Tag Archives: shock

Reducing the Vibration, Upping the Performance

3 Oct

NISMO Rear Performance Damper 350Z

NISMO Front Performance Damper 350Z

There is an old expression in the sports car world “handles like it’s on rails”. In other words, a car that changes direction with such eagerness, authority, and minimal loss of energy, that its akin to a train following a track. To this end, people often go about fitting the stiffest springs they can, with the biggest possible swaybars, and rubber-band thick tires, hoping to reduce lean and roll. This works great on cars with huge sticky tires and lots of downforce (and thus high speeds), and ideally, driven on perfectly smooth tracks. While many try to mimic this on a street car, it’s usually not the case. Normal roads, and even many racetracks around the country are anything but glass-smooth. We’re genernally not running slicks or even R compound tires when we drive to the local diner or for a weekend blast down some backroads, and while we may have installed them on our cars, we’re not generally using dive planes, functional splitters and spoilers to their potential due to street-legal speeds. The same car that handles on rails is also crashing over every imperfection out there. Expansion joints might as well be speedbumps, uneven pavement akin to driving over road spikes. Geometry aside, these super stiff setups often compromise road car handling, more than they improve it. Chassis stiffening is not the same as suspension stiffening, and this is an often-overlooked feature. The chassis of the car is like the skeleton of a high rise building. It’s made of steel girders, because it’s the backbone of the structure. Similarly a cars chassis is the skeleton of the car: it supports everything else.

When NISMO developed the 350Z NISMO edition, mane shunned it as merely a cosmetic upgrade. The engine afterall was the same – but it wore a wildy out there (for a factory car) body kit – a long front bumper with low splitter, a long rear bumper overhang, and a decidedly “Fast and Furious” style spoiler. Delve deeper and you find what makes it so special. The chassis is fully seam welded. Meaning every joint, where 2 pieces of aluminum are bonded together, are full sealed. There are no gaps, there are no open joints. This increases chassis rigidity by a decidely large amount. This is one of the things people often do when bulding a race car from the ground up. To that chassis, Nissan fitted significantly stiffer springs (one of the stiffest out there on a road car) with heavy duty dampers. While the bushings and swaybars remained the same compared to other NISMO cars, the car was noticeably stiffer. But this is, afterall, a road car. While it is very much at home on weekend track days and club events, it’s designed to be a fun, sporting day to day means of transportation. Had it been left alone, it would have been panned for being too obnoxious on the road, too upset by the concrete jungle. To solve those issues NISMO worked with Yamaha to develop a Z-specific pair of body dampers. These attach fore and aft of the shock pointing points, between the 2 biggest “holes” in the chassis – at the front bumper, and in the rear spare tire well. Why there? When a suspension compresses and rebounds, energy is created, stored, and released in very quick succession. The stiffer the spring, the more aggressive the shock valving, the quicker this process happens. Which is why from inside the cabin, that uneven pavement can be downright punishing….whereas in a Toyota Camry, it’s just soaked up effortlessly. The dampers Yamaha and NISMO developed are designed to specifically combat these vibrations, without toning down the benefits that the spring/shock combo gives the handling aspect of the car. When you look at them out of the box, they are basically a strut brace, with a little shock built in. They compress and rebound, like a strut does. However they mount veritcally, whereas shocks mount horizontally. So they combat the natural vibrations the chassis will face when hitting potholes, uneven pavement, and normal bumps in the road. This minimizes energy losses, and lets the spring and shock more efficiently do their job, while keeping the driver comfortable, and thus confident, behind the wheel.

Think it’s still just marketing hype? F1 cars began using similar devices in the 2006 season. Or, just try it for yourself: we have. A 350Z with coilovers (pick your poison, it even helps with wife-friendly coilovers such as Bilstein and KW). With the typical set of low profile 18 or 19 inch tires, and at the typical lowered stance these cars look so good at, it turns the car from a bit erratic over bumps, to downright stable. The suspension is now more able to work in unison, left and right, front to back, whereas without the dampers, it’s a bit of a free-for-all, with the driver being asked to control it all on the fly. It is truly eye-opening how these simple bolt on devices stabilize the vehicle.

The neat thing about these, is they are available for several carswe get here in the US, including the Subaru WRX (02-07), 350Z/G35. Need one for your car? Just drop us a line!

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Regress=Progress

5 Feb

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The trickle down theory may not quite be a perfect operation in public policy, but in the Motorsport world, it certainly holds true. Technological developments born on the track eventually find there way to our daily road cars.

The rage among higher end “reasonably priced” coilovers of the past several years has been the idea of digressive valving. Simplified, its a damper (shock) where the rate of damping force decreases as shaft speed increases. In a traditional damper the damping force increases as shaft speed does. The harder the shock works, the stiffer it gets. Digressive slows this curve down, to better allow the tires to maintain grip and life the harder the car is pushed. as developments on both tire and aero continue, the need and desire for a next generation shock became apparent. I say reasonable in quotes because its a very variable term.

Penske is forever at the forefront of damper technology. Their units can be found in every professional starting grid the world over. NASCAR to GT and everything in between. One of their developments in the last few years has been with regressive valving. This shock works by actually dropping the damping force as shaft speeds increase. In doing do, you are essentially controlling the oscillations the damper would normally experience after it hits a jarring bump. Like the candy canes on a track for example. This lets the spring be controlled more efficiently, keeping the tires planted. The more the tire footprint stays on the ground with an equal level of force acting upon it, the faster the car is. You can brake later, turn faster, put the throttle down sooner. In past setups, on order to maximize the use of downforce, both via front splinters and/or rear spoilers, very high rate springs had to be used. Without them the car would get pushed to the ground…literally. When a super stiff spring is being asked to be controlled by rapid shaft speed, you are forced to dial in very high rebound rates, which in turn kills tire life. But with this new regressive valving, Penske has found they can control the chassis better by dialing in reduced rates of high speed damping force, with increased rates of low speed force. So now instead of that kerbing tossing your 140 mph car airborne, or sideways, it’s better able to remain planted. The former speedbump becomes more akin to nothing more than a pebble.

Now, these are still at their relative early age of development, but with the I created top speeds and aero designs of modern road cars its only a matter of time before this stuff finds its way to the typical sports car/sedan.

Ohlins Shocks for Classic 911

1 Oct

Ohlins latest suspension offering for historic 911 vehicles. Finally, an Ohlins suspension is available for older 911 chassis! The front damper is available in both non-adjustable, single and double adjustable versions. Both non-adjustable and adjustable version are based on a 40 mm OD cylinder tube which fit into the original Porsche McPherson strut casing. The (NA) piston shaft is 12 mm and has a balanced setting developed for both Tarmac and Gravel. The front adjustable version has a 16 mm piston shaft hollowed with a valve and jet that is externally adjustable. This one adjuster adjusts both compression and rebound with the use of a bleed system and also has a temperature compensating system. The rear shock is a 46 mm monotube unit, with a single external adjuster which adjusts both compression and rebound and utilizes a 16 mm piston shaft. This design also has the temperature compensating system and is of course completely servicable/rebuildable. This combination of Öhlins dampers has already shown top performance in various Historic Rallies in Europe. Also available in 2-way or 3-way configurations.

Contact us at z1sales@z1auto.com for your set.