UN­DER THE SKIN OF A BRISCA F1 MON­STER

It may be grass­roots, but BRISCA F1 hides many tech­ni­cal se­crets. By Carl Faux I

Motor Sport News - - Brisca F1 Tech Insight - Carl Faux

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

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