Archive for the 'technical' Category

Hello, BMW’s Carbon Future

Thursday, May 22nd, 2014

Zintro called upon its network of experts to discussed SGL Automotive Carbon Fibers and BMW Group’s plan to invest $200 million to triple the carbon fiber (CF) capacity at their Washington state plant to handle high demand from the automotive sector. This was my response as selected and featured in their newsletter May 22nd, 2014:

This announcement should come at no surprise, and yet it is a delightful harbinger for both the future of BMW models and that of lightweight materials in vehicle construction. ‘No surprise’ because the M3 CRT portended this shift in early 2011, and now in addition to the i3, BMW is now ramping up production of three other vehicles that rely on CFRP to varying degrees: i8, M3, and M4, and given the response to the ‘joy’ reduced weight is bringing back to BMWs lineup, we will surely see its use proliferate beyond the i and M brands to the regular models, just as thermoplastics, aluminum and magnesium have historically played the same role to varying degrees. Don’t be surprised to see increased carbon levels in all BMW vehicles a generation or two from now. This comes at an opportune time for BMW: they’ve lost technological and dynamic footing to competitors like Audi and Cadillac who have used (and marketed) aluminum and lighter metals to bring their weight down just as BMWs was swelling. Carbon based components will help restore BMW’s driving machine ethos and give BMW a marketing edge and halo technology they need to stand out once again, especially given the high performance and racing associations some consumers have with the Carbon Fiber. Those less interested in performance or racing will also see gains given regulatory and market pressures for more fuel efficient vehicles despite increased safety, feature content, and size.

my how you’ve grown

Monday, September 29th, 2008

Nearly two decades ago the Honda/Acura NSX shook up the performance car scene.

This year, the Nissan GT-R is said to be doing the same.

But could the two cars be any more different?

Looking at this picture I stumbled across on the web – is the NSX is too much like a Formula 1 car or is the GT-R is too much like an SUV?

why MINI’s puffed up new Cooper leaves me deflated

Sunday, October 15th, 2006

The old Cooper struck a shockingly artful balance between the rawness of the original and the refinement of a BMW - even the supercharger’s whine mimicked the gear whine of the original.

In remaking the new Cooper, MINI had to do something and the new car will no doubt be an advance in many areas (particularly in having a lighter, aluminum blocked engine). But from a design and intent standpoint, certain things make it more pre to trend than its rather timeless predecessor. They are: Read the rest of this entry »

Acura’s A-Spec package for the TL - don’t drive home without it

Tuesday, January 24th, 2006
The A-SPEC’s performance enhancers involve more aggressive suspension tuning, as designed by Makoto Tamamura, the famed chassis engineer behind Acura’s NSX sports car…. the stock TL torque-steers upon corner exit and understeers severely when pushed hard into a corner. In A-SPEC form, both torque steer and understeer are dramatically reduced—we even experienced an occasional hint of oversteer on aggressive corner turn-in. Braking performance from the factory-installed Brembo four-piston disc brakes improves, too, thanks to reduced nosedive during hard stops and the stickier rubber. source: Motor Trend

(The package improves slalom times by nearly 4 miles per hour and increases lateral grip by .06g. We continue to suggest those in the market for a TL or TSX insist the A-spec suspension be installed before delivery).

a crucial TSX option unknown to salespeople

Thursday, December 29th, 2005

Contrary to what others might tell you the TSX’s suspension and tires are its Achilles heel, but you don’t have to resort to the Radio Flyer ride of an aftermarket kit or cough up $4330 for the A-spec package to get rid of some of the body roll and torque steer.

The best way to improve the TSX is to install the A-spec suspension, which – conrary to what your salesperson might believe – is sold separately (part number 08W60-SEC-200B). If the folks at your local dealership are anything like those at ours, you may need to show them this. Don’t be intimidated by the retail price; you’ll find it for around $600 if you’re willing to mail order…

But the noisy, slippery, twitchy Original Equipment tires should be first to go; I suggest the Michelin Pilot Exalto A/S, $146 plus shipping and installation through this vendor.

driven: MINI Cooper S JCW

Friday, September 16th, 2005

Our first drive of the Mini Cooper S the day it hit dealer stock left us cold. The exhaust was boomy, the gearing too long, the powerband asthmatic and the suspension overdamped and skittish on 16s, underdamped and bouncy on 17s. The car would snap from power-on understeer to trailing-throttle oversteer in a heartbeat. Since then, we’ve actually preferred the normally aspirated Cooper’s low speed response, rising rate powerband, and more BMW-like suspension (it better evinces two adages that MINIs should embody: “it’s more fun to drive a slow car fast than a fast car slow” and “speak softly and carry a big stick”)

Revision to the ‘05 MCS solved all but the motor’s feeling a bit winded before reaching 6,000 rpm and the exhaust boom – if anything the note has grown more prominient with time; changes were instututed for more pops and burbles on the overrun. Revised gearbox ratios and shock damping make for a car that claws its way forward and keys to the surface like the ‘04 and earlier Cooper never did. (The recently added limited slip differential should only improve matters).

