- If you’re looking for the ultimate everyday machine that’s also capable of embarrassing junior supercars then you should check out Birds’ wonderful 435d. Words: Bob Harper. Photography: Gus Gregory.
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Birds’ stunning #BMW-435d-xDrive . Everyday Weapon Birds’ 435d can be either a mild-mannered pussycat or a ripsnorting road warrior.
Depending on which order you’ve read the features in this month’s issue you might have spotted a recurring theme, that of traction. The M235i we drove suffered from a lack of it to a certain extent and the two big power M6’s pace was really hampered by an inability to transmit their prodigious thrust to the greasy Tarmac. Put simply, none of these three cars would have seen which way #Birds ’ innocuous-looking 435d went had we driven them back-to-back on typically slick UK winter roads. Not only is this car devastatingly quick, it also has the ability to be so no matter what the conditions.
I must admit that I’m not normally a huge fan of the ‘Luxury’ trim level that BMW’s foisted on us for the past few years, and it would seem that I’m not alone – the new G30 Five won’t be available as a Luxury model in the UK and neither will the face-lifted 4 Series Coupé that you can read about in our News pages. The bottom line is that hardly anyone was buying the Luxury trim models. Maybe I’m a marketing man’s dream, but I’m a succour for the chunky M Sport styling and now I’m in a position that I’ll be looking to buy my own wheels again I’m drawn to the M Sport kitted used examples like a moth to a candle despite knowing that the equivalent SE will be cheaper to buy and will ride better too! Having said all this I’m also secretly drawn to this Birds car – yes, I know it’s a Luxury, but look at it, it’s just so innocuous – no one would expect it to be a candidate for the ultimate everyday weapon, and in the right conditions a supercar humbler.
We’ve always been impressed with machinery that’s been fully-fettled by Birds as MD Kevin Bird doesn’t do things by halves. While he could simply fit a range of off the shelf tuning products he’d be the first to admit that would be selling his customers short. Sure, there are some parts that can be simply fitted to make an improvement, but to do things properly Kevin always buys a demonstrator to which he can experiment with until he’s happy with the outcome and can then pass on that knowledge to his customers in a series of suitable upgrades safe in the knowledge that the car will be right straight from the word go.
The F3x generation of 3 and 4 Series have been with us for a while now so Kevin’s had quite a while to perfect his upgrades for the car, and without a doubt he’s spent the most amount of time on the car’s suspension as he feels that BMW has lost the plot to a certain degree with its most recent F-prefix cars. He’s not a fan of the adaptive dampers as they never seem to offer the right reactions when extracting the performance from the car – they may be fine for providing a comfortable ride when you’re in cruise mode, but so can a passive set up if it’s properly designed and set up.
After having looked at just about everything the aftermarket had to offer Kevin embarked on the process of having a suspension set up designed to his specifications. While Kevin knows how he wants his cars to perform he’s happy to admit that he doesn’t have the knowledge required to draw out a damper curve for a suspension specialist to work with so he’s enrolled the help of chassis engineers to assist him in the quest for the perfect set up. We’ve had a chance to sample this work on a couple of cars and have always come away impressed, and it was no different on this 435d. Springs and dampers have been attended to and the result is a machine that resists understeer far more effectively than before and one which engenders a real feeling of confidence in what the car’s response is going to be to any given input.
We’ll look at this a little more in a minute but for the time being let’s have a quick look at what else has been installed on Birds’ B4-35d demonstrator. It’s perhaps a sign of the times that diesels are able to develop pretty high power outputs to go with their prodigious torque capabilities and perhaps because of this BMW to a certain extent holds back the outputs of its twin-turbo diesel motors. Straight out of the box the 435d develops 313hp and 465lb ft of torque but after its been treated to the Birds engine management software upgrade we’re looking at an altogether healthier 380hp and a monstrous 575lb ft of torque. Kevin has looked at the various tuning boxes on the market and has concluded that he prefers to have the software reprogrammed as it gives you more control on what changes are being made. Additionally some tuning boxes only really deliver once you’ve applied at least 70 percent throttle, and with these turbo diesel lumps offering so much low down the rev range it’s nice to be able to access the additional performance on part throttle.
From the power and torque figures you don’t need to be a rocket scientist to glean that this is going to be one very rapid 4 Series so Birds has taken the sensible step of offering a brake upgrade on the car too. Birds recommends a 19-inch wheel on the 4 Series and this allows the fitment of its #Alcon 365x32mm discs, gripped by six-piston callipers. This set up features grooved discs, low weight alloy hubs and lightweight callipers and Birds reckon they allow excellent retardation from cold all the way up to the highest temperatures they can generate. On the subject of wheels and tyres it’s worth noting that the first thing Birds would recommend is ditching the runflats if your car is so equipped as the benefits of any suspension work will be negated if these are retained.
