Automotive

BMW lets loose water-injected M4 GTS

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A special edition of the BMW M4 GTS previewed at Pebble Beach earlier this year is set to hit the road
Speccing the Clubsport package in the M4 GTS gives you a bright orange rollcage
Just in case you weren't sure what you're driving
The M4 GTS' racetrack focus is clear in the way it's laid out inside
The GTS' bucket seats have been designed with heavy cornering in mind
The Clubsport Package includes six-point race harnesses
That front splitter is adjustable, and made of carbon fiber
The car's CFRP rear wing is one of the biggest giveaways to its potential
OLED taillights are a part of the GTS package
Because they're so thin, OLEDs let designers create interesting shapes and designs
A titanium exhaust has been fitted to save weight and create a rorty sound
The carbon rear diffuser works with the front splitter and rear wing to create more downforce
The GTS is the first production BMW to be fitted with OLED lights
The car's orange highlights make it stand out in a crowd
The GTS' sticky Michelin tires should give it more grip on the track
The CFRP bonnet and boot contribute to a 50 kg weight saving
The wheels measure 19 inches at the front and 20 inches at the back
Under the bonnet is where BMW has wrought most of the changes to the M4
Water injection offers owners a faster 0-100 sprint with no economy penalty
Only 700 GTS' will be built
The car is designed to celebrate 30 years since the original BMW M3 launched
The strip atop the steering wheel is another racing touch
BMW has remapped the GTS' gearbox to handle the engine's extra power
Carbon fiber is everywhere on the GTS, and it contributes to a 50 kg weight saving
The water injection system in the M4 has been used in the MotoGP pace car all year
The M4 GTS' engine still doesn't make as much power as the C63 AMG S' V8, but the GTS is quicker from 0-100
Water injection has been around for a while, but BMW is one of the first to put it into series production
The water injection system in the M4 has been used in the MotoGP pace car all year
Interior detail - M4 GTS
BMW's classic motorsport colors are spread around the cabin
The car will hit 305 km/h before the limiter kicks in
The M4's sharp design looks good with gaudy orange highlights
The car's OLED taillights accentuate its width
The car's front splitter and spoiler are fully adjustable
Water injection has been around for a while, but BMW is one of the first to put it into series production
A special edition of the BMW M4 GTS previewed at Pebble Beach earlier this year is set to hit the road
The M4's broad rear haunches are accentuated by its big wheels and the carbon diffuser
The M4's sharp handling will no doubt be aided by the BMW's aero and mechanical upgrades
There's no word on the price for the GTS but we're not expecting it to be cheap
View gallery - 38 images

Having previewed water injection in the M4 GTS Concept at Pebble Beach earlier this year, BMW has whipped the covers off a production version. Just 700 examples of the new, lightweight M4 GTS will be built to commemorate 30 years since the original M3 was launched.

Central to the upgrades BMW has fitted to its M4 GTS is a water injection system, which bumps power up to 368 kW (500 hp) and torque up to 600 Nm. That's an extra 59 kW (80 hp) and 50 Nm compared to the standard car, though still 7.5 kW (10 hp) and 50 Nm less than the Mercedes C63S AMG.

BMW has been using water injection to boost the performance of its M4 MotoGP Pace Car, and also previewed the technology in a 1 Series a few months ago, but the M4 GTS is the first production BMW to feature the technology.

Carbon fiber is everywhere on the GTS, and it contributes to a 50 kg weight saving

By cooling the combustion temperature, the water injection system improves fuel economy as well as performance. While it produces plenty of extra power and will hit 100 km/h (62 mph) in 3.8 seconds, the GTS uses the same 8.3 l/100km (34 mpg) as the standard M4.

Power is channeled through a remapped version of the seven-speed M-DCT gearbox, which has had the Launch Control and Shift Modes reworked to handle the engine's extra power.

The GTS has also been on a strict diet. The bonnet, front splitter, bootlid and bonnet have all been made of carbon fiber reinforced plastic, as has the adjustable rear wing. That wing works in tandem with the new carbon fiber rear diffuser and the pouting front splitter to reduce lift at the rear axle for greater high-speed stability.

The stripped-back attitude is also evident inside, where BMW has replaced the standard car's front seats with two lightweight carbon bucket seats and ripped the rear ones out, replacing them with a rollcage if the Clubsport Package is specced. The door handles have also been replaced with fabric loops, and the brace hiding behind the instrument panel is made of carbon fiber.

