AMG Replacing 6.3 V8 with 5.5L Twin Turbo V8

It’s the end of the world as we know it. AMG, Mercedes’ dedicated performance side-arm, will be announcing a new down-sized V8 at the upcoming Geneva show. Considering AMG has always been known for stuffing huge engines in pimped out Mercs, the prospect of a smaller, more efficient AMG engine is a bit hard to stomach at first. But read a little deeper, and you get the feeling it’ll be alright – they’re bolting a set of twin turbos up to it to make up for the drop in displacement, and both power and efficiency are going up.

The M157 V8 is being de-stroked from a massive 6.2L down to “only” 5.5L, but is gaining a pair of exhaust-driven huffers, direct fuel injection (an AMG first) which allows a rather high 10.0:1 compression ratio, and a bag full of new tricks to make it both faster and a little greener. It will first be introduced in the full-size S63 AMG sedan (which will oddly keep the “63″ moniker despite being nowhere close to 6.3L) later this year, with trickle-down to other V8 AMG models expected over the next few years. Other cool tidbits include an aluminum crankcase, an air-to-water intercooler(!), and an alternator that only charges during deceleration to reduce parasitic drag.

Initial numbers are pretty promising. The basic-spec M157 makes 544bhp @ 5500rpm and 586 lb-ft of torque between 2000-4500rpm, with an optional performance package boosting those numbers up to 571bhp and an epic 660lb-ft (894nM) of torque. The S63 also inherits the new 7-speed Speedshift MCT, seen in the SL63 and E63 AMG already – which uses a wet multi-plate clutch setup instead of a traditional torque converter for faster shifts and increased efficiency.

With the basic motor the S63 will run up to an electronically limited 155mph, and with the optional performance pack it’ll do a rather insane 186mph – that seems like more than enough for an S-class, I’d say. 0-100km/h takes 4.5 seconds, or 4.4 with the performance package – seriously quick times for a massive full-size luxobarge.

What’s really neat is that AMG claims the new biturbo V8 will be more efficient than the outgoing 6.2L unit by nearly 25%, meaning it will skirt around the US gas-guzzler tax for the first time in ever – despite having up to 47 horsepower more than the outgoing model. The new M157 will have an engine start/stop mode to waste less gas sitting still, which can’t hurt. Mercedes will be showing a track-prepped S63 AMG in classic racing livery at Geneva alongside a classic 1971 300SEL 6.9 that took second overall at Spa-Francorchamps that year thanks to AMG preparation – and a 428bhp 6.8L V8, of course. Expect to see more pictures and get more details when the Geneva show finally rolls around.

