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The UK’s only supercharged E28s are an impressively eclectic pair owned by an equally different father and son duo with a long-standing love of BMWs.
SUPERCHARGED UK E28s Classic Fives with power!
Owning the only two supercharged E28s in the UK, this father and son duo are the custodians of some seriously cool metal. Words: Elizabeth de Latour. Photos: Matt Woods.
BMW E28s are precious things. Long gone are the days when you could pick one up for £400 (like I once did) and with the vast majority of the shabby ones now having rusted away, those that remain need to be cherished. Whilst the E24 6 Series might be the obvious choice for those looking for something sleek and ‘sharky’ to slam, the E28 is currently getting lots of love, too. Last year no less than three bigpower classic Fives appeared in DRIVE-MY and there are plenty of extremely attractive examples around, like this pair, for example.
Kris Rourke and dad Jon are the custodians of this unlikely pair – one an exceptionally clean sleeper, the other more of a retro hot rod, with the two cars reflecting their owners’ personalities and motoring preferences.
The very clean red car belongs to Jon, with Kris driving the brown bad boy. While both cars are without doubt very different, they share one significant similarity: they are both supercharged. That elevates this pair from being merely modified to really rather special, not least because of how rare a thing a supercharged E28 is.
That father and son own E28s is unsurprising when you learn that Jon has been at it for years, which means Kris was destined to follow. “Dad’s always had BMWs and has had about six or seven E28s,” says Kris. “They were always in my life when I was growing up and my first car was a 2002ti, mum and dad’s 2002 in fact, which they gave me when I passed my test. It all started from there really. I’m also into Jap stuff and have had loads of J-tin, all modified and all with big power.” So the draw of another powerful, modified car was inevitable and the odds of it being a BMW were good.
Pay attention, because things get a bit complicated now. “Two years ago I had a Fiat Cinquecento and loved it but then my other half and I had a baby and I couldn’t get the baby seat in the car so it had to go. Dad had a blue M535i at the time so he gave me that as it was more practical and bought himself the red supercharged car. I then sold the blue one to buy dad’s red one, which is now my brown one, and when I started modding that dad realised he missed it and bought himself the red supercharged one he now owns.” Got it? Good.
For Jon, a London cabbie by trade, the appeal of the E28 is easy to see. “It’s a lovely retro classic car,” he says. “It stands out and it has road presence. All my previous E28s have been standard – as long as they go and work I’m happy,” he chuckles. “This red one is much more of a hooligan car, though. I was just looking around on eBay for interesting cars, spotted it and went for it. It had been in a garage for about seven or eight years and while the body was good, underneath it was rotten,” he says.
Not that you’d have any clue as to the car’s previous state of disrepair now thanks to the amount of time and money that Jon has invested in it. The whole floor has been repaired, as have the sills, while the suspension has been renewed and new brakes have been fitted. Jon also replaced the chrome exterior trim with Shadowline, while inside the original cloth seats have been replaced with leather Sport seats. Thankfully having a rust-free body meant one less area that needed attention and the red colour really looks fantastic on the E28. So too do the 17” Style 5s – easily one of the greatest wheel collaborations between #BBS and #BMW .
Of course, what’s really exciting here, on both these cars, is what’s under the bonnet, and these are the only two supercharged E28s in the UK. Jon’s car has the slightly more stock-looking engine bay, though there’s no missing the supercharger and its accompanying pipework. The kit here is a Jamsport setup, which cost whichever previous owner that decided to fit it a cool £6500, and uses a more traditional centrifugal supercharger.
This E28 may be no spring chicken but you can still appreciate the work that has gone into fabricating the pipework for the kit. It’s all expertly finished and assembled and there’s a lot of engineering squeezed into here. The most impressive part of this setup is the custom alloy rad, intercooler and associated pipework, which originally cost an eye-watering £5000 and comes courtesy of McLaren (hence the price tag and quality of the work itself). The FMIC is tucked behind the kidney grilles and ahead of the rad. On top of that sits an oil cooler for the supercharger, as this older design requires an external feed. It’s not for show, either, with Jon telling us that running at around 6-7psi it’s making 303whp, which is an awful lot of power in a car as light as the E28 and definitely makes it a bit of a handful. Not that he’s complaining, mind, he’s loved every minute of the 18 months he’s spent with the E28 – a long time for him as he likes to change his cars often.
