One Make or Spec Series Racing - Do the Best Drivers Win?

Uncategorized Aug 30, 2016

One Make or Spec Series Racing – Do the Best Driver’s Win?

In this pic, almost certainly yes.  Cameron Hill leading at Winton in the Toyota 86 Series.  How good is this bloke?  He’s 2015 Formula Ford Champion in a car prepared by his Dad, and in the Toyota 86 series, again in a car prepared by his Dad, pole position for both rounds and winner of five out of six races so far - (only beaten off the re-start on the last lap of race 3 at Sydney Motorsport Park.)

For most spec series you can assume that the best drivers are winning. One Make and Spec series are designed to allow drivers with smaller budgets to compete on level terms. 

But perhaps the biggest reason for spec series racing to exist – it’s supposed to give new talent a chance to show what they can do, against proven competition from the longer term stars in a category that is recognised on the national stage.  In days past, the talk was how Touring Car drivers, and later V8 Supercar drivers, Mark Skaife and Tony Longhurst got their starts by performing in one make series racing.  But way more stars than these two guys got their start winning in Formula Ford, so this argument supporting one make series is not that strong.

So maybe we need spec series for reasons of “creating a show”, or as an avenue for sponsorship, or even creating interest for drivers who don’t want to race open wheelers.

Let’s look at the one make/spec series phenomena a little closer.  

V8 ute racing in Australia (a two brand competition Ford vs Holden) is a case in point.  The performance comparison between the brands is close and driving talent shines through.  At the Winton round earlier this year, six cars were under the old lap record, three Fords and three Holdens, all within .7 secs lap time.  Yes, new talent can, and does shine.  Let’s hope there is a future for Ute racing after local manufacture ceases in Australia.  We can give Ute racing a big tick in terms of meeting our criteria above for a good spec series.

At the top end of the spec categories is Carrera Cup racing.  It’s pro racing, requiring a big budget.  Most often, it is a drawcard at major race meetings – and therefore pretty much only for established drivers.

So looking to the lower categories for an ever green national spec category, Aussie Racing Cars is a standout.  An unlikely formula to my way of thinking – the Legend cars they are based on are decidedly odd.  But because they are quick, they’re not bad for spectators.  And as with V8 Utes, good drivers can shine.  

The Toyota 86 Racing Series – the Latest in One Make Racing in Australia

With the blessing of Toyota in Japan, Toyota Australia are running a new series with only the Toyota 86 model car eligible to enter.  The second round in the 2016 series has just been run and won.  And the series is slated to run for 2017 and 2018 as well.

This is fairly big time when you think about it.  Manufacturer supported and racing on the same bill as V8 Supercars.  The series winner will get noticed.

Toyota Australia enters three to five cars that they allocate to well-known established drivers at each event.  The idea is that the name drivers can mentor the young drivers and provide a benchmark.  So far, the factory chosen drivers have been flogged by the young drivers, so I guess it’s not working out like Toyota expected. 

The basis for the race car can be either a new, or second hand 86.  This is an excellent way of containing costs – a lower cost second hand car plus cost of the racing package plus own labour and you save tens of thousands of dollars compared to buying a professionally built new car.

The specification for the car has been set by Neil Bates – long associated with Toyota factory racing and rallying.

How’s the racing?  Well, the field does look good as a spectacle (as per the picture above.)  But the cars are bit slower than they should be, and passing is definitely a problem.  Wot??  No drafting at Sydney Motorsport Park?  I didn’t see the race.  Cameron Hill still led flag to flag mostly unchallenged (race 3 re-start excepted).

At Winton, the only bit of passing I could see in the race results was Ben Grice picking off cars and going from 17th to 12th in race 2, I think it was.  It would be good to see that on the in-car video.  He probably got good instruction from his Dad.  Gricey (his Dad) learnt the hard way.  When he was a young bloke, at Oran Park, he’d spend more time in the Stewards room than on the race track. 

There’s some question about performance parity.  For example, Winton qualifying.  What’s Leanne Tander (one of the name drivers in a Toyota Racing Australia car) doing in position 20 in qualifying, almost 2 seconds off pole?  She’s no mug.  She’s won a round of the Formula Ford championship this year in her own Tander Motorsport Mygale Formula Ford.  If it’s as simple as the new engines being down on horsepower, compared to 100,000km freed up used engines, then Toyota should get their shit together.  No excuses.

Performance and Handling Overview

Power output is rated at 170 Kw.  Sounds OK.  But then, maybe not enough for a 1300kg car with driver.  Weight might be what knocks the edge off the lap times.  The cars are two to three seconds a lap slower than V8 Utes at Winton.  In fact, if Triumph TR6s were allowed in the field, our client, Geoff Byrne could have put his Group S historic TR6 on about position 10 out of 38 cars in qualifying.

For the series, they’ve chosen a Dunlop tyre that may be a little more all-purpose compared to the regularly used semi slicks from Bridgestone and Yokahama.  Anyway, said to be less grip.  Also, they’ve got a “marked tyre” rule and so many new tyres allowed per meeting.  Seems like overkill.  Will stop people from fitting new tyres for every race, I guess.  But who does that?  It remains to be seen if tyres one meeting old can perform well enough, and save on tyre bills over and above your new tyre allowance.

