuit to meet Rizla Suzuki’s Crew Chief and Technical Development Manager Stewart Johnstone. We just simply had to go and find out more…
Andrew: So in simple terms, what is a fuel cell then?
Stuart: We call it a ‘fuel cell’ because it isn’t shaped like a normal fuel tank. If you look at the MotoGP bikes - Rossi’s for example or the RCV - and indeed the factory Fireblade here (the HM Plant bikes) have the back half of the ‘normal’ tank, and down under the seat pad is where the fuel is carried. The front half is just a carbon shell where the airbox would normally go. We’ve modified that idea slightly, the whole tank cover is a carbon and the fuel cell carries the fuel in the same place as the MotoGP bikes, but the way we do it is a little bit cheaper and more economical way of doing it.
The fuel cell is fabricated out of about 15 different parts but there’s no set shape - we can construct to various volumes and shapes quite easily without any major tooling changes that would be necessary if we were stamping panels out etc… It has a lot of complex curves and the shape is quite complex to produce in small batches especially if it’s being made by hand.
Andrew: So, what’s the technology behind it?
Stuart: What we are trying to do is centralise the weight on the bike. Last year’s bike had the ECU at the back of the subframe and a great big wiring loom that ran to the front of the bike into the dash which shows all the info to the rider and is where the datalogger is situated. The battery is under the seat and there was a conventional fuel tank.
So, the first thing we wanted to do was put more weight over the front as well as lower some of the weight. Looking at this year’s bike the ECU is now at the front next to the dash and battery, the regulator and all the electrical hardware that was under the seat is now down by the generator near the sump.
This has two benefits - it centralises the mass a little more, and loses a bit of weight because the loom has lost about 1.2 kilos as it’s no longer 4 ft long. The main part of the loom is only about 8 inches.
This resulted in a clear area under the seat which then allowed the fuel cell to be stretched under the seat which gives about 5 litres of fuel space.
Andrew: How does the relocation of components affect the ‘crashability’ of the bike? Is the repositioned equipment more or less likely to be damaged should the worst happen?
Stuart: No they’re pretty good. We’ve had, err, quite a few test runs with it…
Andrew: I didn’t want to say anything but…
Stuart: It is very robust. Thing is about last year’s bike was if there was a crash and the bike cartwheeled a little what would happen is that the loom would be ripped out of both the ECU at the back and the dash at the front. Now the dash and ECU are £3000 each and the loom is £2000, so you are big cost straight away. Now because they are close together on a prefabricated mount that is very strong so it’s very rare that they part company with the bike. The battery and regulator are neatly tucked in by the sump and don’t stick out so are unlikely to get ripped off on kerbs etc. The seat unit is stronger as we can put more complex curves in it and it’s lighter as the subframe is no longer used for battery storage etc, so it’s little more than a curved aluminium fabrication. It’s very simple as there are no brackets needed to mount all the electrical stuff on etc which makes it easy and cheap to replace.
Andrew: So the principle effects of this are?
Stuart: Well by bringing the components into a smaller area you should end up with a better balance bike. What we do is weigh the bike while static on its wheels to measure the weight distribution - how much of the total weight is carried by each wheel. These changes resulted in a 1% movement in total weight to the front wheel but more significantly it changed the centre of gravity on the bike. The C of G works in the horizontal plane - the weight distribution in about 55/45 to the front, but also in the vertical plane which we’ve lowered due to the fuel being carried lower down on the bike (about a third is under the seat now).
Andrew: which makes the bike better to turn doesn’t it?
Stuart: Well yes but there’s no written rule that says “if you lower the C of G the bike will turn better” because it all works with the setup of the bike.
If you vertically lower the C of G then changing direction from left to right is easier because there is less weight high up to move from one side to another (waiving a bag of sugar from left to right at eye level is easier than with an outstretched arm). But then we also rely on weight transfer under braking and if you lower the C of G too much you won’t get enough over the front (to the point that if the weight is behind rather than over the wheel it could actually ‘push’ the wheel along and counteract the braking force), and similarly there won’t be enough going over the rear under acceleration.
