In the world of performance tuning, diesel power is still a black art to some. But through a never-ending quest for perfection with his tuned BMW 335d E92, Lee Gouldsbrough is proving to be something of a kingpin in the scene…

Feature first appeared in Performance BMW. Words: Daniel Bevis. Photos: Igor Gurgel

If you quizzed The Prodigy about the merits of diesel power back in the 1990s, their thoughts on the subject would have been very clear: “Blows your mind drastically, fantastically,” they’d say. And while the issue of using heavy oil for means of motive power has always been a polarising one, this sense of outlaw mischief has endured across the ages.

However, anyone who’s ever asked a barman for ‘a pint of the black stuff’ and been rewarded with a disappointing tankard of Bovril will be keenly aware that cramming darkness inside isn’t always the path to happiness. It’s no secret that diesel engines have never been auto manufacturers’ mill of choice when it comes to sports cars. Sure, some have bucked the trend (Peugeot won Le Mans with diesel power, the original Skoda Fabia vRS was the first diesel hot hatch, there was the Trident Iceni which… actually, no, forget that one), and Volkswagen has been keen to offer such creations as the Golf GT TDI for decades, but these things are frequently met with a relative lack of enthusiasm from the buying public. BMW, however, has long been better placed than most to exploit the potential of dervs in hot cars, hence the prevalence of diesel motors in balletically poised machines such as the E92 coupé – these sold like hot cakes when they were new, and they’re enjoying huge popularity today, not least because they’re so damn tunable. And the example you see here – well, this illustrates the point with flair and panache. Yes, it’s a BMW 335d E92. And yes, it’s also some manner of road-legal track weapon. With vibrant power, enough torque to uproot a decent-sized oak tree, and a rear wing wide enough to stabilise the aero on a Piper Cub, this is evidently a diesel we need to get to know.

Lee Gouldsbrough (@leeg_94) is the puppet-master pulling the strings, and it’s fair to say he didn’t quite envisage things going this far from the beginning. Indeed, the car was originally purchased with the intention of being a comfy daily which would offer decent mpg, although we all know how this story goes. We may set out with the best intentions, but if you’ve got the devil inside you then there’s no point corking yourself to stop his mischief seeping out. Might as well just succumb to the inevitable and let the madness unleash itself. Comfy dailies are all very well, but they’re not what dreams are made of.

This, interestingly, is Lee’s first BMW, having previously modified Vauxhalls – and the step-change from the likes of Corsas and Astras to a premium-executive coupé like this is not insignificant. “The economy was an important factor in choosing it,” he readily admits. “I wanted something that had enough power to have some fun, but wouldn’t send me broke in fuelling it while I was an apprentice, going to and from work up and down the country.” The car was found on Auto Trader, requiring a little TLC as it had various dents and scratches – but the fact that it was an LCI model with low mileage and the right spec made it too attractive to turn down. “The plan was to just lower it on coilovers, with some OEM wheels and a Stage One map,” he grins. “But then that bug kicked in, and I couldn’t stop…”

He’s not kidding. In fact, Lee’s 335d E92 project has passed through five distinct phases thus far, and it’s not showing any signs of slowing down (in every sense of the term) any time soon. The first iteration saw him fulfilling that initial wish list with a set of BC coilovers, new wheels and a map, but it quickly levelled-up to version two. This entailed fitting a full air-ride setup along with a set of shiny new Rotiforms, window tints, a ducktail spoiler and a custom exhaust system. Version three saw Lee swapping back to coilovers, stripping out the tints, adding CCW wheels and a front splitter, and playing with the turbo-diesel motor a bit – hybrid turbos, EGR delete and swirl flap delete, upgraded fuel pump and intercooler. The fourth evolution ushered in that outrageous wide-arch kit, a pre-production item from Fitment Lab, for which the wheels were built wider. The car was swapped to a manual gearbox with the exterior wrapped in cream, and the interior enjoyed a comprehensive makeover with a roll-cage and rear seat delete, Recaro Pole Positions and a Coolerworx shifter. Meth injection also entered the fray at this point. And finally, we arrive at the car you see here, version five: we’re talking Air Lift Performance 3P suspension, M3 carbon leather trim, an exterior swap back to the original colour, a Wavetrac LSD, a host of chassis upgrades, and that unmissable Big Country Labs GT wing.

