Xtrac Develops Generic Transmission System
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The transmission was developed in partnership with North American vehicle design and niche vehicle manufacturer Brammo. The company, located in the southern Oregon town of Ashland, has been appointed North American distributor. The first application for the Xtrac transmission is the soon to be launched Brammo Rogue GT; the first 1,000 Nm V12 supercar designed and built in the USA. Brammo will make the gearbox available to other specialist supercar manufacturers in North America with customer support complemented by Xtrac’s existing service facility located in Indianapolis. Xtrac will market the transmission in Europe and all other regions of the world. UK production has already commenced with the first batch of transaxles being readied for delivery in the Spring of 2006.
Building on its expertise in specialist race car transmissions, the new road-going variant extends Xtrac’s business into low volume driveline projects for the mainstream automotive industry. Commenting on the company’s decision to invest in an all-new transmission for the upper echelons of the automotive market managing director Peter Digby said:
"With some clients wanting to produce as few as 200 road cars a year they can now largely avoid the engineering costs of commissioning a specially designed transmission. Even if the production costs could be minimised for such low volumes - and that is doubtful - carmakers have until now had no choice but to incur these upfront costs, which includes building prototype gearboxes for test and development, all of which adds significantly to the final cost of the vehicle."
"We are delighted to be working with Xtrac on this prestigious project," said Craig Bramscher founder and chief executive officer of Brammo, "not only as distributor for the important North American market but as a partner with responsibility for key components such as the clutch system. Xtrac recognised the importance of providing this exclusive sector of the market with a quality product and is applying the same standards of design and manufacture as applied to its Formula 1, Racing Sportscar and World Rally Championship transmissions."
He added: "When Brammo set out to build the ultimate supercar we knew the biggest problem with transmitting the power from our massive powerplant was that there was no current solution on the market. After much research we have partnered with Xtrac from the UK to bring the first transverse synchromesh 6-speed gearbox capable of taking the beating our V12 engine can put out in power and torque."
The Brammo/Falconer V12 engine can deliver an incredible power output of up to 1,600bhp (1,200kW) when turbocharged or supercharged. In the launch version of the Brammo Rogue GT the engine has been tuned to deliver 850bhp and 1,000 Nm of torque. The Xtrac transmission is designed to handle massive torque levels of up to 1,100Nm.
Xtrac has a wealth of experience in driveline engineering and is the world’s leading supplier of racecar gearboxes. However, road car transmissions are of significantly different design; consequently it was important to the success of the project that Xtrac engineers had worked previously on a number of bespoke high performance road car projects. Key members of the engineering team include business development manager Robin Price who was the engineering director on the Jaguar XJ220 and McLaren F1 road car transmission projects, Chris Gardner who was a powertrain engineer for the Mercedes-Benz SLR McLaren supercar and Dr Damien Brayshaw who has extensive knowledge of vehicle performance related to differential characteristics from his research at Cranfield University.
Xtrac’s supercar transmission is manufactured and assembled at the company’s purpose built factory at Thatcham in Berkshire, where it employs more than 250 staff including over 50 professional engineers and technicians in its engineering design and research departments. The company has recently recruited more post graduate qualified engineers to expand its capability in the areas of advanced engineering and product development.
Technical specification of Xtrac ‘6012’ transverse transaxle
The maximum gear ratio spread ranges from 15.79:1 to 1.866:1 with the possibility of customers specifying each ratio according to their needs although a standard set of ratios is offered to help reduce the cost of the unit. The overall speed can be altered using a combination of gear ratio, drop gear and final drive gear.
Considering the typical powertrain application for which it’s designed, the aluminium casing and optimised design of internal components have ensured a lightweight 97kg gearbox. The transmission has a transverse layout to allow vehicles to have a short rear overhang, yet still comply with rear impact legislation, with drive transmitted via an engine mounted push-type clutch with a twin-cable gearchange actuation system designed and supplied by Brammo.
The input bevel, six input gears and reverse gear are all mounted on the layshaft. The mainshaft has an integral final drive gear allowing flexibility in overall gearing and design packaging. To meet the demand for durability, mechanical efficiency and refinement, the helical gears have full-form ground teeth with multi-cone synchroniser engagement.
The limited slip differential is a proven Xtrac design ideally suited to prestige cars. It not only offers superior handling but also provides excellent refinement in terms of minimal NVH (noise, vibration and harshness) properties.