The Clubsport Package includes six-point race harnesses

All up, the carbon bits on the car keep weight down to 1,510 kg (3329 lb), 52 kg less than the standard car.

Just in case the carbon add-ons and extra performance wasn't enough for you, BMW has made the M4 GTS its first production car to be fitted with OLED lights. Unlike regular LED units, OLEDS are incredibly slim and light up across their whole surface – which opens the door for designers to play with interesting shapes and forms.

Speaking of interesting shapes and forms, the M4 GTS sits on beautiful, intricately detailed wheels finished in acid orange to make it stand out in a crowd. Those wheels are wrapped in Michelin Pilot Sport Cup 2 tires measuring 265/35 R19 up front and 285/30 R20 at the rear, which should provide even more grip than the already-sticky standard car. BMW's engineers have also fitted the car with three-mode coilovers and lightweight carbon ceramic brakes.

There's no word from BMW on the pricing of the GTS yet, but expect to pay a healthy markup over the M4 Coupe, which starts at US$64,200.

Source: BMW

View gallery - 38 images
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5 comments
christopher
Add a couple of buckets of water, enough for a few minutes of boost, and all the carbon-fibre weight savings are gone...
Stephen N Russell
Darn, cant produce enough to Rent & for Sales.
steveraxx
The hilarious thing about a waste-of-space like this is how the guys who have more money than intelligence and so can afford the payments. They live in ultra-dense areas where traffic is good if it is at 30mph!
Evidently the boy-racer concept is alive and well.
Martin Hone
Water injection has been around since WW2, and used for the same reasons. Cool the incoming air to reduce the onset of detonation thereby allowing higher boost or more advanced ignition timing. For a road car, a bit of a gimmick.
NateBowser
Firstly, water alone may and is used, depending on application. However, what is referred to as water injection is usually a 50/50 of methanol and water, and with more intricate systems multiple tanks, nozzles, and mixtures can be used. For instance on some extremely modded cars I've I use two tanks, one methanol, the other a 50/50mix. I have my controller set to read the boost level, IAT, and duty cycle and program my stages to read certain percentages accordingly. For instance, at my supercharger inlet has a small jet of pure methanol which is softer on the rotors, creates perfect rotor case clearance, and is quicker to cool air as well as prevent heat soak from happening lowering charger temp dramatically. It engages at a set boost and excessive IAT, (boost for roots but twinscrews are the only induction that will heat when slowed down due to it internally compresses, unlike roots which push and compress through volumetric stacking, so an IAT switch helps with those slow traffic overheat issues. Also the pre SC using pure methanol which evaporates quickly and leaves the downstream cool and vapor free, so your cylinder injection settings are unaffected by the SC stage. Before my SC injection, tiny pulleys would burn up oil, bearings, and inevitably rotors which prevented utilizing the biggest bang for buck mod there is, reduction pulleys. Also, the once seering hot SC after jetting is so cool that i can touch it immediately after a drive. "But that's not all" the pre SC injected liquid fills the case and rotor gap creating a perfect clearance retaining higher boost, and unlike the failure of the flaking rotor coat used in recent years. BTW it flakes regardless and engines hate chips. Eaton tried to blame W/M as the cause for damage control, and unfortunately the lemmings have believed this. Well it was the cause, it expedited the removal of an unproven cost adding feature that releases ceramic dust into my motor, and has not a single benefit. I also run a second nozzle post intercooler (which truthfully is just an air slowing relic with injection on) not pre because it can result in improper atomization with a 50/50 mix because while methanol cools quick it doesn't cool long, water will hold heat and atomize well. So before you spend a grand on a 10 degree saving intercooler for $1k, consider this: my intercooler brought IAT to about 120*, with injection IAT hit 62*........in Florida. Kinda hard to argue with. Asides the cooling which not only makes everything last longer and run harder, the colder air when cooled within SC (I will always harp this since no one listens but any expert will tell you) means colder air exits richer in oxygen. Usually Oxygen is lost within the SC and then heat expands it then feeds the intercooler, which only does as titled, it cools the air, it can't add lost oxygen back in. Injection allows more oxygen per cycle, because colder molecules especially oxygen molecules like to huddle when cold and spread out when hot, meaning a square foot of cool air contains drastically more oxygen than the warm foot. cool air goes further for the buck. Nevertheless, no matter how much reading, building, testing and notating I do, the haters gonna hate, well guess what? Haters also hate using their brain, because its easier to use Joe nobody on a forums brain who used his cousin Billy Rays brain. They will troll and troll with false confidence and