SHOCKTACTICS

Ex­eter-based EXE-TC Com­pe­ti­tion Sus­pen­sion pro­duces coil-over damper sets for some of the world’s lead­ing race and rally teams – and they just hap­pen to spe­cialise in Porsches, too

911 Porsche World - - Practical Porsche -

When such lu­mi­nar­ies of the in­ter­na­tional rally stage as Tuthill Porsche, Pro­drive and Citroën WRC have used your prod­ucts, you’re ob­vi­ously do­ing some­thing right, and that is very much the case with EXE-TC Com­pe­ti­tion Sus­pen­sion sys­tems.

Shades of “we’re only mak­ing plans for Nigel…,” but no, it’s not that XTC – rather, EXE-TC, on ac­count of they’re based in Ex­eter and they’re Tech­no­log­i­cal Con­sul­tants. And, pre­sum­ably, the prod­uct is so good it gen­er­ates an ec­static emo­tion on the part of users who, in this case, range from François Dele­cour to Stig Blomqvist and Se­bas­tian Loeb, top cal­i­bre driv­ers who are ac­cus­tomed to only the best.

EXE-TC was founded by Gra­ham Glee­son in 1994, a Kiwi motorbike-and-side­car racer, who sadly died in 2013. Two Devo­nian me­chan­i­cal en­gi­neer­ing grad­u­ates, brothers Rob and Ed Biggs, took over all tech­ni­cal re­spon­si­bil­ity for the de­vel­op­ment of EXE-TC dampers, in­tro­duc­ing new de­signs as well as im­prov­ing and up­grad­ing ex­ist­ing ones. I’d met the Biggs brothers some 15 years ago when they were build­ing an elab­o­rate in­door BMX track in their friend Nicky Of­ford’s barn, and they were also mak­ing BMX bike frames, rac­ing karts and strip­ping down Land Rovers. Clearly, they had a great fu­ture in me­chan­i­cal en­gi­neer­ing. Rob joined EXE-TC around eight years ago, and as he says of Gra­ham Glee­son’s in­spi­ra­tion, ‘when you’re at one with your motorbike, the sus­pen­sion is very ap­par­ent to you, be­cause, if it’s wrong, you feel it, and if it’s right, you feel it too. Gra­ham Glee­son pro­gressed into rally sus­pen­sion at a time when the mod­ern shock ab­sorber wasn't up to the job, and car builders sim­ply flipped them up­side down and hoped for the best.’ Glee­son started off co­op­er­at­ing with sus­pen­sion ex­perts, mainly based in Hol­land, and started pro­duc­ing dampers, ven­tur­ing into Indycar and F1 be­fore mov­ing into the WRC with Pro­drive and then Citroën.

Glee­son’s rad­i­cal and en­thu­si­as­tic ap­proach to sus­pen­sion en­abled the busi­ness to grow swiftly. One of their first com­mis­sions was de­sign­ing and man­u­fac­tur­ing the roller-bear­ing damper sys­tem for Citroën’s se­ries of Xsara T4 WRC cars, and Rob demon­strates one for me. ‘Usu­ally, a rally sus­pen­sion damper con­sists of a tube within a tube, and ob­vi­ously there’s fric­tion in­volved with that, and the more fric­tion you have the less your damper gets to work, so this is a rev­o­lu­tion­ary de­sign with cages hous­ing these rollers; ef­fec­tively you’re re­duc­ing the fric­tion to nearly noth­ing. So, we started sup­ply­ing Citroën WRC with the roller-bear­ing dampers, and seven of Se­bas­tian Loeb’s World Rally Cham­pi­onship wins were achieved us­ing our sus­pen­sion.’

And at this point we veer into Porsche ter­ri­tory: ‘Tuthill’s fit our sus­pen­sion on their 911s in his­toric ral­ly­ing and cir­cuit rac­ing,’ states Rob. ‘The col­lab­o­ra­tion with Tuthill’s led to the cre­ation of the Clas­sic Sa­fari Damper which, on the East African Sa­fari

Rally, is de­signed to work flat-out over 1000kms of very rough ter­rain over a pe­riod of just un­der two weeks.’ With six Tuthill-pre­pared 911s en­tered in the 2017 East African Sa­fari Rally, us­ing EXE-TC sus­pen­sion, that’s as daunt­ing a prospect as ever there was. It’s also a hell of an en­dorse­ment for the dampers. ‘We’re also work­ing on road-go­ing ap­pli­ca­tions with Richard Tuthill,’ con­tin­ues Rob, ‘and he reg­u­larly calls us up with his opin­ions and gives us a lot of feed­back with ac­tual num­bers as to what’s hap­pen­ing with the damp­ing, as it’s got to be ab­so­lutely spot on. You need to know the weight of the car, with or without fuel, and the weight bal­ance front to rear, and with the wheels and tyres fit­ted, and from that you can as­sess spring rates and damp­ing rates and get very close to where you need to be.’