The aluminium housing comprises a single casing with a rear cover for the oil system entry and exit ports and side cover to access the differential. Four locations allow the entire transmission to be mounted on a vehicle rear sub-frame. The overall configuration permits a generic front face to mate to an engine bellhousing casting. The differential output is positioned close to the engine rear face and above the gearbox input to ensure the optimum vehicle, clutch and driveline package, but with a low transmission centre of gravity.
The oil system is an integrated re-circulating type using a single-stage eccentric rotor pump with no oil tank. The advantage of this system is a minimal number of components and hence low weight in the pump assembly. Porous media filters, all baffles, magnets, breathers, filler and level plugs are of F1/aerospace quality. The oil system includes a thermostatically controlled pressure relief valve thereby permitting the gearbox to achieve operating temperature quickly resulting in an improved gearchange and high efficiency. Oil cooler inlet and outlet ports are provided at the rear of the casing so as not to disturb the vehicle underbody airflow.
All gears and internal components are manufactured using steels developed exclusively for Xtrac to its own specification. The development of these special steels follows a metallurgy programme drawing on Xtrac’s application of design, testing and race experience. In addition, most of the rotating parts are shot-peened to further enhance durability and reliability.
Following manufacture and assembly of all components each gearbox is fully qualified on a spin rig before despatching to customers.
"The design philosophy behind this product is one of attention to detail," said senior project engineer Mel Dickinson. "Our objective was to optimise packaging, weight and efficiency without resorting to expensive and time consuming exotic materials and processes, also to use analysis techniques to ensure performance targets were met. For maximum reliability proven Xtrac components have been specified throughout."
"This project is a culmination of many years of experience" said technical director Adrian Moore. "We are acknowledged experts of motorsport transmissions. We have integrated this knowledge with our previous exposure to low volume super car transmissions which we have developed from racing units, and create a purpose designed transmission which is unique in the market place."
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Auto | Autos | Auto News | Automotive | Automobile | Automobiles | Brammo | British | Britain | Car | Cars | Design | Development | Engineering | Engine | Gearbox | High Performance | Innovation | Manufacturer | Manufacturing | Performance | Research | Sportscar | Sportscars | Supercar | Supercars | Technology | Transmission | Transverse Transaxle Transmission | Vehicle | Vehicles | UK | United Kingdom | Xtrac
- Gearbox is designed to handle massive torque levels of 1,100Nm
- First application is Brammo Rogue GT supercar with 850bhp V12 engine
The transmission was developed in partnership with North American vehicle design and niche vehicle manufacturer Brammo. The company, located in the southern Oregon town of Ashland, has been appointed North American distributor. The first application for the Xtrac transmission is the soon to be launched Brammo Rogue GT; the first 1,000 Nm V12 supercar designed and built in the USA. Brammo will make the gearbox available to other specialist supercar manufacturers in North America with customer support complemented by Xtrac’s existing service facility located in Indianapolis. Xtrac will market the transmission in Europe and all other regions of the world. UK production has already commenced with the first batch of transaxles being readied for delivery in the Spring of 2006.
Building on its expertise in specialist race car transmissions, the new road-going variant extends Xtrac’s business into low volume driveline projects for the mainstream automotive industry. Commenting on the company’s decision to invest in an all-new transmission for the upper echelons of the automotive market managing director Peter Digby said:
"With some clients wanting to produce as few as 200 road cars a year they can now largely avoid the engineering costs of commissioning a specially designed transmission. Even if the production costs could be minimised for such low volumes - and that is doubtful - carmakers have until now had no choice but to incur these upfront costs, which includes building prototype gearboxes for test and development, all of which adds significantly to the final cost of the vehicle."
"We are delighted to be working with Xtrac on this prestigious project," said Craig Bramscher founder and chief executive officer of Brammo, "not only as distributor for the important North American market but as a partner with responsibility for key components such as the clutch system. Xtrac recognised the importance of providing this exclusive sector of the market with a quality product and is applying the same standards of design and manufacture as applied to its Formula 1, Racing Sportscar and World Rally Championship transmissions."
He added: "When Brammo set out to build the ultimate supercar we knew the biggest problem with transmitting the power from our massive powerplant was that there was no current solution on the market. After much research we have partnered with Xtrac from the UK to bring the first transverse synchromesh 6-speed gearbox capable of taking the beating our V12 engine can put out in power and torque."
The Brammo/Falconer V12 engine can deliver an incredible power output of up to 1,600bhp (1,200kW) when turbocharged or supercharged. In the launch version of the Brammo Rogue GT the engine has been tuned to deliver 850bhp and 1,000 Nm of torque. The Xtrac transmission is designed to handle massive torque levels of up to 1,100Nm.
