- Post is under moderationThe Art of Deception AC Schnitzer knows a thing or two about suspension as witnessed by its setup for the M4. The M4 is developing a reputation for being a little bit of a handful in slippery conditions, so does it really need more horsepower and other upgrades? Words: Adam Towler. Photography: Gus Gregory. #AC-Schnitzer-ACS4-Sport / #AC-Schnitzer-ACS4-Sport-F82 / #S55B30 / #S55B30-AC-Schnitzer / #AC-Schnitzer / #2015 / #AC-Schnitzer-ACS4-Sport / #BMW-M4-F82 / #BMW-M4 / #AC-Schnitzer-F82 / #BMW-M4-AC-Schnitzer / #BMW / #BMW-4-Series / #2016
It’s quite likely that many readers of this magazine believe the BMW M4 is the finest incarnation of the mid-size German sports coupé yet built. However, it can’t be denied that amongst the car-loving community at large, the M4 has split opinion. No one questions whether its performance is adequate, or for that matter superlative; I can’t give you an exact figure off the cuff but I’m sure it completely demolishes something like an old E46 M3 around a certain German racing circuit, and many others, too.
Let’s consider, though, some of the more esoteric elements of the M4 proposition. The power increase over the old E92 M3 is actually only marginal – an extra 11hp taking it to 431hp – so it’s the torque that’s making the difference, all 406lb ft of the stuff versus the 295lb ft from the naturally aspirated V8. And that’s not all. Forget for a moment the peak difference and consider where that number is now developed: it’s from as little as 1850rpm and is then held all the way to 5500rpm in one arrow-straight line. In one of the older V8s the engine needed to be turning at 3900rpm before the full 295lb ft came on stream. Quite simply, whenever you plant your foot in an M4, as long as the engine is working at more than a whisper above idle speed, things happen… and they happen fast. Gear choice is vastly less critical, and while I won’t get into the highbrow discussions of whether it has become all too easy and the loss of that gorgeous soundtrack, there’s no denying that on modern, crowded roads, the S55 engine’s on-demand haymaker is exceedingly effective.
This sheer grunt does give the M4’s chassis something to really think about. On a smooth, dry surface the car is hugely effective, with EDC damping allowing for a fairly comfortable ride or ruthless body control at the press of a button. But on a cold, greasy, wintry B-road with all the irregularities in surface that are to be expected, it’s a car that can really bite the unwary. Left in the standard setting, the suspension can struggle to contain the torque if deployed clumsily, and sudden crests can make the car very lively indeed. I could probably add that the rather muted steering in the modern style doesn’t assist the challenge, either. In such a situation, you either spend a good deal of your time watching the yellow traction control light flicker incessantly, which is very frustrating, or DSC is switched off whereupon you’re really juggling with the steak knives set.
That’s where this Schnitzer ACS4 comes in. I know, it doesn’t look like it’ll be the answer to this particular problem. Despite keeping an open mind the additional ‘aero’, tuner-style 20-inch rims, lowered ride height, talk of coilovers, plus a comically noisy exhaust threatens to overwhelm me with preconceptions of a negative kind. A ‘slammed’ aftermarket treatment might be the last thing this car needs.
Then there’s the news that really sets the alarm bells ringing: peak power on this M4 has been raised to a massive 510hp. Whatever you say about the new turbo power generation, that’s a figure that any M3 driver just ten years ago would have thought impossible. Moreover, the maximum torque now stands at 479lb ft, which threatens to really give the rear axle something to get in a flap about.
I travel to Schnitzer’s UK importer, Rossiters, near Kings Lynn, to collect the Austin yellow demo car, mine for a few days. Rossiters held the franchise before BMW made things official in the late 1990s, and then picked up the reins ten years later when BMW UK ended that arrangement. Today, you can order Schnitzer parts in 40 of the UK’s BMW main dealers, as well as 20 other non-franchise BMW specialists. This demo car features plenty of the Schnitzer goodies on offer: there’s the engine upgrade, which I’ll come onto in a minute, with a new engine cover for added artistic embellishment; the carbon fibre front spoiler elements, ‘canards’ either side of the nose and carbon rear diffuser (no aerodynamic advantage is implied or given); the ‘RS’ suspension kit; ‘export version’ sports silencer; Type V forged 20-inch rims with Michelin Pilot Super Sport tyres (255/30 R20 front and 275/30 R20 rear); a fancy pedal set; and some stickers for the exterior. All in that’s £20,081.61 added to the price of your M4, including fitting. Let’s see if it’s worth it.