Andrew: Does the rider have to do anything different when riding this bike? Change their style etc?
Stuart: Well not really…..
Andrew: I mean, if the settings were the same as their normal bikes will they really notice a difference and so perhaps have to alter their lines etc.
Stuart: Ok, yeah with the same - base - settings the feedback was “slower corners it’s better, faster corners worse” so then we adjusted the set up of the bike for the type of track, the speed of corners, whether it’s fast and flowing or stop/start.
That was one of the main reasons for trying this fuel cell idea - to give us more scope, more flexibility in setting up the bike for each circuit. We have more ability to change the characteristics of the bike.
Another reason is that this is a cheaper unit to produce, it crashes better. At the moment, for an aluminium fuel tank all painted and on the bike you are looking at £1800…
Andrew: Jeez…
Stuart: And we’ve had a few big crashes…
Andrew: How come they are so much more expensive than a road bike’s tank?
Stuart: Basically it’s because a road bike is normally about 18 litres, and we need a little bit more. There aren’t many tracks where we’ll use more than 18 in a race, but fast tracks like Thruxton and Snetterton we might use 20 litres. Also we need to save weight so whereas the standard tank is steel we use aluminium and then there’s the likelihood that the rider might want a different flare on the compound curve at the back (against the rider’s groin and thighs)…
Andrew: So they are potentially custom fitted to the rider like a Formula 1 racing car’s seat ?
Stuart: Well it means we can potentially change the fit to the ‘nth’ degree if need be, whereas the standard tank has to fit a multitude of shapes, so we definitely improve the shape for sure.
Remember the tank is likely to get either written off or certainly banged about every crash so any saving on that £1800 tank is very worthwhile. For the fuel cell bike the ‘tank’ is simply a carbon shield that costs about £250, is mass produced and easily changed. We have yet to damage the aluminium fuel cell itself - partly because of the inherently strong construction as a result of the use of complex curves, and partly because of its location.
Andrew: Does the engine need any modifying for the fuel cell?
Stuart: The ergonomics are a little different but that’s all. We have to keep the same silhouette for the rules (the bikes look like the road versions) but there have been some changes to the tank/seat pad join.
Andrew: Have the regulations been changed or do they need changing for this technology?
Stuart: The rules for the fuel tank mean that the carbon fibre tanks have to be crash tested until they perform as well as an aluminium one, and there is the profile rule so the cover must look like a road bike’s tank, but otherwise we can pretty much do as we like.
Andrew: Do any other bikes in the paddock use this idea?
Stuart: Only the factory Honda’s - they come as is… but no, no-one else. Many of the other bikes, the Ducati’s for example, already carry their electrical stuff down near the sump so they have less to do anyway.
Andrew: So has mass-centralisation suddenly become the thing to do? On road bikes it’s only been talked about as a selling point over the last 18months when stubby exhausts came out.
Stuart: Yeah, it’s basically following the trend from the MotoGP bikes. Then it carries over to the WSB and us and finally to the road bikes. Some changes have to happen to the road bikes first for our series and the WSB since we are road bike orientated.
Andrew: So is this going to be the big thing for next year? Do you imagine that all the bikes will have changed significantly for optimal mass-centralisation?
Stuart: It’s something that we’ll look into and especially with the cost savings that I’ve mentioned, that’ll definitely be looked at further.
Andrew: The K7 isn’t changing much is it next year…
Stuart: That’s right, we think it’s pretty similar - the engine doesn’t seem any different (the bit that isn’t replaced from the road bike, pretty much everything else bar the frame is).
Andrew: On the subject of engines, why does the Gixxer crackle and pop so much?
Stuart: Basically the Suzuki has a very good engine braking system. In the old days you’d just bang on a slipper clutch (to stop the rear wheel locking when banging down the gearbox) which we still have, but our slipper clutches probably only do 30 - 40% of the work they used to do in 2003.
