I have a 2017 Q60 AWD Red Sport with heavily modified suspension but stock engine. My complete mod list is below. I have been to VIR twice now with my new wheels and tires (Hankook RS-4) and was running into the VDC limiting steering as I got more aggressive and faster. I went to VIR today and turned off VDC l for the first time and the first session went well. The car was no longer fighting me and I easily beat my best time. As the day went on, the track got hotter and likely grippier as more rubber was put down. My next session, the car started fighting me more and limiting steering even with the VDC off. I figured my tire pressures had increased too much so the next session I lowered them. No better, I actually cut my last session short since I was pissed. Tomorrow is supposed to be very wet so I will put the daily tires back on so and VDC.

I am guessing turning the VDC switch doesn't turn off VDC completely? Is there anything else I can do besides driving within the limits of the car's VDC? The one session today was amazing!

Additional thought, the Q60 has a stupid open diff. A LSD was going to be my next mod. Perhaps the VDC is getting messed up more than it should do to the open diff being a horrible track option?

2017 Q60 Red Sport AWD Iridium Blue / Silver's Neomax Coilivers (Swift Springs 14k/10K) / SPL Front UCA, Rear Traction Arms, Rear Toe Arms, Bumpsteer Adjustable Front Tie Rod Ends / Z1 Two Piece Rotors / Carbotech 1521 pads (XP12/XP10 for Track) / SS Brake Lines / 370Z Nismo V1 Wheels with 10mm front 15mm rear Z1 Spacers / Continental ExtremeContact Sport 245/40 /Titan T-R10 18X9.5 +22 (Track Wheels) / Hankook RS-4 275/40 R18 (Track Tires) / Infiniti Helmholtz Exhaust / Hotchkis FSB & RSB / SPL Front & Rear End Links / Z1 Subframe Bushing Collars / Pride Auto AWD Transmission Mount (Poly Insert) / Part Shop Max Solid Steering Rack Bushings / Z1 Rear Diff Brace / AMS Heat Exchanger / Recaro Sportster CS Seat

 

VDC isn't fully disabled sadly, there are still some nannies that have to be bypassed. This is something a lot of the 370z track guys have done. This keeps ABS active but disables the VDC nannies fully. I'm not familiar with the newer Q60 coupes but would assume Nissan/Infiniti hasn't changed too much, but I’m not an Infiniti tech and don’t have a Q60 coupe so please don’t take my word. These articles might work for you, but YMMV. You're right about the OEM differential not helping by any means- for track-worthy differentials, check out Wavetrac and OS Giken. I plan to compete in global time attack in my G37 and have a Wavetrac waiting to go in...rumor has it those are one of the best for cornering and grip. If you drift or want adjustability, OS Giken seems like the way to go. Hope that helps!

DIY Yaw Sensor rocker switch - Nissan 370Z Forum

DIY YAW sensor Switch (how to deactivate stability control) - Nissan 370Z Forum

 

I believe the Q60 also has "Active Trace Control" working on top of VDC.... plus with your suspension mods, the stock VDC system is way out of calibration, never mind what DAS is trying to do.
Be cautious using a 370 "fix" on your Q60, as most of the systems are much newer and different than the 370. Check the factory shop manual to verify.

 

Thanks for the info! I just got back from VIR for another two days and wanted to give some updates. I had the Wavetrac LSD installed shortly before going and between that and more coaching, I lowered my lap times by about 4.8 seconds, so a huge number. If I could have kept going, I think I would have lowered it another second or more as my instructor was making some additional line/braking changes that were helping.

Overall, with my track tires, VDC off, Sport+ (this puts active trace off or at least limits it, I can't remember), I am good 98% of the time. I still fight for steering input right after heavy braking. I think it is just a fraction of a second before the car allows me to input a lot of steering after hard braking and now that I know what it feels like, I can deal with it. I end up with later turn in or backing off the braking a bit earlier. So at my level it is manageable but I am guessing it will be more of a problem next year as I hopefully continue to improve.

I am going to give the Yaw sensor switch some serious thought this winter. This car has a lot of potential in it and I think I can surprise some people out on the track with some more experience if I can solve this issue. Also up for next year is corner balancing but I think that should wait until I don't have instructors in the car with me? I am curious to see what the car weighs with my mods, i bet it is still way too heavy.

 

Pretty interesting info you've collected.

So many infiniti/nissan vehicles utilize an electronic type of limited slip differential by braking the faster wheel a bit. When you install the Yaw cut off switch you get rid of this feature all together and it will cause slower times and uncontrollable turns with an open diff.

You have since installed an aftermarket LSD which improved your times, I suspect this is a collaboration between between the LSD handling the job more properly and the ABS system not inserting as many brake pulses as it would with the factory diff.

The sad reality is that it's probably still working just more efficiently and disabling will slow you down a bit. It appears VDC off still has some ties into the steering input as well so the Yaw off might give you a better handling feel but since VDC is no longer aiding to driver mistakes it will slow you.

A simple test you can do is remove your center console before an event and disconnect the Yaw entirely after you've set your best "aided" time. This will let you know how much is the car assisting electronically vs mechanically.
Another possibility is to get the car flashed/tuned on ECUTEK. I understand that you are stock however this is something that WILL happen as you start getting faster and faster. ECUTEK has the ability to tone up/down traction control and this might be the "in between" that you are looking for.

Completely removing all these nannies might be wasted effort and possibly be a point of no return if you do VS tuning of the system which appears to be where most end up in.

You need to keep this in mind as you attend more and more events being that there are some mechanical tricks and what not that folks have used that have worked. A softer rear sway as contradictory as it seems can help lower oversteer snap since it lets the inside corner flex more and keep both wheels planted, same follows for custom spring rate springs. More track time and ride along with professionals can let you know if you need a higher or lower spring rate.

Lastly corner balancing will improve the car no matter what, there was a member here that did sand bags in the trunk to dial the rear down a bit and swears by it. This trick has been used in motor sports for decades which is proper weight displacement, adding weight to the car seems counter productive only if the weight is not properly placed. If it is then it can help shave a few seconds in the corners and with the tune you wont have to worry about power.

Good luck!