And so we come to the brown E28, Kris’s rowdy, raucous, unashamedly showy counterpart to his dad’s more demure example. Kris was fortunate in that his E28 was in a better state, though as it had come from his dad that’s not much of a surprise. A quick glance at the exterior of the E28 is enough to tell you that there’s clearly something going on here. There’s a sort of rough-edged charm to the whole car, visible in the interior with its auxiliary gauges mounted on a bright red backing plate and that well-used Nardi steering wheel. Where the engine bay of the red E28 is a relatively discreet affair, on the brown car it’s much more of a mad scientist affair. What you’re looking at here is an extremely impressive home brew positive displacement supercharger setup.
In case you don’t know, a centrifugal supercharger produces more boost as engine speed increases, normally producing peak boost very near to the engine’s redline and where it would normally be producing peak power in naturally aspirated form. A positive displacement blower, like a Roots or twin-screw item, on the other hand, produces peak boost instantly, meaning you get massive low-end torque and immediate response from the engine when you put your foot down, making for awesome mid-range thump. Positive displacement superchargers are also a lot more complicated to fit.
Generally speaking they are large, bulky items that are traditionally mounted directly on a custom inlet manifold, feeding air into the engine via a chargecooler. In contrast, centrifugal superchargers are smaller and run cooler, so they can happily operate without any sort of intercooling. The fact that Kris’s car is running a positive displacement blower, an Eaton M90 to be precise, and a home-made installation at that, is very impressive.
Of course, the fact that it’s a homebrewed setup means that it wasn’t perhaps running as best as it could have been when Kris took over custody of the car. “I’ve improved a lot of things since I bought this E28,” he says. “It had no management for starters and was just running a fuel pressure regulator, so I fitted a Megasquirt ECU and had the cam blueprinted. I changed every boost hose and pipe and replaced the FMIC with a chargecooler.” This is that big metal box on the front left of the engine bay. It cools the intake air by passing it through a core filled with water, which is itself passed through and cooled by a heat exchanger mounted at the front of the engine bay, hidden beneath a clever lift-off panel. “This saw intake temperatures drop from 90ºC to 40ºC,” says Kris, “and I’m planning on adding methanol injection, which should bring them down to about 20ºC and help the engine make more power.”
The rather industrial-looking pipework under the bonnet is a bit of a maze but it all begins at the air filter which is shrouded in carbon and fed with cooling air via the hole in the front grille where the passenger-side high beam unit would normally sit. The air travels through the black flexi-pipe and into the supercharger inlet, then up through the outlet on top, round the back of the engine bay and into the chargecooler, through the core, and then into the original inlet manifold on top of the engine. The fact that the E28’s engine bay is quite capacious and allows for the supercharger to be mounted by the side of the engine and to feed into the original inlet manifold is a bonus. There’s a lot more beneath the bonnet beyond the supercharger, though, including a B35 Stage 3 head with bigger valves, a Schrick 296 cam and a Fritz’s Bitz exhaust manifold.
It’s a monstrously impressive installation but how does it perform? According to Kris, the car made 252whp, which is definitely enough to be getting on with, but also an amazing 350lb ft of torque at just 1800rpm, which is the beauty of a positive displacement blower. When Kris had nitrous on the car it ran an 11.8-second quarter-mile, which is extremely impressive and puts it in the company of cars like the Jaguar XJ220, Audi R8 V10 and Aston Martin V12 Vantage S.
“I took the nitrous off as I knew I would never really use it,” he continues. “I was too scared of blowing the engine up… but I might put it back on. I really want 400hp and the supercharger is holding the car back – it’s not making as much boost as it should and I need to run more boost to make more power.
