UNDER THE SKIN OF A BRISCA F1 MONSTER
It may be grassroots, but BRISCA F1 hides many technical secrets. By Carl Faux I
In Carl Faux’s regular life he is chief designer of British Touring Car Championship outfit Team BMR, which has already turned its new Subaru Levorg into a race winner. He is also Jason Plato’s race engineer and has helped the BTCC benchmark to key victories over the last four seasons.
Faux has deep-seated roots in the sport and started his career behind the wheel battling the likes of Le Mans winner Nick Tandy in the junior Ministox category. Although he has now retired from competition, Faux keeps a close eye on the short-oval scene. So he went to Northampton earlier this year to get the lowdown on the quarter-mile monsters: BRISCA F1 rocketships.
I was welcomed by the BRISCA F1 community to a meeting at the Northampton International Raceway, and had access to British champion Lee Fairhurst’s mighty machine. He let me have a good nose around, and I was able to find out the secrets that make the V8 cars rumble.
Make no bones about it, a BRISCA F1 car is intimidating – and it’s not just because the car shakes the ground. With full contact allowed, and even encouraged by the fans, they are built to withstand the heaviest of hits.
The traditional format for the starting grid is that the drivers with the most points in a season are graded and separated into groups.
These groups are staggered from the start line and stretch back to three-quarters of the way around the lap. The final group is for superstars, champions of the past and present. That’s one of the reasons why the races are so exciting. With the fastest cars at the back and having to make their way through to the front, contact is a necessity to speed up progress.
It’s not just the look of the cars that makes them intimidating – the soundtrack is provided by a rumbling and roaring V8 motor that powers these racers around the quarter-mile oval.
At first glance these machines are clearly built for purpose, and the fourinch-square box-section chassis belies the technical trickery hidden under the skin.
As Fairhurst takes me around his car (with a customary pre-race coffee), he explains that the chassis has been in use for 13 years. But there’s a real level of detail that goes into making it do what all race cars need to do: win.
The minimum weight of the car is 1600kg and, as is usual with oval racing, there is a maximum inside-wheel weight and maximum rear-axle weight.
This is something that gets checked post-race for all winners on a technical flat patch, in a similar procedure to the one used in the BTCC.
The chassis has three main objectives. The first is to protect the driver from harm. Bearing in mind that competitors often choose to drive into each other, and it’s a fairly regular occurrence for cars to end up on their roof, this is an essential attribute.
Secondly, the chassis has to hold the drivetrain and all the suspension, while also giving scope for suspension geometry adjustments. The chassis is heavily offset to the inside of the turns for optimum weight distribution.
Finally, there’s the bumpers, which are at the front and rear, with side rails to prevent the wheels interlocking between cars. The size of the bumpers is staggering, but nothing surprises me when you see how big some of the hits can be.
The engine is a small-block Chevrolet 350 cubic-incher with a carburettor that has been the mainstay of stock car racing around the world for many years. A lot of the engines in the cars currently racing in BRISCA have previously been used in ASCAR and are fairly heavily tuned.
The engines push out around 650bhp but, as with National Hot Rods, peak power output is not what’s required. The cars are so tractionlimited with that amount of grunt, so driveability is key.
Fairhurst explains: “We really only get to full throttle for 0.2s per straight around Northampton. I need a throttle that allows me to control that power and a real linear output from the engine through the revs.”
The transmission is a race-spec unit supplied by Doug Nash Engineering. Only three ratios are installed: first, second and reverse. Once off the start line the car never leaves second gear while at racing speeds. There are three final-drive ratios available to choose from, so tuning to the different circuits is achieved by selecting alternative cogs. Even so, it’s clear why a large operating window from the engine is required, especially when you consider that on a wet circuit the cars are running up to five seconds per lap slower.
Actually stopping these beasts is a
work of art. Starting with the hydraulics, there’s a standard mechanical brake-balance adjuster. This works like a seesaw across different-sized master cylinders for the front and rear-braking circuits. You might think that there’s nothing flash with that, but then add in not one but two hydraulic adjusters so both front brakes are independent from the rear, and also each other.
In Fairhurst’s (fully legal) car, there is one other device fitted. In his words, it’s his secret. “I’d rather you not talk about how that works,” he says intriguingly.
