Found new way to go slower

[Hivel]

I managed to trigger a “trans limit” condition. I didn’t feel it during the run; but, the data log shows it. The trans-limit caused throttle body to close at the 2-3 shift. It’s frustrating; cause I managed to get a decent launch.

Anyone know what I could have done to hit the trans-limit?

Thanks,

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[Zinc03svt]

Have you run this by your tuner?

 

[Hivel]

Have you run this by your tuner?

The car is stock. I’m using the data logger as a driver tuning aid. I’ve learned a lot about the car and my right foot.

Cheers,

 

[Hivel]

I see what happened. My 2018 GT ECM uses OS version FSJJ4DZ. That OS has a “Transmission Protection” RPM limit set to 7400 RPM. The TIS hit 7456 RPM before the 2-3 shift and the ETC closed the throttle. I guess that’s why the 2018 GTs have the tachometer red line starting at 7400 RPM.

Cheers,

 

[Rhinogt]

Ok so without know what driving mode you were in, or whether you had traction control/ advance trac on/off it’s hard to say specifically. But from the MPH in the screenshot it looks like you had just launched the car. Is that correct?

Your car uses the transmission to control the rev limit. If you happened to hit the limiter, especially with the nannies turned on, it sounds perfectly logical that the ECM closed throttle when it hit the rev limit. I personally wouldn’t worry too much about it IF all that is the case.

 

[Hivel]

Ok so without know what driving mode you were in, or whether you had traction control/ advance trac on/off it’s hard to say specifically. But from the MPH in the screenshot it looks like you had just launched the car. Is that correct?

The launch occurred at the verticle white line. The shifter was in drive, Advancetrac off, and in drag mode.

I don’t know why the car reved that high on this run. Normally it shifts around 7250. I guess the transmission flared and the input shaft spun up too fast. What sucks is the ETC cut messed up the timing for the rest of the run. I made one more pass and it shifted normally. Maybe the A10 just needed that flare to learn?

Cheers,

 

[Hivel]

It looks like the trans over rev is not a flare. I think it’s the equivalent of a manual trans money shift. You know after topping out second the driver jams it into first and pops the clutch. That’s how you let the money out of a manual trans. The leading driver did it at NASCAR’s Sonoma race this year.

Looking at all the logs; the over rev happens only on the 2-3 and 5-6 shifts. The 1-2, 3-4, and 4-5 shifts are normal. Maybe that’s why Ford has a PCM update available for my car.

Cheers,

 

[Austinj427]

Have you tried manually shifting it? Do those cars let you set your shift light?

If they do, set it at 7000, hope that your reaction time/shifting time is around 7200 or so and it keeps it from over revving.

I'm quite interested in this. I like the data logging.

It will be interesting to see what it does.

 

[Zinc03svt]

Unplug your nannies and get a good tune. Then the car lays you into the seat like a punch into the kidneys on every shift. Way different from stock. .

 

[Hivel]

Austinj427,
No, I haven't tried manual shiting a 1/4 mile pass. Full manual control is only available when the shifter is in Sport. Sport mode is intended for track use and cuts the spark before every shift. I'll get the PCM updated before I go back to the drag strip. Maybe that will cure the trans over rev.


Zinc03svt,
Trust me the 2018 GT's drag mode shifts have more than enough punch! I'm planning to go turbo or maybe a Whipple. So, that's when I will tune it up.

Cheers,

 

[brucelinc]

Hivel, how did you discover that your PCM needs updated?

 

[Hivel]

Hivel, how did you discover that your PCM needs updated?

I used Ford’s ETIS system
https://www.etis.ford.com/

Cheers,

 

[10r80]

Thanks for the info OP mine does this too. I'll sign up for ETIS but when was your born date? Mine is 12/21.

Being new to Ford, is this something I have to bring in to Ford to update?

 

[Hivel]

The’re twins. My car’s BLEND is 120171221. It was assembled in Flat Rock.

I wish there was a way for me to install these updates. The dealer wants to keep the car all day to update the SW.

Cheers,

 

[10r80]

The’re twins. My car’s BLEND is 120171221. It was assembled in Flat Rock.

I wish there was a way for me to install these updates. The dealer wants to keep the car all day to update the SW.

Cheers,

They are twins! That's unfortunate, I would have to take the drag pack off and who know if it would mess with the current tune on there.

I've noticed this doesn't happen in track, I mostly use track for roll racing now so it does not do this. When I use "drag" at the drag strip, it seems to work fine.

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