Andrew: Is that a rule driven change or technology based?
Stuart: Now we have a more sophisticated electronics package on the throttle bodies with some secondary butterflies and a linking cam-system. When the rider starts braking the cam system (which runs off the servo) will keep the throttle open to match the engine speed to the rear wheel speed to stop it backing in so much (when a bike enters a corner sideways - think Haga). The upshot of that is that it runs lean during that period - how much depends on the mapping we are using at the time. It’s a system that runs really well and is very easily altered - there are different cams we can use and the Motec software allows loads of changes for circuit/rider/conditions etc... We can look at the clutch play, the amount of engine braking required and spring pressures needed to set up for a circuit and so you’ll very rarely see a Rizla bike backing into a corner.
Andrew: It’s true and very noticeable, whereas Haslam and the HM Plant bikes are very sideways, Shakey isn’t. He is known for his showmanship so I figured there is more than likely a technical reason for it. Doesn’t stop him getting sideways coming out of the corners though….
Stuart: Err… no, that’s true (laughs) But it has real advantages because if the bike is more settled in the middle of the corner (i.e. not still trying to straighten up and hence moving around) then the rider can get on the throttle earlier and in theory be faster out of the corner.
It also helps with throttle feel during that difficult period of winding it on mid-corner. The electronics have matched the engine speed to the wheel speed and to throttle position so the application of power is more controlled. Some bikes are very difficult to map properly once the throttle is rolled off, especially the bikes using overhead injection systems. Ours is super smooth and that gives our bikes an advantage we try to maximise.
Andrew: How’s James (Haydon) doing? I saw him at Oulton and he looked a bit second hand still.
Stuart: He’s due a medical this week coming and then he’ll be able to get back on the bike for testing.
Andrew: And Steve (Plater - replacement rider).
Stewart: He’s going ok, but it’s difficult as he’s coming back from injury too. It’s hard to come back as everyone is running a second or more faster than last year so he’s had to jump on, after a break anyway, and immediately go a second quicker just to keep up.
He’s come here after knowing the bike a little better so he’s got to find his feet with it; we’ve got to find our feet with him - what settings he likes etc… We can’t just give him James’ or Shakey’s, sometimes that works but often you go backwards - so it takes time.
This time of the year, two thirds of the way through the season, most of the teams are just fine tuning their settings as they know the riders and bikes inside out. We are starting again from scratch with Steve - it’s like the other teams are 9 months ahead of us in development and testing.
Andrew: It must be nice to have, and he won’t thank me for this, seasoned veterans who can step in and they know the score, rather than a young kid.
Stuart: Yeah absolutely. Pro’s cut the time in half it takes to get up and running. You can get a lot from datalogging etc… but at least 50% of setup comes from the rider. You can change fork internals and shocks and they are very difficult to see on the datalogging - it must come from the rider.
Andrew: Tell him he’ll have change his helmet though, it doesn’t go so well with the Rizla blue.
Stuart: He he, yeah…
LB: Do you guys have much to do with the MotoGP guys now you’re all under the same sponsor?
Stuart: Not a great deal only really, a little PR work with many of the sponsors - we had a run out with them at a Crescent thing a while ago.
Andrew: That must be so exciting for you guys especially as their machines are pretty spectacular?
Stuart: Yeah but they don’t let us too close to them.
Andrew: Ha ha… So you’ll be like us then, trying to poke your heads in to the garages and fiddle with stuff.
Stuart: Ha ha… Yeah that’s probably why they don’t let us in.
Andrew: Ok then Stewart, it’s been great and thanks for you time. Good luck to the lads.
Stuart: Thanks a lot mate.
We would like to thank Rizla Suzuki’s Crew Chief and Technical Development Manager Stewart Johnstone for taking out the time for this interview. We would also like to thank Rizla Suzuki’s Jason McClean for making it possible.
Related Linkswww.rizla-suzuki.co.uk
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