From an engineering point of view, the braking system has to be the most impressive part of the car. It also gives a real insight into what’s required from these guys to make the cars work so well. The regulations offer a choice of two brake-pad-material options, both supplied by Mintex. Fairhurst uses the opening part of the meeting at Northampton to bed in the front and rear pads.
As with most formulas now, spec parts are part and parcel of the category to try to keep costs from spiralling. Along with the brake pads, dampers are part of the regulations too. These are single adjustable units, a step back from what some cars were previously fitted with – but it’s the same for everyone and therefore a justified limitation. The range is a total damping adjustment for both bump and rebound forces and, like all oval cars, is dependant on which corner the unit is fitted. They can change on each wheel, meaning myriad set-up options.
On the rear, the dampers mount to a heavily modified live axle. The basis of this is Ford proprietary – from a trusty Transit van. However, the biggest difference is the stagger put into it. The inside length is reduced to match the chassis offset and the whole thing is then strengthened to take the rough and tumble that the racing provides. The installation is free to the designer; in Fairhurst’s case, there is a single link for simplicity. Despite that, multi-link is evident as well.
Lateral control is ubiquitously Panhard rod because of its simplicity and strength. “I’ve tried Watts linkage and A-frame over the years, but the reliability and ease of adjustment Panhard rod gives means it clearly outweighs all other options,” says Fairhurst.
The front axle is also based on a Ford proprietary part, again from the Transit. It’s a beam axle that’s modified to maximum width and with camber added: approximately three degrees negative camber on the front-right and zero on the front-left; this is, of course, dictated by the anti-clockwise direction of the racing. This has multi-link installation and is heavily biased kinematically for the nature of the track.
Tyres are a key element and have a huge influence on handling, as I learned. “We use tyres with four- to six-inch stagger on the rear,” says Fairhurst.
Because the car has a locked differential, the inside and outside rear wheels want to travel the same distance. However, that’s not the case if one has a larger circumference than the other, and this is one of the big tools that gets used between races for set-up adjustments.
“If there is too much push [understeer] then we increase the stagger by putting a smaller-diameter tyre on the inside,” says Fairhurst. “We will do the opposite if it’s got too much rotation [oversteer].”
Fairhurst gives this insight as he measures tyres after practice. “We use a specification tyre, but there are differences in both width and diameter,” he adds. “On the inside, we use a rally-spec tyre and quite often people buff the tyre to a set diameter and have a range sitting in the truck depending what they need at any particular event.”
One of the most distinctive things that people associate with BRISCA F1 machines is the seemingly oversized rear wing. That was something I wanted to find about. I asked Fairhurst and he palmed me off with the reply, “It’s great for sponsors”. The reality turns out to be that yes, it does generate some downforce, but its biggest effect is on stability, which is down to the huge endplates on the inside edge of the wing. These also provide a nice area of real estate that sponsors can buy. Also there needs to be somewhere for the race number to go.
After the opening race of the meeting, I went to have a quick chat about where Fairhurst thought the balance was, and he was in a very optimistic mood. The feeling was that improvements could still be made – some inside-front-wheel locking on the brakes, and due to the frenetic nature of the race there was no time to dial the adjustments in during the encounter. In fairness, he did a huge amount of overtaking as he battled his way from the back of the grid to come home in third position.
The cars are relatively simple and low-tech, but once you’ve had a look around the pits area you are left in no doubt about the knowledge and high level of preparation that goes into them.
In all forms of motor racing, you only have to be a little bit faster than the opposition to gain a crucial edge, and that is no different for BRISCA F1 cars on the short ovals. It is all about the refinement of set-up and the tiny nuances of each discipline – that, along with driving talent, always shines through.
BRISCA F1 cars are at the pinnacle of motorsport where contact is allowed. But don’t think it’s all about the huge hits and bumper-crunching: part of the skill is conquering the fine detail that goes in to the cars, and the brute ability to drive them at their limit. For a combination of those elements, you will not get any better than BRISCA F1. ■
BRISCA F1 cars are built for contact
BRISCA F1 cars use relatively simple chassis that are built for strength
Axles come from Ford Transit van