The most exciting snippet of information I gather from talking to Chris Rossiter and Lorcan Parnell at AC Schnitzer UK is that their colleagues back in Germany have developed this kit over many miles of road testing, and that their mantra is ‘better fast not hard’ (stop sniggering at the back please). In addition, the finer points of the setup have been tweaked after driving on the lanes close to Rossiters’ Norfolk workshop. This attention to what matters in a road car and not a pursuit of lap times bodes very well already. Such thoughts momentarily leave my mind when the ACS4 fires up with a boom and idles angrily. The cat-back exhaust keeps the factory valving system, but when they’re open – especially on cold-start – it is mercurially loud.
The modifications to the engine consist solely of altering the messages from the ECU. Schnitzer achieves this not by remapping what’s already there, but by fitting a ‘piggyback’ second ECU that adjusts the electronic information accordingly. It claims that the achieved outputs remain inside the limitations of the gearbox, and it supplies the car with a twoyear/ 60,000km warranty that sits alongside the regular BMW warranty for the car. This can be extended to three years for an additional £1082.02. Quite rightly, Rossiters feel this peace of mind elevates the conversion above some of the straightforward remaps out there.
It may well have over 500hp but that’s not what is grabbing my attention at the moment. Leaving the small town of Dersingham it’s the ACS4’s low speed ride that I’m most aware of. With such low profile rubber fitted it’s no great surprise that the car picks out every last little bump on the road, which makes for a busy experience. This coilover option is the third and highest level of modification offered by Schnitzer for the M4, and forsakes the factory EDC dampers for a passive setup that is nonetheless adjustable manually for rebound, compression and ride height.
Fairly soon we’re beyond the limits of the town and the speeds inevitably increase, whereupon it occurs to me that the jostling has petered out considerably. During my time with the car I become obsessed with this aspect of the ACS4: there are occasions when I think it’s too busy, and on a particular surface that it doesn’t like – one busy dual carriageway springs to mind – it seems to make a meal of a road that I’d never thought that bad. But overall I sense that while the suspension is working hard, it does filter out the worst of the movements entering the cabin. It sounds worse than it is: the intrusions banging through the M4’s structure and causing the odd rattle here and there, but my head isn’t nodding against my chest and my wobbly bits aren’t being, er, wobbly. I learn to live with it, and soon accept it as ‘normal’.
The faster your drive the ACS4, the better it gets. And going fast is one thing this car does very well indeed. The sheer rate of acceleration is now shocking. It’s easy to get into the mindset where you work the engine between 2000-4000rpm and can’t imagine going much quicker. Then an odd occasion presents itself where the engine can really be wrung out to the redline and it’s simply biblically fast. Or at least it is when it can find traction. In the middle of winter, that isn’t all that often, it must be said.
This is where the Schnitzer bits really shine. I find it most refreshing that the damper setting on the dash can be ignored, primarily because it’s one less thing to meddle with on the move. The real advantage is that as a driver, you learn the car, get to know how it will react in certain situations and under certain provocations. There’s something really straightforward about this car which, if you switch the DSC systems off partially or completely, means it’s nowhere near as scary as a 500hp coupé should be. Compressions and crests don’t hold any fear for the Schnitzer driver, the ACS4 piercing through them without any of the unsettling behaviour of the standard car, and even the steering seems to have gained a little more feedback, tugging slightly this way and that depending on the road’s surface.