I’m considering my options. I might rebuild the supercharger or I might go for a turbo conversion. It’s quite a lot of money but it would definitely mean I could hit 400hp. And I like the idea of having a turbo. I have 90% of the parts I need, so I’m almost ready.”
Of course, we can’t discuss Kris’s car without discussing its colour. It’s not paint or a wrap but is, in fact, Plasti Dip – the spray-on, peel-off rubbery coating that can provide a quick and easy way to change the colour of your car and then change it back again when you get bored! “I was approached by DipMyVehicle, who offered to dip my car for free in exchange for having it on the company’s stand at the Santa Pod show, so I went for it,” Kris explains. The colour is called Sunset bronze. Although it may look pretty brown when the light hits it there’s a subtle change in colour and you can see a light metallic element in the coating. Combined with the aggressive drop on Spax springs and black, 19” CSL-wheels it makes this E28 into a bit of a bad boy.
The brakes have also been uprated, with E34 540i discs and calipers front and rear running Mintex pads, while the gearbox is a 260/6 unit running the ratios from the E28 dog-leg transmission with a separate bellhousing, Black Diamond Stage 3 clutch, and modified centre donut on the propshaft.
Both cars have had a vast amount of time and effort devoted to them – Jon’s car on the bodywork and Kris’s on the mechanicals – but the results speak for themselves. E28s need love and attention so we’re delighted that this father and son team stepped up to the plate.
It’s a lovely retro classic car. It stands out and has road presence.
DATA FILE Eaton supercharged E28 M535i
3.4-litre straight-six #M30B34 , compression ratio lowered to 8.1:1, #B35 Stage 3 head with 1mm bigger valves, #Schrick 296 cam, B35 inlet manifold, 550cc injectors, #Sytec FPR, #Bosch-044 fuel pump, 8-micron fuel filter, CDA carbon air box with cold air feed, custom crank pulley, #Eaton-M90 supercharger, ported top hat, custom charge cooler system, #Brownlow alloy radiator, Fritz’s Bits heat wrapped manifold and full system, #Megasquirt ECU running MS2. 252whp, 350lb ft wtq
/ #Getrag-260/6 gearbox with separate bellhousing, #Black-Diamond-Stage-3 clutch, modified centre donut on propshaft, factory #LSD / #Getrag-260
8.5x19” (front) and 9.5x19” (rear) M3 CSL wheels with 225/40 (front) and 245/35 (rear) Bridgestone tyres, #Bilstein gas dampers all-round, #Spax lowering springs, polyurethane front torque arm bushes, E34 540i discs and floating calipers front and rear, #Mintex racing pads all-round
Plasti Dipped in Sunset bronze over original #Zinnobar red, driver’s-side high beam removed for cold air feed, clear front and rear indicator lenses
Standard E28 M535i leather, three-spoke Nardi leather steering wheel, M5 gear knob, Innovative wideband #AFR gauge and boost gauge in centre pod
Paul Higgs, Ed at Fusion Motorsport and Justin from dipmyvehicle.com
DATA FILE Rotrex supercharged E28 M535i
3.4-litre straight-six #M30B34 / #M30 / #BMW-M30 , #Rotrex supercharger, custom alloy radiator and intercooler system, 440cc injectors, #Gotech-Pro-X-ECU with custom wiring loom, #Ram air filter, Fritz’s Bits manifold and exhaust system. 303whp @ 7psi
Standard M535i dog-leg ’box, standard factory LSD
8.5x17” (front) and 9.5x17” (rear) #BBS-RC090 Style 5 wheels with 225/40 (front) and 245/40 (rear) tyres, #Bilstein dampers, uprated lowering springs, front and rear strut braces, #Black-Diamond drilled and grooved discs, EBC Redstuff pads
Zinnobar red, dechromed, clear front indicator lenses,
Standard M535i leather seats
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