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Discussion Starter #1
A Skyline GTR is pretty good at making you look like a better driver than you really are without ruining all your fun! In fact I've a few people get out of the car on track days and ask "Are you sure it's four wheel drive?"

I've been looking at data logs to understand exactly how it does it. Essentially: RWD normally, moving to around 25% to 30% front drive to help manage "mildly fruity" moments and finally 50/50 split for high speed stability.

This matches what I've read over the years and the feedback you feel in the car, so it's nice to confirm that all with real data and be able to show it in practice.

Here's 30 seconds of data, three corners and a straight at Silverstone to demonstrate these basics.


This example is a 32 but the 33 and 34 are fairly similar in basic operation. Apparently the ATTESA ETS intervenes quicker and more intelligently in the newer cars but the basic principles are the same. What you do see on my logs is the 250ms-500ms the 32 system takes to build pressure at the transfer case and bring in the front wheel drive, doesn't sounds long but you can get quite sideways in half a second:runaway:
 

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Discussion Starter #6 (Edited)
1.3 g is really impressive. Are you still on the AD08R's?

Good to see you having fun, anymore footage?
Yes still on the AD08Rs, they are 18mths old now I think, only done a few dry trackdays on them though. Seemed to rain every time I went on track last year!

The figures look good but they were a bit more noisy than the RSRs and no longer have the grip levels of the A048Rs which they pretty much had when brand new.

Lots of raw footage from the 19th not much edited yet. Just the geakery above and this sport with an amusingly driven 991 Turbo.
 

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Yes still on the AD08Rs, they are 18mths old now I think, only done a few dry trackdays on them though. Seemed to rain every time I went on track last year!

The figures look good but they were a bit more noisy than the RSRs and no longer have the grip levels of the A048Rs which they pretty much had when brand new.

Lots of raw footage from the 19th not much edited yet. Just the geakery above and this sport with an amusingly driven 991 Turbo.
Thats some nice driving, your car is rapid.
 

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Alex, how are you collecting the 4WD torque split data? are you probing the CAN bus? I would like to get the same into my VBOX logs but I guess I would need to find the PIDs and then ask Racelogic to add those.
 

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Discussion Starter #12
Sorry I think you was talking to the OP not me haha
Hehe I couldn't tell either. I saw some of your onboard though, looked great, 620 is a nice number, interesting you've detuned a bit, I've also turned down the wick, I was running 1.2bar and have managed 2:32 fairly consistent with a 2:30 fluke once in 2014. Now only 1bar but with much better response after Mark at Abbey dialed in the closed loop boost on the Link using the data we sent back and for in the course of the day at Silverstone. I get full boost after a gear change a full second sooner now. The result is around 450-470fwhp I guess which is pretty nice. I've also taken out the ABS and not yet got to grips with that so I'm afair bit slower over a lap, where I was getting 1.2g on the brakes I now squeak 0.9g and you see it in the logs killing the lap times, best I managed in decent conditions was a 2:36 on the 19th. Not all about lap times though and its really lovely to drive now. I was temped to switch back to high boost when I cpuldn't quite pass that Turbo on the straight though.:chuckle:
 

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Discussion Starter #13
Alex, how are you collecting the 4WD torque split data? are you probing the CAN bus? I would like to get the same into my VBOX logs but I guess I would need to find the PIDs and then ask Racelogic to add those.
The old style ATTESA doesn't have any data output really so I fitted a pressure sensor into the transfer case itself and fed that into a gauge and then into an analog input on the link ecu. In due course I will output that onto the CAN bus and log it on my race technology video 4 logger which is already reading everything else from the Link CAN bus output, but for now its just logged in the Link ECU.

On an R35 no doubt it will all be on the bus so it may just a question of getting the CAN ids for your logger. The race technology logger can input box is configurable so if you know the can stream/frame details you can add it yourself which is very handy.
 

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Thanks, I will try and find the PID for it and contact Racelogic, it would be interesting to see how the R35 torque split compares with the older generations.
 

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Nice one AlexJ, definitely much better than what I read from my defi!
Now I really know how the AtTESSA helps me to look good.. hahhaha

Do you mind if I post the video in my local R32 whatsapp group?
 

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Yes that was a crap and confusing post- sorry!

Good seeing all these figures and trying to understand them. Thanks for the vids :)
 

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Discussion Starter #19
Do you have any logging under braking?
I've had a good look through the logs and very occasionally the pressure will tick up to 50-60psi under braking. This seems to be associated with the more extreme brake zones, esp where the final speed is lower and two downshifts are required, the "simple" brake zones even with high g (-1g) say 130 down to 70mph with one or no gear change don't trigger it. Perhaps the lower speed is increasing the chances of lockup and the ATTESA is intervening.

For the most part there is no ATTESA activity on the brakes though.
 

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I've had a good look through the logs and very occasionally the pressure will tick up to 50-60psi under braking. This seems to be associated with the more extreme brake zones, esp where the final speed is lower and two downshifts are required, the "simple" brake zones even with high g (-1g) say 130 down to 70mph with one or no gear change don't trigger it. Perhaps the lower speed is increasing the chances of lockup and the ATTESA is intervening.

For the most part there is no ATTESA activity on the brakes though.
Interesting, thanks.
 
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