The ACS4 likes to go sideways, usually at every opportunity. This is one of those cars that can be made to lose traction at the rear almost at will, but once you’ve got a handle on what happens next it is surprisingly controllable. Time and again the big yellow 4 Series has me giggling with euphoric nervousness at having kept things facing in the right direction, but the control once the tail has swung around is just lovely, and it’s a great feeling to have it all hooked up on the exit of a corner just on the cusp of wheelspin. If anything, the ACS4 makes 500hp seem more manageable at times than the standard car’s 431hp. It’s worth saying, though, however obvious, that it would be foolish to treat this M4 as if it were a grownup Mazda MX5. If there’s one thing you’re always aware of, even when having a lot of fun, is that it is an inherently overpowered, rear-drive car that’s tractionlimited in bad weather. It’s unwise to take too many liberties with any 500hp+ car, however progressive it seems most of the time. An aural indication of this is the snort released through the quad tailpipes when you lift suddenly off the throttle under full boost. It’s an ugly kind of noise, akin to a lightning bolt cracking through the atmosphere, and it adds to the impression that this is one bad car to know.
By the end of my time with this M4 it has really got under my skin. I’ve really enjoyed its transparency in a modern car market obsessed with modes and button pressing. Left in the normal drivetrain setting it’s a more refined proposition without the fake engine ‘noise’ (I think the straight-six sounds nice just as it is to be honest), and the benefits that the suspension bring to the body control and predictability of the chassis in extremis are really appealing. I’d do without the body addenda, although that may well be at the top of your list – these things are, of course, down to personal preference. I’d forsake the wheels, mainly because I’d love to try this car on standard 19-inch wheels fitted with tyres that have a larger sidewall to see what the ride and road noise were like then. The engine upgrade is one of those mods that once experienced there is simply no going back, and given it’s under a warranty I don’t think I could say ‘no’. I could drone on for paragraphs about how rapid this car now feels, but it’s something that has to be experienced to be believed in truth: it never, ever, feels dull. I’d leave the exhaust though, ostensibly to stay a bit more ‘under the radar’, and anyway, there are no performance claims made for it either. In other words, just taking the engine and suspension options adds around £7000 to an M4, and given the performance and dynamic benefits they bring, that seems like a very good deal to me. Sometimes, appearances can be deceptive.
CONTACT: AC Schnitzer UK / Tel: 01485 542000 Website: www.ac-schnitzer.co.uk
TECH DATA AC #Schnitzer ACS4 Sport
ENGINE: Twin-turbo, straight-six
MAX POWER: 510hp
MAX TORQUE: 476lb ft
0-62MPH: 4.0 seconds
50-120MPH: 6.2 seconds
TOP SPEED: 155mph (limited)
ENGINE: AC Schnitzer performance upgrade: £3641.04; engine optics package: £378.73; optional third year warranty: £1082.02
EXHAUST: Quad sports exhaust system (export version) with black tailpipes: £3275.75
WHEELS & TYRES: AC Schnitzer Type V lightweight forged alloy wheels with Michelin Pilot Super Sport tyres. Front: 9x20-inches with 255/30 R20 tyres. Rear: 10x20-inches with 275/30 R20 tyres: £5949.66 (including wheel bolts and RDC tyre pressure valves)
SUSPENSION: AC Schnitzer RS adjustable suspension package: £3473.75; wheel alignment: £144
STYLING: AC Schnitzer carbon fibre ‘canards’: £960.50; carbon fibre front spoiler: £1050.26; carbon fibre rear diffuser: £1319.50
INTERIOR: AC Schnitzer aluminium pedal set: £195.60 All prices quoted include parts, labour and VAT
I’ve really enjoyed its transparency in a modern car market obsessed with modes and button pressing.
It might look pretty standard in the interior from the driver’s seat, but the driving experience is anything but standard!
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- How fast? Looking at your performance figures for the AC Schnitzer ACS4 Sport I have to assume there is an error regarding the 50-120mph time? Unless How fast? Looking at your performance figures for the AC Schnitzer ACS4 Sport I have to assume there is an error regarding the 50-120mph time? Unless it’s rocket-powered it would have to be 16.2 seconds rather than 6.2? If not, then that means a 0-120mph time of less than ten seconds?! More ...
- While we haven’t independently verified AC Schnitzer’s figures Chris, we have no reason to doubt them; even in its standard form the M4 is a staggerinWhile we haven’t independently verified AC Schnitzer’s figures Chris, we have no reason to doubt them; even in its standard form the M4 is a staggeringly quick machine! Schnitzer tested the standard car through this speed increment (80-180km/h, which equates to 50-120mph) and recorded a time of 7.9 seconds, so with 80hp more we wouldn’t be surprised if Schnitzer’s ACS4 Sport was indeed that fast.
