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

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