We recently had the opportunity to put an ‘05 Cooper S with the JCW engine kit and 18” wheels through its paces, and it wasn’t at all what we expected.

Walking up to the car you eye the exhaust and the 18’s and think “this is going to hurt.” But once underway you find that the exhaust is less prominent and boomy at small throttle openings yet more melliflous at high revs. Even more of a shock, the combination of lightweight wheels and 18” Dunlops are less leaden than the stock 17s. You’d expect the 18s to throw impact absorbtion out the window, but they unsettle the car less than than the 17” wheels and Pireli eufori@ run-flats or Dunlop 9000 DSSTs. Only the sharpest square edged ridges elicit a metallic whack from the suspension. As an added bonus steering gain is less abrubt than with the eufori@s and more linear than with the 9000s. Back to back drives with the 115hp Cooper on sport (rather than sport plus) suspension showed the ostensibly smoother car to be the rougher riding of the two. In the MCS on 18s it feels as though the kid in the seat behind you is misbehaving, in the Cooper it feels as though the tires are are as round as medicine balls. Go figure.

There’s no question the engine kit does what’s claimed. The car now pulls strongly right into the rev limiter, something that’s more easily enjoyed with the ‘05 and later car’s revised ratios. The flexibility is such that you can pull cleanly in the upper ratios with less than 2,000 rpm on the tach (the standard car deosn’t wake up til nearly 3,000). In the standard model 6th is for cruising only – in the JCW it can be used for passing as well. The added urge gives the S motor what it should have had all along – zeal. As evo pointed out in Dec. of 2004, “immediately the throttle response is cleaner and more decisive, while the supercharger’s whine has less drone and more zing.”

If we have one criticism of the 2006 model, it’s that the engine kit is bundled with a limited slip differential and the JCW brake kit. While this saves you money should you want all the ‘upgrades’, we preferred the flexibility of ordering a la carte.

The LSD and suspension kit we’ll take, but those bigger front brakes add unsprung weight and rotational inertia while requiring 17s which add more of the same. The unsprung weight forces you to slow down over lumy pavement while the rotational inertia menas the car is steered less with the palms than the forearms – you have to wrestle the car into the turn that much more. The inertia also dulls some of the JCW engine kit’s extra shove – you notice the reshaped power curve more than you feel your neck snap back as you crack the throttle. Plus the 18s miss the point of the MINI somewhat; the car trades some of its stealth quotient, its indifference to surface conditions, and its playful eagerness to wag its tail for a fair amount of texture dependent tire rumble, which quashes more of that BMW level refinement. For the track-day junkie the brakes will be a Godsend but for a (U.S.) street-driven Cooper they opening something of a Pandora’s Box.

Many armchair reviewers say you can get more bang for the buck via aftermarket modifications, but before you talk yourself out of the added cost of the JCW equipment, find a way to try a JCW equipped Cooper S for yourself. It’s an experience you simply can’t put a price on or express in numbers. The effect of the upgrades is greater than the sum of its parts and would make the late John Cooper beam with pride.

UPDATE: We recently sampled an 03 MCS with the JCW engine kit. Like the all of the pre-05 MCSs, the gearing is just too damn long (to reduce wheelspin in tighter corners?) but the JCW kit does make the engine pull more cleanly – esp. from a stop – and ensure that you don’t get blown off by the bog standard Cooper sitting next to you at a light. (Well not unless he’s on smaller, lighter wheels…)

The moral: if you don’t think you can afford an ‘05 or later S, save more pennies. (If the JCW engine kit can’t overcome the gearing and make the car feel as alert as something bearing the Cooper name should be, nothing will…)

UPDATE 2: Today we had the opportunity to compare a Cooper S (on 17” S-lites and Goodyear RS-As) to an ‘06 JCW kit equipped car (on 17” Web Spokes and Dunlop 9000s).

Once again the JCW exhaust proved less tiring and more mellifluous, speaking up only under larger throttle openings and singing with a less raspy voice. The increased in gear flexibility and broader powerband improve drivability and give the engine the same big motor feel at freeway speeds that 3 series car with 3.0L sixes enjoy.

The 17” web spokes and Dunlop 9000s had a similarly large effect, the reduced unsprung mass leading to a less disjointed feel over bumps while the 9000’s softer steering response caused the car to bend into corners rather than dart into them – the tradeoff being less zig-zag motion when trying to go straight. Compared to the 18” wheels we had sampled previously this combo wasn’t as sharp in the steering but the tire noise was significantly lower. The flinty metallic report you get from the 18s over larger bumps wasn’t apparent either.

Finally the limited slip device works exactly as advertised: feed in more throttle in a corner and the car first feints that it’s going to run wide – ignore this and squeeze further and you’ll feel the nose sniff towards the inside shoulder. Coopers have always been at their best near the apex – LSD only improves matters.