It is an unusual increment to time, but if one has a look at quarter-mile times for the M4 many magazines have posted pretty impressive figures for the standard car. Car and Driver recorded a 0-100mph time of 8.6 seconds for an M4 on its way to a 12.1-second quarter-mile time with a terminal velocity of 119mph. With the additional power and torque of the Schnitzer car we reckon it’s probably just about spot-on.
The bottom line is that cars these days are hugely faster than they used to be! More ...
- Post is under moderationWILD THING #BMW-F82 M4 TUNING #AC-Schnitzer-F82 #BMW-F32 based #S55 engined
AC Schnitzer’s been busy fettling the new M4 with its ACS4 Sport. The standard #BMW-M4-F82 is far from shy but AC Schntizer has proven that it doesn’t take a whole lot to turn it into a monster with its ACS4 Sport package Words: Simon Holmes. Photography: Dave Smith.
When the M4 was launched last year there were plenty of critics, both inside and outside the core BMW fan club, quick to label the latest M car offering as a little soft. On paper you could kind of see their point: there was no roaring V8 engine anymore and although the styling was aggressive it was notably more refined and grown-up. Of course, those who have seen an M4 in the flesh and experienced it first-hand know full well it’s a more than worthy successor to the throne in every way. But if further proof were needed, then perhaps AC Schnitzer’s ACS4 Sport truly highlights what kind of thinly veiled beast is hiding within. The spoilers and splitters enhance the existing looks, rather than form them, and the M4’s hugely capable chassis and carbon brakes soak up the increase in power, to a monstrous 510hp no less, with ease.
All of the parts displayed on this car are available to buy individually or as a package, and there are also alternative ‘softer’ options for the suspension and aero. But as this very car was due to partake in a German track event shortly after we photographed it, it was in full race mode, with virtually everything from the AC Schnitzer catalogue fitted. There are clearly plenty of changes, both on and under the surface, so we’ll begin with the exterior modifications, as perhaps these make the single biggest difference to the car.
Upon first gaze in the flesh, the styling certainly bombards your senses. The various spoilers, wings and splitters sprouting out from around the car transform the M4’s overall look from mildly mean to entirely menacing. It all looks very purposeful, helped by the beautiful, high quality, carbon fibre finish found on many of the parts. And, of course, virtually everything is designed to have an impact on performance. The complete aerodynamic package featured here improves downforce as well as aesthetics, although Schnitzer offers the kit as individual parts or a complete package.
Starting at the front, there are three stages of aerodynamic aids. It begins with the two lower spoiler elements, which attach directly to the bottom of the front bumper. Made from carbon fibre, these contoured spoilers enhance the shape of the original bumper design. They bring the car lower to the floor for a more pronounced and aggressive front-end look, whilst still looking relatively subtle.
The next addition is the much more prominent front splitter, which sees the two lower spoilers joined along the bottom with a large, flat, single-piece design finished in gloss black. This aero aid protrudes a good few inches from the front of the car, connected with a single sculptured support in the centre. To top it off, last of all comes the four individual side wings, or canards, mounted on the outside edges of the bumper. These work in conjunction with the splitter to further improve airflow passing by the front end, optimising downforce.
To balance all of that front-end downforce there’s also plenty going on at the rear. It begins low down with a central rear diffuser section having been added to the bottom of the bumper. It’s actually relatively subtle compared to the rest of the kit and slots in neatly between the quad tailpipes. On a standard M4 this section is usually colour-coded to the car but the carbon fibre finish of the Schnitzer part helps break it up with some contrast, helped here by the bright body colour. The diffuser also incorporates subtle sculptured lines that flow down to the bottom for added style.
The rear wing, mounted directly to the boot lid, is a lot harder to miss. There are actually two versions of this wing and this one was unveiled at the Geneva Motorshow back in March, but a lower, less extreme version is also available that carries the full TüV approval required in Germany. The larger one pictured here is generally for export outside of Germany. Named the ‘Racing’ version, it sits a good few inches taller on raised mountings, although the aerofoil itself is the same carbon fibre item. The additional gurney lip mounted to the very rear of the aerofoil itself has been added only for the aforementioned track event and does not feature on the standard item. Even so, the imposing spoiler balances the large front splitter perfectly.
