Showing posts with label Brake. Show all posts
Showing posts with label Brake. Show all posts

Thursday, 26 January 2012

2012 Jeep Liberty

2012 Jeep Liberty PhotosNo question about it, the Jeep Liberty is boxy and rugged. And while we're becoming accustomed to seeing carlike vehicle masquerading in trail clothes, that's not at all the case here: The 2012 Jeep Liberty remains mostly truck. But for families who plan on spending most of the time on pavement—and with the trail-focused Renegade model dropped—the Liberty's appeal is limited because of its poor fuel economy and lack of comfort.


Looking tough and traditional—though a bit slab-sided from some angles—the Jeep Liberty appearance hasn't changed much over the years. A few years ago, Jeep amped up the macho-man appeal and added chunky details to look even more trail-tough. The Liberty's styling inside keeps to that role with a stark and simple look, although there are more hard plastics than in most crossovers this size.

The Liberty's powertrain can move the Liberty quickly enough, but we have no kind words for it. The 210-horsepower, 3.7-liter V-6 engine is torquey enough, but its rather low-revving, raspy, and not altogether smooth character just barely fits in with the Liberty's more rugged character. Because it's a low-revver, relatively speaking, it manages just fine with the somewhat rough-shifting four-speed automatic. But this powertrain's true downfall is gas mileage; at 15/21 mpg with 4WD, the Liberty is no more fuel-efficient than a full-size SUV.
Off-roading remained one of the best reasons for choosing the Liberty over a more easygoing crossover model, yet Jeep has, puzzlingly, dropped the trail-focused Renegade model for 2012. Two 4WD systems remain offered: Selec-Trac II is a full-time system that's also off-road capable but better oriented for snowy roads, while Command Trac is a part-time system intended for trail-running.

At first impression, the 2012 Jeep Liberty feels relatively well laid-out—as well as airy, given the tall greenhouse. Seats feel skimpy, though, and don't offer much support. But there's enough space in back, even for adults on a weekend trip, for instance. And the story is pretty good if you plan to haul cargo and gear: The cargo floor is low, too, and the seats fold neatly.

But there's still plenty to make the Liberty an unappealing choice in today's market, which is brimming with well-designed, family-friendly utility vehicles. The Liberty's on-the-road ride and refinement are probably the biggest turn-offs of this vehicle. There's a fair amount more interior road and wind noise than in more carlike compact crossover vehicles. And as a tall, narrow vehicle with a pitchy ride, the Liberty results in lots of 'head toss' on rough roads, or even choppy freeways, and blemished road surfaces seem to upset the composure of occupants just as much as they seem to upset the Liberty's grip.

Safety features are respectable in the 2012 Liberty, but the federal government hasn't tested it under the new ratings system, and the IIHS gave it a worrisome 'marginal' in side impact and 'acceptable' in rear impact. Base Sport, more luxurious Limited, and new Limited Jet trims are offered. Limited Jet models offer a spiced-up appearance, with big 20-inch aluminum wheels, chrome molding, and other black and bright trim throughout, plus a leather-wrapped steering wheel and alarm system. Limited models are dressed up with a a long list of equipment over the sport, including leather upholstery, heated front seats, steering-wheel audio controls, a Bluetooth hands-free interface, and a garage-door opener. There are plenty of cool options, such as a music hard drive system, a new Garmin nav system, rain-sensing wipers, and a Sky Slider sunroof, if you don't mind the higher price tag.

For 2012, Jeep has dropped prices on Liberty Jet models by $795, and it's added a Bluetooth hands-free interface (with voice command), a garage-door opener, overhead console, and rear park assist as standard equipment on all models.

Wednesday, 8 June 2011

Sludge Sliding 101, DirtFish Style: Turn, then Brake, Dummy…

CLINK!

“That’s first gear,” my instructor says nonchalantly. “Don’t worry about all that clanking and grinding. The cut gears just sound like that.”

This is how every transmission on the planet should engage: gritty, raw, clinking and clunking. Nevertheless, I hope I don’t break it, because this thing costs way more than your average halo car sitting on a dealer lot.

Thanks to the generous guys and gals at DirtFish Rally School, I’m belted into the tight Recaro bucket of an FIA-approved Group N Subaru Impreza WRX STI racecar constructed by Vermont SportsCar (the same outfit that has assembled race/stunt cars for Ken Block, Dave Mirra, Travis Pastrana and others) for my first taste of off-road rally racing.

