Efficient Performance

You might have seen the “Efficient Performance” logo on our website when looking at AC Schnitzer performance upgrades.

What do we mean by this? This logo represents AC Schnitzer’s commitment to increasing performance “without compromise” to daily driving. This includes the area of emissions. We’ve all seen poorly tuned cars emitting black smoke on acceleration, but this is not necessary. The power output of a vehicle can be increased without making emissions worse – in fact the specific emissions (CO2 per HP) can go down.

Here is an example. This X3 M 40i has the B58 engine, which is shared with many other models.

You can see that the performance of this car has been substantially improved. The 0-60mph (0-100km/h) time is just two tenths of a second quicker, but once rolling the AC Schnitzer tuned car is a healthy two seconds quicker in every other test. This equates to safer overtaking and even more driving pleasure.

Now look at the CO2 figures. The result, according to the latest WLTP / Euro 6d temp test, is that emissions are the same as the standard car. That’s efficient performance from AC Schnitzer!

AC Schnitzer conversion for BMW X5 (G05)

The BMW X5 has always been a go-to vehicle for AC Schnitzer, ever since the first E53 version which we adorned with aerodynamic parts, 22″ wheels and lowered suspension.

The cars have evolved but even though our tuning program has evolved too, the core elements are still the same. More aggressive styling, larger wheels and lower suspension for enhanced handling and more muscular appearance.

For a limited time we’re offering AC Schnitzer conversion for the latest X5 (G05) models for just £9995, fully installed.

This example conversion includes:
22” AC1 alloy wheel set, 10J front and 11.5J rear, in your choice of bi-colour or matt anthracite finish
Continental sports tyres with tyre pressure sensors installed
Suspension lowering kit
Front spoiler colour coded
Roof spoiler colour coded
Bumper protection strip
Side protection strips
Alloy pedal set and footrest
AC Schnitzer decal set

Further information on this conversion is available here:
https://shop.rossiters.co.uk/ac-schnitzer-acs5-conversion-f…

Individual component prices can be found here: https://shop.rossiters.co.uk/bmw-x5-g05-804-c.asp

Spoiler alert – all about AC Schnitzer aerodynamics.

Possibly the first thing you notice (apart from wheels) on an AC Schnitzer car is the body styling. Sporty and muscular looking, AC Schnitzer aerodynamic components turn the visual impact of your BMW or MINI up to 11. Our intention is not to change the look of the vehicle completely, just to enhance it. These components don’t just look good though – they are actually functional, keeping your car more firmly planted on the road. Let’s see what’s involved.

At AC Schnitzer, all draft designs originate from a true Italian artist: Michele Viandante, who has been chief designer for over 30 years. Michele uses his vast experience and every technique at his disposal including CAD and clay modelling to produce the designs, may of which are function tested in the wind tunnel. Only when all the performance, legal and safety requirements for German TÜV approval are met are the designs finalised and put into production.

Chief designer Michele Viandante

PU-RIM

The majority of AC Schnitzer aerodynamic components are made in PU-RIM, a type of polyurethane widely used in the automotive industry due to its outstanding mechanical properties. Lightweight, yet tough and dimensionally stable, PU is easily formable and paints extremely well, even repeatedly if necessary. This makes it perfect for spoilers and skirts that are to be painted in body colour for a perfect match to the standard bodywork. Unlike fibreglass or some other plastics, it will last for many years without becoming brittle or causing the paint to craze.

AC Schnitzer front spoiler elements in PU-RIM

CARBON FIBRE

Carbon fibre reinforced plastic, CFRP or carbon for short, is ultra light but extremely strong. This combination of properties explain why it has become so widely used in motorsport and aerospace. However, high quality carbon is time consuming and expensive to produce. Experienced craftsmen working only by hand mould fragile carbon mat and resin into complex shapes before hardening it in an autoclave. The end result must be free of distortions in the carbon weave and have a flawless finish. Only then can it be sold as genuine AC Schnitzer.

AC Schnitzer carbon fibre rear diffuser, racing wing and tailpipes for BMW 8 series.