Xtrac has a wealth of experience in driveline engineering and is the world’s leading supplier of racecar gearboxes. However, road car transmissions are of significantly different design; consequently it was important to the success of the project that Xtrac engineers had worked previously on a number of bespoke high performance road car projects. Key members of the engineering team include business development manager Robin Price who was the engineering director on the Jaguar XJ220 and McLaren F1 road car transmission projects, Chris Gardner who was a powertrain engineer for the Mercedes-Benz SLR McLaren supercar and Dr Damien Brayshaw who has extensive knowledge of vehicle performance related to differential characteristics from his research at Cranfield University.
Xtrac’s supercar transmission is manufactured and assembled at the company’s purpose built factory at Thatcham in Berkshire, where it employs more than 250 staff including over 50 professional engineers and technicians in its engineering design and research departments. The company has recently recruited more post graduate qualified engineers to expand its capability in the areas of advanced engineering and product development.
Technical specification of Xtrac ‘6012’ transverse transaxle
The maximum gear ratio spread ranges from 15.79:1 to 1.866:1 with the possibility of customers specifying each ratio according to their needs although a standard set of ratios is offered to help reduce the cost of the unit. The overall speed can be altered using a combination of gear ratio, drop gear and final drive gear.
Considering the typical powertrain application for which it’s designed, the aluminium casing and optimised design of internal components have ensured a lightweight 97kg gearbox. The transmission has a transverse layout to allow vehicles to have a short rear overhang, yet still comply with rear impact legislation, with drive transmitted via an engine mounted push-type clutch with a twin-cable gearchange actuation system designed and supplied by Brammo.
The input bevel, six input gears and reverse gear are all mounted on the layshaft. The mainshaft has an integral final drive gear allowing flexibility in overall gearing and design packaging. To meet the demand for durability, mechanical efficiency and refinement, the helical gears have full-form ground teeth with multi-cone synchroniser engagement.
The limited slip differential is a proven Xtrac design ideally suited to prestige cars. It not only offers superior handling but also provides excellent refinement in terms of minimal NVH (noise, vibration and harshness) properties.
The aluminium housing comprises a single casing with a rear cover for the oil system entry and exit ports and side cover to access the differential. Four locations allow the entire transmission to be mounted on a vehicle rear sub-frame. The overall configuration permits a generic front face to mate to an engine bellhousing casting. The differential output is positioned close to the engine rear face and above the gearbox input to ensure the optimum vehicle, clutch and driveline package, but with a low transmission centre of gravity.
The oil system is an integrated re-circulating type using a single-stage eccentric rotor pump with no oil tank. The advantage of this system is a minimal number of components and hence low weight in the pump assembly. Porous media filters, all baffles, magnets, breathers, filler and level plugs are of F1/aerospace quality. The oil system includes a thermostatically controlled pressure relief valve thereby permitting the gearbox to achieve operating temperature quickly resulting in an improved gearchange and high efficiency. Oil cooler inlet and outlet ports are provided at the rear of the casing so as not to disturb the vehicle underbody airflow.
All gears and internal components are manufactured using steels developed exclusively for Xtrac to its own specification. The development of these special steels follows a metallurgy programme drawing on Xtrac’s application of design, testing and race experience. In addition, most of the rotating parts are shot-peened to further enhance durability and reliability.
Following manufacture and assembly of all components each gearbox is fully qualified on a spin rig before despatching to customers.
"The design philosophy behind this product is one of attention to detail," said senior project engineer Mel Dickinson. "Our objective was to optimise packaging, weight and efficiency without resorting to expensive and time consuming exotic materials and processes, also to use analysis techniques to ensure performance targets were met. For maximum reliability proven Xtrac components have been specified throughout."
"This project is a culmination of many years of experience" said technical director Adrian Moore. "We are acknowledged experts of motorsport transmissions. We have integrated this knowledge with our previous exposure to low volume super car transmissions which we have developed from racing units, and create a purpose designed transmission which is unique in the market place."
Web Sites:
Related Articles:
Keywords:
Auto | Autos | Auto News | Automotive | Automobile | Automobiles | Brammo | British | Britain | Car | Cars | Design | Development | Engineering | Engine | Gearbox | High Performance | Innovation | Manufacturer | Manufacturing | Performance | Research | Sportscar | Sportscars | Supercar | Supercars | Technology | Transmission | Transverse Transaxle Transmission | Vehicle | Vehicles | UK | United Kingdom | Xtrac
posted by Jon Fry at 12:01:00 AM
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