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If you think you’ve seen everything supercharged M3s can offer, think again, as we get to grips with an awesome antipodean #Eaton-supercharged E90. Think you know supercharged M3s? Well, think again, because down in Oz there’s a company that’s doing things a bit differently… Words: Elizabeth de Latour. Photos: Jan Glovac.
Supercharger installation is incredibly neat and discreet. This car’s previous owner had maintained it meticulously.
Here at DRIVE-MY we love the E9x M3, and with good reason: it’s an absolutely awesome car. It looks good, the chassis is sublime and the engine is magical. The way it revs and the way the power just builds and builds, it’s an experience that mere words on a page simply can’t convey. We hope that every one of you reading this will one day get to feel what it’s like to be in an E9x M3 at full throttle because it’s something that you won’t forget in a hurry. For many of us performance #BMW fans, it’s a dream car, something we would love to own and we’ve featured some incredible examples over the years. It’s not just an incredible sports car but also an capable all-round package and a car that you can really use every day. But it does have a couple of problems, namely the N54 and N55 turbocharged straight-six engines that you’ll find in the 35i models.
Now, out-of-the-box, impressive as a 335i or 135i may be, it can’t hold a candle to an E9x M3. However, once a 35i has been breathed on and is running at the 400hp mark, it’s not so clear cut. The two cars are not just evenly matched – watch some videos and you’ll often see the 35i emerging victorious. Obviously in terms of a complete package, as far as braking, handling and the driving experience are concerned, the M3 is the sharper tool by far, and we’re talking about head-to-head racing from a roll, but it does highlight one of the M3’s shortcomings: torque, or rather the lack of it.
The S65 is an awesome engine, a mechanical masterpiece, but it’s a relatively small capacity V8 that’s been built to develop a large amount of power at high revs. When sister title BMW Car pitched the E90 M3 Saloon against the E39 M5 there was virtually nothing in it performance-wise, despite the M3’s weight advantage, and that’s because the M5’s additional 900cc of displacement endows it with more power and torque at every point in the rev range below 6000rpm, and it’s only in that last 2300rpm above that where the M3 makes its extra 20hp.
A stock 35i makes 306hp and 295lb ft of torque from its turbocharged straight-six, matching the M3 for torque but putting it 114hp down on the V8. Once modified to around the 400hp mark, however, a 35i will make around 400lb ft of torque and that means that when it comes to in-gear response, the 35i is going to be an absolute beast. In contrast, in an M3 you’ll have to make sure you’re in the right gear and at the right revs to get the most out of it. The best way to get a serious power boost from your M3 is to supercharge it. And while we’ve driven a number of ’charged E9x M3s over the years (and they’ve all been awesome), they’ve also all used centrifugal superchargers, which produce all their boost at the top of the rev range and don’t fully address the S65’s low-end torque deficit. And that, rather long explanation brings us to this car because beneath the bonnet of this particular E90 M3 sits something very special.
It resides in Perth and belongs to Thomas Thai, who juggles being a student with running his own clothing business (Alpha Legion) and he has, in a short space of time, rattled through some ridiculously modified machinery. He cut his teeth on an RX-7 Bathurst R edition, which ended up with 370whp. Then there was the HSV Maloo R8 (mental V8 pick-up truck) with a supercharger and 590whp, as well as a 2012 Subaru WRX STi Spec R with a spec list that reads like a Jap performance car fan’s dream build and which was making 360whp once Thomas had finished with it.
This young man is clearly no stranger to modifying and happy to play with serious power, though we can’t help but wonder why he moved away from the world of easily modified J-Tin and big power Yank V8- engined Aussie muscle in favour of a naturally aspirated BMW that is not best known for being eager to make big power without some serious work? “I have always been fascinated by BMWs but could never afford one,” explains Thomas. “I love their rich history in motorsport and the fact that they are a true driver’s car. This is my first BMW. I bought it as I wanted something I could daily drive as well as take to the track and still be competitive. I bought this particular car as I knew its previous owner and he had maintained it meticulously.”
Despite his history with modified cars Thomas had no plans to modify his newly acquired M3, bar upgrading the stereo but, as you clearly see, this resolution didn’t last long. It seems 420hp wasn’t enough for Thomas and, having previously owned a supercharged V8, we wager the thought of owning another ’charged V8 was an appealing one. Living in Australia meant that Thomas was located in the same country as a company called Harrop. While it may not be a household name on this side of the globe, Harrop has been involved in the automotive and motorsport worlds since the ’60s and is closely involved with Eaton – a company famous for its Roots-type superchargers. And that just happens to be what you’ll find under the bonnet of this M3, as Harrop has produced the world’s first positive displacement supercharger kit for the S65.
