PRODUCT SPECIFICATION - ARB USA bag suspension models are available for the Jeep WK2 and this new...

1OME Suspension System - Jeep Grand Cherokee WK2: 2011 & On || www.arbusa.com

DATE: June 2014

DESCRIPTION: Old Man Emu Suspension

APPLICATION: Jeep Grand Cherokee WK2: 2011 & On

PART NO. : See Table Page 5

PRICING:See Table Page 5 AVAILABILITY DATE:August 2014

PRODUCT SPECIFICATIONOLD MAN EMU SUPENSION SYSTEMS

Determining the right solution for your vehicle and your requirements demands special attention to many factors. Unlike numerous aftermarket suspension systems, which are only available in a single configuration targeting lift height, Old Man Emu (OME) now offers a range of tuned and matched integrated suspension systems engineered specifically for the Jeep Grand Cherokee WK2. This ensures the right suspension is available to suit how the vehicle is outfitted and the conditions it will encounter. This full line of suspension options will cover the range of builds from lightly built and stock vehicles up to those with 660 lbs. of constant weight being fitted.

DESIGN & DEVELOPMENT

The objective of OME engineering team was to develop an integrated suspension system for the Jeep Grand Cherokee WK2. The WK2 runs an independent front and independent rear suspension setup and is available in a number of engine variants. In some markets there is a tow pack option, which comes with a Nivomat (self-leveling) rear shock absorber. Air bag suspension models are available for the Jeep WK2 and this new OME suspension system does NOT replace, nor is compatible, with the Quadra-Lift airbag system.

The key areas that were addressed in the design of these components were lift, load carrying capability, and comfort. With the WK2 being a mid-sized SUV, the original suspension provided a comfort-orientated ride, which had a tendency to top out and frequently contact the bump stops, especially on rougher surfaces and over speed bumps. The WK2’s factory geometry allowed for a 40 to 50mm lift, which improves overall wheel travel and off road capability. To meet this need longer travel shocks and struts were developed for improved down travel and were tuned to match the new spring specifications.

Comprehensive fitting instructions have been created to assist in the fitment of the WK2 suspension system due to the level of complexity involved in removing the factory components.


TESTING:

As there are known failures of stock and aftermarket WK2 front struts, extensive testing was conducted to ensure that these Old Man Emu components would exceed the demands of the harsh conditions and weight carrying stresses that these vehicles are put through around the globe. The following are standard OME test procedures which the WK2 components were subjected to.

FATIQUE AND DURABILITY: Fatigue testing the front clevis & body assembly:

Three samples of original equipment shock absorber & three samples of the proposed OME body were fatigue tested on the MTS shock dyno. The clevis bracket was assembled to the lower mounts width of 72 mm, using an original equipment bolt and dealer specified torque to replicate vehicle fitment. For this test, a cyclic load of 700 kg tensile & a compressive 2,200 kg were applied at a frequency of 5 Hz. The original equipment samples cracked, fatigued and broke through clevis leg at 1.3, 1.7 & 3.5 million cycles. Three Old Man Emu samples were tested, and the tests were halted between 5 and 6 million cycles with no evidence of cracking or deterioration.

Fatigue testing the rear suspension clevis & body assembly:

Three original equipment shock absorbers & three samples of the OME body were fatigue tested on the MTS shock dyno. The clevis bracket was assembled to the lower mount width of 62 mm, using an original equipment bolt and manufacturer specified torque to replicate vehicle fitment. For this test a cyclic load of 700 kg tensile & 1,900 kg compressive were applied at a frequency of 10 Hz. The original equipment samples cracked, fatigued, and broke through the clevis leg at 93, 118, & 136 thousand cycles. The failure point for the OME samples were found at 600, 247, & 517 thousand cycles.

Fatigue testing of the aftermarket spring seat on weld ring of body assembly:

This test consisted of cyclic loaded 800 kg to 1,500 kg for 500,000 cycles. The sample was tested with tooling to represent spring contact on the spring seat. This specific test represents load at the spring length of 305 mm (full extension) ranging to the minimum spring length of 190 mm (full compression). No evidence of failure was found, confirming the strength and durability of spring seat internal plate.


WELD ANALYSIS:

The OME body assembly was sectioned & analyzed for weld quality compliance. The welds were metallurgically assessed for fillet throat size, depth of penetration, undercut, cracks, notching, melt back, porosity, under fill and non-metallic inclusions. It was found that the welds met the requirements of the quality specified in Specification W27-031 (Class A welds).

New stud, washer & rod projection welded assemblies for rear standard suspension product were also sectioned and analyzed for weld quality compliance. These welds were metallurgically assessed for adequate fusion zone, grain size in heat affected zone, cracks, holes, porosity, & non-metallic inclusions. The requirements of weld quality specified in Specification W27-001 were also met for these welds.

FRONT SUSPENSION:

Three spring options were created for each engine variant to cater for a range of front accessory fitments. Each front strut option was tuned to match the spring weights and minimize the frequency of bump stop contact and top out events during on and off road driving. Extensive development went into the front strut, as there has been some reported issues of durability, specifically around the front clevis in both OE and other aftermarket products. Another challenge with manufacturing of the front strut was the physical length of the strut, which is now the longest body shock absorber in the OME range.

A significant development project was undertaken to model and optimize the clevis design using 3D CAD modeling and Finite Element Analysis (FEA). A number of manufacturing options were considered, which resulted in a forged and machined clevis design being chosen. This final product is considerably stronger and more durable than the original equipment component that came on the vehicle from the factory. Another unique design feature is an outer body assembly housing a twin tube cartridge that increases the overall strength of the strut assembly. Further to FEA testing, extensive physical tests were conducted to verify all computer aiding engineering and benchmark against the original.

A front trim packer was developed to assist with fine-tuning ride heights.


REAR SUSPENSION

A 50mm lift was achieved and 2 progressive rate spring designs were created to cater for medium loads and constants loads of 660lbs. As the Jeep WK2 is available with an optional tow pack, 2 different designs needed to be created. The tow pack option introduces a factory Nivomat (self-leveling) rear shock absorber that has a different top pin mount and different extended and compressed lengths. With 2 different shock designs and 2 springs to cater for loading options, the result is 4 different shock options for the rear. Please note when replacing factory Nivomat shocks, you must fit the appropriate OME spring. To identify whether a vehicle has the standard fitment rear shock or Nivomat shock, the outer body diameter will need to be measured.

Standard fitment: 51mm (outside diameter)Nivomat: 63mm (outside diameter)


Part Number Description Retail Price3059 Coil Spring WK2 F Medium $187.003060 Coil Spring WK2 R Heavy $226.003070 Coil Spring WK2 F V6 No Bar $187.003072 Coil Spring WK2 V6 w/Bar $187.003073 Coil Spring WK2 F Diesel No Bar $187.003074 Coil Spring WK2 R Medium $226.003085 Coil Spring WK2 F Diesel w/Bar $187.003086 Coil Spring WK2 F Diesel Bar $187.0060124 Sport Shock WK2 R Medium $139.0060125 Sport Shock WK2 R Heavy $139.0060126 Sport Shock WK2 Nivo Fit Medium $139.0060127 Sport Shock WK2 Nivo Fit Heavy $139.0090026 Sport Strut Jeep WK2 $242.00FK79 Trim Packer - 5mm $13.00

PART NUMBER INFORMATION & PRICING

PRODUCT SPECIFICATION - ARB USA bag suspension models are available for the Jeep WK2 and this new...

Documents

Transcript of PRODUCT SPECIFICATION - ARB USA bag suspension models are available for the Jeep WK2 and this new...