One thing not often discussed when looking at the Toyota 86 – it has a high front weight percentage, 54% front, 46% rear.  It could be a packaging the problem - if you try to get the wide boxer engine back far enough in the chassis, maybe it interferes with the suspension.  The boxer engine also means you have to put the staeering rack behind the front axle location, which is not ideal. 

The ideal weight distribution for a rear wheel drive car for racing is actually heavier in the rear than the front.  This can only be achieved in a modern road car with mid-engine.  For front-engine, the best we can expect is 50-50 as per the new Mazda MX5 ND.

The 86 designers talk up one benefit of the Boxer engine – it's possible to have a lower centre of gravity at the front – ie some amount less longitudinal and lateral weight transfer.  Lower CofG is always a good thing, but I don’t know how much this is worth, performance wise, in this case.

There are specified rotors and AP brakes.

Largest cost item in the race package is a fairly comprehensive roll cage.  This is to provide quite a stiff chassis platform to get the best out of the handling. (But they have not followed through with the required spring stiffness to match the cage, see below.)  Neal Bates says the comprehensive roll cage is mainly for safety concerns, in case of big accidents. 

The Suspension Package and Analysis with the Weight Transfer Worksheet™

This is a suspension and handling blog, so now begins the interesting stuff. 

First up, there is a coilover package supplied by MCA (Murray Coote Automotive.)  The springs are a special make by King Springs with MCA part numbers.  The part numbers indicate that the front spring rate is 6kg/mm and rear spring rate, 5kg/mm.  Apart from an allowance for camber adjustment, the rest of the suspension is standard, including the anti-roll bars.

Using some rough numbers, analysis in the Weight Transfer Worksheet™ yields the following results:

(For a detailed explanation on the Weight Transfer Worksheet™ numbers, see our on-line training “Suspension Tuning 101 and 102”.  You can access it for free in the "Course Offers" link in the main menu at the top of the page.)

Suspension Natural Spring Frequency:    123 CPM (2.05 Hz) Front           107 CPM (1.78 Hz) Rear
(Ride Stiffness)

Balance of the Car (based on rough numbers): 
Standard Car: FWTD 3%.   ie 3% in the direction of understeer
Series Race Car:  FWTD 6%.   ie 6% in the direction of understeer

I won’t dwell on the balance calculations because I do not have exact numbers.  Suffice to say that if the standard car is a little towards oversteer balance when driven on the race track, then the race car will be better balanced.  But is it enough?  What if you can’t pass because the car gets too nervous when you rush down the inside under brakes?  This category should include stiffer, adjustable anti-roll bars, so you can adjust the balance of the car for understeer/oversteer.  The stiff roll cage will allow for the car balance to be highly sensitive to anti-roll bar adjustment.

It's a surprise that front spring frequency, at 123CPM, is so low.  We would never specify a race car this low on ride stiffness.  And check out the roll angle of the cars in the top photo - too soft in springs and anti-roll bars. 

The standard anti-roll bars make no sense.  Aftermarket adjustable sway bars (limited adjustment at the rear because of short links) would fix this right up.  All at low cost to competitors.  Would also give the driver a small but usefull window to adjust the balance of the car for oversteer/understeer.

If you were setting up a Toyota 86 as a track car yourself, you could use our Weight Transfer Worksheet™ to get a good baseline set-up.

The range of stiffness for circuit racing cars is 125 CPM to 170 CPM.  The lower end 125CPM to 135CPM is for bendy historic cars, and the higher end 150CPM to 170CPM is for stiff modern cars, especially cars like this spec series 86, with stiff welded in roll cage and strut front suspension (wheel loads acting directly on the springs, not via bendy suspension arms as in double A-Arm).

Optimising suspension stiffness is the single biggest thing in our setups that improves lap time, equating in most instances to seconds per lap improvement.

Need more spec series examples to get a handle on this? 

Hyundai Excel series rules have changed for 2016.  Springs and shocks are free (no canisters allowed).  Low cost coil overs do the job perfectly.  We had no time to measure up in detail for our client.  We settled on 135CPM front (not a stiff car, so maybe 150CPM would be too stiff).  He got pole and won 3 out 3 races, first time out.  What a breath of fresh air this rule change is.  Free anti-roll bars as well.  Means you can target the ideal setup for the driver and the conditions.  And it is not expensive for the owners to get this level of tunability. (NOTE: A year later, the rules went back to a limit on springs and anti-roll bars.)

Spec E46 racing in the US specifies 750lb/in front springs.  This equates to a suspension frequency around 160CPM to 170CPM.  This is at the high end of our range of spring frequency for non-aero cars.  Jay Morris, the highly regarded suspension tuner from Ground Control, makes a number of the parts in the suspension package, so maybe he had a hand in spec’ing these springs.  Certainly there’s no performance left on the table for smooth tracks. 

So, where’s this leave us with the 86 series race car?  Too little front stiffness and too soft in the rear, relative to the front, for best track performance.  In fact, these are spring rates you could use on the road.  You’d be pretty comfortable with the soft rears (rear stiffness has greatest influence on ride comfort).  

Incidentally, this would be news to all drivers in the category, including the highly experienced name drivers selected by Toyota.  It is important to remember that drivers cannot tell in isolation whether more grip might be available from a spring change or whatever – they can only tell by back to back comparison.  When improvement in grip and/or balance comes from a given set up change, all experienced drivers will be capable of going quicker.

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