CASE STUDY

The graph below is the result of TÜV testing on an ACS2 Sport (BMW M2). The test compared a standard M2 with one fitted with a M Performance rear spoiler, an AC Schnitzer carbon boot spoiler, AC Schnitzer carbon “racing” wing and finally the carbon racing wing with “Gurney strip” added. The results speak for themselves! Greater downforce means enhanced stability and control at speed.

AC Schnitzer Carbon boot spoiler
AC Schnitzer Carbon “racing” wing, with optional Gurney strip
AC Schnitzer ACS4 Sport (BMW M4) using AC Schnitzer aerodynamic components to set a new lap record at Sachsenring, Germany.
AC Schnitzer carbon fibre canards add to to the overall aerodynamic effect by creating a vortex along the side of the car, drawing air out from underneath to reduce pressure and therefore increase downforce.

FITTING

PU-RIM products, and occasionally some mounting components included with carbon fibre products, will need to be primed and painted before installation. Painting and fitting should be carried out by a competent, experienced bodyshop.

All AC Schnitzer aerodynamic components come with comprehensive fitting instructions and a fitting kit included. The fitting kit may include some hardware (bolts, washers, spacers etc), a bonding agent, or a combination of these. If necessary, a cutting or mounting template might also be included. If any components are bonded on, the car should be left to stand overnight before being driven. This allows the bonding agent to cure properly.

You spin me right round, baby – your guide to AC Schnitzer alloy wheels.

One of the most obvious upgrades you can make to your car is to change the wheels. Larger, wider, lighter, or just a sportier design, the combination of upgraded alloys with lowered suspension can often do far more to make an otherwise standard car look muscular and athletic than anything else. We’re sometimes asked which “body kit” a car has, when in fact only the wheels and suspension have been changed – the visual effect of these changes can be that dramatic. Why is this? And what are the other advantages of upgrading your wheels?

Dimensions

We’re all familiar with wheels of different diameter – 18″, 19″ and so on. Larger diameter wheels can look more impressive, but they can also be heavier, which can affect the suspension and steering response, and they can be less comfortable – more on that later.

The width of the wheel is expressed as “J” – 8J means 8″ (measured just inside the rim where the bead of the tyre sits). BMW M series cars have wider wheel arches to accommodate wider wheels and tyres.

A measurement which sometimes causes confusion is wheel offset. Offset is the distance from the centre line of the wheel to the mounting face i.e. the wheel hub. This is often stamped on the wheel as ET, followed by this distance in mm e.g. ET45. A larger number like ET55 means that the wheel rim will be more tucked inside the bodywork and will run closer to the suspension components. A smaller number like ET25 means that the wheel rim will stick out further and run closer to the wheel arch. High offset wheels tend to look flat-faced. Low offset wheels look more concave or dished.

AC Schnitzer AC1 wheel for MINI F56. This 18″ x 7.5J wheel was specially developed to fit the MINI and has an offset of ET49.
AC Schnitzer Type V Forged wheel. This 20″ x 10J wheel has an offset of ET33, which gives a dished or concave shape, perfect for the wide wheel arches of this E92 M3.

Fitment

Of course, every car model has a unique body shape – we’ve already mentioned the wider arches on M cars. To give the optimum fitment on each wheel AC Schnitzer use either a centering ring or a hubcentric adaptor, also known as a “spacer”.

Hubcentric adaptor with corresponding longer wheel bolts. A 10mm thick adaptor needs 10mm longer bolts to maintain the integrity of the fastening.

The effect of the adaptor is to move the wheel further out, so away from the suspension components and nearer to the wheel arch. This effectively reduces the offset of the wheel by moving the centre line of the wheel nearer to the mounting surface. So an ET43 wheel with a 10mm adaptor is effectively ET33, even though the shape of the wheel itself has not changed.

You’ll notice that the adaptor is not simply a flat disc, it has a “nose” in the centre for the wheel to locate on and ensure it is perfectly centred when mounted. To accommodate this nose and give the optimum offset, most AC Schnitzer wheels have a centre bore of 82mm.

