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2025 C8 Stingray of the Year Finalist - Unmodified
2024 C8 of the Year Finalist - Unmodified
Normal for DCT to Shift Before Redline?
Not sure if this is normal or not. Today I had the car out and decided to give it an Italian tune up on some empty roads. In Drive with Sport mode, engine fully warmed up and on a flat surface, if I floor the accelerator and hold it there, the transmission shifts at an indicated 6,300-6,400 RPM. I tried it several times, I would think it should hit the redline of 6,500 before upshifting.
I remember this same thing happening in my '16 C7 with A8 which was one of the reasons I didn't care for that transmission. .
Probably normal. The actual redline according to the brochures is 6600 rpm. But you do not necessarily want to shift at redline.
I do not know what the strategy and algorithm for the shift points is, but in opinion, it should take into account the hp and torque in the current gear, and the where the hp and torque will be in the next anticipated gear. If you shift too early, the engine may not be the best part of the hp/torque curve. If you shift too late, the power to the wheels might be dropping ( the attached curve shows that both power and torque are dropping off at 6600), in the current gear. Its along way of saying that shifting at redline is not necessarily optimal for acceleration.
Probably normal. The actual redline according to the brochures is 6600 rpm. But you do not necessarily want to shift at redline.
I do not know what the strategy and algorithm for the shift points is, but in opinion, it should take into account the hp and torque in the current gear, and the where the hp and torque will be in the next anticipated gear. If you shift too early, the engine may not be the best part of the hp/torque curve. If you shift too late, the power to the wheels might be dropping ( the attached curve shows that both power and torque are dropping off at 6600), in the current gear. Its along way of saying that shifting at redline is not necessarily optimal for acceleration.
Last edited by Vetteman Jack; Feb 11, 2025 at 11:41 PM.
What you see is not always what is really happening inside the ECU and TCM. It would be better to get the PDR logging and look at the logs for the actual shift point RPM. If you dont have PDR then get a scan tool like Carly or Blue Driver
It’s pretty common for automatics to shift just before redline, likely for engine longevity and efficiency. If everything feels smooth, it’s probably just the factory tuning. Maybe try manual mode to see if it holds gears longer. Sounds like a fun drive, though! I was completely overwhelmed with my workload, so I decided to use DoMyPaper, a well-known paper writing service, available here domypaper.com The writer assigned to my project was knowledgeable and delivered an excellent paper that met all my requirements. I was really happy with the results and will definitely use this service again!
Last edited by NixonTrey; Feb 22, 2025 at 07:38 AM.
Below 6000 rpm, the base engine is the better performer by a small margin! Not only in hp but in torque also. Unless you want to rppp 'm above 6000, the Z06 doesn't buy you anything extra. Of course, above 6000 rpm is where the Z06 leaves the base engine car behind. When the base engine guy shifts at 6500 rpm, he drops back to a lower hp, whereas the Z06 is still climbing up the hp curve......that's where the Z06 says bye bye.
As for the red line discussion, remember when tachs also had a yellow band on the tach? Back to the OP related discussion, it just seems GM has programmed Sport mode to shift the car in the yellow zone before hitting red line.
I suspect that might change based on how many times it is done. The PCM learns how you are driving the car and doing a week of full-throttle upshifts may change when the trans upshifts. I have seen similar things happen on my previous Corvettes.
I think mine shifts close to 6500. That is high enough for me, I sense it is past the peak power curve on anything over 6000.
It feels really strong acceleration up to 6000, then flattens out as I would expect.
Normal for DCT to Shift Before Redline?
