EcuTek Tuned Quickly wagging tail out?

[HarryBo]

2024 Nismo Z w AMS Heat Exchanger, Intakes, Intercoolers, Catted downpipes, and custom AMS EcuTek tune and Michelin Pilot Sports, recently back end coming out to the right more easily on hard throttle. 1st and 2nd gear pulls were always crazy, 3rd anything under 80 kph, gotta be careful, but now even 1/2 to 3/4 throttle, that damn rear end wants to pull and break out to the right (passenger side). Now even 4th gear i have to watch. Tires have less than 5,000 km on them. Road temps were a bit cooler, but wow!

Any thoughts?

I'll get the bushings and anchor points inspected, alignment checked and corners weighed, as well as compare Sport + to Sport and Normal, and 93 vs 91 tune. Tires are +10 mm on all 4 corners on oem wheels, no spacers.

 

[HarryBo]

Have you tried the low boost map? My tuner offered me a low boost tune - i asked why? He said i would not be able to drive the car in the rain on the high boost tune - lol

Going to compare but 93 octane high is what my focus is on that never used to swing out this much.

 

[HarryBo]

I had RaceBox dial back my throttle sensitivity in lower RPMs to ensure smooth drivability.

Might need to consider this. Thx

 

[HarryBo]

Also the slope/crown of the road if you're in a LHD country(probably the largest factor).

The squishy rear subframe bushings probably don't help, though I installed solid inserts and it still goes to the right just feels a lot more solid.


The Diff also rotates quite a bit to the right due to their only being one offset rear mount that applies a torque to the front two diff bushings whenever power is applied:

This not only allows diff rotation to the full extent the front bushings allow but has also been a known failure point since the 350z which has a nearly identical rear subframe, just in aluminum with slightly different rear suspension geometry. The New Z and the 370 rear subframes are steel and 100% identical. All three share the single bolt diff mounting.

This is from YouTube video but the car was at the drag strip with sticky tires and full bolt ons ~500 WHP and the single stud failed:

Luckily since our platform is so mature, the aftermarket already has it figured out:

Greddy dual stud (hard to find)

)

GKtech:

You have modify the subframe for these but GK sells the needed bits.

Will look into this and any defect in mounting.

 

[HarryBo]

I presume that you have not modified wheel fitment (spacers; increased/decreased wheel offset; tire size; etc....)

Try weighing each tire quadrant for significant center of gravity changes (added bolt-on items like the HE, Intakes, Inter-C, and down pipes) ...check for a heavier nose/light rear-end condition. Get CG results including driver station weight... specially when doing the driver's side. Also, check what effect... if any, tire pressure and fuel level variations may have on traction. and obviously, watch your steering alignment and control technique. Also... when all else fails, try checking alignment including proper camber....

Good luck!

+10mm on all 4 corners on my new PS4S mounted on oem nismo rims. No spacers.

 

[HarryBo]

Thanks everyone for input and some very detailed technical information that will certainly help working this out. Parking car for winter any day now, but may get to try some of these solutions prior. I'll report back.

 

[thesilverbullet]

Going to compare but 93 octane high is what my focus is on that never used to swing out this much.

I don’t know what low boost is but I’m thinking about asking for a slightly less than full tilt - like maybe 17.5psi

 

[Houston.RZ34]

I'm gonna ask the "See the forest for the trees" question.....What kind of tires are you running?

 

[HarryBo]

I'm gonna ask the "See the forest for the trees" question.....What kind of tires are you running?

Michelin PS4S +10mm all 4 corners on oem Nismo wheels, no spacers.