tear down your research with quotes, but notice it's always a quote from "someone they knew", or some stockroom kid at a distributer who was playing iPhone when questioned and BSing. The cyber "thesis" is met with hostility, usually from the owner of whatever product you just disproved. These discussions of opposition never begin with, "Firstly, this is good research, and it seems you worked hard acquiring it. I however have also researched extensively through various text books, testing, and contacted several experts. I do however have some discrepancies in my research and think we should discuss and compare notes and possibly help each other create progress"......nope....never....not gonna hear it.......The rebuttal you'll actually hear sounds like it came from written dictation of a social leech with 5 brat kids in Walmart, and they're yelling "Hey, Hey, your an idiot! You said Bat Boys not real, well then why's it on the cover of the Sun Magazine!, you is so stupid". In this case it's "boost". To trolls boost is a magic element that horses eat for power......Wrong!!! According to my buddy webster it means to push, or force against, therefore Boost =Pressure, no merit on oxygen content whatsoever. Fire eats oxygen not pressure, if it did we'd use the O2 sensor to read boost......pretty easy when given a little thought. Remember trolls have one power that makes them impervious to being swayed in a discussion, they're idiots, because an idiot thinks they know it all, which makes you impossible to teach. So as I've always said, I will not argue, I will discuss. Thats where we both speak civilized with our collection of facts and theorems with an open mind and analyze objectively. If I am right, than good. You learned something, if I you are right, also good. I learned something. If we correct each other and improve, better. Everyone learned something. Not the case with troll, he argues. Again, Hit your dictionary, boost means a measurement of pressure not oxygen, so of course your small IC and mach jesus rpm charger make more boost, they've inadvertently creating a pressure cooker which actually inhibits the amount of oxygen that can inhabit the intake area, so please stop reading boost as the one all number, you'll damage or limit something. A pre and post IC sensor will prove this, but even simpler proof is. Blow up a balloon, but not excessively, and tie it off, now take a blowdryer and carefully at a distance warm up the balloon, your 5 year old child can tell you what happens next....it expands, and since it was tied off we know the oxygen content is identical in both, and if we pretend a cardboard box is the intake then I believe we can deduce more small balloons will fit in the box vs big balloons. We can even leave some space in the box and even though that'd decrease pressure (boost), the small balloon box has more oxygen and therefore power. So just how Horsepower means nothing without Wt, Tq, Rpm, or transient response. Well boost means nothing without IAT, and mostly your AFR tells if your gaining power or basically putting a blowdryer in the intake. Lastly W/M before intake manifold (and/or direct ported into runners for high power and direct nitrous) really should be 50/50 mix. Pure methanol will add octane but will evaporate and not remove heat like water, water is ingredient #1. the true magic is the elimination of pre detonation which will ruin your car, bank account, and ego. When pushing high boost or nitrous you must mind the triangle of combustion. Spark, Fuel, Oxygen. If the pyramid tips over it's gonna tip back on your engine and combust on your bank account. Boost and NO2 add oxygen, and if a mixture is too lean meaning not enough octane, and too hot then grab your popcorn and enjoy the fireworks. W/M doesn't just aid in prevention of detonation, it's the proverbial penicillin. The water cools temps and the methanol raises octane, balancing the scales. In fact, it's so damn amazing in a NO2 setup, I can't fathom why it's not common knowledge other than winners aren't keen on sharing. Usually with Nitrous you use a system to retard timing usually 2* for every 50 hp added, pulling time also effects crank power, so it's a tradeoff and balance. Now with an integrated W/M injection you balance the scale that NO2 tips. NO2 is an oxygenator, W/M adds fuel and prevent excess heat, so timing can be left alone for the most part. In fact it's common to run 250 hp NO2 shots with not only no retard but slight advancing as well. Now for all you new car people, you have been unfortunately duped with direct injection, which injects fuel into the cylinder rather than over the valves, and have invented a whole new car epidemic "intake carb build", and invented a new lucrative industry of walnut blasting intake salves because without gasoline cleaning the valves from above they're caked in residue, burnt particles and what not, eventually blocking up, so after you lose 1/2 of your HP you can call the dealer to blast for $800, or me for$500, I gotta machine in the corner, so the fact I'm writing an article on water methanol benefits is pretty dumb on my part, but I know no one listens so I'l continue. W/M methanol is a solvent of sorts, water turns to steam and a lot of pressure. Thats a combo for clean ass engine, called Carb Be Gone!