CAlexio

Please martin don't try it, you'll have both head AND engine blowing up if you try no lift downshift (whatever that is)... . Not sure what you're reading here but that's not accurate..

bretster

By what mechanism does the car slow the engine to rev match on the upshift? Or does it just keep it from falling too far as the revs decrease naturally? Surely there is no brake on the flywheel or some such.

richardbf

throttle is electrically controlled so it would just cut throttle electronically for a moment rather than you doing it by lifting your foot.

Wild Weasel

I still think my scenario of it effectively acting like an automatic kick-down is plausible. With a PDK if you're puttering along and want to accelerate, you mash the pedal and it'll downshift and go. That's a no-lift downshift. Everything I'm reading here suggests this should work with the manual and this no-lift shifting business going on.

Now... to be fair... I'm not seeing value in any of this. The huge value in rev-matching to me is the perfect heel-toe downshifts. I'm mediocre at best at it and when I let the car do it there's zero question in my mind that I couldn't possibly have matched what it did. There's no heel-toe up-shifting though. I'm perfectly capable of managing the throttle on my own during an up-shift. This no-lift business sounds just lazy to me and isn't a thing I need help with. That said... maybe I'll change my mind when I try it. You never know. Maybe it's really neat.

Everything that's going on here is being done by electronically controlling the throttle and doing things with it that you're not doing with your foot.

CAlexio

I'm Utterly confused by what you're saying here???? Scenario of automatic kickdown??? I have to ask the question, have you actually driven the car or just enjoying the act of ?

Wild Weasel

Haven't driven one. I mentioned that earlier. This is all speculation based on what I'm reading here.

But here's my scenario. Let me know what you think happens.

You're cruising along in 6th gear at some low RPM. You decide you want to speed up. Here's the sequence you perform:

1. Mash pedal to the floor.
2. Clutch in.
3. Shift to 3rd.
4. Clutch out.

What does the car do?

In my imagination, based on what I'm reading here about this no-lift shifting, the car will not just rev up to the rev limiter like any normal car would as soon as you put the clutch in. I imagine it holding the RPM when you push the clutch in and, when the gear lever goes into 3rd the computer rev-matches for 3rd appropriately and when you let the clutch out you're accelerating as hard as you can.

Is this complete fiction or is this what actually happens?

robmypro

Here's the situation. If you floor a PDK-S in auto and you are going any speed, it will drop down to the optimal lowest gear pretty much instantaneously. It knows the lowest gear it can do at any given speed/rev range, and it can make that decision instantly. In the manual, you can mash the peddle and make the wrong decision about what gear to downshift into, then you will need a new motor. So you better know exactly what you are doing before you try that. For example, you are putting in 3rd gear totally ******* the motor going 25 mph, and you floor it while simultaneously throwing it into 1st. If you get the speed right you won't over-rev. Otherwise, get out your checkbook.

I personally would never try that stunt, which is why it is great to be able to do that same thing without risk in the PDK.

Wild Weasel

What's you're describing here is just downshifting. If you do it wrong, bad things can happen.

Are you saying you'd never downshift in a manual?

If so, then you have definitely made the right choice in sticking with PDK. I'm assuming I've somehow misunderstood you though.

robmypro

First, yes you misunderstood. Second, I am talking about flooring the car first, then downshifting. So power-shifting while downshifting, hopefully from a low starting RPM.

Footsoldier

Dalema

robmypro

gago1101

I do personally like throttle blipping myself when downshifting, but the 991.2 GT3 is capable of doing no-lift downshifts. The manual clearly states that you do not need to take your foot off the accelerator pedal while shifting gears. If this only referred to up shifting, it would have been clearly stated.

This no lift downshift is really not useful anyway. I guess you can do it when cruising on the highway and want to downshift and accelerate quickly. Definitely useless and can't be used at the track.

Here is a short video I did today demonstrating the no-lift downshifts.

Chris88

I used to do no lift downshifts in my mom's VW when I was a kid (a very long time ago). I would simply make sure I was at the right speed and shift from 4th to 3rd, and the revs would go up to match the lower gear. Sometimes it worked perfectly and I got a very smooth (on power) downshift. Fun stuff.

LSs1Power