Sludge Sliding 101, DirtFish Style: Turn, then Brake, Dummy… imageDirtFish’s home turf is the stunning Old Mill Adventure Park near Snoqualmie, Washington. It’s heaven for motorheads and a dream for photographers. Students learn driving basics on 350 acres of mixed surfaces, and if they make it through the full three-day Advanced Rally program ($2795), they can try the demanding rally circuit that puts their skills to a high-speed, multi-maneuver test.

Prior to being engulfed by the Subie’s HANS-compatible throne, I learn a number of basic principles from Forest Duplessis, DirtFish’s chief instructor. Two of them – Lift, Turn, Wait (LTW), and Lift, Turn, Brake (LTB) – are key to any rallying situation. “Lift” refers to lifting off the throttle, while “Wait” means waiting for the tires to grip. For the second principle, “Brake” replaces “Wait” so that the car’s weight is dramatically shifted to the front axles, creating additional nose grip.

My three-hour crash course begins on the skidpad to learn car control by left-foot braking and throttle modulation. Then it’s onto to the slalom to use those skills in a trickier situation and to further my understanding of weight distribution. Last, I try my luck on the rally circuit.

“Remember to lift, turn, then wait for the grip. It’ll snag; all you have to do is wait,” Duplessis says as I begin what feels like a never-ending left turn on the gravel pit. Although 25 years young, Duplessis has driven competitively for most of his life, which means he’s pretty good at flinging just about anything with four wheels around a corner with low-to-no grip.

Surprisingly, even with a gentle rain creating a mud plain filled with gravel cement, the Subie snapped left with no throttle input whatsoever. Waiting, it seems, does produce very good results.Sludge Sliding 101, DirtFish Style: Turn, then Brake, Dummy… image

“The best brakers are the best drivers,” Duplessis philosophized. “Now instead of waiting, apply the brakes gently with your left foot. Then once you feel the weight move forward and the grip appears, roll onto the throttle. See what happens.”

With a Euro-spec 300-plus-hp, 2.0-liter boxer and five-speed manual dogbox under its composite hood, the lightened and reinforced STI hauls copious amounts of ass. If I keep the revs up high enough in any gear I’ll be churning mud for days.

I roll onto the throttle after a smooth brake engagement, but the rear end immediately slides out. I’ve spun and stalled.

“Too much go-pedal,” Duplessis surmises.

The next time around, I get the hang of it. My speed rises, and the order of operation becomes more natural. The key is to be completely smooth.

As the rain falls harder, we move on to the slalom. The lesson plan’s difficulty just doubled.

“Look up and towards to the next cone, but always remember LTB,” says my co-driver. “I want to feel those brakes!”

Easier said than done. I’m having a hard time remembering the LTB order of operations as my speed climbs. All the years of brake-then-turn track driving are ingrained into to my brain and muscle memory. If that wasn’t detrimental enough, my eyes wander to the closest cone, not two cones down.

“Good, you’re getting the hang of it. Now let’s do it again,” Duplessis encourages. He repeats that for the next eight runs. Each revolution on the pad, I’m reciting, “LTB, LTB, LTB…”

By the tenth go, I’m confident on the muddy slalom.Sludge Sliding 101, DirtFish Style: Turn, then Brake, Dummy… image

“You’re ready. Want to try something fun?” Duplessis teases from the passenger seat. “Next time you turn around on the course, turn in, grab the e-brake, downshift to first, then get on the throttle. You really have to feel the entire orchestration. Let’s see what happens.”

Coming into a coned hairpin on mud at 40 mph in a crackling second gear — with rain pelting the composite panels and body heat fogging my windshield — is probably the most thrilling way to undertake a full e-brake slide and turn. And this is on my first try.

As soon as I pull the brake, the rear end kicks out, and the front stays planted. Everything outside of the cockpit rotates in a matter of milliseconds. The boxer’s revs die. I stall. Great.

“All good. Let’s try again. You got this! Just keep the revs up and roll onto the throttle, then it’s into the cone attacking all over again,” Duplessis says. Throughout my training session, his encouragement and excitement never wane.

With 40 clicks on the speedo, I attack my lonely cone once more — this time with complete WRC no-blink focus and determination. This cone will not defeat me.