The aim of adjusting the fitment this way is to give an attractive look, close to the wheel arch, but no so close that the tyres rub, and also to give the best handling characteristics from the slightly wider track. In some cases we’ll even recommend specific tyres to give the best result possible. This attention to detail, combined with lower suspension, is what gives cars the AC Schnitzer look or “stance”.

When you buy a wheel set or wheel/tyre set from AC Schnitzer we will supply the wheels with the correct adaptors for your car. The fitment has already been checked to make sure they will fit perfectly, without any issues, whether you have AC Schnitzer suspension or not.

Construction

The standard construction for light alloy wheels is by casting. Essentially this means pouring molten metal into a mould and letting it cool. The metal “blank” is then machined to finalise the shape before the cosmetic finish is applied. For most wheels we offer a choice of bi-colour (very dark gloss metallic grey with polished edges to the spokes and rim) or anthracite (dark metallic grey all over with a matt finish).

AC Schnitzer AC1 wheel with anthracite finish.

For some SUVs we offer split-rim wheels. Due to the large diameter of SUV wheels, it sometimes makes sense to use different materials for the rim and the spokes and then bolt the sections together. These wheels look very dynamic and come in sizes up to 23″.

AC Schnitzer AC1 Multipiece black.

For high performance cars we also offered forged wheels. The forging process uses high pressure as well as temperature to form the metal blank. This aligns the crystalline structure of the molten metal more closely while it cools, resulting in a stronger, denser alloy. This inherent strength means that more of the metal can be machined away, making the finished product lighter than a comparable cast wheel. A cast Type VIII wheel of 19″ x 8.5J is 13kg, the forged version is just 8.2kg, even though it looks similar.

AC Schnitzer Type VIII wheel, cast vs. forged comparison. The forged version has a lighter rim with slimmer spokes and strengthening webs where they meet.

Why does this matter? The wheel/tyre combination carries a lot of rotational inertia. The heaver it is, the more force is required to accelerate it, turn it and stop it. Lighter wheels accelerate faster and turn quicker. In addition, suspension and braking response is improved due to the reduced weight on the end of the suspension arm. Due to the extra processes involved in making forged wheels, they usually cost at least twice the price of an equivalent cast wheel.

BMW E92 M3 with AC Schnitzer 19″ Type VIII Forged wheels.

Safety

Safety never takes a day off at AC Schnitzer! All genuine AC Schnitzer wheels are tested and TUV certificated, for your specific vehicle, for the safety of you and others. This means that not only are the production standards high, but also the size, offset and load rating is also correct for your specific vehicle. Cheap “replica” wheels are often not tested to any safety standard – don’t risk it! Buy genuine AC Schnitzer wheels from an authorised dealer.

Everything you ever wanted to know about performance upgrades (but were afraid to ask).

BMW M2 with AC Schnitzer performance upgrade and engine optic.

AC Schnitzer have been tuning BMWs and MINIs for over 30 years. Early efforts included big-bore engines with wild cams and even superchargers bolted on. Things have moved on, but the subject of performance upgrades is still one that takes up more of our time when talking with customers than any other. The bewildering range of terms used (remaps, chips, flashes, tuning boxes…), the technical differences between them and the pros and cons of each tuning method is enough to make your head spin. Then there are the warranty implications to consider. Oh dear!

Thankfully, AC Schnitzer offer a clear upgrade path that won’t cause you any sleepless nights. It’s not for everyone, as we’ll see in a moment, but for many BMW and MINI owners there is no better choice than AC Schnitzer.

“I’ve seen AC Schnitzer upgrades advertised – they are expensive!”

It’s fair to say that we hear this comment often, and we’re aware of course that there are many less expensive alternatives out there. But there are sound reasons behind this. Let’s take a look at them.

