I was in a parking garage in San Francisco today and had to stop at the top of a very steep ramp to insert a ticket / open the gate. Normally, no big deal - I've driven an unbroken string of manual transmission cars for the last 30 years. So, I brake, put the ticket in, the gate opens, and I release the brake, slip the clutch a bit, give it gas...the usual...and the car doesn't want to move. It felt like I was in third instead of first. So I checked...found out that I was in first...thanked God that nobody was behind me...and tried again. Same feeling.

To trunkate a long story, I then remembered that the the 997.2 MT cars have a drive-off assist feature, and it was trying to do its job. The trouble is, I had (and still have) no idea how it works. I feel like I used up way more clutch than if the car hadn't tried to help.

I poked around to try to understand how it works, but it's not exactly clear. I gather that it's not something that I can turn off. Does anyone know what the car is doing and / or have recommendations about how I get along with this "feature?"

Thanks in advance!

 

Huh, interesting, I didn't know this was in the .2 MT cars (it's not in the .1)

There's a thread on rennlist about it :

http://forums.rennlist.com/rennforum...assistant.html

Apparently if you just apply enough gas it should let go of the brakes even before the 2 second timer.

This was copy-pasted from an unknown source :

Essentially, the entire Drive-Off Assistant
function depends on the position of the
vehicle on the hill and the desired direc-
tion of travel as well as the selected gear.
If the vehicle is stationary facing uphill
with a forward gear engaged, the Drive-
Off Assistant can be activated by press-
ing the operating brake sufficiently. The
function is deactivated when the vehicle
is put into reverse gear in order to park
the vehicle for example. The Drive-Off
Assistant can only be activated in reverse
gear if the vehicle is facing downhill.
As soon as the vehicle comes to a stop
on a hill by specifically using the brakes,
the hydraulic brake pressure selected by
the driver prevents it from rolling forward
or back for as long as the driver presses
the brake pedal. When the driver releas-
es the brake pedal, the Drive-Off Assis-
tant maintains the selected brake pres-
sure on all four wheels for about 2 sec-
onds. The brake pressure is then
reduced slowly.
The brake pressure is also reduced when
taking off directly on a hill if the driver
accelerates (on vehicles with Porsche
Double-clutch (PDK)) or accelerates and
releases the clutch (on vehicles with
manual transmission) immediately after
releasing the brake pedal, thereby build-
ing up sufficient drive torque.
The Drive-Off Assistant is not needed in
areas with very slight inclines (up to
approx. 4 - 5%). Since the vehicle only
starts moving slowly in such areas when
the brakes are released, the driver can
easily move off in a controlled manner
without the Drive-Off Assistant.

 

Yep, nice feature, even if it's just for a few seconds. I can only imagine how nice it would be in San Fran.

 

Thanks for pasting that in - yeah, I read it on the other forum. Seems like it would be helpful, and I guess it's just a matter of getting used to it. It was kind of startling the first time. I'll have to find a hill and practice. The manual is spectacularly unhelpful. It has a page on the topic, but it doesn't tell you much besides how it gets activated.

I'm telling you, after driving a stick for so long, the feeling is weird!

And yeah, I understand that this is a feature introduced with the .2 cars.

 

Copied from a known source

 

Thanks Steve - I read that. It's the last point, "drive off as usual" that doesn't ring true to me - at least not on a steep slope. Seems as though the brakes don't immediately release, or at least from the seat of my pants, the car doesn't respond like I expect it to.

Again, it's probably just a getting used to it sort of thing.

 

Agree - the feeling is odd and disconcerting at first usage. After a year+, still not sure what I think about it. Very tricky if you are trying to ease your way up a steap drive or onto a flatbed - giving it enough gas to let loose but not lunge forward.

 

Steve - thanks for the validation. I'm not ranting or complaining, just wondering how others are finding the / adjusting to the assist. It was freaking embarrassing to be in an enclosed garage and look like an idiot with a nice car that doesn't know how to drive a stick. Never thought I'd be forty-something and have to practice something so basic as smooth hill starts!

 

The trick is that you have to accelerate a little more. It disengages and goes.

 

A friend of mine has a very short, steep driveway - getting up it to get my *** out of the road, without scraping the car, and without lunging forward crashing into his garage door, with hill assist is a stunt at best - I wish there were a disable button for those situations, because I don't think it helps - I'd rather use the hand brake if necessary, which apparently is about to be history, in those situations. Porsche seems to do a pretty good job with the tech tricks, but I don't think they thoroughly considered the "gently creep forward up a hill" scenario with this - that or I need to reconsider my technique.

And yes, I found that a little embarrassing too.

 

I think that if you hold the car with the hand brake and do not use the foot brake, hill-assist will be off.

 

Good idea - thanks.

 

I suggest you try it. It should work. Those Weissach guys know what they are doing.

 

Worth a try - I could never quite figure out the whole parking brake thing, but it would be handy if it works.

+1 - thanks for the idea!

 

You would have noticed, that with clutch in and foot off brake... the car doesn't roll back. (or were you using the handbrake to keep the car in place while you moved from brake to gas?)

That holding of the brakes is what the assist does. It is depending upon the ANGLE of the car and I believe, the selected gear (ie if the selected gear would have you go in a direction opposite where gravity will pull you.. though I cannot be sure; ie if you are pointed nose uphill, and select reverse, the assist does not come on, but if you are pointing downhill and selected reverse, the assist does come on).

The manual for the car has a good description of the process.

It does take some time getting used to it; it feels initially like a lot of force is needed to release the brake. Once you let off of the brake pedal, the car holds the brakes on for a fixed amount of time, or until the engine provides enough forward torque. You just need to get used to having to drive through that resistance.