The kit we’ve so far discussed – springs and dampers, a set of 19-inch non-run flats, the performance upgrade and the Alcon brakes – are packaged together by Birds as what it terms its complete conversion for the 435d and while it might look a lot at a smidgen over £8000 (including all parts, labour and VAT) it offers to transform the performance of your 3 Series or 4 Series. Quality components don’t come cheap and it’s also worth remembering Birds offers a 24-month warranty on complete conversions so obviously has complete confidence in the products it offers. For those wishing to add additional items – such as anti-roll bars or a Quaife limited slip differential – these can again be bundled together as part of a package or added individually as the customer wishes. One of the joys in visiting Birds is that the company accepts that each of its customers may have slightly differing requirements and is happy to tailor its products and advice accordingly.
The proof of the pudding is in the eating though so we set forth from Birds HQ to cruise up the M40 to our photoshoot location where some challenging roads await. Obviously we’re expecting it to perform well when the going gets tough, but in order for the Birds car to fulfil its duality of purpose it first needs to be able to demonstrate that it’s a usable everyday machine in cut and thrust traffic. Initial impressions are favourable with the eight-speed auto quietly and unobtrusively doing its thing in the background while tickling the throttle every now and then is accompanied by a meaningful shove in the back, even on part throttle loads. Having just stepped out of a car sitting on much smaller wheels and with no pretensions to being a sporting machine the ride does, at first, seem to be a little on the hard side but as the miles pass under the 435d’s wheels we become accustomed to the slightly firmer than standard set up and end up not being able to fault the car’s behaviour on the motorway. It rides the crests and troughs very well, always seeming to be able to complete its movement before hitting the next bump or road imperfection whereas sometimes in a normal BMW you’re left with the feeling that the underpinnings are still trying to deal with one road imperfection when it hits the next which can have an unsettling effect.
Pulling off the motorway and onto some more demanding roads and the 435d demonstrates what a devastatingly quick cross-country machine this can be.
There’s power and torque seemingly everywhere in the rev range and you can have the choice of using delicate and measured inputs to ride the wave of torque or being a bit more brutal in which case the eight-speed auto drops cogs with alacrity and flies you up the road, slurring one ratio into the next as only that #ZF ‘box can do. And it’s at this point that you realise you haven’t dialled in Sport mode and once you do there seems to be a whole new level of performance to dip into.
At which point one is invariably really travelling so it’s reassuring that those Alcon brakes can wash off speed without breaking into a sweat – the pedal feels is very reassuring and even on the slippery sections of road we encounter it resists the temptation to trigger the ABS very well. Invariably though once one has knocked a chunk of speed off the dial when tackling the corner that one wanted to slow for it becomes apparent that you’ve actually washed off too much speed and that the 435d could corner much quicker. In fast sweepers the chassis inspires real confidence, gripping hard and resisting understeer very effectively while it’s a similar story amongst the tighter stuff, too. The front end clings on for dear life and the only thing you really have to do is to remember to get onto the throttle earlier than you would in an equivalent rear-wheel drive BMW so you can bring the front axle’s drive capabilities into play, and when you do you can feel the front end pulling you through just as the rear tyres start to scrabble for grip. It’s deeply satisfying and we can’t really imagine that there are all that many machines that would show this 435d a clean set of exhaust pipes, especially on these tight roads where a bigger machine would struggle somewhat.
Once we’ve finished playing and got a set of pictures in the bag it’s time to head home and sample the car’s cruising abilities once again. Snapper Gus gets behind the wheel and once we emerge back at Birds HQ he’s got a big smile on his face and concludes “That’s quite a weapon isn’t it.” Quite so. Swapping back into my everyday car I couldn’t help but feel how sloppy and stodgy it felt, it had felt fine in the morning!
This 435d is currently up for sale at Birds so if you fancy a stunning everyday supercar slayer that will pass quietly under the radar we’d very much urge you to get in touch. We can’t imagine it’ll hang around for long…
CONTACT: #BMW-F30-Birds / Tel: 01753 657444 / Web: www.birdsauto.com
There’s power and torque seemingly everywhere in the rev range
Birds-B4 component prices
ENGINE MANAGEMENT SOFTWARE 380HP: £2106
B4 XDRIVE ANTI-ROLL BAR KIT: £914
QUAIFE BMW LSD CONVERSION: £1605
B4 SPORT SUSPENSION: From £1723
EXCHANGE QUAIFE BMW FINAL DRIVE: £1710
SPORT SUSPENSION SPRINGS: £679
ALCON AE BRAKE KIT FRONT, 365X32: £2862
ALCON AE BRAKE KIT REAR, 343X28: £2377
OZ WHEEL & TYRES SET: POA
Please note: All prices quoted within this panel refer to components fitted individually not as part of a B4 Dynamic Package. Prices include parts and labour but not VAT.
/ #Birds-B4-Package prices
B4-3.5d 380HP COMPLETE CONVERSION: £6803
Engine management software, Alcon 365mm front brakes, B4 Sport suspension, 19-inch non-run flat tyres
B4 DYNAMICS PACKAGE 1 £2312
B4 anti-roll bar kit, Quaife LSD
B4 DYNAMICS PACKAGE 2: £3096
B4 anti-roll bar kit, Sport suspension springs, #Quaife LSD
B4 DYNAMICS PACKAGE 3: £4039
B4 anti-roll bar kit, B4 Sport suspension, #Quaife-LSD
Please note: All prices quoted with this panel include parts and labour but not VAT.