Worldwide, many AC Schnitzer dealers are also BMW dealers. AC Schnitzer is owned by the Kohl BMW Group. So AC Schnitzer aim their product range at new and nearly new cars (under 3 years old). All AC Schnitzer upgrades must meet the following requirements:

  • The upgrade must not alter the vehicle software
  • The performance increase must be safe and legal, for you and for the car
  • The power delivery characteristic must be like standard
  • There must be no change to servicing and diagnosis procedures
  • The car must still meet all emissions requirements
  • The engine components and drivetrain must still be covered by warranty.

“Can’t I just get a re-map?”

Leaving aside the highly variable quality of software tuning (re-maps) on the market, AC Schnitzer upgrades are always made with hardware. This means an extra engine control unit (ECU) mounted in the engine bay to take care of the tuning duties. AC Schnitzer don’t offer tuning via software because this can affect the car’s warranty, and also means that if BMW needed to apply a service update that software could be overwritten. BMW check your car every time it visits the dealer to see if the software has been altered from standard. Inconvenient, at best. At worst, a major warranty claim could be denied.

AC Schnitzer engine control unit and loom. The red/blue twisted pair is the CANBUS connection.

“So it’s an expensive tuning box then.”

In a way, yes, but a sophisticated one. Unlike some tuning boxes which simply manipulate boost sensor or fuel pressure information to increase power without any safety checks, or allow the owner to flip dip-switches without knowing what they are getting into, the AC Schnitzer control unit is developed to be safe for anyone to use. On a brand new car, from day one. To prove it, AC Schnitzer warrant the engine and drivetrain for 3 years – the same as the BMW warranty.

To enable this the control unit (in most cases) connects to the CANBUS system on the car which carries all the sensor information. It constantly monitors channels like boost pressure, exhaust gas temperature (EGT), injector duration and many other inputs, to make sure that the performance increase is being delivered in a safe way. The full power increase is only available when the engine is fully warmed up, and running on the recommended fuel (98 octane on petrol engines). We can only give an engine warranty by tuning the car in this way.

“Tell me more about this warranty.”

All AC Schnitzer performance upgrades include a warranty that runs alongside the BMW factory warranty from the date of first registration. In the UK, this is for the first 3 years of the car’s life. The warranty stays with the car, not the owner.

There are conditions. Read more about them here. But in essence this warranty is the best available in the tuning world. It’s designed to cover any faults arising from the tuning that BMW won’t cover. In most cases an engine fault will be unrelated to the tuning and will still be rectified under your BMW warranty, but should you need it we can step in. AC Schnitzer in Germany will help diagnose and rectify the problem and our network of friendly BMW and independent dealers will help too.

“My car is 5 years old, what now?”.

We may still be able to offer tuning, but we can’t warrant the engines on older cars, sorry. Please contact us for advice.

“I want to buy/move/sell a used AC Schnitzer upgrade – what happens with the engine warranty?”

Contact us with details – we may be able to help with warranty in these cases.

Summary

AC Schnitzer performance upgrades are the best option for new and nearly new cars. They cost more than other tuning products because they are the best developed, from the best BMW tuner, with the best warranty.

  • Safe and reliable power increase
  • Driveability just like standard
  • 3 year engine/drivetrain/OPF warranty included
  • No need to remove upgrade for servicing
  • BMW service updates can be applied as usual
  • Can’t be accidentally overwritten
  • Can be ordered at selected BMW dealers

Which suspension upgrade?

Suspension is our biggest-selling product at AC Schnitzer UK and, along with a performance upgrade, forms the core of any true AC Schnitzer car. But, which suspension type should you go for? Why even bother to upgrade your suspension at all, standard suspension is fine isn’t it?

Well, yes it is fine, if all you need is to get from A to B it will do that perfectly adequately. But there is so much more enjoyment to be had from that journey, let me tell you.

“So where do I start?”

Our entry-level product is a suspension spring kit. These kits start at around £300, plus fitting. In most cases, the kit consists consists of four coil springs, to replace the four already on your car. The AC Schnitzer springs will be slightly shorter and slightly stiffer compared to the standard ones.

AC Schnitzer suspension spring kit

“That’s going to make the ride hard, right?”