What makes positive displacement superchargers so good for an application like the S65 V8 is that they make full boost the moment you put your foot on the throttle. If you go full throttle at, say, 2000rpm, your positive displacement blower will deliver full boost there and then, and that means monstrous low-end torque spread across a wide rev-range.
Owners have likened the Harrop kit to having a six-litre V8 under the bonnet and when it comes to in-gear acceleration, overtaking punch, or drive out of corners, a positive displacement supercharger is unbeatable. At the very top end of the rev range and at very high speed a centrifugal supercharger will have the edge, but looking at dyno charts the Harrop kit makes more power and more torque below 6000-7000rpm than centrifugal kits. This means in the real world (and especially with an engine that’s light on torque), a positive displacement blower will transform your car. What’s especially impressive about the Harrop kit is how it looks. If it wasn’t for the company branding on the plenum chamber, you would need to take a long, hard look to notice that the air box isn’t stock or that there’s a supercharger pulley poking out from the side of the intake piping.
The Eaton R1740 supercharger uses two four-lobe rotors and sits between the banks of the engine’s Vee, with air being expelled upwards into the plenum, where it passes through one of two chargecoolers, which are located on either side of the supercharger, and then down into the cylinders. It’s an incredibly neat, compact setup with everything mounted on top of the engine for a very clean install and comes with everything required, such as an uprated fuel pump, bigger injectors and so on. The kit makes just over 500whp, so roughly somewhere in the region of 560hp+, but Thomas has added a few additional engine modifications with ACL bearings, ARP head studs, forged Mahle pistons, Dinan valvesprings and the engine internals were also polished while it was apart. The engine has also been treated to an upgraded oil cooler while the exhaust has been fitted with a set of custom crossover pipes running to a Corsa cat-back to deliver a proper V8 soundtrack.
To go along with the massive increase in power Thomas has upgraded the brakes with a set of Pagid Yellow pads, braided hoses and Motul racing brake fluid. He says the combination has made a huge difference to the braking performance, though a Harrop big brake kit is on the cards. On the suspension front, he’s fitted a set of H&R springs for a bit of a drop whilst allowing him to retain the factory EDC and the M3 looks menacing on its 19” Varrstoen ES6 wheels. “I did consider going for Rays TE37 SLs but they weren’t quite in the budget range at the time,” he explains, and anyway the Varrstoens certainly look the part, measuring 9.5 inches wide up front and 11 inches at the rear, which has allowed Thomas to wrap them in some seriously meaty rubber, with 245/30 and 275/30 Yokohama AD08Rs front and rear respectively delivering plenty of grip and traction. Beyond the wheels, the exterior styling changes have been kept very subtle with Thomas saying he was “aiming for a clean look that would draw attention to the car’s natural lines”. All the chrome trim has been sprayed black, there’s a subtle ducktail rear spoiler and a carbon fibre front lip plus a custom grille, while on the inside a set of custom BMW door lights have been fitted. If you could ever call an M3 a sleeper, this would be it.
While a lot of people would no doubt consider a supercharged M3 to be a weekend toy, even with well over 500hp this one’s duties as a daily demonstrate that, even when supercharged, the E9x M3 remains as practical and usable a proposition as it ever did. Supercharged M3s are awesome and Harrop’s positive displacement blower kit opens up a whole new dimension of performance.
DATA FILE #Eaton supercharged #BMW-E90 / #BMW-M3 / #BMW-M3-E90 / #BMW-S65 / #S65 / #BMW-S65-Eaton-supercharged / #BMW-M3-Eaton-supercharged-E90 /
ENGINE AND TRANSMISSION 4.0-litre #V8 #S65B40 , ACL bearings, #ARP head studs, forged #Mahle pistons, polished engine internals, #Dinan valve springs, #Harrop-TVS1740 supercharger kit, Corsa cat-back system, custom crossover pipes, upgraded oil cooler, standard seven-speed #M-DCT gearbox
CHASSIS 9.5x19” ET25 (front) and 11x19” ET23 (rear) #Varrstoen-ES6 wheels with 245/30 (front) and 275/30 (rear) Yokohama AD08R tyres, #H&R springs with standard EDC, #Pagid-Yellow pads, braided hoses, #Motul racing brake fluid
EXTERIOR Custom kidney grille, carbon fibre front lip, blacked out trim, ducktail rear spoiler
INTERIOR Custom #BMW logo door lights
THANKS Bucciarelli BMW, GalvsportStream item published successfully. Item will now be visible on your stream.