Working up the car, last of all comes the subtle roof spoiler mounted just above the rear window. This one is easier to miss, especially as it comes matched to the roof skin’s carbon fibre finish. It still adds to the overall effect of the rear end package, in terms of both visual and technical, as Schnitzer tells us it further improves downforce and rear end stability. The last of the exterior changes are the carbon fibre wing mirror covers which simply look good, tie into the other carbon parts and, of course, offer a small weight saving.
Inside, there have also been a couple of small changes in the form of an AC Schnitzer aluminium pedal set and footrest, keyholder, floor mats and handbrake lever. For manual transmission cars there’s also the option to add a matching gear knob that features a nifty digital display in the top to tell you what gear you’re in. The track event this car is due to attend has also meant the original seats have been replaced with lightweight Recaro items, although the original seat belts remain.
Whilst that concludes the exuberant styling and aero package, the wheels also undoubtedly add to the overall look of the ACS4 and these AC Schnitzer designed Type VIII items are the lightweight forged versions, finished in BiColour anthracite. Whilst the thin-spoke design looks great, it’s the size of them that makes the bigger impact here. At the front, they measure a wholesome 9x21 inches and are fitted with 255/30 R21 Continental CSC 5P tyres. Just like a standard car, they’re an inch wider at the rear, measuring 10x21 inches with a huge 295/25 R21 tyre. Schnitzer offers several wheel packages ranging in size and design and this is the biggest it offers.
Although it does look a tad ‘over-wheeled’, it compliments the car’s spoilers and splitters to give a 1990s Touring-car-esqué look and feel. This is further aided by the suspension changes, which see the tops of the tyres begin to disappear into the bodywork. That brings us on nicely to the mechanical changes of the car, starting with the lower ride height. This car sits on Schnitzer’s ‘racing’ suspension package, which consists of a replacement coilover setup that lowers the ride height by 30-40mm. The kit also offers adjustable compression and rebound damping for further fine tuning. Schnitzer says it is “suitable for normal road use, driving courses and track use. An ideal compromise between everyday practicality and motorsport fun”.
For those looking for a milder improvement Schnitzer is also offering a replacement spring kit designed for use with the existing #BMW dampers. This far simpler package lowers the car around 25- 30mm at the front and 10-15mm at the rear. Both suspension packages are sure to offer improved handling as they were developed and tested at the Nürburgring by Schnitzer’s own suspension team under the supervision of none other than chassis expert and Touring Car driver, Manfred Wollgarten.
Elsewhere, further modifications extend to the engine side of things. Here, #AC-Schnitzer has undertaken a performance upgrade that significantly increases power from 431hp to 510hp, which it makes higher up, from 6000-7000rpm. Likewise, torque has increased from 406lb ft to 476lb ft produced at a raised 4000rpm peak. The increase in power equates to improved performance, with 62mph arriving from rest 0.1 of a second quicker than standard at 4.0 seconds dead. But more telling is the 50-120mph time, which crumbles to just 6.2 seconds, an improvement of 1.7 seconds over a standard M4.
The Schnitzer exhaust rounds off the upgrades on offer, and the system consists of a dual sports rear silencer and sound pipe, which retains the valve control of the original BMW system. There’s also an export sound pipe option for a louder note and a choice of either Sport or Racing Evo Carbon tailpipe finishers, the latter of which is featured on this car. The ACS4 has plenty going on then, from suspension tweaks to floor mats, increased power to improved aero and, visually, it’s undoubtedly gorgeous, in a fully functional way. But the proof is in the pudding when it comes to a package like this, and I’m keen to try out the car for myself.