How To: Install New Shocks With Minimal Injury

The reason old cars feel old and tired is that everything has a lifespan. Rubber bushings crumble and fail, hinges loosen and sag, plastics become brittle and rattly - sort of like humans. Time may heal all wounds, but it's not a great beautician. The best way to give an old car a new lease on life is to replace tired, worn out components - and the suspension is a fantastic place to start. My SPG had a set of "God knows how ancient" KYB Gas-A-Just dampers on it when I bought it, and they've always made me pretty uneasy. They've always felt a little floaty and underdamped, plus the serious terminal rust on the shock bodies I discovered when I mounted the new tires made me decide it was time to toss out the old 'n busted, and go for the new hotness. Cue an eBay hunt for some suitable replacement shocks! After approximately 20 minutes of searching and almost 2 weeks of waiting, these puppies arrived at my doorstep: 4 brand-new-in-box KYB GR-2 dampers, for both axles of the 900. Total cost: $120, give or take - quite a bargain! The GR-2 is KYB's basic OEM-replacement level shock absorber, with a twin-tube design and using nitrogen as the damper medium. They're not crazy double-bypass Fox racing shocks or rock-hard Bilstein Sports, but for a daily-driven car they will work wonders - and the price is hard to beat. Now, where to start... I started out at the driver's side front shock. First order of business is to raise the corner of the car far enough off the ground with a floor jack to remove the wheel/tire, and then set the car down on a jackstand - as you'll be needing the jack later. Once it's off the ground, start working under the hood. On the driver's side, it helps to move the coolant overflow tank out of the way as it's basically sitting right smack-dab on top of the upper shock mount. This is done by removing one big long bolt that goes through the center of it, and then stuff it down there next to the oil dipstick, being careful not to crack any rubber cooling hoses. Now for the fun part. The Bentley manual just says "remove top mounting nut and hardware (dished washer and rubber bushing.)" As if it's that easy. That SOB has been sitting there for probably 15 years, and hasn't moved the entire time - so of course it's frozen in place with rust and grime. My suggestion would be to put 5-10 drops of Liquid Wrench (a rust-dissolving solvent) on it, and tap the shaft a few times with a hammer to let it sink it. Then wait ten minutes while the chemicals do their job - better living through science! Of course, the top shock mount is down between the brake booster and the strut tower, below some hard brake lines - so it's a b*$&^ to get to. So here's how it works: Get enough 3/8" extensions that you can get a socket down on the top shock mount, and then get a set of vice-grips on the shock body as tight as they'll freakin' go. Brute force is the only thing that's gonna get that nut loose, although having a friend hold the vice-grips doesn't hurt. Hold the shock body in place and push with all your might, until the nut finally loosens and your hand flies into the firewall, taking half the skin off your knuckle with it. Lovely! Remember, Blood Sweat and Tears wasn't just a funk band. Hey, these things happen! Once you've bandaged your bleeding hand, grab (another) beer and hop back in with both feet. Remove the top nut and hardware and now it's time to turn your attention to the bottom, which is significantly easier. There's a large (18mm) nut and washer that attach the bottom of the shock to the lower control arm. Utilize a long breaker bar to get it loose, then a ratcheting socket wrench to get the nut almost all the way off - this will prevent the shock from popping off violently and hitting your foot. Then use a pry bar (or in my case, a really big screwdriver) to leverage the shock off the control arm mounting point. Once it's loose, remove the nut and the shock will fall out. Picture of the old and busted next to the new hotness is necessary here, I feel: I didn't take duplicate pictures from the passenger's side (the process is the same) but I felt compelled to get a picture of what happens to shocks that don't cooperate with me when I'm trying to remove them. The body was so rusted out it basically collapsed under the pressure of the vice-grips, so I had to use a pair of dykes to cut the cover so I could grip the shaft. Old rusted crap parts are so fun. You can almost smell the tetanus. Next, make sure to mount all the hardware in the right direction - bushings and washers below and above the body. Then insert the shock into the opening on the body, and after putting a little grease on the lower bushing, mount it to the lower control arm. Then, using the jack, compress the lower control arm and spring upward so that there's enough thread showing on the top of the shock to thread the nut. Tighten down the lower shock mount (75 lb-ft of torque), lower the jack, then hold the shock body with one hand and tighten the top mount until the edges of the bushing squish outside the washer. Presto change-o, new shock installed! Get your coilovers at demon tweeks. The rear is a similar process, but since they are different suspension types (the front is independent with double control arms and an ARB, the rear is a solid axle with panhard bar and ARB) the details are slightly different. Here's what I was starting with - yikes! Use the floorjack to raise the spring link (the big metal bar the spring and shock connect to) slightly to relieve some load from the shock after you remove the wheel, then get to unbolting the lower shock mount. It's a big chunky bolt that runs through both sides of the spring link and the bottom of the shock, and it's secured with a big 19mm nut on the other end. It's best to use a big socket wrench and an 19mm box-end wrench on the other side; the nut's hard to get to. Again, some force is necessary here to break the blasted nut loose.. For the top, it's time to use the Liquid Wrench trick again, as well as the vice grips and socket wrench technique to get the frozen nut loose. Thankfully you have more space to work with here so it's not so hellish. Wearing gloves is a sign you learn from mistakes; that way when the nut finally loosens and you bang your hand on the fenderwell you don't lose any more skin! After this, it's a matter of getting enough leverage to get the bottom of the shock out of it's mount - it's a really tight fit - and again I recommend the use of a BFS - screwdriver. Once you get the bottom up past the spring link, just wiggle the shock out to the side and discard all the old crap. Again, an old 'n busted to New Hotness comparison shot: After that, it's a matter of compressing the shock enough to get it in place and bolting everything down. Easy as pie! Now, on to dealing with those worn-out brakes. That's a post for another day, I suppose. These 900's are like Medusa: fix one problem and you notice three more. The rear rotors are totally shagged, and all four sets of brake pads could due for replacement. Also, the brake pedal's getting spongy so a brake bleeding is in order. So much to do!