I turn in, pull the brake, swing the butt around, clutch in, shift down into first, and mash the throttle. I realize the engine is still alive and revving, and we’re moving forward fast. My eyes fixate on the cone immediately ahead of me, then the next. Second gear caught, the original LTB comes back into play and it’s on to the last cones.

“Awesome! Time to play on our course. Head over there,” Duplessis points to a multistory wooden building. It’s the tallest freestanding wooden building in the country, DirtFish claims, and was widely seen in the recent Global RallyCross.

The 0.7-mile course has 12 makeshift turns, each varying in severity and size. Duplessis runs me through it three times. I tackle it cautiously at first, braking after I turn in. On certain very slippery tarmac corners, I brake well ahead of the apex, then turn and wait.Sludge Sliding 101, DirtFish Style: Turn, then Brake, Dummy… image

By my third lap, I’m throwing the orange STI sideways with complete confidence and control. My orchestration amazes me. My right foot modulates the slim pedal while the diff chatters wildly, my right arm yanks at the E-brake, my left foot dances between brake and clutch. Whoever said rallying was easy has never properly tried it.

“Dude, you rock. In a matter of hours, you became a better braker,” Duplessis says with a smile and a fist bump. “Good job, man.”

Luckily for me, becoming a better “braker” also means not breaking anything or anybody during my day in the dirt. And that sounds as good as straight cut cogs in a racing dogbox.

For more information on what Dirtfish has to offer, check out their website at http://www.dirtfish.com

Editor’s Note: While I generally describe how to flog a car around, I strongly advise against doing it unless you’re at a closed complex like DirtFish with an experienced instructor like Duplessis.

Photo Credit: Sean M. Donough, Nate Martinez



View the original article here

Saturday, 21 May 2011

Why the Boss Mustang Failed Our Brake Test


2012-ford-mustang-boss-302-rear-in-motion
Road test editor Scott Mortara headed down the quarter mile in the bright-yellow Boss 302 Mustang, steadying his speed for Motor Trend’s standard brake test, just as he’s done a thousand times before. Back in the day, before anti-lock brakes and stability control systems and decent tires, you never knew quite which direction the car might be facing when you finished a brake test. These days, though, it’s fairly simple: At about 70 mph, you grenade the brake pedal and hang on. The electronic nannies keep the cars nice and straight, and our sophisticated on-board data-logging equipment automatically captures the distance it takes to decelerate from 60 mph to a standstill.

So when Scott punched the Mustang’s brake pedal and it went straight to the floor, it got his attention. He quickly ran the six-speed manual back through the gears, slowing the car enough to make it through the gap in the wall at the end of the track.

Why the Boss Mustang Failed Our Brake Test imageTotal brake failure during regular performance testing is a very rare occurrence. I’ve had plenty of cars get squishy pedals and smelly pads after hot laps around a road course. But in more than 25 years of testing, I’ve never known of such a complete—and potentially catastrophic—loss of braking.

Earlier, this particular Boss 302 had repeatedly lapped Laguna Seca and been driven enthusiastically along some of California’s more challenging back roads. Scott had then driven it directly back to Motor Trend HQ in El Segundo so we could get the photos, video, and test numbers we needed for last month’s print and iPad editions, as well as our website and YouTube channel. Had the Mustang’s brake pedal gone to the floor any time in the week before it did, the consequences could have been horrifying.

So what went wrong? Scott heard a metallic snap as he braked. A quick look in the Mustang’s footwell revealed the pin connecting the pedal to the master cylinder clevis rod end had sheared.

The Mustang’s brake pedal arm is normally located between the two sides of the clevis, and even if the clevis pin should fail, after a very short interval the back side of the pedal arm would act against the base of the clevis with enough force to actuate the master cylinder and apply the brakes. But for some reason, the pedal arm in this car had been pinned to the outside of the clevis, on the right-hand side. This concentrated all the force acting on the clevis pin on a single point, causing it to shear; and when the pin failed, the pedal slid past the rod that actuated the master cylinder. The result? No brakes.

Why the Boss Mustang Failed Our Brake Test imageFord reacted instantly to news of the failure. Our Boss 302 was collected and sent away for a tear-down and inspection. The Mustang line was shut down, and every brake assembly checked. Ford also reviewed its process to ensure incorrect attachment of the brake pedal arm to the master cylinder clevis rod end could not occur. We’re told no anomalies were found. And we haven’t seen anything awry on the Mustangs we’ve checked since.