As soon as the photographs are done I grab the keys and nestle into the non-standard Recaro seats. They grip you reassuringly in all the right places, although it feels a little odd not using a proper harness with a bucket seat like this one. I’m warned the car is in track configuration, which means it’s been corner weighted and set to rather stiff suspension settings. Once in position, a press of the button the engine booms into life and I make my way towards the local hillside roads. Immediately it becomes clear that it’s actually the exhaust that dominates the driving experience in many ways. The soundtrack it emits has an angry undertone that snarls, cracks, pops and barks its way up and down the rev range. Its aggressive note suits the nature of the car and its sound is addictive; it’s fun gunning the throttle and then letting off just to hear the exhaust snap back like a cracked whip.
Burying the throttle also reveals the extra pulling power the car possesses. However, its character has changed slightly. You have to work the engine and gearbox a little harder to really highlight the increase, as the peak power and torque bands have risen notably. It still pulls hard and fast from low down, just like a normal M4, but it feels strongest as it approaches the limiter and clicking back the gearshift paddle to summon another cog reveals the car is only just getting into its stride in the lower gears. Even so, when stringing a couple of winding hill sections together, despite the slightly damp road, the car squirms a little before catapulting you towards the next corner with savage execution. Thankfully, the carbon ceramic brakes provide so much confidence you find yourself pushing the braking point further and harder at each corner, before turning in and straightening the wheel enough so you can feed the throttle in hard to repeat the process once again.
In this environment the suspension does feel too hard and it’s clearly out of its comfort zone as it skips and scrabbles around under power. But body roll is exceptionally controlled and the car feels absolutely rigid, making you feel utterly connected with the car. I’ve soon wasted a decent a chunk of fuel so make my way back to AC Schnitzer’s HQ whilst pondering how devastatingly effective the car must feel on a dry track where it would be able to truly flex its muscles. Despite demonstrating immense capability on these roads as a lightening-quick point-to-point car, it feels a little too focused for this environment. Of course, it would do, being in track mode, but it would be nice to really sample the full effects of the aero and suspension changes. Perhaps a back-to-back test with a standard M4 for a direct comparison is required, as I suspect the changes here are benefiting me much more than I realise.
Either way, the ACS4 is a monster of a car and the beauty of Schnitzer’s package is that the enhancements are, in fact, relatively simple. All are easy to fit, bolt-on parts and yet the car’s character, both visually and sensorially, has changed significantly. But then, it wasn’t going to take much to unleash the beast within…
AC Schnitzer UK
Tel: 01485 542000
AC Schnitzer (Germany)
Tel: +49 (0) 241 5688130
The carbon ceramic brakes provide so much confidence you find yourself pushing the braking point further and harder at each corner.
Schnitzer has undertaken a performance upgrade that significantly increases power.
Schnitzer’s forged rims are lightweight and certainly look the part; ceramic stoppers offer excellent retardation.
TECH DATA #2015 #AC-Schnitzer-ACS4-Sport F82 #BMW-M4-AC-Schnitzer
ENGINE: Twin-turbo, straight-six #S55B30 #S55B30-AC-Schnitzer
MAX POWER: 510hp
MAX TORQUE: 476lb ft
0-62MPH: 4.0 seconds
50-120MPH: 6.2 seconds
TOP SPEED: 155mph (limited)
ENGINE: AC Schnitzer performance upgrade and exhaust system with valve control and Racing Evo carbon tailpipe trims.
WHEELS & TYRES: AC Schnitzer Type VIII lightweight forged in BiColour anthracite. Front: 9x21-inches with 255/30 R21 Continental CSC 5P tyres. Rear: 10x21-inches with 295/25 R21 Continental CSC 5P tyres.
SUSPENSION: AC Schnitzer adjustable coilover ‘Racing’ package, lowered 30mm at the front and 40mm at the rear.
STYLING: AC Schnitzer carbon front spoiler elements, rear diffuser, upper rear spoiler, Racing front splitter, side wings, rear spoiler with higher struts, carbon fibre wing mirror covers, rear skirt protection film.
INTERIOR: AC Schnitzer aluminium pedal set and footrest, handbrake handle, key holder and floor mats.
To balance all of that front-end downforce there’s also plenty going on at the rear.
Schnitzer’s ‘Racing’ front spoiler for the M4 is a complex amalgam of parts with a carbon fibre main section to which is added a lower lip and small carbon winglets just ahead of the front wheels. It looks very purposeful and aggressive.Stream item published successfully. Item will now be visible on your stream.