I posted this info from another forum… not my writing or pictures.
So today, a guy that worked on the Nissan GT-R transmission through BorgWarner came and gave us a presentation on dual clutch transmissions and had a cutaway GT-R transmission on display.
So here it is:
Here are the 2 clutches:
They are in a parallel and have 6 plates each and are a wet style clutch. The outer(right) one is for the odd gears, the inner for the evens. The reasoning behind this is the odd gear needs a smaller shaft and is therefor the inner of the concentric shafts.The clutches are engaged via hydraulic fluid and do not have a slave cylinder. The pressure of the fluid is controlled by solenoids and is dependent on throttle position.
While we are at the front of the transmission:
Behind the clutch, you can see the output shaft to the front wheels. Normally you wouldn’t see that, but rather the 2 stage clutch that transfers torque to the front wheels. That clutch is gear driven by the forward end of the layshaft.
Here are the actuators for the clutch and shift forks:
The green and grey parts in the top left are the two clutch actuators. The two gold pieces at the bottom are the actuators for 2 of the even gears. The grey part coming out of it is the shift fork. The part highlighted in blue is the filter housing. There are 2 filters, a low pressure one that sits in the bottom just like a normal auto transmission. The other high pressure filter(up to 20 bar) goes in this filter housing.
Here are the even gears:
The odd/even gears are divided into 2 sections. The even ones are in a forward compartment. That bar going across is an oil sprayer.
Behind the even gears are the odd gears:
The yellow is a cutaway of the triple cone synchros.
And at the back is the rear diff:
It uses separate fluid from the rest of the transmission.
This is the clutch actuator by itself. It also contains the oil pump, which is driven off the gear on the bottom side.
This is the actuator board for the even gears. The piece in the back is part of a wiring harness for the DCT in an ///M3.
Heres a close up:
Some other interesting facts since this guy also worked on the DSG transmission and the Veyron’s transmission.
-VW had to beef up the tachs on the DSG cars, because the transmission shifted so fast it was snapping the tach needle back too fast and breaking them.
-The Veyron originally had a 3 bank 18 cylinder engine with 6cyl per bank, but it was changed to the W16 because it was snapping crankshafts.
-The GT-R was supposed to have the trans in the front just like the GT-R’s of old. In fact the area around the firewall is essentially a G35. But in the end it was moved to the back for weight distribution.
-He got a ride one of the prototypes. Apparently the first time he rode in it they cut back power to 75%, did a few laps. Then he got checked out by a doctor to make sure he was handling the G’s okay before they bumped it up to 100% power.
-For the transmission to shift from 6th to 2nd, it has to go from 6th to 5th to 2nd.
-I talked with him about the transmission failures. Here’s what he basically said. He stated that the whole unit is rated for 600nm of torque and that there is a a torque limiter put in place on first gear. In making the switch for launch control, Nissan disabled the torque limiter. He said their intention behind this was for use on low friction surfaces to help torque get to the tires faster for rocking the car out of stuff. He also said that they did testing and said that usually that the transmission was good for 50 launches when done on tarmac like that. That being said, BorgWarner only write basic software for the transmission, not stuff like launch control. They also didnt make the gears. Those are made by the same people that make the regular manual transmissions for Nissan. BorgWarner only does the 2 main clutches, actuators, and synchros.
