GR86 GR86 Track Prep - GR Cup insider knowledge

[GRinning]

Hi All,

A friend of mine managed to get chatting to someone who helped setup a GR Cup race series, and asked a few questions about how they prep the cars. Hope the following is helpful!

“He said the gearboxes are tough, but fail quickly with the factory oil, particularly the synchros. He recommended to monitor for debris from the synchro in the gearbox and to change the oil, they use Ravenol 75w140.

The engines they fit with baffled sumps (possibly this) and additional oil pressure warning sensors. They run 5w30 thickness and said he hasn't seen it as a problem.

Suspension, they run
5.5° front camber with 2° toe out,
1° toe in rear
2.7° rear camber

The factory clutch is another failure point. Although he said it's only the Friction plate material that's poor, they keep a spring damped friction disk not solid, but they run a better friction material. He couldn't remember the brand.

Lastly, the sliding collar on input shaft to the gearbox that gets moved by the cluch fork. He said the cars all wear here and you should monitor it. On track they often replace gearboxes (2hr job apparently) but on a road car it's just something to keep an eye on when you change the clutch.”

 

[KobayashiMaru86]

I'm sure someone said before but how mean litres does the box need? I'll buy some in advance of the service. Will need diff oil too

 

[sim86]

Transmission is 2.2L of GL4 fluid (75w), Diff is 1.2L of GL5 (75w-85).

Diff is on the schedule for the major service, if you're happy with OEM.

 

[ZN8]

Interesting stuff. I take it they must run oil coolers too?

I get the impression 4th gear synchro is the weak spot, mainly only a problem with those that track the car. It's an Aisin AZ6 box which was rated to 250NM in the GT86, I know they strengthened some components for the GR86 but I imagine it's still on the limit based on the torque from the FA24.

 

[Jianlun]

Curious. Why do you say specifically 4th gear? Its the gear with the carbon synchro.

 

[AdamST205]

There are lots of people developing larger capacity sumps at the moment. This is what I am waiting for before I even think of taking my GR86 on track.

Larger capacity oil sump + oil cooler.
Cusco front top mounts + rear adjustable arms.
Uprated brake pads and RBF700/SRF brake fluid.

Good to go for track work then and will have a solid reliable car that will eat up the miles with full adjustability.

 

[ninjin]

Hi All,

A friend of mine managed to get chatting to someone who helped setup a GR Cup race series, and asked a few questions about how they prep the cars. Hope the following is helpful!

“He said the gearboxes are tough, but fail quickly with the factory oil, particularly the synchros. He recommended to monitor for debris from the synchro in the gearbox and to change the oil, they use Ravenol 75w140.

The engines they fit with baffled sumps (possibly this) and additional oil pressure warning sensors. They run 5w30 thickness and said he hasn't seen it as a problem.

Suspension, they run
5.5° front camber with 2° toe out,
1° toe in rear
2.7° rear camber

The factory clutch is another failure point. Although he said it's only the Friction plate material that's poor, they keep a spring damped friction disk not solid, but they run a better friction material. He couldn't remember the brand.

Lastly, the sliding collar on input shaft to the gearbox that gets moved by the cluch fork. He said the cars all wear here and you should monitor it. On track they often replace gearboxes (2hr job apparently) but on a road car it's just something to keep an eye on when you change the clutch.”

4th Gear is the weak link. In the Japanese GR cup, they take 2 gearboxes. One used for qualifying and one used for actual race.

There is a list of parts that you can fit to the car for the GR86 Japan race series. I'll post it if I can find it again.

Here is a privateer who previously won in Macau. He has decided to compete in the Japan GR86.

 

[GRinning]

Hi All,

A friend of mine managed to get chatting to someone who helped setup a GR Cup race series, and asked a few questions about how they prep the cars. Hope the following is helpful!

“He said the gearboxes are tough, but fail quickly with the factory oil, particularly the synchros. He recommended to monitor for debris from the synchro in the gearbox and to change the oil, they use Ravenol 75w140.

The engines they fit with baffled sumps (possibly this) and additional oil pressure warning sensors. They run 5w30 thickness and said he hasn't seen it as a problem.

Suspension, they run
5.5° front camber with 2° toe out,
1° toe in rear
2.7° rear camber

The factory clutch is another failure point. Although he said it's only the Friction plate material that's poor, they keep a spring damped friction disk not solid, but they run a better friction material. He couldn't remember the brand.

Lastly, the sliding collar on input shaft to the gearbox that gets moved by the cluch fork. He said the cars all wear here and you should monitor it. On track they often replace gearboxes (2hr job apparently) but on a road car it's just something to keep an eye on when you change the clutch.”

Sorry guys think there was a miscommunication somewhere, I don’t think they replace the gearbox oil with 75w140 - possibly the diff? But that seems far too thick for the gearbox!