The proof of the pud­din, as they say, and former World Rally Cham­pion Stig Blomqvist won the East African Sa­fari Rally in 2015 in a Tuthill 911 armed with EXE-TC shocks, and there’s no more for­mi­da­ble chal­lenge than that. Or maybe there is. Pro­drive’s Subaru WRX STI equipped with orig­i­nal (re­fur­bished) EXE-TC Roller-bear­ing Dampers and helmed by Mark Hig­gins holds the lap record for cars around the Isle of Man’s Snae­fell course, cov­er­ing the 37.7-mile route in 17m 3s in 2016. ‘That was great for us in terms of ex­po­sure and get­ting our name out there, be­cause ob­vi­ously win­ning world cham­pi­onships and break­ing records is some­thing we’re very proud of, and as far as the me­chan­i­cal side of it is con­cerned, the WRC is ask­ing as much of your dampers as you’re ever go­ing to ask them.’

A large part of their busi­ness is the sale of dampers for mod­ern Porsches for road, rally or track use: ‘In Spain and Mex­ico es­pe­cially, there are a num­ber of 997 GT3 Cup cars and a lot of them are run­ning our sus­pen­sion. Over in the States we have Gavin Riches, who races a gen 1 996 GT3 RS, and he reg­u­larly com­petes at his lo­cal track, Se­bring, where our back­ground of ral­ly­ing pays off bril­liantly be­cause it’s a rough cir­cuit, and he can quite of­ten be fly­ing past other peo­ple who are strug­gling.’

So, what con­sti­tutes EXE-TC com­pe­ti­tion sus­pen­sion? It’s not a large op­er­a­tion, con­sid­er­ing their suc­cess. Based in a mod­ern two-storey build­ing on an in­dus­trial es­tate near Ex­eter Air­port, close to the M5 and A30 junc­tion, the damper units are de­signed and man­u­fac­tured in-house. Rob and Ed work up­stairs, along with Luke Glee­son (Gra­ham’s son) who’s re­spon­si­ble for mar­ket­ing and sales, and Ju­lia Glee­son (Gra­ham’s widow) who’s the man­ag­ing di­rec­tor. Vanessa, the of­fice man­ager, han­dles the com­plex process of or­der­ing parts and raw ma­te­ri­als. Down­stairs, three tech­ni­cians build the dampers and pre­pare the com­po­nent parts, and two ex­pe­ri­enced ma­chine op­er­a­tors man­age a mill and CNC lathe in the ma­chine shop, fab­ri­cat­ing the parts out of solid bil­let.

Six Tuthill 911s en­tered the 2017 Sa­fari Rally, us­ing EXE-TC sus­pen­sion

The rest of the com­po­nen­try is made by trusted lo­cal ma­chine shops.

The damper tubes and in­ter­nal items are stored on shelves and in draw­ers, and se­lected on a ‘Kan­ban’ ba­sis by the tech­ni­cians, who con­struct the units on work­shop benches in the assem­bly rooms. There’s a cham­ber into which a car can be driven to have dampers fit­ted, though Ex­eTC’S out­put is mainly dis­patched di­rect to cus­tomers. In­ter­nals for the shocks are pro­duced in the ma­chine shop us­ing liq­uid­cooled lathes and drills, and there are presses that put as­sem­bled damper units to the test by sub­ject­ing them to any num­ber of com­pres­sions at vary­ing speeds. Rob de­scribes this mes­meris­ing func­tion: ‘That’s the ac­tual plung­ing mo­tion that you’re look­ing for in sus­pen­sion; these rollers are guid­ing the top tube, and within the damper it­self there are more rollers in­side the tubes and the two to­gether give you a very nice mov­ing pack­age, which you feel the fric­tion of when you’ve got the weight in the car. It’s mainly a tool to check that ev­ery­thing is con­sis­tent in what we’re pro­duc­ing, and it will flag up any er­rors. It goes up in in­cre­ments, get­ting faster and faster, and it gen­er­ates a graph, which we use for ev­ery damper that we pro­duce. We al­ways check them when we re­build them, and it cov­ers ev­ery­thing that we’ve ever done, so we can com­pare and check that what we’re mak­ing to­day is the same as 10 years ago.’ In a sense it’s a pro­duc­tion line, and there’s only a wait for prod­ucts if there’s new de­sign work in­volved: ‘worst case is four to six weeks,’ Ed tells me.

