Owen Developments GBT6988 Turbo
The 69mm frame GBT is the largest in the range. This option caters for the larger displacement or higher revving engines requiring greater power outputs. The 69mm is capable of producing engine output from 440- 820bhp using 2.0 to 4.0 litre engine configurations. As with the 61mm frame, there are 5 compressor wheel size choices and the Ma7 and Ma5 covers can both be used.
GBT 6976 Compressor wheel: Trim = 52.4 Inducer Diameter = 55.0mm Exducer Diameter = 76.0mm Power Range 440-600 BHP (engine configuration dependant)
GBT 6979 Compressor wheel: Trim = 52.4 Inducer Diameter = 57.2mm Exducer Diameter = 79.0mm Power Range 460-660 BHP (engine configuration dependant)
GBT 6982 Compressor wheel: Trim = 52.3 Inducer Diameter = 59.3mm Exducer Diameter = 82.0mm Power Range 490-720 BHP (engine configuration dependant)
GBT 6986 Compressor wheel: Trim = 52.4 Inducer Diameter = 62.3mm Exducer Diameter = 86.0mm Power Range 510-760 BHP (engine configuration dependant)
GBT 6988 Compressor wheel: Trim = 52.2 Inducer Diameter = 63.6mm Exducer Diameter = 88.0mm Power Range 530-820 BHP (engine configuration dependant)
Choose your turbo
The Owen Development GBT series of turbo allow you choose your fitting, The NT7.0 housing featuring V-Band inlet and Outlet (0.82 A/R), NT7.1 T3 Flanged inlet and V Band Outlet (0.82 A/R), NT7.2 T3 Flanged inlet and V Band Outlet (0.62 A/R)
Water cooling is commonly run through O.E.M. and motorsport turbochargers, alike. However, for those applications where plumbing restrictions, packaging and weight saving is a key focus, then there is an option to upgrade the GBT unit to run an air-cooled housing. Owen Developments specially designed air and oil-cooled casting, has radial air fins, giving it a large surface area. Heat soak from the turbine wheel is dissipated substantially more than just using basic oil-cooling alone. Drawing heat away from the oil, bearing and rotational assembly parts reduces oil breakdown rates and improves component longevity. Walton Motorsport would always recommend Water cooling other than in exceptional circumstances.
MA3 Housing features a 3? Inlet and 2? outlet with a 0.58 A/R, MA5 Housing features a 4? Inlet and 2? outlet with a 0.61 A/R and the MA7 Housing features a 4? Inlet and 2.5? outlet with a 0.69 A/R
PORTED, NON-PORTED AND RESTRICTED COMPRESSOR COVERS – Generally, Owen Developments would suggest choosing a compressor cover with anti-surge ports; especially with the larger wheel sizes, as it widens the safe operating zone within the compressor map, increases top end flow and protects against low down surge. The advantage to not porting a cover is that it is significantly quieter. Most applications which run air restrictors are non-ported. The choice is down to the customer and either option can be provided. Bespoke restrictor fitment for specific race series can also be carried out with additional, custom inlet machining.
The GBT units come with a red anodised compressor wheel and black adaptor ring as standard. However, there is an option to select silver anodised wheels and adaptor ring if desired. In addition to giving the turbos a unique aesthetic appearance, the anodising creates a protective surface layer on the aluminium that prevents oxidisation and increases wear and scratch resistance.
Oil Filter and Restrictor in the feed union as standard
Many turbochargers fail due to debris contamination in the oil feed which can catastrophically damage the motorsport bearing components. This, newly designed, oil feed union houses a stainless steel mesh filter which will capture all, potentially damaging, debris and vastly increase turbo longevity. In-house testing has shown that the oil feed union will supply the bearing with an optimal amount of oil between 3 and 4 bar of oil pressure. When excessive oil is being supplied to the turbo as a result of higher oil pressure, a modified oil restrictor can be used. This can be inserted into the union and reduce oil flow by around 23%.
Boost Pressure Take off and Speed Sensor Fitment
Owen Developments have designed their new compressor cover castings so that they can be drilled and tapped for boost pressure and speed sensor fitment. This gives complete flexibility to what data needs to be extracted from the turbo when in operation. Speed sensor kits and boost pressure take-off kits can also be supplied on request.