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| Prototype Cobb compressor bypass valves feature a piston instead of a diaphragm for smooth reliable action |
For reliability of the rumored to be fragile transmission, the transmission controller needs to be reprogrammed. The transmission controller communicates with the engine’s ECU and if it detects too much calculated torque it does things like reduce hydraulic line pressure to provide protective cushion on shifts. Well this sort of behavior will also cause slippage which can destroy the transmission with wear and heat. Cobb also tunes the transmission controller to behave correctly when the power is greatly increased by reducing shift overlap and increasing line pressure to reduce slippage. Thus the “fragile” GTR transmission is made much more reliable if launch mode is avoided. Amazingly enough, with this level of bolt on mods and tuning, a GTR can easily run low 10 second quarter mile times with a very streetable easy to drive power delivery while not using the abusive launch control.
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| This Mocal oil to water cooler uses the engines coolant to act as the first stage cooler for the transmission |
One issue that the GTR suffers from is that the transmission gets hot and the car goes into limp mode in a few laps at racing speed. To combat this heat, the transmission fluid is circulated through a rear mounted Mocal water to oil cooler, then through a Setrab oil to air heat exchanger fed by a ducted fan. The differential oil is circulated through a second Setrab ducted fan fed heat exchanger. The engine oil is fed through the stock oil cooler and a Cobb secondary oil cooler located in a Cobb air duct in the unused drivers side bumper duct. Engine bearing damage can start at oil temperatures of around 260 degrees and the Cobb cooler keeps the oil temps below 235 degrees. Surprisingly the GOTO team has found the stock radiator to work well!
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| These two coolers with ducted fans are the second stage transmission cooler and the differential cooler. All of these coolers prevent the transmission from going into limp mode. |
Amazingly this is the extent of the engine and drivetrain mods!
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| The interior of the Cobb GTR is only mildly gutted. The car has a relatively simple roll cage for driver protection and chassis stiffening. |
The GTR is a portly pig, weighing as much as some trucks. GOTO racing lightened the car by mildly gutting it. Some of the stock interior panels and dash still remain and it looks like the car could actually be returned to street condition with a few hours of work! A straightforward and simple roll cage has been welded in to comply with rules and the seats replaced with a lightweight racing seat. All the factory glass remains. With mild lightening the car still smashes the scales at 3600 lbs making it hold the record as the heaviest time attack car on the circuit!
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The GTR uses a Racetech head protecting seat. Knee brace also provides leg protection from side impacts.
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| Motec dash is used for data logging and track mapping. |
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The carbon dash panel has controls for the Motec dash and lights.
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| The drycell battery is remounted from high in the engine compartment to low in the passenger compartment to help with CG location and weight distribution. Look how deep the frame rails are, the GTR is a stiff car from the factory. |
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| Halon fire system helps ensure safety. |