Not at all. AC Schnitzer go to great lengths to make sure the ride is still very comfortable. Drawing on their expertise gained in over 30 years of production, AC Schnitzer develop springs using extensive real-world testing at the Nürburgring and also on the road. The springs are wound in such a way that ride comfort is maintained. Some even say improved!

The first thing you’ll notice about a car fitted with AC Schnitzer springs is that it sits a little lower to the ground. The wheel arch gap is reduced, making the car look sportier and more muscular. It’s not until you drive it that the real benefits appear though.

The steering is sharper, more responsive and holds a line better. The car body rolls less in corners, dives less at the front when you hit the brakes, and doesn’t squat so much at the rear when you accelerate. It’s tauter, more agile, less floaty and feels more “planted” on the road. This is due to the fact that the centre of gravity of the car has been lowered. It’s not magic, it’s physics! And it’s much more pleasant to drive.

Read customer reviews for 3 series spring kits here.

“So that’s all I need? Four springs?”

For many people, yes, this is all they need to get more enjoyment from their car. It looks better and feels better to drive. A little sportier than stock, more planted and stable, but still perfectly comfortable for everyday use.

“OK I really like my car with the springs fitted, but it still feels a bit bouncy on uneven roads, why is that?”

The spring’s function is to absorb bumps, but it’s the function of the damper, sometimes called the strut or shock absorber, to control how quickly the spring compresses and also how fast it rebounds. Here too, there is scope for improvement over the original part.

BMW damper top, AC Schnitzer sports damper below.

AC Schnitzer sports dampers are available for all 1-4 series BMWs and deliver improvements in body control by using high quality components, superbly calibrated by AC Schnitzer test drivers and engineers. The price range is around £1500-2000 for this kit (plus fitting), but if you already have the spring kit you can order the dampers on their own at a lower price.

If your car has BMW “adaptive” suspension, the sports kit from AC Schnitzer will delete that function electronically. Why? Because it’s not needed any more. In fact, it’s better without it (honest!). The reason is AC Schnitzer sports dampers have a damping rate calibrated to match the spring rate, so the springs and dampers work harmoniously together – all the time and in all conditions. Your car will now tackle bumps and undulations with fluidity, stability and confidence.

Read customer reviews for the 1 series sports kit here.

“You do make adjustable suspension though?”

Yes, we do. We call it AC Schnitzer RS suspension, which is “coilover” suspension. RS suspension starts at around £2500 (plus fitting).

Without getting into the technicalities, this suspension is for experienced drivers looking for the ultimate in body control and handling. Many of these drivers will have experienced and owned other great handling cars, and will want their suspension to be as good as it can be. Available most 1-4 series, Z cars and all M series cars, RS suspension is adjustable for ride height (using threaded collars), compression damping and rebound damping (using click adjusters). This means it can be dialled-in to give exactly the suspension response the driver is looking for, or adjusted for a specific requirement, like a track day for example.

AC Schnitzer RS suspension

RS suspension comes pre-set for fast road use by AC Schnitzer, but it’s still very comfortable. Few owners will deviate from these settings by much, as the settings arrived at by the AC Schnitzer test drivers are already excellent. The body control from this kit is another step up even from our own sports kit; Evo magazine described it as “nothing short of genius”. We’re tempted to agree!

Read customer reviews for M4 RS suspension here.

We hope this article has answered some of your questions about suspension. Don’t hesitate to contact us with your questions or for further details.

Hello world!

Hello BMW and MINI fans, and welcome to the blog of AC Schnitzer UK. The AC Schnitzer brand is made in Germany and distributed in the UK and Ireland by us: Rossiters Ltd., based in Norfolk.

You may have arrived here via our website, in which case you might have browsed some of our products already, or maybe you came here via a social media link. Either way, we’re going to be talking about some of our favourite products, asking questions , maybe answering a few, and discussing why you should even be thinking about modifying your car (you really should).

If you don’t have Facebook, or even if you do, we’d like to hear from you. Tell us what you think, ask questions, send us photos. We’re here to make your ownership and driving experience more enjoyable and more fun – that’s what it’s all about, isn’t it?

Lorcan Parnell, AC Schnitzer UK.