Two pairs of coil-over damper units sit on the of­fice ta­ble, and Rob de­liv­ers the sci­ence. ‘Those with the or­ange springs are for a 997 Cup Car, so ob­vi­ously the set­tings are de­signed for that ap­pli­ca­tion. They’ve got pro­gres­sive spring rates, and the coils are evenly spread, so that gives you lin­ear load, and as you in­crease the load, it’s pro­gres­sive, so the more you com­press the spring the stiffer it’s get­ting, so it will give you a very dif­fer­ent feel. But of­ten that can give you the best of both worlds, be­cause you can have a nice, com­pli­ant ride, and then it will

In­ter­nals for the shocks are pro­duced in the ma­chine shop

stiffen up be­fore the damper closes com­pletely; be­cause, if you start to run springs which are too soft, ob­vi­ously there’s noth­ing to stop the wheel go­ing up and you can start to bot­tom out; if they’re nice and soft and you’re go­ing over speed bumps, let’s say, the wheel will just come straight up, and then any­thing can hap­pen.

Dampers are com­plex items: as well as the ba­sic func­tion, there’s the oil reser­voir, ad­justers, lin­ers to dis­si­pate heat and keep the oil cool, es­pe­cially in the prox­im­ity of the en­gine, plus a breather sys­tem. ‘Ev­ery con­ven­tional damper – apart from some very mod­ern tech­nol­ogy – dis­places oil as it plunges so you have a reser­voir here which is ba­si­cally a tank that the oil goes into, but you need that dis­placed oil be­cause it passes through the ad­justers, and that’s what gives you the con­trol through the damper. That works on the front dampers, and the rears’ would just be in­ter­nal to the dampers.’

We look at an­other pair of shocks, in grey this time. ‘These are for a clas­sic Porsche,’ says Rob. ‘They’re our own new de­sign, in­clud­ing an in­sert for the front ones to re­tain the orig­i­nal hard­ware, but this up­right is our own forg­ing. This is a cir­cuit rac­ing ap­pli­ca­tion, but the same set up with dif­fer­ent springs can also be used for Tar­mac or gravel ral­ly­ing, and that’s the main rea­son for do­ing our own forg­ing be­cause, com­pared to a stan­dard one, it’s much stronger, while still re­tain­ing the orig­i­nal ap­pear­ance. Broadly, the di­men­sions are the same, but it’s a more for­mi­da­ble piece of kit. No­tice the way it’s got tri­an­gu­lated brac­ing off the damper it­self. There’s a lot of twist­ing go­ing on; think of the weight of the cor­ner of your car – hence the brac­ing. They don’t have the ex­ter­nal ad­justers be­cause that’s dic­tated by the reg­u­la­tions. That makes it much more tricky to de­sign, and also gives you a smaller win­dow of ad­just­ment, though you do have a range of ad­just­ment, but it’s nowhere near as big a range as you would have on the three­way ad­juster, which can be set up for rough, wet Tar­mac, or smooth, hot Tar­mac.’

While Tuthill’s ex­em­pli­fies Exe-tc’s sus­pen­sion in ral­ly­ing and his­toric rac­ing, the ap­pli­ca­tions ex­tend to mod­ern ral­ly­ing, too. ‘Richard Tuthill had al­ways wanted to take a mod­ern Porsche 911 and go ral­ly­ing with it in the gravel, so we made sus­pen­sion for a gravel car – a 997 GT3 – which un­for­tu­nately never raced, due to FIA reg­u­la­tions, but the Tar­mac ver­sion was very suc­cess­ful, with François Dele­cour win­ning the R-GT class of the Fi­a­world Rally Cham­pi­onship in 2015.’

As for springs, they are gen­er­ally bought in. ‘We have three or four main sup­pli­ers for our springs; some are off the shelf, which any­body can buy, but we also have our own de­signs for a spe­cific car ap­pli­ca­tion, and they do get used in var­i­ous dif­fer­ent in­car­na­tions. It can just hap­pen that weights end up be­ing the same, so it might be in the rear of a Porsche or in the front of a Subaru.’

So, things are go­ing well for EXE-TC. I don't want to put a damper on it, but Rob tells me they are work­ing on an ex­cit­ing project that’s due to be re­leased later this year, but it’s em­bar­goed for now by an NDA. Hint: think of a song by Elkie Brooks and, no, it’s not a sewing ma­chine. What­ever, it will un­doubt­edly be a shock an­nounce­ment: hope springs eter­nal. ( That’s enough puns. Ed). PW

We made sus­pen­sion for a gravel car - a 997 GT3 - which never raced

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