How the arm was misassembled on our Boss 302 tester remains a mystery to Ford, and to us. The only thing we can think of is this particular car’s master cylinder had been removed after it left the factory, and the incorrect connection to the brake pedal arm made when it was reinstalled, although we have no proof either way. Based on the evidence, we’re prepared to chalk this incident up to a freakish combination of circumstances.

Modern cars are amazingly robust and reliable. However, stuff can—and occasionally does—go wrong. That’s why we test.

Angus Mackenzie on April 26 2011 12:03 PM

Tags : 2012 Ford, 2012 Ford Mustang, 2012 Ford Mustang 2012 Boss 302 RWD 2-Dr Coupe V8, Coupes, Ford, Ford Mustang, Ford Mustang 2012 Boss 302 RWD 2-Dr Coupe V8, Sports


View the original article here

Friday, 6 May 2011

Why the Boss Mustang Failed Our Brake Test


2012-ford-mustang-boss-302-rear-in-motion
Road test editor Scott Mortara headed down the quarter mile in the bright-yellow Boss 302 Mustang, steadying his speed for Motor Trend’s standard brake test, just as he’s done a thousand times before. Back in the day, before anti-lock brakes and stability control systems and decent tires, you never knew quite which direction the car might be facing when you finished a brake test. These days, though, it’s fairly simple: At about 70 mph, you grenade the brake pedal and hang on. The electronic nannies keep the cars nice and straight, and our sophisticated on-board data-logging equipment automatically captures the distance it takes to decelerate from 60 mph to a standstill.

So when Scott punched the Mustang’s brake pedal and it went straight to the floor, it got his attention. He quickly ran the six-speed manual back through the gears, slowing the car enough to make it through the gap in the wall at the end of the track.

Why the Boss Mustang Failed Our Brake Test imageTotal brake failure during regular performance testing is a very rare occurrence. I’ve had plenty of cars get squishy pedals and smelly pads after hot laps around a road course. But in more than 25 years of testing, I’ve never known of such a complete—and potentially catastrophic—loss of braking.

Earlier, this particular Boss 302 had repeatedly lapped Laguna Seca and been driven enthusiastically along some of California’s more challenging back roads. Scott had then driven it directly back to Motor Trend HQ in El Segundo so we could get the photos, video, and test numbers we needed for last month’s print and iPad editions, as well as our website and YouTube channel. Had the Mustang’s brake pedal gone to the floor any time in the week before it did, the consequences could have been horrifying.

So what went wrong? Scott heard a metallic snap as he braked. A quick look in the Mustang’s footwell revealed the pin connecting the pedal to the master cylinder clevis rod end had sheared.

The Mustang’s brake pedal arm is normally located between the two sides of the clevis, and even if the clevis pin should fail, after a very short interval the back side of the pedal arm would act against the base of the clevis with enough force to actuate the master cylinder and apply the brakes. But for some reason, the pedal arm in this car had been pinned to the outside of the clevis, on the right-hand side. This concentrated all the force acting on the clevis pin on a single point, causing it to shear; and when the pin failed, the pedal slid past the rod that actuated the master cylinder. The result? No brakes.

Why the Boss Mustang Failed Our Brake Test imageFord reacted instantly to news of the failure. Our Boss 302 was collected and sent away for a tear-down and inspection. The Mustang line was shut down, and every brake assembly checked. Ford also reviewed its process to ensure incorrect attachment of the brake pedal arm to the master cylinder clevis rod end could not occur. We’re told no anomalies were found. And we haven’t seen anything awry on the Mustangs we’ve checked since.

How the arm was misassembled on our Boss 302 tester remains a mystery to Ford, and to us. The only thing we can think of is this particular car’s master cylinder had been removed after it left the factory, and the incorrect connection to the brake pedal arm made when it was reinstalled, although we have no proof either way. Based on the evidence, we’re prepared to chalk this incident up to a freakish combination of circumstances.

Modern cars are amazingly robust and reliable. However, stuff can—and occasionally does—go wrong. That’s why we test.

Angus Mackenzie on April 25 2011 12:03 PM

Tags : 2012 Ford, 2012 Ford Mustang, 2012 Ford Mustang 2012 Boss 302 RWD 2-Dr Coupe V8, Coupes, Ford, Ford Mustang, Ford Mustang 2012 Boss 302 RWD 2-Dr Coupe V8, Sports


View the original article here