But we’ve rushed through a whole lot of history there, haven’t we? Let’s take some time to drill down into the details, starting with that hair-raising engine spec. “It took around two-and-a-half years to get the engine to the level it’s at now,” says Lee, and the sturdy M57 certainly appears to be taking its new-found sporting pretensions in its stride. “It has a straight-through exhaust which is 3” from the turbo back, just so it doesn’t sound like a tractor. I’m also running an R90 high-pressure fuel pump from an earlier 535d, a swirl flap delete to prevent any future problems, EGR delete, Turbo Dynamics hybrid turbos for more boost, and an uprated intercooler. There’s a meth injection setup to keep the intake temps down, an ATM induction kit for less restrictive airflow and an M50d rail sensor. I decided to go for these mods as, at the time, it was the best way to get more power from the engine. However, the Americans and Europeans have now taken the M57 further and there are more readily available mods to push more power.” Something Lee’s undoubtedly sizing up for the future, but the figures today are still pretty hair-raising: we’re talking 404hp and a meaty 630lb ft at the wheels.

Naturally, the transmission has had to be strengthened somewhat to deploy all of this, and Lee needed to put a bit of work in to determine the details. “At the time, I think there were only two BMW 335ds in the UK which had been converted to manual, an E90 and an E91,” he recalls. “So I contacted both asking for information on what they used in terms of gearbox, clutch and so on. I managed to find someone stripping an E90 pre-LCI 330d which apparently has the strongest gearbox to handle the torque, and once that was in it was time to think about clutch options… I found a company not too far away who make clutches for drift cars, and they made a custom pressure plate, solid flywheel and a triple-plate clutch – which is a nightmare to set off in! I went with the triple-plate only to prevent future problems when I start chasing the power. Finally, the Coolerworx short-shifter completely transforms the ’box.”

The inherent tension throughout the project is that, on the one hand, Lee wants to build the 335d E92 into the most efficient and performance-orientated version of itself possible, while on the other hand he loves going to car shows and letting the tuned BMW peacock. The air-ride is a keen nod to the show scene, as is the wheel choice – CCW Classics chosen as they’re simply something a bit different. But while airing out provides that killer stance, we all know that Air Lift gear is honed for the track, and he’s been busy making further performance upgrades under the skin. It’s now packing M3 arms with poly bushes, the subframe’s also been poly bushed, the manual ’box is solid mounted, and there are Whiteline anti-roll bars at either end. And while the car was up on the ramp, it was a no-brainer to slot in a Wavetrac LSD too, as they really are the business.

You see, this isn’t a car built for posing and posturing. Sure, it can hold its own on the showground, but Lee built it to be a hardcore driver’s machine. “I love the manual conversion, it feels like a completely new car to drive,” he beams. “Due to the solid flywheel, it makes a loud rattling noise when it’s stationary in neutral; recently I was at a set of traffic lights and let the clutch out, and when I glanced over to the pavement there was a woman stood there looking into the sky trying to find a plane or helicopter. I pressed the clutch down and she stopped looking around. After a couple of seconds, I released it again, and she started looking again, walking around the corner staring into the sky… by this point, I’m laughing so hard my eyes are streaming!”

All part of the fun, of course. This isn’t just a car, it’s a compadre, which explains the relentless spec changes. A couple of mates having fun, and one of those mates happens to be a car. In fact, the new look is already well underway, with Lee sourcing a Seibon carbon bonnet and a Samsonas shifter; he’s also going to rebuild the wheels and the headlights and is planning Hardrace camber arms, M Performance six-pot brakes, and a quick-release CSL boot lid. “Then, next year, I’ll be making a start on the engine again to try and achieve over 500whp,” he says. This diesel tuning lark is clearly very addictive – when we ask Lee what he’d do to the car if money were no object, he answers quick-as-a-flash that he’d shoehorn a Mercedes OM606 diesel in there. And if he were to sell it, what could replace it? He reckons an E36 fitted with an M57 diesel. Clearly diesel is a way of life for Lee and his tuned BMW 335d E92 is an absolute beast. Blowing your mind drastically, fantastically.

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