Why did my tach seem to go past redline on upshift?

[Neebs]

I shifted my 4BW MT from 4th near the redline into 5th. As I was looking at the tach, the graphic / line on tach that briefly appears to show peak rpm / shift point appeared higher than redline at around 6700 rpm or so. Rev match was off and I certainly didn’t go into 3rd as I released the clutch, 5th was engaged and I kept driving. No power cut, feeling of bouncing against rev limiter or anything else. Why would the tach make it seem like I overreved on upshift? May be my eyes played a trick. Has me a little worried (hopefully for no good reason).

Has anyone noticed / experienced this?

 

[poor-sha]

Perfectly normal. It was inertia in the motor when decoupled from the driveline at high engine speed. There is nothing acting on the motor to slow it like when you hit spark cut with the clutch still engaged. I see it all the time in data from no lift shifts and wouldn’t worry about it.

 

[RDATLTE]

I shifted my 4BW MT from 4th near the redline into 5th. As I was looking at the tach, the graphic / line on tach that briefly appears to show peak rpm / shift point appeared higher than redline at around 6700 rpm or so. Rev match was off and I certainly didn’t go into 3rd as I released the clutch, 5th was engaged and I kept driving. No power cut, feeling of bouncing against rev limiter or anything else. Why would the tach make it seem like I overreved on upshift? May be my eyes played a trick. Has me a little worried (hopefully for no good reason).

Has anyone noticed / experienced this?

Ti rods!

 

[Neebs]

Perfectly normal. It was inertia in the motor when decoupled from the driveline at high engine speed. There is nothing acting on the motor to slow it like when you hit spark cut with the clutch still engaged. I see it all the time in data from no lift shifts and wouldn’t worry about it.

Beautiful - makes sense. Thanks for the explanation. I guess no reason to hold back and hit redline a few times again this am!

 

[theprototype]

On a similar note anyone else have their digital dash glitch out and not show the tach or background graphics? Mine was just black on the drive to work this morning. Could still see the MPH and gear (track mode dash) and the other numbers just not the background graphic or horizontal tach.

 

[Neebs]

You sure tach wasn’t in stealth mode? If you go all the way down on the display brightness dimmer wheel, think it puts it in stealth mode (or whatever Cadi calls it).

 

[M2Cto4BW]

Sounds like stealth/dark/night whatever it's called mode. The bottom 2 rungs on the dash light roller will set it to really minimal and dark, less minimal and dark.

 

[theprototype]

Interesting, sounds like that’s probably it. Wonder what the point of it is though

 

[Blackwing16]

I had something weird happen to me today too. Was doing a decent amount of throttle from 2nd to 3rd gear and the car just fell flat on its face with my foot all the way into the throttle once I shifted to 3rd. The revs dropped way down to around 3k and it felt like I had to start accelerating again. Could this have been traction control trying to save the car? I didn't notice any wheel spin at the top of 2nd gear so it seems weird that it would've fallen like that.

 

[raptor5244]

I had something weird happen to me today too. Was doing a decent amount of throttle from 2nd to 3rd gear and the car just fell flat on its face with my foot all the way into the throttle once I shifted to 3rd. The revs dropped way down to around 3k and it felt like I had to start accelerating again. Could this have been traction control trying to save the car? I didn't notice any wheel spin at the top of 2nd gear so it seems weird that it would've fallen like that.

Possibly, the traction control algorithm usually lets you slip the tires a little bit without cutting power assuming you are pointed straight. However, if you start spinning them too much then it will cut power like you experienced. There may be a light on the dash that illuminates when traction control kicks in.

Was it cool or wet out, tires warmed up? I would expect some spin in 1st or maybe the top of 2nd but not 3rd gear assuming the roads are dry.

 

[Throat Yogurt]

I had something weird happen to me today too. Was doing a decent amount of throttle from 2nd to 3rd gear and the car just fell flat on its face with my foot all the way into the throttle once I shifted to 3rd. The revs dropped way down to around 3k and it felt like I had to start accelerating again. Could this have been traction control trying to save the car? I didn't notice any wheel spin at the top of 2nd gear so it seems weird that it would've fallen like that.

Sounds like traction control. That won't happen with PTM active.